Leptospirosis in Humans (2024)

Leptospirosis is a widespread and potentially fatal zoonosis that is endemic in many tropical regions and causes large epidemics after heavy rainfall and flooding. Infection results from direct or indirect exposure to infected reservoir host animals that carry the pathogen in their renal tubules and shed pathogenic leptospires in their urine. Although many wild and domestic animals can serve as reservoir hosts, the brown rat (Rattus norvegicus) is the most important source of human infections. Individuals living in urban slum environments characterized by inadequate sanitation and poor housing are at high risk of rat exposure and leptospirosis. The global burden of leptospirosis is expected to rise with demographic shifts that favor increases in the number of urban poor in tropical regions subject to worsening storms and urban flooding due to climate change. Data emerging from prospective surveillance studies suggest that most human leptospiral infections in endemic areas are mild or asymptomatic. Development of more severe outcomes likely depends on three factors: epidemiological conditions, host susceptibility, and pathogen virulence (Fig. 1). Mortality increases with age, particularly in patients older than 60 years of age. High levels of bacteremia are associated with poor clinical outcomes and, based on animal model and in vitro studies, are related in part to poor recognition of leptospiral LPS by human TLR4. Patients with severe leptospirosis experience a cytokine storm characterized by high levels of IL-6, TNF-alpha, and IL-10. Patients with the HLA DQ6 allele are at higher risk of disease, suggesting a role for lymphocyte stimulation by a leptospiral superantigen. Leptospirosis typically presents as a nonspecific, acute febrile illness characterized by fever, myalgia, and headache and may be confused with other entities such as influenza and dengue fever. Newer diagnostic methods facilitate early diagnosis and antibiotic treatment. Patients progressing to multisystem organ failure have widespread hematogenous dissemination of pathogens. Nonoliguric (high output) renal dysfunction should be supported with fluids and electrolytes. When oliguric renal failure occurs, prompt initiation of dialysis can be life saving. Elevated bilirubin levels are due to hepatocellular damage and disruption of intercellular junctions between hepatocytes, resulting in leaking of bilirubin out of bile caniliculi. Hemorrhagic complications are common and are associated with coagulation abnormalities. Severe pulmonary hemorrhage syndrome due to extensive alveolar hemorrhage has a fatality rate of >50 %. Readers are referred to earlier, excellent summaries related to this subject (Adler and de la Peña-Moctezuma 2010; Bharti et al. 2003; Hartskeerl et al. 2011; Ko et al. 2009; Levett 2001; McBride et al. 2005).

Open in a separate window

Fig. 1

Factors contributing to leptospirosis. Development of leptospirosis depends on three types of factors (epidemiology, host, and pathogen) and their interactions. Epidemiologic factors include sanitation, housing, rainfall, and whether flooding occurs. Incidence is linked to income level, occupation, and travel, representing epidemiologic factors linked to specific hosts. Hosts vary in susceptibility depending on age, genetic factors (e.g., HLA-DQ6), skin integrity, and whether protective clothing (e.g., gloves and boots) are worn. The ways in which the host and leptospires interact determine the route, exposure, and dose of the pathogen. Leptospiral pathogens differ in their ability to cause disease, a reflection of their virulence, motility, and ability to survive in the host, a reflection (at least in part) of complement resistance. The types of reservoir hosts determine the types of pathogens present in a particular epidemiologic setting

1.1 Sources of Infection

Pathogenic leptospires are widespread in nature, reflecting maintenance in the kidneys of many wild and domestic reservoir hosts. The leptospiral life cycle involves shedding in the urine, persistence in the ambient environment, acquisition of a new host, and hematogenous dissemination to the kidneys through the glomerulus or peritubular capillaries. Once leptospires gain access to the renal tubular lumen of the kidney, they colonize the brush border of the proximal renal tubular epithelium, from which urinary shedding can persist for long periods of time without significant ill effects on the reservoir host. For this reason, leptospiral infection of the reservoir host can be considered a commensal relationship (Fig. 1).

Small mammals are the most important reservoirs, with large herbivores as additional significant sources of infection. Pathogenic Leptospira species have been isolated from hundreds of mammalian species, including bats and pinnipeds (see the chapter by W.A. Ellis, this volume). In addition, leptospires have been recovered from poikilothermic animals such as frogs and toads, and it is possible that these animals play a role in the circulation of leptospirosis in the environment, although they may not be significant reservoirs of human infection. Only a few studies have reported isolation of leptospires from amphibians (Babudieri et al. 1973; Everard et al. 1988; Gravekamp et al. 1991). However, the results justify further attempts to understand the role of amphibians in maintaining leptospires in nature (Adler and de la Peña-Moctezuma 2010; Bharti et al. 2003; Hartskeerl et al. 2011; Ko et al. 2009; Levett 2001; McBride et al. 2005; Felzemburgh et al. 2014).

Leptospirosis is primarily a zoonosis, with humans serving as accidental hosts. However, it is worth noting that transient leptospiral shedding does occur during human infection and human-to-human infection, although extremely rare, has occurred through sexual intercourse (Doeleman 1932; Harrison and Fitzgerald 1988) and during lactation (Bolin and Koellner 1988). Transplacental transmission may occur if infection occurs during pregnancy, resulting in abortion (Chung et al. 1963) or still birth (Coghlan and Bain 1969; Faine et al. 1984).

1.2 Transmission

Portals of entry include cuts and abrasions or mucous membranes such as the conjunctival, oral, or genital surfaces. Exposure may occur through either direct contact with an infected animal or through indirect contact via soil or water contaminated with urine from an infected animal. Individuals with occupations at risk for direct contact with potentially infected animals include veterinarians, abattoir workers, farm workers (particularly in dairy milking situations), hunters and trappers, animal shelter workers, scientists, and technologists handling animals in laboratories or during fieldwork. The magnitude of the risk depends on the local prevalence of leptospiral carriage and the degree and frequency of exposure. Most of these infections are preventable by the use of appropriate personal protective equipment such as rubber boots, gloves, and protective eyewear. Since many of these infections are covered by occupational health and safety regulations, local risk assessments and training are essential (Steneroden et al. 2011).

Indirect contact with water or soil contaminated with leptospires is much more common, and can be associated with occupational, recreational, or avocational activities. In addition to the risks associated with outdoor work listed above, sewer work, military exercises, and farming in high rainfall tropical regions are recognized; the latter is by far the most important numerically. Agricultural workers at risk for leptospirosis include rice field workers, taro farmers, banana farmers, and sugar cane and pineapple field harvesters (Levett 2001). These occupations involve activities likely to result in exposure of cuts and abrasions to soil and water contaminated with the urine of rodents and other animals attracted to food sources. For example, banana workers accounted for two-thirds of the reported leptospirosis cases in a tropical region of Queensland, Australia (Smythe et al. 1997).

Recreational exposures include all freshwater water sports including caving (Self et al. 1987), canoeing (Waitkins 1986), kayaking (Jevon et al. 1986; Shaw 1992), rafting (Wilkins et al. 1988), and triathlons (Morgan et al. 2002; Sejvar et al. 2003). The importance of this type of exposure has increased over the past 20 years as the popularity of adventure sports and races has increased, and also because the relative cost of travel to exotic destinations has decreased (Lau et al. 2010a). Competitive events create the potential for large outbreaks; 80 and 98 leptospirosis cases occurred as part of the 2000 Eco-challenge competition (Fig. 2a) (Sejvar et al. 2003) and 1998 Springfield triathlon (Morgan et al. 2002), respectively. Participants in international events may become ill after having returned home, often to multiple destination countries, which complicates recognition and investigation of outbreaks. In many series, the incidence of leptospirosis is much higher in males than females (Everard et al. 1992; Guerra-Silveira and Abad-Franch 2013; Katz et al. 2011). However, it seems likely that gender differences in leptospirosis incidence are due entirely to exposure-related bias, as reports of leptospirosis outbreaks related to athletic events where males and females have similar levels of exposure have found no significant effects of gender on development of illness (Morgan et al. 2002; Sejvar et al. 2003).

Open in a separate window

Fig. 2

Epidemiologic settings for leptospirosis. a A high proportion of contestants in the 2000 Eco-Challenge multisport race held in Malaysian Borneo developed leptospirosis. Of 189 participants contacted by the Centers for Disease Control, 80 (42 %) met the case definition for leptospirosis. Risk factors included exposure for extended periods of time to the rain-swollen Segama river (photograph credit Reed Hoffmann). b This rural village in Laos is a typical epidemiologic setting for leptospirosis. Residents of tropical regions of the world with high levels of rainfall are at increased risk of leptospirosis, particularly when standing water is contaminated by urine from wild or domesticated animals, which may serve as reservoir hosts for pathogenic Leptospira species (photograph credit Ben Adler)

Avocational exposures are by far the most important exposures, affecting millions of people living in tropical regions. As illustrated in Fig. 2b, lack of adequate sanitation and poor housing combine to exacerbate the risk of exposure to leptospires in both rural and urban slum communities (Bharti et al. 2003; Felzemburgh et al. 2014; Hotez et al. 2008; Reis et al. 2008). The role of poor housing is also suggested by the study of Maciel et al. (2008), which showed a greatly increased risk (odds ratio 5.29) of leptospirosis exposure among individuals who live in the same household as a leptospirosis patient. These factors are most likely surrogates for rat exposure, as proximity to uncollected trash and sighting of rats increased the risk of leptospirosis among residents of urban slums (Reis et al. 2008). The recognition of large outbreaks following excess rainfall events (Ahern et al. 2005; Dechet et al. 2012; Ko et al. 1999; Zaki and Shieh 1996) led to the labeling of leptospirosis as an emerging infectious disease two decades ago (Levett 1999). More recently, the interaction of urbanization and climate change has been identified as a significant risk for both increased incidence and increasing frequency of outbreaks of leptospirosis (Lau et al. 2010b). The need for interdisciplinary research to understand the effects of anthropogenic change and its effect on the epidemiology of leptospirosis has been proposed (Vinetz et al. 2005).

1.3 Global Burden of Disease

Early studies of leptospirosis incidence concentrated on occupational disease, primarily in developed countries related to leptospirosis in livestock animals (Alston and Broom 1958; Faine et al. 1999). As the importance of the disease in tropical countries became better recognized, guidelines were developed for the diagnosis and control of leptospirosis (Faine 1982). As diagnostic methods became more widely available, numerous epidemiologic studies were reported from many countries. An initial attempt to gather global data on the incidence of leptospirosis was published over 15 years ago (WHO 1999). Based on global data collected by International Leptospirosis Society surveys, the incidence was estimated to be 350,000–500,000 severe leptospirosis cases annually (Ahmed et al. 2012). Despite these efforts, the global burden of leptospirosis was felt to be largely underestimated for a number of reasons, including the fact that the vast majority of countries either lack a notification system or notification is not mandatory (Ahmed et al. 2012). To address these shortcomings, the WHO established the Leptospirosis Burden Epidemiology Reference Group (LERG) (Abela-Ridder et al. 2010). The LERG met for the first time in 2009 and for a second time in 2010. The specific objectives of the second LERG meeting were: (1) To review and appraise the revised systematic review of mortality, morbidity, and disability from human leptospirosis; (2) To review a draft disease transmission model for leptospirosis and provide technical input for the further development and refinement of the model; (3) To assemble preliminary estimates of the disease burden; (4) To identify gaps in knowledge and research; and (5) To advise WHO on the next steps for estimation of the burden of human leptospirosis and the implications for policy. The resulting LERG report included a systematic literature review that estimated the overall global annual incidence of endemic and epidemic human leptospirosis at 5 and 14 cases per 100,000 population, respectively (WHO 2011). Endemic human leptospirosis rates varied by region from 0.5/100,000 population in Europe to 95/100,000 population in Africa.

3.1 Incubation Phase

The incubation phase from exposure to onset of symptoms averages from 7 to 12 days, though it can be as short as 3 days or as long as a month. The remarkable variability in the duration of the incubation phase is evident in the 6–29 day lag between exposure and onset of symptoms among 52 athletes who developed laboratory-confirmed leptospirosis after participating (all on the same day) in the Springfield Triathalon (Morgan et al. 2002).

3.2 Presentation

Patients typically present with sudden onset of fever, chills, and headache. These signs and symptoms are nonspecific and also occur with other causes of acute febrile syndrome that, depending on the setting, could also be caused by influenza, dengue fever, or malaria. The headache is often severe and has been described as a bitemporal, frontal throbbing headache accompanied by retro-orbital pain and photophobia.

Muscle pain and tenderness is common and characteristically involves the calves and lower back. A tip-off to identification of leptospirosis is conjunctival suffusion (dilatation of conjunctival vessels without purulent exudate), which occurs frequently in leptospirosis, but is uncommon in other infectious diseases. Additional ocular findings typically include subconjunctival hemorrhages and icterus (Fig. 4a). Rash is uncommon in leptospirosis and when it occurs in the setting of an acute febrile illness, may suggest an alternative diagnosis such as dengue or chikungunya fever (Burt et al. 2012; Zaki and Shanbag 2010). An erythematous rash limited to the pretibial areas of both legs appearing on about the fourth day of illness was a feature of an outbreak of “Fort Bragg Fever” which also included headache, malaise, and splenomegaly among soldiers in North Carolina, the etiology of which was later determined to be L. interrogans serovar Autumnalis (Gochenour et al. 1952).

A nonproductive cough has been noted in 20–57 % of leptospirosis patients and can potentially lead clinicians to incorrectly diagnose the patient with influenza or another respiratory illness. Gastrointestinal symptoms are frequently observed, and may include nausea, vomiting, diarrhea, and abdominal pain. Nausea and other gastrointestinal symptoms may contribute to dehydration in patients with high-output nonoliguric renal failure caused by leptospirosis. The abdominal pain may be due to acalculous cholecystitis and/or pancreatitis. In patients admitted to the hospital for leptospirosis, abdominal pain associated with abnormal serum amylase and/or lipase levels is relatively common (O’Brien et al. 1998). It should be kept in mind that impaired renal function alone can elevate pancreatic enzyme levels when the creatinine clearance is less than 50 ml/min (Collen et al. 1990). While most cases of pancreatitis due to leptospirosis are self-limited, some cases are more severe and associated with fatal outcomes (Spichler et al. 2007).

Severe leptospirosis is characterized by dysfunction of multiple organs including the liver, kidneys, lungs, and brain. The combination of jaundice and renal failure, known as Weil’s disease, was first described in 1886 (Weil 1886) and remains one of the most clinically recognizable forms of leptospirosis (see the chapter by B. Adler, this volume). Evidence of organ dysfunction indicates a more advanced stage of infection, yet may develop suddenly and be present in a large percentage of patients at the time of presentation.

Leptospirosis patients are typically found to have mild to moderate elevations in levels of liver transaminases and direct (conjugated) bilirubin. The frequency of jaundice varies widely among case series, perhaps due in part to the virulence of the causative organism. Katz et al. (2001) found a strong association between infection with the Icterohaemorrhagiae serogroup and jaundice and elevated bilirubin levels. Acute hemolytic anemia can contribute to jaundice which, not surprisingly, is more common in leptospirosis patients with glucose-6-phosphate dehydrogenase deficiency (Avdeeva et al. 2002). Such patients have a higher percentage of unconjugated (i.e., indirect) bilirubin. Many patients have leukocytosis and thrombocytopenia, though usually not to the extent that would cause spontaneous hemorrhage. Leukopenia in the setting of thrombocytopenia and anemia can suggest bone marrow suppression.

Clinical signs of bleeding are common and occur in the majority of patients with severe leptospirosis. Most bleeding manifestations are mild, including petechiae, ecchymoses, and epistaxis. However, some patients have severe gastrointestinal (melena or hematemesis) or pulmonary hemorrhage. Thrombocytopenia frequently occurs, although usually not to the extent that would cause spontaneous hemorrhage. In a study of severe leptospirosis performed in the Netherlands, all patients had coagulation disorders, including prolongation of the prothrombin time (PT) and the length of the PT was associated with severe bleeding manifestations (Wagenaar et al. 2010).

The kidney is a major target organ in leptospirosis, perhaps due to the intrinsic renal-tropic homing ability of leptospires in their reservoir hosts. The kidneys are commonly involved, as manifested by elevations in serum blood urea nitrogen and creatinine levels and findings on urinalysis of pyuria, hematuria, and elevated urine protein levels (Katz et al. 2001). Leptospirosis causes a unique nonoliguric potassium wasting nephropathy characterized by impaired sodium reabsorption and potassium wasting (Seguro et al. 1990). When poor oral intake due to nausea and high-output renal failure combine to cause dehydration, patients are at risk of oliguria and renal failure, a frequent cause of death in areas where peritoneal or hemodialysis is not available.

Progression to severe leptospirosis and circulatory collapse may be accompanied by acute respiratory distress syndrome (ARDS). As in other causes of ARDS, leptospirosis causes diffuse lung injury characterized by impaired gas exchange and the need for mechanical ventilation. Massive hemoptysis, representing extensive alveolar hemorrhage, is an ominous complication of leptospirosis associated with fatality rates >50 % (Gouveia et al. 2008). Pulmonary hemorrhage associated with leptospirosis was first reported in Switzerland in 1943 (Moeschlin 1943), and since then has been reported with increasing frequency from a variety of locations (Park et al. 1989). Leptospirosis-associated severe pulmonary hemorrhage syndrome (SHPS) can occur sporadically or in outbreaks that can be confused clinically with viral pneumonitis (Sehgal et al. 1995; Trevejo et al. 1998). For example, a 1995 outbreak of SPHS that occurred after heavy rainfall and flooding in Nicaragua was initially thought to be due to hantavirus pulmonary syndrome until silver staining and immunohistochemistry of postmortem lung tissue revealed leptospires (Trevejo et al. 1998). SPHS can present as hemoptysis associated with cough or may be discovered after patients undergo pulmonary intubation (Yersin et al. 2000). Chest radiographs show diffuse alveolar infiltrates (Fig. 4b). Epidemiologic evidence suggests that SPHS may be a relatively new problem, suggesting emergence of a new clone of L. interrogans with enhanced virulence. However, it is also possible that SPHS is an old problem that is finally being recognized and documented.

As noted above, headache is frequently severe and when accompanied by meningismus may prompt performance of lumbar puncture. Typical findings on CSF examination include a lymphocytic predominance with total cell counts of up to 500/mm³, protein levels between 50 and 100 mg/mL, and normal glucose levels, consistent with aseptic meningitis (Berman et al. 1973). Depending on the epidemiologic setting, leptospirosis may be a predominant cause of aseptic meningitis in some areas (Silva et al. 2002a). Patients with aseptic meningitis due to leptospirosis may be anicteric, making the diagnosis more challenging (Berman et al. 1973; Karande et al. 2005). In severe leptospirosis, altered mental status may be an indicator of meningoencephalitis. A variety of other neurologic complications may also occur including hemiplegia, transverse myelitis, and Guillain–Barré syndrome (Levett 2001).

3.3 Risk Factors for Morbidity and Mortality

In an active surveillance study of 326 cases of leptospirosis in Salvador, Brazil, the strongest independent predictor of a fatal outcome was altered mental status (odds ratio 9.12), which typically began with confusion and obtundation without focal neurologic signs (Ko et al. 1999). Other independent risk factors for death identified in the Salvador study included oliguria (odds ratio 5.28), age over 36 years (odds ratio 4.38), and respiratory insufficiency (2. 56) (Ko et al. 1999). The risk of a fatal outcome increases with increased age; compared to individuals aged 19–29, the increased risk of death rose from 3.7-fold for 40–49 year olds to 7.3-fold among those 60 or older (Lopes et al. 2004). Lung involvement, as indicated by dyspnea (odds ratio 11.7) or alveolar infiltrates on chest X-ray (odds ratio 7.3), was found to be associated with mortality in a retrospective study of 68 leptospirosis cases at Pointe-à-Pître Hospital in the French West Indies, along with oliguria (odds ratio 9), repolarization abnormalities on electrocardiogram (odds ratio 5.95), and a white blood count >12,900/mm³ (odds ratio 2.54) (Dupont et al. 1997). A retrospective review of leptospirosis cases associated with an outbreak of leptospirosis in India identified pulmonary involvement and altered mental status as independent predictors of death (Pappachan et al. 2004). Additional poor prognostic signs identified in other studies include acute renal failure, hypotension, and arrhythmias (Daher et al. 1999; Panaphut et al. 2002).

3.4 Recovery Phase

With proper supportive care (see Management below), most leptospirosis patients recover completely (Spichler et al. 2011). Patients with acute renal failure who require dialysis typically regain most of their renal function, although there may be evidence of persistent mild renal impairment (Covic et al. 2003). In addition, there is growing recognition that many patients suffer from chronic postleptospirosis symptoms. In a recent study of laboratory-confirmed leptospirosis patients in the Netherlands, 30 % of patients experienced persistent complaints after acute leptospirosis (PCAC) characterized by fatigue, myalgia, malaise, headache, and weakness (Goris et al. 2013a). Of patients with PCAC, 21 % reported that their complaints lasted for more than 24 months.

Ocular involvement in the form of uveitis is well-known to occur during the convalescent phase of leptospirosis. Eye involvement ranges in severity from insidious onset of mild anterior uveitis to acute, severe panuveitis involving the anterior, middle, and posterior segments of the eye (Rathinam 2005). Leptospiral uveitis may occur either as a single, self-limited event or as a series of recurrent episodes, which appears to occur more frequently in patients with severe uveitis. In one study, 80 % of patients had leptospiral DNA in the aqueous humor, detected by PCR (Chu et al. 1998). However, the relative contributions of infection and autoimmunity are uncertain. There are parallels between recurrent uveitis in humans and equine recurrent uveitis (ERU) and autoimmunity to lens proteins has been suggested to play a role in ERU (Verma et al. 2010).

4.1 Molecular Diagnosis

Leptospiral DNA has been amplified from serum, urine, aqueous humor, CSF, and a number of organs post mortem (Levett 2004). Conventional PCR and other assays such as LAMP and NASBA were reviewed recently (Ahmed et al. 2012) and will not be discussed further. Many quantitative PCR assays have been described, which target a number of different genes (Ahmed et al. 2009; Merien et al. 2005; Palaniappan et al. 2005; Smythe et al. 2002; Stoddard et al. 2009). Assays developed for diagnostic use can be considered in two broad categories, targeting either housekeeping genes, such as rrs, gyrB, or secY, or pathogen-specific genes such as lipL32, lig, or lfb1 (Ahmed et al. 2012). Examples of these two types of quantitative assay were evaluated in a large case-control study in a high-prevalence population in Thailand (Thaipadunpanit et al. 2011), that confirmed earlier reports that PCR detection in blood samples collected at admission to hospital was more sensitive than culture, but serology using the microscopic agglutination test (MAT) ultimately detected more cases (Brown et al. 1995). Real-time PCR assays have been used to quantify the bacterial load in leptospirosis (Agampodi et al. 2012; Segura et al. 2005; Tubiana et al. 2013).

A limitation of PCR-based diagnosis of leptospirosis is the current inability of PCR assays to identify the infecting serovar. While this is not significant for individual patient management, the identity of the serovar has both epidemiological and public health value. Serovar identification requires isolation of the infecting strain from patients or carrier animals. However, whole genome sequencing has recently been applied to the diagnosis of neurological leptospirosis (Wilson et al. 2014) and it is probable that direct serovar identification will be possible in the near future, limited only by the quality of sequences obtained from specimens.

4.2 Isolation and Identification of Leptospires

Culture of leptospires requires specialized media (see the chapter by C.E. Cameron, this volume). Leptospires can be recovered from humans during the acute phase of the illness and during the so-called immune phase. Leptospiremia occurs during the first stage of the disease, beginning before the onset of symptoms and has usually declined by the end of the first week of the acute illness. Timing of culture of different specimens depends upon an accurate date of onset of symptoms, so a careful history is essential. Blood cultures should be taken as soon as possible after the patient’s presentation. One or two drops of blood are inoculated into 5–10 ml semisolid or liquid medium at the bedside (Turner 1970). Multiple cultures yield higher recovery rates, but this is rarely possible. Inoculation of media with dilutions of blood samples may increase recovery (Sulzer and Jones 1978). Leptospires have been shown to survive in commercially available conventional blood culture media for periods of time ranging from 48 h to 4 weeks (Palmer and Zochowski 2000). Blood cultures with no growth can be used to inoculate leptospiral culture medium (Turner 1970).

Other samples that may be cultured during the first week of illness include CSF and peritoneal dialysate. Urine should be cultured from the beginning of the second week of symptomatic illness. The duration of urinary excretion varies, but may be several weeks (Bal et al. 1994). Survival of leptospires in voided human urine is limited, so urine should be collected into sterile phosphate buffered saline (Turner 1970). Contamination of urine cultures is a major problem and the use of selective media containing 5-fluorouracil or other antimicrobial agents (see the chapter by C.E. Cameron, this volume) is strongly recommended. Cultures are incubated at 28–30 °C and examined weekly by dark field microscopy, for up to 13 weeks.

Isolated leptospires are identified either by serological methods, or more recently, by molecular techniques. Traditional methods relied on cross-agglutinin absorption (Dikken and Kmety 1978). The number of laboratories which can perform these identification methods is small. Monoclonal antibodies are available for identification of many, but not all, serovars (Korver et al. 1988). The limitations of these approaches are discussed by Hartskeerl and Smythe (see the chapter by R.A. Hartskeerl and L.D. Smythe, this volume).

Molecular methods for identification and subtyping have been studied extensively. Increasingly, sequence-based identification of Leptospira is becoming the standard (Ahmed et al. 2012) and this can be performed on the products of diagnostic PCR (Ganoza et al. 2010; Perez and Goarant 2010). Pulsed-field gel electrophoresis (PFGE) has been shown to identify most serovars (Galloway and Levett 2010; Herrmann et al. 1992), but complements, rather than replaces, serological identification (Ahmed et al. 2012). Identification of serovars by whole genome sequencing will likely become standardized in the near future (Ahmed et al. 2012).

Strain subtyping for epidemiological purposes can be accomplished by simple methods using restriction enzymes or variations of PCR conditions that can generate banding patterns that allow strains to be differentiated (Ahmed et al. 2012). However, reproducibility is poor, particularly between laboratories. More recently, sequence-based methods such as MLVA (Pavan et al. 2008; Salaun et al. 2006; Slack et al. 2005) and MLST (Ahmed et al. 2006, 2011; Boonsilp et al. 2013; Leon et al. 2009; Thaipadungpanit et al. 2007) have been applied. These methods are reproducible and can yield significant information at a subserovar level (Boonsilp et al. 2013). MLST data can be analyzed online (http://leptospira.mlst.net).

4.3 Serological Diagnosis

Most cases of leptospirosis are diagnosed by serology, because capacity for culture and PCR is limited. IgM antibodies are detectable in the blood 5–7 days after the onset of symptoms. Serological methods can be divided into those which are genus-specific and those which are serogroup-specific. The use of agglutination tests was described soon after the first isolation of the organism and the microscopic agglutination test remains the definitive serological investigation in both human and animals.

5.1 Antimicrobial Susceptibilities

Leptospires are susceptible to β-lactams, macrolides, tetracyclines, fluoroquinolones, and streptomycin (Alexander and Rule 1986; Faine et al. 1999). Problems in the determination of susceptibility include the long incubation time required, the use of media containing serum, and the difficulty in quantifying growth accurately. These constraints have limited the development of rapid, standardized methods for susceptibility testing. Most studies have used a limited range of laboratory strains and/or a small number of antimicrobial agents. However, microdilution methods have been described recently (Murray et al. 2004; Ressner et al. 2008), which will facilitate the study of large numbers of isolates against a wide range of antimicrobial agents, with the potential of identifying new agents for prophylaxis or treatment of leptospirosis.

6.1 Human Leptospirosis Vaccines

Immunization of humans with killed, whole-cell vaccines has generally been restricted to individuals in high-risk occupations and in response to floods and epidemics. One of the first reports of human leptospirosis immunization involved the vaccination of thousands of miners in Japan using a culture-derived L. interrogans serovar Icterohaemorrhagiae vaccine (Wani 1933). Although local and generalized reactions were common, a significant decrease in the incidence of leptospirosis among the miners was observed. Immunization of large populations at risk of leptospirosis due to extensive flooding has been performed in China (Chen 1985). A Cuban leptospirosis vaccine trial involving >100,000 persons reported that local pain and “general discomfort” were significantly greater than in a control group given a recombinant hepatitis B vaccine (Martinez et al. 2004). The vaccine showed an efficacy of >97 % against the prevalent local serovars. Concern over reactions to host proteins led to the development of a leptospiral vaccine derived from leptospires grown in a chemically defined medium (Shenberg and Torten 1973); however, growth in protein media is generally poorer and such media have not gained widespread use.

Some of the most detailed safety and efficacy studies involved a leptospirosis vaccination program for Parisian sewer workers. In response to a request by the City of Paris, the Pasteur Institute developed a killed, whole-cell vaccine derived from L. interrogans serovar Icterohaemorrhagiae strain Verdun. Mailloux et al. (1983) examined the safety of this vaccine and reported three systemic (nausea) reactions and seven local reactions among 1,157 immunizations of 454 vaccines. Importantly, after the vaccine was introduced in 1979, the incidence of leptospirosis dropped from 1.3 cases per year (29 cases from 1951 to 1979) to zero (no cases reported from 1981 to 1988) during a 7 year follow-up period. The recommended vaccination protocol involves two booster doses after the initial immunization followed by reimmunization every 2 years. More recent reports of safety and efficacy have been published since the vaccine was marketed as Spirolept^™ (Benbrick et al. 2001; Laurichesse et al. 2007; Pouliquen and Catilina 2000).

As described in chapter by B. Adler, this volume, the active component of killed, whole-cell vaccines is leptospiral LPS, a serovar-specific antigen (Chapman et al. 1990). LPS-based immunity is generally considered to provide protection against hom*ologous or closely related, but not heterologous, serovars. For example, f*ckumura (1984) reported that individuals immunized with a serovar Pyrogenes vaccine were protected from infection by that serovar but not from serovars Autumnalis and Hebdomadis with antigenically unrelated LPS, leading to development of a trivalent vaccine consisting of all three serovars. Research on development of leptospirosis vaccines with a low side-effect profile that induce long-lasting, cross-protective immunity is focused on an improved understanding of the leptospiral outer membrane (see the chapters by D.A. Haake and W.R. Zückert and by B. Adler, this volume).

6.2 Chemoprophylaxis

Unavoidable short-term exposure can be mitigated by chemoprophylaxis. Pre-exposure prophylaxis with doxycycline (200 mg orally once per week) was effective for military personnel undergoing high-risk jungle training exercises (Takafuji et al. 1984). Doxycycline has also been studied for postexposure prophylaxis of local populations after heavy rainfall in endemic areas (Gonsalez et al. 1998; Sehgal et al. 2000). One of these two studies found that postexposure doxycycline prophylaxis reduced the incidence of symptomatic disease (Sehgal et al. 2000). Alternatives to doxycycline, such as azithromycin or amoxicillin, have not been studied, but may be considered in pregnant women and children and individuals at risk of photosensitivity.

• Abdulkader RC, Seguro AC, Malheiro PS, Burdmann EA, Marcondes M. Peculiar electrolytic and hormonal abnormalities in acute renal failure due to leptospirosis. Am J Trop Med Hyg. 1996;54:1–6. [PubMed] [Google Scholar]
• Abela-Ridder B, Sikkema R, Hartskeerl RA. Estimating the burden of human leptospirosis. Int J Antimicrob Agents. 2010;36(Suppl 1):S5–S7. [PubMed] [Google Scholar]
• Adler B, Faine S. The antibodies involved in the human immune response to leptospiral infection. J Med Microbiol. 1978;11:387–400. [PubMed] [Google Scholar]
• Adler B, de la Peña-Moctezuma A. Leptospira and leptospirosis. Vet Microbiol. 2010;140:287–296. [PubMed] [Google Scholar]
• Agampodi SB, Matthias MA, Moreno AC, Vinetz JM. Utility of quantitative polymerase chain reaction in leptospirosis diagnosis: association of level of leptospiremia and clinical manifestations in Sri Lanka. Clin Infect Dis. 2012;54:1249–1255. [PMC free article] [PubMed] [Google Scholar]
• Ahern M, Kovats RS, Wilkinson P, Few R, Matthies F. Global health impacts of floods: epidemiologic evidence. Epidemiol Rev. 2005;27:36–46. [PubMed] [Google Scholar]
• Ahmed A, Engelberts MF, Boer KR, Ahmed N, Hartskeerl RA. Development and validation of a real-time PCR for detection of pathogenic Leptospira species in clinical materials. PLoS ONE. 2009;4:e7093. [PMC free article] [PubMed] [Google Scholar]
• Ahmed A, Grobusch MP, Klatser PR, Hartskeerl RA. Molecular approaches in the detection and characterization of Leptospira. J Bacteriol Parasitol. 2012;3:1000133. [Google Scholar]
• Ahmed A, Thaipadungpanit J, Boonsilp S, Wuthiekanun V, Nalam K, Spratt BG, Aanensen DM, Smythe LD, Ahmed N, Feil EJ, Hartskeerl RA, Peaco*ck SJ. Comparison of two multilocus sequence based genotyping schemes for Leptospira species. PLoS Negl Trop Dis. 2011;5:e1374. [PMC free article] [PubMed] [Google Scholar]
• Ahmed N, Devi SM, de Valverde ML, Vijayachari P, Machang’u RS, Ellis WA, Hartskeerl RA. Multilocus sequence typing method for identification and genotypic classification of pathogenic Leptospira species. Ann Clin Microbiol Antimicrob. 2006;5:28. [PMC free article] [PubMed] [Google Scholar]
• Alexander AD, Rule PL. Penicillins, cephalosporins, and tetracyclines in treatment of hamsters with fatal leptospirosis. Antimicrob Agents Chemother. 1986;30:835–839. [PMC free article] [PubMed] [Google Scholar]
• Alston JM, Broom JC. Leptospirosis in man and animals. E. & S. Livingstone; Edinburgh: 1958. [Google Scholar]
• Amato MB, Barbas CS, Medeiros DM, Magaldi RB, Schettino GP, Lorenzi-Filho G, Kairalla RA, Deheinzelin D, Munoz C, Oliveira R, Takagaki TY, Carvalho CR. Effect of a protective-ventilation strategy on mortality in the acute respiratory distress syndrome. N Engl J Med. 1998;338:347–354. [PubMed] [Google Scholar]
• Andrade L, Cleto S, Seguro AC. Door-to-dialysis time and daily hemodialysis in patients with leptospirosis: impact on mortality. Clin J Am Soc Nephrol. 2007;2:739–744. [PubMed] [Google Scholar]
• Andrade L, de Francesco Daher E, Seguro AC. Leptospiral nephropathy. Semin Nephrol. 2008;28:383–394. [PubMed] [Google Scholar]
• Appassakij H, Silpapojakul K, Wansit R, Woodtayakorn J. Evaluation of the immunofluorescent antibody test for the diagnosis of human leptospirosis. Am J Trop Med Hyg. 1995;52:340–343. [PubMed] [Google Scholar]
• Araujo ER, Seguro AC, Spichler A, Magaldi AJ, Volpini RA, De Brito T. Acute kidney injury in human leptospirosis: an immunohistochemical study with pathophysiological correlation. Virchows Arch. 2010;456:367–375. [PubMed] [Google Scholar]
• Arean VM. The pathologic anatomy and pathogenesis of fatal human leptospirosis (Weil’s disease) Am J Pathol. 1962;40:393–423. [PMC free article] [PubMed] [Google Scholar]
• Avdeeva MG, Moisova DL, Gorodin VN, Kostomarov AM, Zotov SV, Cherniavskaia OV. The role glucose-6-phosphate dehydrogenase in pathogenesis of anemia in leptospirosis. Klin Med (Mosk) 2002;80:42–44. [PubMed] [Google Scholar]
• Babudieri B, Carlos ER, Carlos ET., Jr Pathogenic Leptospira isolated from toad kidneys. Trop Geogr Med. 1973;25:297–299. [PubMed] [Google Scholar]
• Bajani MD, Ashford DA, Bragg SL, Woods CW, Aye T, Spiegel RA, Plikaytis BD, Perkins BA, Phelan M, Levett PN, Weyant RS. Evaluation of four commercially available rapid serologic tests for diagnosis of leptospirosis. J Clin Microbiol. 2003;41:803–809. [PMC free article] [PubMed] [Google Scholar]
• Bal AE, Gravekamp C, Hartskeerl RA, de Meza-Brewster J, Korver H, Terpstra WJ. Detection of leptospires in urine by PCR for early diagnosis of leptospirosis. J Clin Microbiol. 1994;32:1894–1898. [PMC free article] [PubMed] [Google Scholar]
• Benbrick E, Pouliquen P, Domont A. Evaluation de la tolerance de la vaccination contre Leptospira icterohaemorrhagiae chez 50 employe’s de canaux. Arch Mal Prof. 2001;62:35–40. [Google Scholar]
• Berman SJ, Tsai C, Holms K, Fresh JW, Walten RH. Sporadic anicteric leptospirosis in South Vietnam. A study of 150 patients. Ann Intern Med. 1973;79:167–173. [PubMed] [Google Scholar]
• Bharti AR, Nally JE, Ricaldi JN, Matthias MA, Diaz MM, Lovett MA, Levett PN, Gilman RH, Willig MR, Gotuzzo E, Vinetz JM. Leptospirosis: a zoonotic disease of global importance. Lancet Infect Dis. 2003;3:757–771. [PubMed] [Google Scholar]
• Blackmore DK, Schollum LM, Moriarty KM. The magnitude and duration of titres of leptospiral agglutinins in human sera. NZ Med J. 1984;97:83–86. [PubMed] [Google Scholar]
• Bolin CA, Koellner P. Human-to-human transmission of Leptospira interrogans by milk. J Infect Dis. 1988;158:246–247. [PubMed] [Google Scholar]
• Boonsilp S, Thaipadungpanit J, Amornchai P, Wuthiekanun V, Bailey MS, Holden MT, Zhang C, Jiang X, Koizumi N, Taylor K, Galloway R, Hoffmaster AR, Craig S, Smythe LD, Hartskeerl RA, Day NP, Chantratita N, Feil EJ, Aanensen DM, Spratt BG, Peaco*ck SJ. A single multilocus sequence typing (MLST) scheme for seven pathogenic Leptospira species. PLoS Negl Trop Dis. 2013;7:e1954. [PMC free article] [PubMed] [Google Scholar]
• Brandão AP, Camargo ED, da Silva ED, Silva MV, Abrão RV. Macroscopic agglutination test for rapid diagnosis of human leptospirosis. J Clin Microbiol. 1998;36:3138–3142. [PMC free article] [PubMed] [Google Scholar]
• Brown PD, Gravekamp C, Carrington DG, Van de Kemp H, Hartskeerl RA, Edwards CN, Everard COR, Terpstra WJ, Levett PN. Evaluation of the polymerase chain reaction for early diagnosis of leptospirosis. J Med Microbiol. 1995;43:110–114. [PubMed] [Google Scholar]
• Burt FJ, Rolph MS, Rulli NE, Mahalingam S, Heise MT. Chikungunya: a re-emerging virus. Lancet. 2012;379:662–671. [PubMed] [Google Scholar]
• Chapman AJ, Faine S, Adler B. Antigens recognized by the human immune response to vaccination with a bivalent hardjo/pomona leptospiral vaccine. FEMS Microbiol Immunol. 1990;2:111–118. [PubMed] [Google Scholar]
• Chen T. Development and present status of leptospiral vaccine and technology of production of the vaccine in China. Nihon Saikingaku Zasshi. 1985;40:755–762. [PubMed] [Google Scholar]
• Chu KM, Rathinam R, Namperumalsamy P, Dean D. Identification of Leptospira species in the pathogenesis of uveitis and determination of clinical ocular characteristics in South India. J Infect Dis. 1998;177:1314–1321. [PubMed] [Google Scholar]
• Chung HL, Ts’ao WC, Mo PS, Yen C. Transplacental or congenital infection of leptospirosis. Clinical and experimental observations. Chin Med J. 1963;82:777–782. [PubMed] [Google Scholar]
• Coghlan JD, Bain AD. Leptospirosis in human pregnancy followed by death of the foetus. Brit Med J. 1969;1:228–230. [PMC free article] [PubMed] [Google Scholar]
• Collen MJ, Ansher AF, Chapman AB, Mackow RC, Lewis JH. Serum amylase in patients with renal insufficiency and renal failure. Am J Gastroenterol. 1990;85:1377–1380. [PubMed] [Google Scholar]
• Corwin A, Ryan A, Bloys W, Thomas R, Deniega B, Watts D. A waterborne outbreak of leptospirosis among United States military personnel in Okinawa, Japan. Int J Epidemiol. 1990;19:743–748. [PubMed] [Google Scholar]
• Covic A, Goldsmith DJ, Gusbeth-Tatomir P, Seica A, Covic M. A retrospective 5-year study in Moldova of acute renal failure due to leptospirosis: 58 cases and a review of the literature. Nephrol Dial Transplant. 2003;18:1128–1134. [PubMed] [Google Scholar]
• Cumberland PC, Everard COR, Levett PN. Assessment of the efficacy of the IgM enzyme-linked immunosorbent assay (ELISA) and microscopic agglutination test (MAT) in the diagnosis of acute leptospirosis. Am J Trop Med Hyg. 1999;61:731–734. [PubMed] [Google Scholar]
• Cumberland PC, Everard COR, Wheeler JG, Levett PN. Persistence of anti-leptospiral IgM, IgG and agglutinating antibodies in patients presenting with acute febrile illness in Barbados 1979–1989. Eur J Epidemiol. 2001;17:601–608. [PubMed] [Google Scholar]
• Daher E, Zanetta DM, Cavalcante MB, Abdulkader RC. Risk factors for death and changing patterns in leptospirosis acute renal failure. Am J Trop Med Hyg. 1999;61:630–634. [PubMed] [Google Scholar]
• Dechet AM, Parsons M, Rambaran M, Mohamed-Rambaran P, Florendo-Cumbermack A, Persaud S, Baboolal S, Ari MD, Shadomy SV, Zaki SR, Paddock CD, Clark TA, Harris L, Lyon D, Mintz ED. Leptospirosis outbreak following severe flooding: a rapid assessment and mass prophylaxis campaign; Guyana, January–February 2005. PLoS ONE. 2012;7:e39672. [PMC free article] [PubMed] [Google Scholar]
• Desakorn V, Wuthiekanun V, Thanachartwet V, Sahassananda D, Chierakul W, Apiwattanap*rn A, Day NP, Limmathurotsakul D, Peaco*ck SJ. Accuracy of a commercial IgM ELISA for the diagnosis of human leptospirosis in Thailand. Am J Trop Med Hyg. 2012;86:524–527. [PMC free article] [PubMed] [Google Scholar]
• Dikken H, Kmety E. Serological typing methods of leptospires. In: Bergan T, Norris JR, editors. Methods in microbiology. Academic Press; London: 1978. pp. 259–307. [Google Scholar]
• Doeleman FPJ. Ziekte van Weil, rechstreeks overgebracht van mensch op mensch. Ned Tijdschr Geneeskd. 1932;76:5057. [Google Scholar]
• Dupont H, Dupont-Perdrizet D, Perie JL, Zehner-Hansen S, Jarrige B, Daijardin JB. Leptospirosis: prognostic factors associated with mortality. Clin Infect Dis. 1997;25:720–724. [PubMed] [Google Scholar]
• Edwards CN, Nicholson GD, Hassell TA, Everard CO, Callender J. Penicillin therapy in icteric leptospirosis. Am J Trop Med Hyg. 1988;39:388–390. [PubMed] [Google Scholar]
• Everard CO, Carrington D, Korver H, Everard JD. Leptospires in the marine toad (Bufo marinus) on Barbados. J Wildl Dis. 1988;24:334–338. [PubMed] [Google Scholar]
• Everard COR, Bennett S, Edwards CN, Nicholson GD, Hassell TA, Carrington DG, Everard JD. An investigation of some risk factors for severe leptospirosis on Barbados. J Trop Med Hyg. 1992;95:13–32. [PubMed] [Google Scholar]
• Everard JD, Everard COR. Leptospirosis in the Caribbean. Rev Med Microbiol. 1993;4:114–122. [Google Scholar]
• Faine S. Guidelines for the control of leptospirosis. World Health Organization; Geneva: 1982. [Google Scholar]
• Faine S, Adler B, Christopher W, Valentine R. Fatal congenital human leptospirosis. Zentralbl Bakteriol Mikrobiol Hyg [A] 1984;257:548. [PubMed] [Google Scholar]
• Faine S, Adler B, Bolin C, Perolat P. Leptospira and leptospirosis. 2. MediSci; Melbourne: 1999. [Google Scholar]
• Felzemburgh RD, Ribeiro GS, Costa F, Reis RB, Hagan JE, Melendez AX, Fraga D, Santana FS, Mohr S, Dos Santos BL, Silva AQ, Santos AC, Ravines RR, Tassinari WS, Carvalho MS, Reis MG, Ko AI. Prospective study of leptospirosis transmission in an urban slum community: role of poor environment in repeated exposures to the Leptospira agent. PLoS Negl Trop Dis. 2014;8:e2927. [PMC free article] [PubMed] [Google Scholar]
• f*ckumura K. Epidemiological studies on leptospirosis in Okinawa. Part 1. Prevalence of leptospirosis in Izena Island and the prevention by vaccination. Yamaguchi Med J. 1984;33:257–268. [Google Scholar]
• Galloway RL, Levett PN. Application and validation of PFGE for serovar identification of Leptospira clinical isolates. PLoS Negl Trop Dis. 2010;4:e824. [PMC free article] [PubMed] [Google Scholar]
• Galton MM. Methods in the laboratory diagnosis of leptospirosis. Ann NY Acad Sci. 1962;98:675–684. [Google Scholar]
• Ganoza CA, Matthias MA, Saito M, Cespedes M, Gotuzzo E, Vinetz JM. Asymptomatic renal colonization of humans in the peruvian Amazon by Leptospira. PLoS Negl Trop Dis. 2010;4:e612. [PMC free article] [PubMed] [Google Scholar]
• Gochenour WS, Smadel JE, Jackson EB, Evans LB, Yager RH. Leptospiral etiology of Fort Bragg fever. Publ Hlth Rep. 1952;67:811–813. [PMC free article] [PubMed] [Google Scholar]
• Gonsalez CR, Casseb J, Monteiro FG, Paula-Neto JB, Fernandez RB, Silva MV, Camargo ED, Mairinque JM, Tavares LC. Use of doxycycline for leptospirosis after high-risk exposure in Sao Paulo, Brazil. Rev Inst Med Trop Sao Paulo. 1998;40:59–61. [PubMed] [Google Scholar]
• Goris MG, Wagenaar JF, Hartskeerl RA, van Gorp EC, Schuller S, Monahan AM, Nally JE, van der Poll T, van’t Veer C. Potent innate immune response to pathogenic Leptospira in human whole blood. PLoS ONE. 2011a;6:e18279. [PMC free article] [PubMed] [Google Scholar]
• Goris MGA, Leeflang MMG, Boer KR, Goeijenbier M, van Gorp ECM, Wagenaar JFP, Hartskeerl RA. Establishment of valid laboratory case definition for human leptospirosis. J Bacteriol Parasitol. 2011b;S5-001:1–8. [Google Scholar]
• Goris MG, Kikken V, Straetemans M, Alba S, Goeijenbier M, van Gorp EC, Boer KR, Wagenaar JF, Hartskeerl RA. Towards the burden of human leptospirosis: duration of acute illness and occurrence of post-leptospirosis symptoms of patients in the Netherlands. PLoS ONE. 2013a;8:e76549. [PMC free article] [PubMed] [Google Scholar]
• Goris MGA, Leeflang MMG, Loden M, Wagenaar JFP, Klatser PR, Hartskeerl RA, Boer KR. Prospective evaluation of three rapid diagnostic tests for diagnosis of human leptospirosis. PLoS Negl Trop Dis. 2013b;7:e2290. [PMC free article] [PubMed] [Google Scholar]
• Gouveia EL, Metcalfe J, de Carvalho ALF, Aires TSF, Villalobos-Bisneto JC, Queiroz A, Santos AC, Salgado K, Reis MG, Ko AI. Leptospirosis-associated severe pulmonary hemorrhage syndrome, Salvador, Brazil. Emerg Infect Dis. 2008;14:505–508. [PMC free article] [PubMed] [Google Scholar]
• Gravekamp C, Korver H, Montgomery J, Everard COR, Carrington D, Ellis WA, Terpstra WJ. Leptospires isolated from toads and frogs on the island of Barbados. Zentralbl Bakteriol. 1991;275:403–411. [PubMed] [Google Scholar]
• Guerra-Silveira F, Abad-Franch F. Sex bias in infectious disease epidemiology: patterns and processes. PLoS ONE. 2013;8:e62390. [PMC free article] [PubMed] [Google Scholar]
• Harrison NA, Fitzgerald WR. Leptospirosis—can it be a sexually transmitted disease? Postgrad Med J. 1988;64:163–164. [PMC free article] [PubMed] [Google Scholar]
• Hartskeerl RA, Collares-Pereira M, Ellis WA. Emergence, control and re-emerging leptospirosis: dynamics of infection in the changing world. Clin Microbiol Infect. 2011;17:494–501. [PubMed] [Google Scholar]
• Herath NJ, Kularatne SA, Weerakoon KG, Wazil A, Subasinghe N, Ratnatunga NV. Long term outcome of acute kidney injury due to leptospirosis? A longitudinal study in Sri Lanka. BMC Res Notes. 2014;7:398. [PMC free article] [PubMed] [Google Scholar]
• Herrmann JL, Bellenger E, Perolat P, Baranton G, Saint Girons I. Pulsed-field gel electrophoresis of NotI digests of leptospiral DNA: a new rapid method of serovar identification. J Clin Microbiol. 1992;30:1696–1702. [PMC free article] [PubMed] [Google Scholar]
• Hospenthal DR, Murray CK. In vitro susceptibilities of seven Leptospira species to traditional and newer antibiotics. Antimicrob Agents Chemother. 2003;47:2646–2648. [PMC free article] [PubMed] [Google Scholar]
• Hotez PJ, Bottazzi ME, Franco-Paredes C, Ault SK, Periago MR. The neglected tropical diseases of Latin America and the Caribbean: a review of disease burden and distribution and a roadmap for control and elimination. PLoS Negl Trop Dis. 2008;2:e300. [PMC free article] [PubMed] [Google Scholar]
• Hull-Jackson C, Glass MB, Ari MD, Bragg SL, Branch SL, Whittington CU, Edwards CN, Levett PN. Evaluation of a commercial latex agglutination assay for serological diagnosis of leptospirosis. J Clin Microbiol. 2006;44:1853–1855. [PMC free article] [PubMed] [Google Scholar]
• Jevon TR, Knudson MP, Smith PA, Whitecar PS, Blake RL. A point-source epidemic of leptospirosis. Postgrad Med. 1986;80:121–129. [PubMed] [Google Scholar]
• Karande S, Patil S, Kulkarni M, Joshi A, Bharadwaj R. Acute aseptic meningitis as the only presenting feature of leptospirosis. Pediatr Infect Dis J. 2005;24:390–391. [PubMed] [Google Scholar]
• Katz AR, Manea SJ, Sasaki DM. Leptospirosis on Kauai: investigation of a common source waterborne outbreak. Am J Public Health. 1991;81:1310–1312. [PMC free article] [PubMed] [Google Scholar]
• Katz AR, Ansdell VE, Effler PV, Middleton CR, Sasaki DM. Assessment of the clinical presentation and treatment of 353 cases of laboratory-confirmed leptospirosis in hawaii, 1974–1998. Clin Infect Dis. 2001;33:1834–1841. [PubMed] [Google Scholar]
• Katz AR, Buchholz AE, Hinson K, Park SY, Effler PV. Leptospirosis in Hawaii, USA, 1999–2008. Emerg Infect Dis. 2011;17:221–226. [PMC free article] [PubMed] [Google Scholar]
• Ko AI, Galvao Reis M, Ribeiro Dourado CM, Johnson WD, Jr, Riley LW. The Salvador Leptospirosis Study Group (1999) Urban epidemic of severe leptospirosis in Braz. Lancet. 354:820–825. [PubMed] [Google Scholar]
• Ko AI, Goarant C, Picardeau M. Leptospira: the dawn of the molecular genetics era for an emerging zoonotic pathogen. Nat Rev Microbiol. 2009;7:736–747. [PMC free article] [PubMed] [Google Scholar]
• Korver H, Kolk AHJ, Vingerhoed J, van Leeuwen J, Terpstra WJ. Classification of serovars of the Icterohaemorrhagiae serogroup by monoclonal antibodies. Israel J Vet Med. 1988;44:15–18. [Google Scholar]
• Lau C, Smythe L, Weinstein P. Leptospirosis: an emerging disease in travellers. Travel Med Infect Dis. 2010a;8:33–39. [PubMed] [Google Scholar]
• Lau CL, Smythe LD, Craig SB, Weinstein P. Climate change, flooding, urbanisation and leptospirosis: fuelling the fire? Trans R Soc Trop Med Hyg. 2010b;104:631–638. [PubMed] [Google Scholar]
• Laurichesse H, Gourdon F, Smits HL, Abdoe TH, Estavoyer JM, Rebika H, Pouliquen P, Catalina P, Dubray C, Beytout J. Safety and immunogenicity of subcutaneous or intramuscular administration of a monovalent inactivated vaccine against Leptospira interrogans serogroup Icterohaemorrhagiae in healthy volunteers. Clin Microbiol Infect. 2007;13:395–403. [PubMed] [Google Scholar]
• Leon A, Pronost S, Fortier G, Andre-Fontaine G, Leclercq R. Multilocus sequence analysis for typing Leptospira interrogans and Leptospira kirschneri. J Clin Microbiol. 2009;48:581–585. [PMC free article] [PubMed] [Google Scholar]
• Levett PN. Leptospirosis: re-emerging or re-discovered disease? J Med Microbiol. 1999;48:417–418. [PubMed] [Google Scholar]
• Levett PN. Leptospirosis. Clin Microbiol Rev. 2001;14:296–326. [PMC free article] [PubMed] [Google Scholar]
• Levett PN, Branch SL. Evaluation of two enzyme-linked immunosorbent assay methods for detection of immunoglobulin M antibodies in acute leptospirosis. Am J Trop Med Hyg. 2002;66:745–748. [PubMed] [Google Scholar]
• Levett PN. Usefulness of serologic analysis as a predictor of the infecting serovar in patients with severe leptospirosis. Clin Infect Dis. 2003;36:447–452. [PubMed] [Google Scholar]
• Levett PN. Leptospirosis: a forgotten zoonosis? Clin Appl Immunol Rev. 2004;4:435–448. [Google Scholar]
• Lingappa J, Kuffner T, Tappero J, Whitworth W, Mize A, Kaiser R, McNicholl J. HLA-DQ6 and ingestion of contaminated water: possible gene-environment interaction in an outbreak of leptospirosis. Genes Immun. 2004;5:197–202. [PubMed] [Google Scholar]
• Lopes AA, Costa E, Costa YA, Sacramento E, De Oliveira AR, Junior, Lopes MB, Lopes GB. Comparative study of the in-hospital case-fatality rate of leptospirosis between pediatric and adult patients of different age groups. Rev Inst Med Trop Sao Paulo. 2004;46:19–24. [PubMed] [Google Scholar]
• Lupidi R, Cinco M, Balanzin D, Delprete E, Varaldo PE. Serological follow-up of patients in a localized outbreak of leptospirosis. J Clin Microbiol. 1991;29:805–809. [PMC free article] [PubMed] [Google Scholar]
• Maciel EA, de Carvalho AL, Nascimento SF, de Matos RB, Gouveia EL, Reis MG, Ko AI. Household transmission of Leptospira infection in urban slum communities. PLoS Negl Trop Dis. 2008;2:e154. [PMC free article] [PubMed] [Google Scholar]
• Mailloux M, Lambert R, Chenu M. Human vaccination against leptospirosis icterohaemorrhagiae. Med Hyg (Geneve) 1983;41:1025–1030. [Google Scholar]
• Marotto PC, Ko AI, Murta-Nascimento C, Seguro AC, Prado RR, Barbosa MC, Cleto SA, Eluf-Neto J. Early identification of leptospirosis-associated pulmonary hemorrhage syndrome by use of a validated prediction model. J Infect. 2010;60:218–223. [PMC free article] [PubMed] [Google Scholar]
• Martinez R, Perez A, del Quinones MC, Cruz R, Alvarez A, Armesto M, Fernandez C, Menendez J, Rodriguez I, Baro M, Diaz M, Rodriguez J, Sierra G, Obregon AM, Toledo ME, Fernandez N. Efficacy and safety of a vaccine against human leptospirosis in Cuba. Rev Panam Salud Publica. 2004;15:249–255. [PubMed] [Google Scholar]
• McBride AJ, Athanazio DA, Reis MG, Ko AI. Leptospirosis. Curr Opin Infect Dis. 2005;18:376–386. [PubMed] [Google Scholar]
• McClain JBL, Ballou WR, Harrison SM, Steinweg DL. Doxycycline therapy for leptospirosis. Ann Intern Med. 1984;100:696–698. [PubMed] [Google Scholar]
• Merien F, Truccolo J, Rougier Y, Baranton G, Perolat P. In vivo apoptosis of hepatocytes in guinea pigs infected with Leptospira interrogans serovar icterohaemorrhagiae. FEMS Microbiol Lett. 1998;169:95–102. [PubMed] [Google Scholar]
• Merien F, Portnoi D, Bourhy P, Charavay F, Berlioz-Arthaud A, Baranton G. A rapid and quantitative method for the detection of Leptospira species in human leptospirosis. FEMS Microbiol Lett. 2005;249:139–147. [PubMed] [Google Scholar]
• Miyahara S, Saito M, Kanemaru T, Villanueva SY, Gloriani NG, Yoshida SI. Destruction of the hepatocyte junction by intercellular invasion of Leptospira causes jaundice in a hamster model of Weil’s disease. Int J Exp Pathol. 2014;95:271–281. [PMC free article] [PubMed] [Google Scholar]
• Moeschlin S. Lungeninfiltrate beim Ikterus infeciosus Weil. Schweitz Med Wochenschr. 1943;73:1227–1230. [Google Scholar]
• Morgan J, Bornstein SL, Karpati AM, Bruce M, Bolin CA, Austin CC, Woods CW, Lingappa J, Langkop C, Davis B, Graham DR, Proctor M, Ashford DA, Bajani M, Bragg SL, Shutt K, Perkins BA, Tappero JW. Outbreak of leptospirosis among triathlon participants and community residents in Springfield, Illinois, 1998. Clin Infect Dis. 2002;34:1593–1599. [PubMed] [Google Scholar]
• Murray CK, Ellis MW, Hospenthal DR. Susceptibility of Leptospira serovars to antimalarial agents. Am J Trop Med Hyg. 2004;71:685–686. [PubMed] [Google Scholar]
• Murray CK, Gray MR, Mende K, Parker TM, Samir A, Rahman BA, Habashy EE, Hospenthal DR, Pimentel G. Use of patient-specific Leptospira isolates in the diagnosis of leptospirosis employing microscopic agglutination testing (MAT) Trans R Soc Trop Med Hyg. 2011;105:209–213. [PubMed] [Google Scholar]
• Nabity SA, Ribeiro GS, Lessa Aquino C, Takahashi D, Damião AO, Gonçalves AH, Miranda-Filho DB, Greenwald R, Esfandiari J, Lyashchenko KP, Reis MG, Medeiros MA, Ko AI. Accuracy of a dual path platform (DPP) assay for the rapid point-of-care diagnosis of human leptospirosis. PLoS Negl Trop Dis. 2012;6:e1878. [PMC free article] [PubMed] [Google Scholar]
• Nahori MA, Fournie-Amazouz E, Que-Gewirth NS, Balloy V, Chignard M, Raetz CR, Saint Girons I, Werts C. Differential TLR recognition of leptospiral lipid A and lipopolysaccharide in murine and human cells. J Immunol. 2005;175:6022–6031. [PubMed] [Google Scholar]
• Nally JE, Chantranuwat C, Wu XY, Fishbein MC, Pereira MM, Da Silva JJ, Blanco DR, Lovett MA. Alveolar septal deposition of immunoglobulin and complement parallels pulmonary hemorrhage in a guinea pig model of severe pulmonary leptospirosis. Am J Pathol. 2004;164:1115–1127. [PMC free article] [PubMed] [Google Scholar]
• O’Brien MM, Vincent JM, Person DA, Cook BA. Leptospirosis and pancreatitis: a report of ten cases. Pediatr Infect Dis J. 1998;17:436–438. [PubMed] [Google Scholar]
• Palaniappan RU, Chang YF, Chang CF, Pan MJ, Yang CW, Harpending P, McDonough SP, Dubovi E, Divers T, Qu J, Roe B. Evaluation of lig-based conventional and real time PCR for the detection of pathogenic leptospires. Mol Cell Probes. 2005;19:111–117. [PubMed] [Google Scholar]
• Palmer MF, Zochowski WJ. Survival of leptospires in commercial blood culture systems revisited. J Clin Pathol. 2000;53:713–714. [PMC free article] [PubMed] [Google Scholar]
• Panaphut T, Domrongkitchaip*rn S, Thinkamrop B. Prognostic factors of death in leptospirosis: a prospective cohort study in Khon Kaen, Thailand. Int J Infect Dis. 2002;6:52–59. [PubMed] [Google Scholar]
• Panaphut T, Domrongkitchaip*rn S, Vibhagool A, Thinkamrop B, Susaengrat W. Ceftriaxone compared with sodium penicillin G for treatment of severe leptospirosis. Clin Infect Dis. 2003;36:1507–1513. [PubMed] [Google Scholar]
• Pappachan MJ, Mathew S, Aravindan KP, Khader A, Bharghavan PV, Kareem MM, Tuteja U, Shukla J, Batra HV. Risk factors for mortality in patients with leptospirosis during an epidemic in northern Kerala. Natl Med J India. 2004;17:240–242. [PubMed] [Google Scholar]
• Park SK, Lee SH, Rhee YK, Kang SK, Kim KJ, Kim MC, Kim KW, Chang WH. Leptospirosis in Chonbuk Province of Korea in 1987: a study of 93 patients. Am J Trop Med Hyg. 1989;41:345–351. [PubMed] [Google Scholar]
• Pavan ME, Cairó F, Brihuega B, Samartino L. Multiple-locus variable-number tandem repeat analysis (MLVA) of Leptospira interrogans serovar Pomona from Argentina reveals four new genotypes. Comp Immunol Microbiol Infect Dis. 2008;31:37–45. [PubMed] [Google Scholar]
• Perez J, Goarant C. Rapid Leptospira identification by direct sequencing of the diagnostic PCR products in New Caledonia. BMC Microbiol. 2010;10:325. [PMC free article] [PubMed] [Google Scholar]
• Pouliquen P, Catilina P. Enquete de pharmacosurveillance aupres des medecins vaccinateurs. Rev Med Trav. 2000;27:83–88. [Google Scholar]
• Que-Gewirth NS, Riberio AA, Kalb SR, Cotter RJ, Bulach DM, Adler B, Saint Girons I, Werts C, Raetz CRH. A methylated phosphate group and four amide-linked acyl chains in Leptospira interrogans lipid A. J Biol Chem. 2004;279:25420–25429. [PMC free article] [PubMed] [Google Scholar]
• Rathinam SR. Ocular manifestations of leptospirosis. J Postgrad Med. 2005;51:189–194. [PubMed] [Google Scholar]
• Reis EA, Hagan JE, Ribeiro GS, Teixeira-Carvalho A, Martins-Filho OA, Montgomery RR, Shaw AC, Ko AI, Reis MG. Cytokine response signatures in disease progression and development of severe clinical outcomes for leptospirosis. PLoS Negl Trop Dis. 2013;7:e2457. [PMC free article] [PubMed] [Google Scholar]
• Reis RB, Ribeiro GS, Felzemburgh RD, Santana FS, Mohr S, Melendez AX, Queiroz A, Santos AC, Ravines RR, Tassinari WS, Carvalho MS, Reis MG, Ko AI. Impact of environment and social gradient on Leptospira infection in urban slums. PLoS Negl Trop Dis. 2008;2:e228. [PMC free article] [PubMed] [Google Scholar]
• Ressner RA, Griffith ME, Beckius ML, Pimentel G, Miller RS, Mende K, Fraser SL, Galloway RL, Hospenthal DR, Murray CK. Antimicrobial susceptibilities of geographically diverse clinical human isolates of Leptospira. Antimicrob Agents Chemother. 2008;52:2750–2754. [PMC free article] [PubMed] [Google Scholar]
• Ribeiro MA, Assis CSN, Romero EC. Serodiagnosis of human leptospirosis employing immunodominant antigen. Serodiagn Immunother Infect Dis. 1994;6:140–144. [Google Scholar]
• Romero EC, Caly CR, Yasuda PH. The persistence of leptospiral agglutinins titers in human sera diagnosed by the microscopic agglutination test. Rev Inst Med Trop São Paulo. 1998;40:183–184. [PubMed] [Google Scholar]
• Salaun L, Merien F, Gurianova S, Baranton G, Picardeau M. Application of multilocus variable-number tandem-repeat analysis for molecular typing of the agent of leptospirosis. J Clin Microbiol. 2006;44:3954–3962. [PMC free article] [PubMed] [Google Scholar]
• Schreier S, Doungchawee G, Chadsuthi S, Triampo D, Triampo W. Leptospirosis: current situation and trends of specific laboratory tests. Expert Rev Clin Immunol. 2013;9:263–280. [PubMed] [Google Scholar]
• Segura ER, Ganoza CA, Campos K, Ricaldi JN, Torres S, Silva H, Cespedes MJ, Matthias MA, Swancutt MA, Lopez Linan R, Gotuzzo E, Guerra H, Gilman RH, Vinetz JM. Clinical spectrum of pulmonary involvement in leptospirosis in a region of endemicity, with quantification of leptospiral burden. Clin Infect Dis. 2005;40:343–351. [PMC free article] [PubMed] [Google Scholar]
• Seguro AC, Lomar AV, Rocha AS. Acute renal failure of leptospirosis: nonoliguric and hypokalemic forms. Nephron. 1990;55:146–151. [PubMed] [Google Scholar]
• Sehgal SC, Murhekar MV, Sugunan AP. Outbreak of leptospirosis with pulmonary involvement in North Andaman. Indian J Med Res. 1995;102:9–12. [PubMed] [Google Scholar]
• Sehgal SC, Sugunan AP, Murhekar MV, Sharma S, Vijayachari P. Randomized controlled trial of doxycycline prophylaxis against leptospirosis in an endemic area. Int J Antimicrob Agents. 2000;13:249–255. [PubMed] [Google Scholar]
• Sejvar J, Bancroft E, Winthrop K, Bettinger J, Bajani M, Bragg S, Shutt K, Kaiser R, Marano N, Popovic T, Tappero J, Ashford D, Mascola L, Vugia D, Perkins B, Rosenstein N. Leptospirosis in “eco-challenge” athletes, Malaysian Borneo, 2000. Emerg Infect Dis. 2003;9:702–707. [PMC free article] [PubMed] [Google Scholar]
• Self CA, Iskrzynska WI, Waitkins SA, Whicher JW, Whicher JT. Leptospirosis among British cavers. Cave Sci. 1987;14:131–134. [Google Scholar]
• Shaw RD. Kayaking as a risk factor for leptospirosis. Mo Med. 1992;89:354–357. [PubMed] [Google Scholar]
• Shenberg E, Torten M. A new leptospiral vaccine for use in man. I. Development of a vaccine from Leptospira grown on a chemically defined medium. J Infect Dis. 1973;128:642–646. [PubMed] [Google Scholar]
• Signorini ML, Lottersberger J, Tarabla HD, Vanasco NB. Enzyme-linked immunosorbent assay to diagnose human leptospirosis: a meta-analysis of the published literature. Epidemiol Infect. 2013;141:22–32. [PMC free article] [PubMed] [Google Scholar]
• Silva HR, Tanajura GM, Tavares-Neto J, de Gomes Md ML, daLinhares Ad AC, Vasconcelos PF, Ko AI. Aseptic meningitis syndrome due to enterovirus and Leptospira sp in children of Salvador, Bahia. Rev Soc Bras Med Trop. 2002a;35:159–165. [PubMed] [Google Scholar]
• Silva JJ, Dalston MO, Carvalho JE, Setubal S, Oliveira JM, Pereira MM. Clinicopathological and immunohistochemical features of the severe pulmonary form of leptospirosis. Rev Soc Bras Med Trop. 2002b;35:395–399. [PubMed] [Google Scholar]
• Sitprija V, Evans H. The kidney in human leptospirosis. Am J Med. 1970;49:780–788. [PubMed] [Google Scholar]
• Slack AT, Dohnt MF, Symonds ML, Smythe LD. Development of a multiple-locus variable number of tandem repeat analysis (MLVA) for Leptospira interrogans and its application to Leptospira interrogans serovar Australis isolates from far North Queensland. Australia. Ann Clin Microbiol Antimicrob. 2005;4:10. [PMC free article] [PubMed] [Google Scholar]
• Smits HL, Hartskeerl RA, Terpstra WJ. International multi-centre evaluation of a dipstick assay for human leptospirosis. Trop Med Int Health. 2000a;5:124–128. [PubMed] [Google Scholar]
• Smits HL, van Der Hoorn MA, Goris MG, Gussenhoven GC, Yersin C, Sasaki DM, Terpstra WJ, Hartskeerl RA. Simple latex agglutination assay for rapid serodiagnosis of human leptospirosis. J Clin Microbiol. 2000b;38:1272–1275. [PMC free article] [PubMed] [Google Scholar]
• Smits HL, Chee HD, Eapen CK, Kuriakose M, Sugathan S, Gasem MH, Yersin C, Sakasi D, Lai AFRF, Hartskeerl RA, Liesdek B, Abdoel TH, Goris MG, Gussenhoven GC. Latex based, rapid and easy assay for human leptospirosis in a single test format. Trop Med Int Health. 2001a;6:114–118. [PubMed] [Google Scholar]
• Smits HL, Eapen CK, Sugathan S, Kuriakose M, Gasem MH, Yersin C, Sasaki D, Pujianto B, Vestering M, Abdoel TH, Gussenhoven GC. Lateral-flow assay for rapid serodiagnosis of human leptospirosis. Clin Diagn Lab Immunol. 2001b;8:166–169. [PMC free article] [PubMed] [Google Scholar]
• Smythe L, Dohnt M, Norris M, Symonds M, Scott J. Review of leptospirosis notifications in Queensland 1985 to 1996. Commun Dis Intell. 1997;21:17–20. [PubMed] [Google Scholar]
• Smythe LD, Smith IL, Smith GA, Dohnt MF, Symonds ML, Barnett LJ, McKay DB. A quantitative PCR (TaqMan) assay for pathogenic Leptospira spp. BMC Infect Dis. 2002;2:13. [PMC free article] [PubMed] [Google Scholar]
• Smythe LD, Wuthiekanun V, Chierakul W, Suputtamongkol Y, Tiengrim S, Dohnt MF, Symonds ML, Slack AT, Apiwattanap*rn A, Chueasuwanchai S, Day NP, Peaco*ck SJ. The microscopic agglutination test (MAT) is an unreliable predictor of infecting Leptospira serovar in Thailand. Am J Trop Med Hyg. 2009;81:695–697. [PubMed] [Google Scholar]
• Spichler A, Spichler E, Moock M, Vinetz JM, Leake JA. Acute pancreatitis in fatal anicteric leptospirosis. Am J Trop Med Hyg. 2007;76:886–887. [PubMed] [Google Scholar]
• Spichler A, Athanazio D, Seguro AC, Vinetz JM. Outpatient follow-up of patients hospitalized for acute leptospirosis. Int J Infect Dis. 2011;15:e486–e490. [PMC free article] [PubMed] [Google Scholar]
• Steneroden KK, Hill AE, Salman MD. Zoonotic disease awareness in animal shelter workers and volunteers and the effect of training. Zoonoses Public Health. 2011;58:449–453. [PubMed] [Google Scholar]
• Stern EJ, Galloway R, Shadomy SV, Wannemuehler K, Atrubin D, Blackmore C, Wofford T, Wilkins PP, Ari MD, Harris L, Clark TA. Outbreak of leptospirosis among adventure race participants in Florida, 2005. Clin Infect Dis. 2010;50:843–849. [PubMed] [Google Scholar]
• Stoddard RA, Gee JE, Wilkins PP, McCaustland K, Hoffmaster AR. Detection of pathogenic Leptospira spp. through TaqMan polymerase chain reaction targeting the LipL32 gene. Diagn Microbiol Infect Dis. 2009;64:247–255. [PubMed] [Google Scholar]
• Stoenner HG, Dodd T, Larsen C. Antigenic variation of Borrelia hermsii. J Exp Med. 1982;156:1297–1311. [PMC free article] [PubMed] [Google Scholar]
• Sulzer CR, Jones WL. Leptospirosis: methods in laboratory diagnosis. U.S. Department of Health, Education and Welfare; Atlanta: 1978. [Google Scholar]
• Takafuji ET, Kirkpatrick JW, Miller RN, Karwacki JJ, Kelley PW, Gray MR, McNeill KM, Timboe HL, Kane RE, Sanchez JL. An efficacy trial of doxycycline chemoprophylaxis against leptospirosis. N Engl J Med. 1984;310:497–500. [PubMed] [Google Scholar]
• Thaipadungpanit J, Wuthiekanun V, Chierakul W, Smythe LD, Petkanchanapong W, Limpaiboon R, Apiwatanap*rn A, Slack AT, Suputtamongkol Y, White NJ, Feil EJ, Day NP, Peaco*ck SJ. A dominant clone of Leptospira interrogans associated with an outbreak of human leptospirosis in Thailand. PLoS Negl Trop Dis. 2007;1:e56. [PMC free article] [PubMed] [Google Scholar]
• Thaipadunpanit J, Chierakul W, Wuthiekanun V, Limmathurotsakul D, Amornchai P, Boonslip S, Smythe LD, Limpaiboon R, Hoffmaster AR, Day NP, Peaco*ck SJ. Diagnostic accuracy of real-time PCR assays targeting 16S rRNA and LipL32 genes for human leptospirosis in Thailand: a case-control study. PLoS ONE. 2011;6:e16236. [PMC free article] [PubMed] [Google Scholar]
• Torten M. Leptospirosis. In: Stoenner HE, Torten M, Kaplan W, editors. CRC handbook series in zoonoses section a: bacterial, rickettsial and mycotic diseases. CRC press; Boca Raton: 1979. pp. 363–420. [Google Scholar]
• Trevejo RT, Rigau-Perez JG, Ashford DA, McClure EM, Jarquin-Gonzalez C, Amador JJ, de los Reyes JO, Gonzalez A, Zaki SR, Shieh WJ, McLean RG, Nasci RS, Weyant RS, Bolin CA, Bragg SL, Perkins BA, Spiegel RA. Epidemic leptospirosis associated with pulmonary hemorrhage-Nicaragua, 1995. J Infect Dis. 1998;178:1457–1463. [PubMed] [Google Scholar]
• Truccolo J, Serais O, Merien F, Perolat P. Following the course of human leptospirosis: evidence of a critical threshold for the vital prognosis using a quantitative PCR assay. FEMS Microbiol Lett. 2001;204:317–321. [PubMed] [Google Scholar]
• Truccolo J, Charavay F, Merien F, Perolat P. Quantitative PCR assay to evaluate ampicillin, ofloxacin, and doxycycline for treatment of experimental leptospirosis. Antimicrob Agents Chemother. 2002;46:848–853. [PMC free article] [PubMed] [Google Scholar]
• Tubiana S, Mikulski M, Becam J, Lacassin F, Lefevre P, Gourinat AC, Goarant C, D’Ortenzio E. Risk factors and predictors of severe leptospirosis in New Caledonia. PLoS Negl Trop Dis. 2013;7:e1991. [PMC free article] [PubMed] [Google Scholar]
• Turner LH. Leptospirosis II. Serology. Trans R Soc Trop Med Hyg. 1968;62:880–889. [PubMed] [Google Scholar]
• Turner LH. Leptospirosis III. Maintenance, isolation and demonstration of leptospires. Trans R Soc Trop Med Hyg. 1970;64:623–646. [PubMed] [Google Scholar]
• Verma A, Kumar P, Babb K, Timoney JF, Stevenson B. Cross-reactivity of antibodies against leptospiral recurrent uveitis-associated proteins A and B (LruA and LruB) with eye proteins. PLoS Negl Trop Dis. 2010;4:e778. [PMC free article] [PubMed] [Google Scholar]
• Vinetz JM, Wilcox BA, Aguirre A, Gollin LX, Katz AR, Fujioka RS, Maly K, Horwitz P, Chang H. Beyond disciplinary boundaries: leptospirosis as a model of incorporating transdisciplinary approaches to understand infectious disease emergence. EcoHealth. 2005;2:1–16. [Google Scholar]
• Viriyakosol S, Matthias MA, Swancutt MA, Kirkland TN, Vinetz JM. Toll-like receptor 4 protects against lethal Leptospira interrogans serovar Icterohaemorrhagiae infection and contributes to in vivo control of leptospiral burden. Infect Immun. 2006;74:887–895. [PMC free article] [PubMed] [Google Scholar]
• Wagenaar JF, Goris MG, Partiningrum DL, Isbandrio B, Hartskeerl RA, Brandjes DP, Meijers JC, Gasem MH, van Gorp EC. Coagulation disorders in patients with severe leptospirosis are associated with severe bleeding and mortality. Trop Med Int Health. 2010;15:152–159. [PubMed] [Google Scholar]
• Waitkins S. Leptospirosis in man, British Isles: 1984. Brit Med J. 1986;292:1324. [PMC free article] [PubMed] [Google Scholar]
• Wani H. Über die prophylaxe der pirochaetosis icterohaemorrhagica Inada (Weilschen Krankheit) durch Schutzimpfung. Zeitschr Immunforsch Exp Therap. 1933;79:1–26. [Google Scholar]
• Watt G, Padre LP, Tuazon ML, Calubaquib C, Santiago E, Ranoa CP, Laughlin LW. Placebo-controlled trial of intravenous penicillin for severe and late leptospirosis. Lancet. 1988;1:433–435. [PubMed] [Google Scholar]
• Weil A. Ueber eine eigenthümliche, mit Milztumor, Icterus und Nephritis einhergehende, acute Infectionskrankheit. Dtsch Arch Klin Med. 1886;39:209. [Google Scholar]
• Werts C, Tapping RI, Mathison JC, Chuang T-H, Kravchenko V, Saint Girons I, Haake D, Godowski PJ, Hayashi F, Ozinsky A, Underhill D, Aderem A, Tobias PS, Ulevitch RJ. Leptospiral endotoxin activates cells via a TLR2-dependent mechanism. Nat Immunol. 2001;2:346–352. [PubMed] [Google Scholar]
• Werts C. Leptospirosis: a Toll road from B lymphocytes. Chang Gung Med J. 2010;33:591–601. [PubMed] [Google Scholar]
• WHO . Leptospirosis worldwide, 1999. Wkly Epidemiol Rec. 1999;74:237–242. [PubMed] [Google Scholar]
• WHO. Report of the second meeting of the leptospirosis burden epidemiology reference group. 2011. [Google Scholar]
• Wilkins E, Cope A, Waitkins S. Rapids, rafts, and rats. Lancet. 1988;2:283–284. [PubMed] [Google Scholar]
• Wilson MR, Naccache SN, Samayoa E, Biagtan M, Bashir H, Yu G, Salamat SM, Somasekar S, Federman S, Miller S, Sokolic R, Garabedian E, Candotti F, Buckley RH, Reed KD, Meyer TL, Seroogy CM, Galloway R, Henderson SL, Gern JE, DeRisi JL, Chiu CY. Actionable diagnosis of neuroleptospirosis by next-generation sequencing. N Engl J Med. 2014;370:2408–2417. [PMC free article] [PubMed] [Google Scholar]
• Winslow WE, Merry DJ, Pirc ML, Devine PL. Evaluation of a commercial enzyme-linked immunosorbent assay for detection of immunoglobulin M antibody in diagnosis of human leptospiral infection. J Clin Microbiol. 1997;35:1938–1942. [PMC free article] [PubMed] [Google Scholar]
• Wolff JW. The laboratory diagnosis of leptospirosis. C.C. Thomas; Springfield, Illinois: 1954. [Google Scholar]
• Yagupsky P, Nolte FS. Quantitative aspects of septicemia. Clin Microbiol Rev. 1990;3:269–279. [PMC free article] [PubMed] [Google Scholar]
• Yang CW, Hung CC, Wu MS, Tian YC, Chang CT, Pan MJ, Vandewalle A. Toll-like receptor 2 mediates early inflammation by leptospiral outer membrane proteins in proximal tubule cells. Kidney Int. 2006;69:815–822. [PubMed] [Google Scholar]
• Yersin C, Bovet P, Merien F, Clement J, Laille M, Van Ranst M, Perolat P. Pulmonary haemorrhage as a predominant cause of death in leptospirosis in Seychelles. Trans R Soc Trop Med Hyg. 2000;94:71–76. [PubMed] [Google Scholar]
• Zaki SA, Shanbag P. Clinical manifestations of dengue and leptospirosis in children in Mumbai: an observational study. Infection. 2010;38:285–291. [PubMed] [Google Scholar]
• Zaki SR, Shieh WJ. Leptospirosis associated with outbreak of acute febrile illness and pulmonary haemorrhage, Nicaragua, 1995. Lancet. 1996;347:535–536. [PubMed] [Google Scholar]