Leptospirosis: case reports of an outbreak in Guyana

Impact of wars and natural disasters on emerging and re-emerging infectious diseases

Emerging Infectious Diseases (EIDs) and Re-Emerging Infectious Diseases (REIDs) constitute significant health problems and are becoming of major importance. Up to 75% of EIDs and REIDs have zoonotic origin. Several factors such as the destruction of natural habitats leading humans and animals to live in close proximity, ecological changes due to natural disasters, population migration resulting from war or conflict, interruption or decrease in disease prevention programs, and insufficient vector control applications and sanitation are involved in disease emergence and distribution. War and natural disasters have a great impact on the emergence/re-emergence of diseases in the population. According to a World Bank estimation, two billion people are living in poverty and fragility situations. Wars destroy health systems and infrastructure, curtail existing disease control programs, and cause population movement leading to an increase in exposure to health risks and favor the emergence of infectious diseases. A total of 432 catastrophic cases associated with natural disasters were recorded globally in 2021. Natural disasters increase the risk of EID and REID outbreaks by damaging infrastructure and leading to displacement of populations. A Generic National Action Plan covering risk assessment, mechanism for action, determination of roles and responsibilities of each sector, the establishment of a coordination mechanism, etc. should be developed.

Epidemiology of human leptospirosis in urban and rural areas of Brazil, 2000-2015

Background

Leptospirosis is one of the most widespread zoonosis in the world and Brazil has the highest number of cases in Latin America. Transmission occurs mainly through exposure to water and soil contaminated by the urine of infected animals. The goals of this study are to describe the geographic distribution, demographic characteristics and exposure factors of urban and rural cases of leptospirosis, and identify spatial clusters in urban and rural areas of Brazil.

Methods/results

A retrospective epidemiological study was carried out using 16 years (2000–2015) of surveillance data from the Brazilian Ministry of Health. Cases were described by age, sex and race, and exposure factors were characterized in urban and rural areas. A spatial autocorrelation analysis was conducted using local Moran’s I to identify urban and rural clusters of disease. On average 3,810 leptospirosis cases were reported annually with higher numbers in urban areas. National urban and rural incidence rates were the same (1.9 cases/100,000 population), however, regional differences were observed. Urban incidence rates were higher in the North and Northeast regions, while rural incidence rates were higher in the Southeast and South. The main exposure factor reported in urban and rural areas was exposure to places with signs of rodents, followed by flood in urban areas and agriculture and animal farming in rural areas. Clusters of leptospirosis were identified in densely populated urban areas of the North, Southeast and South regions, while rural clusters were concentrated in of the Southern region with large agriculture and animal farming practices.

Conclusions

This study highlights that leptospirosis is an important public health problem in both urban and rural areas of Brazil. The results provide decision-makers with detailed information about where disease incidence is high and can be used in the development of prevention and control strategies for priority areas and risk groups.

[Update on leptospirosis]

Leptospirosis is a worldwide spirochetal zoonosis whose global incidence is increasing and is probably underestimated. Leptospirosis has long been associated with occupational contact with animals (rats and cattle) and has become in developed countries a pathology more related to recreational activities with exposure to fresh water (canoeing, swimming, canyoning) and to an environment contaminated by urine from leptospires excretory rodents. Leptospirosis should be one of the differential diagnoses to be considered when returning from travel to tropical areas, particularly Southeast Asia, and particularly during the rainy season. The clinical symptoms, particularly in the initial phase, are not specific and can limit to a flu-like syndrome or "dengue-like" making diagnosis often difficult. It is then necessary to look carefully for clinical (muscle pain, cough, conjunctival involvement, jaundice) and biological arguments (thrombocytopenia, cholestasis, rhabdomyolysis, frank elevation of CRP) that will help to diagnose leptospirosis and lead to quick antibiotic therapy before the progression to a severe icterohaemorrhagic (Weil's disease) or respiratory form associated with significant mortality. Treatment is based on injectable beta-lactams in severe forms (mainly cephalosporins) and amoxicillin, doxycycline or azithromycin in non-severe forms. Some atypical or delayed forms of leptospirosis occurring in the late immune phase of the disease are to know. Rapid diagnostic tools are currently being studied to improve diagnosis in remote areas and facilitate access to early treatment.

Flooding: what is the impact on pregnancy and child health?

Floods are the most common type of natural disaster in both developed and developing countries and have led to extensive morbidity and mortality throughout the world. Worldwide, over the past 30 years, flooding has claimed the lives of more than 200,000 people and affected more than 2.8 billion others. The impact of flooding on health varies among populations and depends primarily on vulnerability and the kind of event experienced. It severely disrupts livelihoods and has a significant impact on the health of pregnant women and children. In addition, it may exacerbate a range of negative psychological and physiological child and reproductive health outcomes. Awareness-raising, education, and the issuing of warnings appear to be key initiatives to mitigate or prevent flood morbidity and mortality, especially among people living in low- and middle-income countries. Agencies responding to emergencies also need to be more cognisant of the dangers, specifically those engaged in healthcare, nutrition, and water safety programmes.

Leptospirosis in Latin America: exploring the first set of regional data

OBJECTIVES

To demonstrate the importance of country surveillance systems for leptospirosis and their use for preliminary epidemiological analysis, as well as to generate research questions for future, morecomprehensive studies on the disease.

METHODS

In 2015, for the first time, the Pan American Health Organization (PAHO) included human cases of leptospirosis in its Regional Core Health Data Initiative, an open-access database that collects annual health indicators from the countries and territories of the Americas. This new information was used to analyze leptospirosis cases by country and sex and to calculate cumulative incidence rates. Maps were used to help present the results. To supplement that general review of leptospirosis in the Americas, more detailed descriptions of the epidemiological situation and the surveillance programs of four selected countries (Brazil, Colombia, Cuba, and Honduras) were provided.

RESULTS

In this first year of PAHO requesting leptospirosis data, of the 49 countries and territories in the Americas, 38 of them (77.6%) reported information. Among those 38, 28 of them (73.7%) reported the presence of human cases; the majority of instances of zero cases were in Caribbean territories. From those 28, a total of 10 702 human cases were recorded. The largest numbers of cases in Latin America were in Brazil (40.2%), Peru (23.6%), Colombia (8.8%), and Ecuador (7.2%). The cumulative incidence rate for Latin America was estimated to be 2.0 per 100 000 population. On average, 65.1% of cases were males.

CONCLUSIONS

This study demonstrates that many countries in Latin America are making efforts to establish strong surveillance systems and programs for leptospirosis. The study also shows the importance of having leptospirosis surveillance systems as well as how the information generated can be used for evidence-based decision-making on leptospirosis.

The Use of Chemoprophylaxis after Floods to Reduce the Occurrence and Impact of Leptospirosis Outbreaks

Record-breaking and devastating rainfall events have occurred in the past decade. Rain and floods are considered the main risk factors for leptospirosis and several outbreaks have been reported following extreme weather events. In such situations, one possible intervention to prevent leptospirosis cases in high-risk groups is the use of chemoprophylaxis. However, not enough evidence of its effect is available. The objectives of this study were to review the literature on the current practices of chemoprophylaxis for leptospirosis and to explore, using a mathematical model, how various chemoprophylaxis scenarios may affect the progression of a leptospirosis outbreak. Twenty-six peer-reviewed publications were selected (10 quantitative studies, two systematic reviews and 14 articles of other types). Oral doxycycline was the most used antibiotic for chemoprophylaxis of leptospirosis. Post-exposure prophylaxis was assessed in four studies following a natural disaster. Although evidence of the effectiveness of post-exposure prophylaxis is inconsistent, the direction of association supported a protective effect for morbidity and mortality. The theoretical model showed how the assumed benefit of chemoprophylaxis was influenced by the time and rate of administration. Future models should consider the heterogeneity of affected communities, improved estimates of the effect of chemoprophylaxis on leptospirosis infection and disease, as well as potential detrimental impacts. Additional research is critical to provide clear evidence-based recommendations for leptospirosis control during an outbreak. The results of this study suggest that chemoprophylaxis may provide some protection in reducing the number of leptospirosis cases after a high-risk exposure; however, the effective benefit may depend on a variety of factors such as the timing and coverage of prophylaxis. The information summarized can be used to support decision-making during a high-risk event.

[Leptospirosis in French Guiana and the Guiana shield: Current knowledge in 2016]

Leptospirosis is a cosmopolitan zoonosis caused by bacteria of the genus Leptospira. Whether the distribution is worldwide, the hot and humid climate of the tropics is particularly conducive to its expansion. In most French overseas departments and territories, leptospirosis is considered as a public health problem. In French Guiana, a French department located in the northeastern part of the Amazon rainforest, it is supposed to be rare. The objective of this review was to make an inventory of the knowledge on human and animal leptospirosis in French Guiana and neighboring countries. A comprehensive search was conducted through the indexed and informal medical literature in English, French, Spanish and Portuguese. Thus, respectively ten and four publications were identified on human and animal leptospirosis in French Guiana, published between 1940 and 1995 in the form of case reports or case series. The publications concerning this disease in the other countries of the Guiana Shield, eastern Venezuela, Guyana, Suriname, and Brazilian state of Amapá, also scarce or nonexistent. However recent data from the French National Centre of leptospirosis showed a recent and sudden increase in the number of cases in the department, probably partly due to the development of diagnostic tools such as Elisa IgM serology. It is likely that leptospirosis is a neglected disease in the region, due to the lack of diagnostic tools readily available, the lack of knowledge of the local clinicians on this disease and the existence of many other pathogens with similar clinical presentation such as malaria, arboviruses and Q fever and Amazonian toxoplasmosis. The establishment of more large-scale studies on animal and human leptospirosis is necessary and urgent to know the true burden of this disease in our region.

Leptospirosis in Rio Grande do Sul, Brazil: An Ecosystem Approach in the Animal-Human Interface

BACKGROUND

Leptospirosis is an epidemic-prone neglected disease that affects humans and animals, mostly in vulnerable populations. The One Health approach is a recommended strategy to identify drivers of the disease and plan for its prevention and control. In that context, the aim of this study was to analyze the distribution of human cases of leptospirosis in the State of Rio Grande do Sul, Brazil, and to explore possible drivers. Additionally, it sought to provide further evidence to support interventions and to identify hypotheses for new research at the human-animal-ecosystem interface.

METHODOLOGY AND FINDINGS

The risk for human infection was described in relation to environmental, socioeconomic, and livestock variables. This ecological study used aggregated data by municipality (all 496). Data were extracted from secondary, publicly available sources. Thematic maps were constructed and univariate analysis performed for all variables. Negative binomial regression was used for multivariable statistical analysis of leptospirosis cases. An annual average of 428 human cases of leptospirosis was reported in the state from 2008 to 2012. The cumulative incidence in rural populations was eight times higher than in urban populations. Variables significantly associated with leptospirosis cases in the final model were: Parana/Paraiba ecoregion (RR: 2.25; CI95%: 2.03-2.49); Neossolo Litolítico soil (RR: 1.93; CI95%: 1.26-2.96); and, to a lesser extent, the production of tobacco (RR: 1.10; CI95%: 1.09-1.11) and rice (RR: 1.003; CI95%: 1.002-1.04).

CONCLUSION

Urban cases were concentrated in the capital and rural cases in a specific ecoregion. The major drivers identified in this study were related to environmental and production processes that are permanent features of the state. This study contributes to the basic knowledge on leptospirosis distribution and drivers in the state and encourages a comprehensive approach to address the disease in the animal-human-ecosystem interface.

Knowledge, perceptions, and environmental risk factors among Jamaican households with a history of leptospirosis

BACKGROUND

Leptospirosis is a globally important zoonotic disease caused by pathogenic Leptospira, and outbreaks typically follow heavy rainfall and flooding. This study examined the knowledge and perceptions concerning leptospirosis, factors associated with environmental hygiene and sanitation, and the presence of Leptospira in water samples from households with or without a history of the disease in the parish of St. Mary, Jamaica.

METHODS

The study employed a cross-sectional design in 43 communities within the parish of St. Mary, Jamaica between September 2008 and March 2009. Households that had at least one confirmed case of leptospirosis during the 2005 or 2007 outbreaks were assessed for living conditions, environmental hygiene, and for knowledge and risk perceptions about leptospirosis. A parallel sampling scheme was used for households with no reported cases during the outbreak years.

RESULTS

Almost 97% of the participants reported having heard of leptospirosis; however, less than 40% of respondents from households with a history of leptospirosis agreed that leptospirosis was a problem in the parish. Among households without a history of leptospirosis, this perception was greater in urban/peri-urban households than in rural households (59% vs. 21%; p=0.04). Risk behaviors or living conditions were common; however, there was a high level of awareness about the health risks associated with flooding. Among households with history of leptospirosis, the perception that nothing can be done to control rodents was significantly higher (p<0.04) in rural (50%) than in urban/peri-urban (17.6%) households. Nine (4%) water samples were positive for Leptospira; 56% of these were from water stored for domestic purposes. Overall, residence in rural communities, presence of a garbage dump, and leptospiral DNA in water samples correlated with households with the history of the disease (p<0.01).

CONCLUSIONS

Education of rural communities regarding leptospirosis and its prevention through proper waste disposal and rodent control should be urgently initiated.

Leptospirosis outbreaks in Nicaragua: identifying critical areas and exploring drivers for evidence-based planning

Leptospirosis is an epidemic-prone zoonotic disease that occurs worldwide. In Central America, leptospirosis outbreaks have been reported in almost all countries; Nicaragua in particular has faced several outbreaks. The objective of this study was to stratify the risk and identify "critical areas" for leptospirosis outbreaks in Nicaragua, and to perform an exploratory analysis of potential "drivers". This ecological study includes the entire country (153 municipalities). Cases from 2004 to 2010 were obtained from the country's health information system, demographic and socioeconomic variables from its Census, and environmental data from external sources. Criteria for risk stratification of leptospirosis were defined. Nicaragua reported 1,980 cases of leptospirosis during this period, with the highest percentage of cases (26.36%) in León, followed by Chinandega (15.35%). Among the 153 municipalities, 48 were considered critical areas, 85 were endemic and 20 silent. Using spatial and statistical analysis, the variable presenting the most evident pattern of association with critical areas defined by top quintile of incidence rate is the percentage of municipal surface occupied by the soil combination of cambisol (over pyroclastic and lava bedrock) and andosol (over a volcanic ashes foundation). Precipitation and percentage of rural population are also associated with critical areas. This methodology and findings could be used for Nicaragua's Leptospirosis Intersectoral Plan, and to identify possible risk areas in other countries with similar drivers.

Leptospirosis outbreak following severe flooding: a rapid assessment and mass prophylaxis campaign; Guyana, January-February 2005

BACKGROUND

Leptospirosis is a zoonosis usually transmitted through contact with water or soil contaminated with urine from infected animals. Severe flooding can put individuals at greater risk for contracting leptospirosis in endemic areas. Rapid testing for the disease and large-scale interventions are necessary to identify and control infection. We describe a leptospirosis outbreak following severe flooding and a mass chemoprophylaxis campaign in Guyana.

METHODOLOGY/PRINCIPAL FINDINGS

From January-March 2005, we collected data on suspected leptospirosis hospitalizations and deaths. Laboratory testing included anti-leptospiral dot enzyme immunoassay (DST), immunohistochemistry (IHC) staining, and microscopic agglutination testing (MAT). DST testing was conducted for 105 (44%) of 236 patients; 52 (50%) tested positive. Four (57%) paired serum samples tested by MAT were confirmed leptospirosis. Of 34 total deaths attributed to leptospirosis, postmortem samples from 10 (83%) of 12 patients were positive by IHC. Of 201 patients interviewed, 89% reported direct contact with flood waters. A 3-week doxycycline chemoprophylaxis campaign reached over 280,000 people.

CONCLUSIONS

A confirmed leptospirosis outbreak in Guyana occurred after severe flooding, resulting in a massive chemoprophylaxis campaign to try to limit morbidity and mortality.

Neighborhood-level socioeconomic and urban land use risk factors of canine leptospirosis: 94 cases (2002-2009)

Associations of housing, population, and agriculture census variables, and presence near public places were retrospectively evaluated as potential risk factors for canine leptospirosis using Geographic Information Systems (GIS). The sample population included 94 dogs positive for leptospirosis based on a positive polymerase chain reaction test for leptospires on urine, isolation of leptospires on urine culture, a single reciprocal serum titer of 12,800 or greater, or a four-fold rise in reciprocal serum titers over a 2-4 week period; and 185 dogs negative for leptospirosis based on a negative polymerase chain reaction test and reciprocal serum titers less than 400. Multivariable logistic regressions revealed different risk factors among different census units; however, houses lacking complete plumbing facilities [OR=2.80, 95% C.I.=1.82, 4.32 (census unit, block group); OR=1.36, 95% C.I.=1.28, 1.45 (census tract); OR=3.02, 95% C.I.=2.60, 3.52 (county)]; and poverty status by age (18-64) [OR=2.04, 95% C.I.=1.74, 2.39 (block group); OR=1.53, 95% C.I.=1.41, 1.67 (census tract); and OR=1.62, 95% C.I.=1.50, 1.76 (county)] were consistent risk factors for all census units. Living within 2500 m of a university/college and parks/forests were also significantly associated with leptospirosis status in dogs. Dogs that live under these circumstances are at higher risk for leptospirosis and pet owners should consider vaccination.

Antibiotics for leptospirosis

BACKGROUND

Leptospirosis has a wide-ranging clinical and public health impact. Leptospira are globally distributed. Case attack rates are as high as 1:4 to 2:5 persons in exposed populations. In some settings mortality has exceeded 10% of infected people. The benefit of antibiotic therapy in the disease has been unclear.

OBJECTIVES

We sought to characterise the risks and benefits associated with use of antibiotic therapy in the management of leptospirosis.

SEARCH METHODS

We searched the The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded regardless of study language. This was augmented by a manual search. The last date of search was November, 2011.

SELECTION CRITERIA

To be included in assessment of benefits, trials had to specifically assess the use of antibiotics in a randomised clinical trial. A broad range of study types were incorporated to seek potential harms.

DATA COLLECTION AND ANALYSIS

Included trials were systematically abstracted, as were excluded studies for the purposes of assessing harms. Analyses were conducted in accordance with The Cochrane Handbook and practices of The Cochrane Hepato-Biliary Group.

MAIN RESULTS

Seven randomised trials were included.  Four trials with 403 patients compared an antibiotic with placebo or no intervention. Three trials compared at least one antibiotic regimen with another antibiotic regimen. The trials all had high risk of bias. The trials varied in the severity of leptospirosis among trial patients. The ability to group data for meta-analysis was limited. While all four trials that compared antibiotics with placebo reported mortality and used parenteral penicillin, there were no deaths in two of them. Since odds ratio calculations cannot employ zero-event trials, only two trials contributed to this estimate. The number of deaths were 16/200 (8.0%) in the antibiotic arm versus 11/203 (5.4%) in the placebo arm giving a fixed-effect OR 1.56 (95% CI 0.70 to 3.46). The random-effects OR is 1.16 (95% CI 0.23 to 5.95). The heterogeneity among these four trials for the mortality outcome was moderate (I(2)= 50%). Only one trial (253 patients) reported days of hospitalisation. It compared parenteral penicillin to placebo without significant effect of therapy (8.9 versus 8.8 days; mean difference (MD) 0.10 days, 95% CI -0.83 to 1.03). The difference in days of clinical illness was reported in two of these trials (71 patients). While parenteral penicillin therapy conferred 4.7 to 5.6 days of clinical illness in contrast to 7.7 to 11.6 days in the placebo arm, the size of the estimate of effect increased but statistical significance was lost under the random-effect model (fixed-effect: MD -2.13 days, 95% CI -2.46 to -1.80; random-effects: MD -4.04, 95% CI -8.66 to 0.58). I(2) for this outcome was high (81%). When duration of fever alone was assessed between antibiotics and placebo in a single trial (79 patients), no significant difference existed (6.9 versus 6.6 days; MD 0.30, 95% CI -1.26 to 1.86). Two trials with 332 patients in relatively severe and possibly late leptospirosis, resulted in trends towards increased dialysis when penicillin was used rather than placebo, but the estimate of effect was small and did not reach statistical significance (42/163 (25.8%) versus 31/169 (18.4%); OR 1.54, 95% CI 0.91 to 2.60). When one antibiotic was assessed against another antibiotic, there were no statistically significant results. For mortality in particular, these comparisons included cephalosporin versus penicillin (2 trials, 6/176 (3.4%) versus 9/175 (5.2%); fixed-effect: OR 0.65, 95% CI 0.23 to 1.87, I(2)= 16%), doxycycline versus penicillin (1 trial, 2/81 (2.5%) versus 4/89 (4.5); OR 0.54, 95% CI 0.10 to 3.02), cephalosporin versus doxycycline (1 trial, 1/88 (1.1%) versus 2/81 (2.5%); OR 0.45, 95% CI 0.04 to 5.10). There were no adverse events of therapy which reached statistical significance.

AUTHORS' CONCLUSIONS

Insufficient evidence is available to advocate for or against the use of antibiotics in the therapy for leptospirosis. Among survivors who were hospitalised for leptospirosis, use of antibiotics for leptospirosis may have decreased the duration of clinical illness by two to four days, though this result was not statistically significant. When electing to treat with an antibiotic, selection of penicillin, doxycycline, or cephalosporin does not seem to impact mortality nor duration of fever. The benefit of antibiotic therapy in the treatment of leptospirosis remains unclear, particularly for severe disease. Further clinical research is needed to include broader panels of therapy tested against placebo.

Emergence of new leptospiral serovars in American Samoa - ascertainment or ecological change?

Background

Leptospirosis has recently been discussed as an emerging infectious disease in many contexts, including changes in environmental drivers of disease transmission and the emergence of serovars. In this paper, we report the epidemiology of leptospiral serovars from our study of human leptospirosis in American Samoa in 2010, present evidence of recent serovar emergence, and discuss the potential epidemiological and ecological implications of our findings.

Methods

Serovar epidemiology from our leptospirosis seroprevalence study in 2010 was compared to findings from a study in 2004. The variation in geographic distribution of the three most common serovars was explored by mapping sero-positive participants to their place of residence using geographic information systems. The relationship between serovar distribution and ecological zones was examined using geo-referenced data on vegetation type and population distribution.

Results

Human leptospirosis seroprevalence in American Samoa was 15.5% in 2010, with serological evidence that infection was caused by three predominant serovars (Hebdomadis, LT 751, and LT 1163). These serovars differed from those identified in an earlier study in 2004, and were not previously known to occur in American Samoa. In 2010, serovars also differed in geographic distribution, with variations in seroprevalence between islands and different ecological zones within the main island.

Conclusions

Our findings might indicate artefactual emergence (where serovars were long established but previously undetected), but we believe the evidence is more in favour of true emergence (a result of ecological change). Possibilities include changes in interactions between humans and the environment; introduction of serovars through transport of animals; evolution in distribution and/or abundance of animal reservoirs; and environmental changes that favour transmission of particular serovars.

Future research should explore the impact of ecological change on leptospirosis transmission dynamics and serovar emergence, and investigate how such new knowledge might better target environmental monitoring for disease control at a public health level.

Evaluations of land cover risk factors for canine leptospirosis: 94 cases (2002-2009)

Associations of land cover/land use variables and the presence of dogs in urban vs. rural address locations were evaluated retrospectively as potential risk factors for canine leptospirosis in Kansas and Nebraska using Geographic Information Systems (GIS). The sample included 94 dogs positive for leptospirosis predominantly based on a positive polymerase chain reaction test for leptospires in urine, isolation of leptospires on urine culture, a single reciprocal serum titer of 12,800 or greater, or a four-fold rise in reciprocal serum titers over a 2-4 weeks period; and 185 dogs negative for leptospirosis based on a negative polymerase chain reaction test and reciprocal serum titers less than 400. Land cover features from 2001 National Land Cover Dataset and 2001 Kansas Gap Analysis Program datasets around geocoded addresses of case/control locations were extracted using 2500m buffers, and the presence of dogs' address locations within urban vs. rural areas were estimated in GIS. Multivariate logistic models were used to determine the risk of different land cover variables and address locations to dogs. Medium intensity urban areas (OR=1.805, 95% C.I.=1.396, 2.334), urban areas in general (OR=2.021, 95% C.I.=1.360, 3.003), and having urban address locations (OR=3.732, 95% C.I.=1.935, 7.196 entire study region), were significant risk factors for canine leptospirosis. Dogs regardless of age, sex and breed that live in urban areas are at higher risk of leptospirosis and vaccination should be considered.

Climate change, flooding, urbanisation and leptospirosis: fuelling the fire?

Flooding and heavy rainfall have been associated with numerous outbreaks of leptospirosis around the world. With global climate change, extreme weather events such as cyclones and floods are expected to occur with increasing frequency and greater intensity and may potentially result in an upsurge in the disease incidence as well as the magnitude of leptospirosis outbreaks. In this paper, we examine mechanisms by which climate change can affect various ecological factors that are likely to drive an increase in the overall incidence as well as the frequency of outbreaks of leptospirosis. We will discuss the geographical areas that are most likely to be at risk of an increase in leptospirosis disease burden owing to the coexistence of climate change hazard risk, environmental drivers of leptospirosis outbreaks, local socioeconomic circumstances, and social and demographic trends. To reduce this disease burden, enhanced surveillance and further research is required to understand the environmental drivers of infection, to build capacity in emergency response and to promote community adaptation to a changing climate.