Beatris Mario Martin

Introduction: Previous studies up to early 2000s found that leptospirosis incidence in humans was high across the Caribbean region (CR), yet up-to-date and reliable surveillance data are scarce. Limited research capacity in the region has further contributed to less robust characterisation of transmission drivers, perpetuating a cycle of neglect. To address these gaps and support evidence-based public health responses, this study aims to update incidence estimates in the CR by integrating data from multiple data sources, including peer-reviewed publications, surveillance reports and environmental and sociodemographic datasets. Methodology/Principal findings: We used mixed-effects hierarchical negative binomial models at the country/territory-year level, incorporating covariates (precipitation, temperature, gross domestic product, biodiversity loss, human footprint, population density, populations exposed to crop areas and frequency of extreme weather events) to estimate annual case numbers by country/territory. Temporal patterns in case fatality rate (CFR) were modelled using locally estimated scatterplot smoothing regressions. Between 2001 and 2023, we estimated 38,659 (95%CI 26,006–56,527) cases in the region. Annual incidence (cases/100,000 population) with small- to medium-sized population islands exhibiting the highest estimated incidence (Guadeloupe 23.0 (95%CI 17.2-30.3) and Saint Vincent and the Grenadines 21.3 (95%CI 11.3-36.0)). Estimated CFR increased over the study period, from 8.8% (95%CI 4.1-13.4) in 2001 to 12.2% (2.2-22.2 in 2022). Conclusions/Significance: Leptospirosis remains an important public health concern in the CR, where small island developing states bear a disproportionate burden of the disease. These findings underscore the urgent need for strengthening surveillance systems and laboratory capacity in the region, particularly in small states, to provide accurate data to prioritise public health and environmental health interventions to reduce transmission and improve diagnosis and treatment.

Leptospirosis remains an important yet underreported public health concern in the Caribbean. Urbanisation, biodiversity loss and human encroachment into natural habitats have contributed to shifts in its epidemiological patterns. However, accurate assessment of disease burden is hindered by limited diagnostic capacity, surveillance challenges, and scarce research. We aim to describe geographical and temporal distribution of leptospirosis epidemiology in Caribbean Island Countries and Territories (CRICTs) and identify patterns and gaps in knowledge. We conducted a systematic search across PubMed, Web of Science, Embase, Scopus, and the Latin America and Caribbean Health Sciences Literature databases, between 2000–2022, without language restrictions. Eligible publications were routine surveillance-based studies or cross-sectional seroprevalence surveys. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews (PRISMA-ScR) protocol. Of 110 full-text articles reviewed, 16 met inclusion criteria, documenting leptospirosis in 15 of 27 CRICTs (55.6%). Between 2000–2010, we identified an average of 2.6 studies per year, compared to just 1.2 between 2011–2022. Nine studies (60.0%) reported surveillance data, and six (40.0%) were seroprevalence surveys. Two studies reported hospitalisation rate (12.5%), and five studies, case fatality rate (31.3%). There were more than one publication from Guadeloupe, Jamaica, Puerto Rico, St. Lucia and Trinidad and Tobago. Although most studies acknowledged links between leptospirosis and extreme weather, only three were specifically designed to investigate this association. Our findings highlight critical gaps in leptospirosis burden and research across the Caribbean. The scarcity of recent studies investigating epidemiological differences across rural and urban settings, and the impact of environmental changes, contributes to limited characterisation of evolving transmission patterns across the region. Strengthening regional research capacity and surveillance systems is essential to inform targeted public health strategies and reduce the disease’s burden locally. Leptospirosis continues to affect communities across the Caribbean. Growing cities and population, closer contact between people and wildlife, and more frequent heavy rain and flooding can facilitate Leptospira survival and transmission. Despite its importance, the most recent regional estimates were published over a decade ago and relied on information that largely predates the year 2000. This limits the effectiveness of public health responses and disease control strategies. To address this gap, we conducted a scoping review of studies published between 2000–2022 to provide an updated overview of leptospirosis epidemiology across Caribbean Islands Countries and Territories (CRICTs). We identified 16 studies reporting data from 15 of 27 CRICTs, revealing substantial gaps in surveillance, geographic coverage, and research on environmental drivers. Our findings underscore the need for strengthened regional research capacity and improved surveillance systems to better understand evolving transmission patterns and inform targeted interventions to reduce the burden of leptospirosis in the Caribbean.

Introduction: Previous studies up to early 2000s found that leptospirosis’ incidence in humans was high across the Caribbean region (CR), yet up-to-date and reliable surveillance data are scarce. Limited research capacity in the region has further contributed to less robust characterisation of transmission drivers, perpetuating a cycle of neglect. To address these gaps and support evidence-based public health responses, this study aims to update incidence estimates in the CR by integrating data from multiple data sources, including peer-reviewed publications, surveillance reports and environmental and sociodemographic datasets. Methodology/Principal Findings: We used mixed-effects hierarchical Poisson models at the country/territory-year level, incorporating covariates i.e., precipitation, temperature, gross domestic product, biodiversity loss, human footprint, water flow accumulation index, populations exposed to forested areas and frequency of extreme weather events to estimate annual case numbers by country/territory. Temporal patterns in case fatality rate (CFR) were modelled using locally estimated scatterplot smoothing regressions. Between 2001 and 2023, we estimated 32,311 (95% CI 28,646-36,832) cases in the region. Annual incidence (cases/100,000 population) showed a decrease trend, with small- to medium-sized population islands exhibiting the highest predicted incidence (Guadeloupe 22.7 (95%CI 20.5-25.0) and Saint Vincent and the Grenadines 22.3 (95%CI 17.6-27.9)). Estimated CFR increased over the study period, from 8.8% (95%CI 4.1-13.4) (2001) to 12.2% (.2.2-22.2) (2022). Conclusions/Significance: Leptospirosis remains an important and often overlooked public health concern in the CR, where small island developing states bear a disproportionate burden of the disease. These findings underscore the urgent need for strengthening and integrating the surveillance systems and laboratory capacity in the region, particularly in small states, to provide accurate data to support cost-effective public health interventions. Authors summary: Leptospirosis is a bacterial infection that affects both animals and humans and is common across the Caribbean. Yet, many countries and territories in the region lack reliable and up-to-date information on disease incidence and mortality. This is partly due to limited laboratory capacity, inconsistent case reporting, and competing health priorities. As a result, the true burden of leptospirosis remains unclear, especially for resource-limited small island nations, which are vulnerable to potential impacts of climate change and extreme weather events on leptospirosis transmission. In this study, we combined information from peer-reviewed publications, national surveillance reports, and environmental and sociodemographic datasets to estimate annual incidence and mortality across the Caribbean. Using statistical modelling, we estimated over 32,000 cases between 2001 and 2023, with small- and medium-sized islands showing the highest incidence (cases/100,000 population). We also estimated a slight increase in case-fatality rate over time. Our findings highlight that small island developing states carry a disproportionate burden of this disease. Improving local surveillance systems and strengthening regional level collaboration are essential to help countries better identify risk, prepare for outbreaks, and reduce illness and deaths.

Background: Leptospirosis remains an important yet underreported public health concern in the Caribbean. Urbanisation, biodiversity loss and human encroachment into natural habitats have contributed to shifts in its epidemiological patterns. However, accurate assessment of disease burden is hindered by limited diagnostic capacity, surveillance challenges, and scarce research. We aim to describe geographical and temporal distribution of leptospirosis epidemiology in Caribbean Island Countries and Territories (CRICTs) and identify patterns and gaps in knowledge. Methodology/Principal findings: We conducted a systematic search across PubMed, Web of Science, Embase, Scopus, and the Latin America and Caribbean Health Sciences Literature databases, between 2000-2022, without language restrictions. Eligible publications were routine surveillance-based studies or cross-sectional seroprevalence surveys. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews (PRISMA-ScR) protocol. Of 110 full-text articles reviewed, 16 met inclusion criteria, documenting leptospirosis in 15 of 27 CRICTs (55.6%). Between 2000-2010, we identified an average of 2.6 studies per year, compared to just 1.2 between 2011-2022. Nine studies (60.0%) reported surveillance data, and six (40.0%) were seroprevalence surveys. Two studies reported hospitalisation rate (12.5%), and five studies, case fatality rate (31.3%). There were more than one publication from Guadeloupe, Jamaica, Puerto Rico, St. Lucia and Trinidad and Tobago. Although most studies acknowledged links between leptospirosis and extreme weather, only three were specifically designed to investigate this association. Conclusions/Significance: Our findings highlight critical gaps in leptospirosis burden and research across the Caribbean. The scarcity of recent studies investigating epidemiological differences across rural and urban settings, and the impact of environmental changes, contributes to limited characterisation of evolving transmission patterns across the region. Strengthening regional research capacity and surveillance systems is essential to inform targeted public health strategies and reduce the disease’s burden locally. Author Summary: Leptospirosis continues to affect communities across the Caribbean. Growing cities and population, closer contact between people and wildlife, and more frequent heavy rain and flooding can facilitate Leptospira survival and transmission. Despite its importance, the most recent regional estimates were published over a decade ago and relied on information that largely predates the year 2000. This limits the effectiveness of public health responses and disease control strategies. To address this gap, we conducted a scoping review of studies published between 2000-2022 to provide an updated overview of leptospirosis epidemiology across Caribbean Islands Countries and Territories (CRICTs). We identified 16 studies reporting data from 15 of 27 CRICTs, revealing substantial gaps in surveillance, geographic coverage, and research on environmental drivers. Our findings underscore the need for strengthened regional research capacity and improved surveillance systems to better understand evolving transmission patterns and inform targeted interventions to reduce the burden of leptospirosis in the Caribbean.

Spatial variation in drivers of leptospirosis transmission in the Dominican Republic is poorly understood. To inform targeted public health interventions, we aimed to characterise risk factors and drivers of transmission on a fine spatial scale. We analysed data from 2078 participants in two provinces, Espaillat and San Pedro de Macoris (SPM), collected from a 2021 cross-sectional survey. We used geographically weighted regression to quantify associations between leptospirosis seropositivity and spatial environmental and sociodemographic data. In Espaillat, higher odds of seropositivity were associated with exposure to freshwater (OR 6.51, ranging between 5.95 and 6.99), bare ground coverage above 1.44% (OR 3.70;3.49–3.92), river density surrounding the household at the highest quartile (OR 2.43;2.41–2.45) and average precipitation in the last five years at the highest quartile (2.57; 2.52–2.65). In SPM, rat exposure was associated with higher odds of seropositivity (OR 2.59;1.23–3.14). By identifying locally important drivers of transmission, our study provides evidence to support more tailored public health interventions to optimise the control and prevention of leptospirosis.

Background: Drivers of leptospirosis transmission can vary across regions, leading to spatial clustering of infections. This study aims to identify clusters of leptospirosis seroprevalence in the Dominican Republic (DR) and factors associated with high-risk areas. Methodology/Principal Findings: We analysed data from two provinces, Espaillat and San Pedro de Macoris (SPM), obtained on a national survey conducted in 2021 (n = 2,078). Samples were tested by microscopic agglutination testing (MAT) to detect leptospirosis antibodies. We used flexible spatial scan statistics to locate significant clusters for seropositive individuals (all serogroups combined) in each province and calculated risk ratios (RR) at the household and community level. Environmental and sociodemographic risk factors associated with clusters were assessed by logistic regression. One cluster was identified in each province. Participants living inside a cluster were more likely to live further from health facilities (OR 1.86, p < 0.001 and OR 4.41, p = 0.044 by motorized travel time in Espaillat and SPM, respectively). Cluster participants were also less likely to live in areas of higher population density (OR 0.76, p < 0.01 and OR 0.29, p < 0.001 in Espaillat and SPM, respectively) and in communities with higher gross domestic product (GDP) (OR 0.70, p < 0.001 and OR 0.42, p < 0.001 in Espaillat and SPM, respectively). Additional risk factors varied between Espaillat and SPM. Conclusion/Significance: Our findings confirm the clustered spatial pattern of leptospirosis and highlight that transmission drivers vary by province. While both provinces show higher transmission in impoverished areas, modifiable factors differ, requiring tailored public health interventions.

We conducted a systematic review of infectious disease (ID) prevalence studies in the Samoan Islands from 2000 to 2024 and aimed to synthesise the prevalence of IDs, the purpose of the studies, and the potential utility of survey results for informing public health decision-making. We searched five academic databases, the Western Pacific Region Index Medicus, and grey literature up until April 2024. English language publications of ID surveys in American Samoa and Samoa were included. Each study’s aim, design, and prevalence results were extracted and categorised by disease and data sources. We identified 46 publications reporting the prevalence of 15 different IDs; 42 publications (91%) reported data from 31 original surveys, of which three (9%) investigated the prevalence of multiple IDs. Twenty-eight (62%) publications primarily aimed to report prevalence to inform public health interventions. Samples from one survey, initially conducted for leptospirosis, were subsequently tested to confirm transmission, describe prevalence, and investigate risk factors for seven other diseases. We emphasise the valuable contribution of prevalence studies in supporting evidence-based public health interventions. The extensive prevalence studies in the Samoan Islands illustrate the need for adopting integrated multipathogen approaches to surveillance to reduce costs, document burden, and generate actionable insights to support evidence-based decisions to prevent, control, and eliminate infectious diseases.