Leptospirosis in the western Indian Ocean islands: what is known so far?

Clinical manifestations of human leptospirosis: bacteria matter

Introduction

A high incidence of human leptospirosis is recorded on Mayotte, an oceanic island located in southwestern Indian Ocean, but the severity of the disease appears relatively mild in terms of mortality rate and admission to the intensive care unit. It has been proposed that mild leptospirosis may result from a limited virulence of some of the occurring Leptospira species to which the population is exposed.

Methods

Clinical and biological data of patients admitted to the Centre Hospitalier de Mayotte were collected and the infecting Leptospira species were determined through molecular typing.

Results

Leptospira interrogans was detected in the minority of admitted patients but most of these patients suffered from severe forms, with 50% admitted to intensive care unit and suffering from organ failures. Nineteen percent of patients infected with Leptospira borgpetersenii were admitted to the intensive care, with 13% displaying organ failures, and one patient died. Leptospira mayottensis was found in 28% of the patients and not a single severe case was observed.

Discussion

The distribution of Leptospira species in patients was not different from that reported 10-15 years ago and bacterial genotypes were very closely related to those previously reported. These results highlight the importance of the diversity of pathogenic Leptospira circulating on Mayotte island and are in keeping with distinct outcome of the disease depending on the infecting Leptospira. Altogether, presented data support that the infecting Leptospira species is an important driver of disease severity in humans.

Range Dynamics of Striped Field Mouse (Apodemus agrarius) in Northern Eurasia under Global Climate Change Based on Ensemble Species Distribution Models

The striped field mouse (Apodemus agrarius Pallas, 1771) is a widespread species in Northern Eurasia. It damages crops and carries zoonotic pathogens. Its current and future range expansion under climate change may negatively affect public health and the economy, warranting further research to understand the ecological and invasive characteristics of the species. In our study, we used seven algorithms (GLM, GAM, GBS, FDA, RF, ANN, and MaxEnt) to develop robust ensemble species distribution models (eSDMs) under current (1970-2000) and future climate conditions derived from global circulation models (GCMs) for 2021-2040, 2041-2060, 2061-2080, and 2081-2100. Simulation of climate change included high-, medium-, and low-sensitivity GCMs under four scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). We analyzed the habitat suitability across GCMs and scenarios by constructing geographical ranges and calculating their centroids. The results showed that the range changes depended on both the sensitivity of GCMs and scenario. The main trends were range expansion to the northeast and partial loss of habitat in the steppe area. The striped field mouse may form a continuous range from Central Europe to East Asia, closing the range gap that has existed for 12 thousand years. We present 49 eSDMs for the current and future distribution of A. agrarius (for 2000-2100) with quantitative metrics (gain, loss, change) of the range dynamics under global climate change. The most important predictor variables determining eSDMs are mean annual temperature, mean diurnal range of temperatures, the highest temperature of the warmest month, annual precipitation, and precipitation in the coldest month. These findings could help limit the population of the striped field mouse and predict distribution of the species under global climate change.

Seroepidemiological investigation of animal leptospirosis and molecular characterization of the first Leptospira strain isolated from Fernando de Noronha archipelago, Brazil

Leptospirosis has been widely reported in insular environments worldwide, characterizing a major public health threat. Although low-genetic biodiversity is expected in these regions, the introduction of domestic and synanthropic mammals may contribute to the wider diversity of leptospiral strains in insular settings. This study proposes a large-scale seroepidemiological investigation of Leptospira infection in animals from Fernando de Noronha archipelago and describes the characterization of the first leptospiral strain ever isolated from an insular setting in Brazil. A total of 1,265 blood samples from domestic (n = 682), synanthropic (n = 133) and wild (n = 450) animals were collected between 2007 and 2014, totalling 12 species. The presence of anti-Leptospira spp. antibodies was investigated by the microscopic agglutination test (MAT), and kidney samples from 20 synanthropic rodents were collected for the isolation of Leptospira spp. The leptospires recovered were further characterized by serogrouping with polyclonal antibodies, whole-genome sequencing and multilocus sequence typing (MLST). The MAT results revealed the presence of agglutinins in 90 samples (7.1%) and the most frequently found serogroup was Icterohaemorrhagiae (n = 57) in practically all species included. Viable leptospires were recovered from one brown rat, and characterization revealed that the isolate belongs to L. interrogans serogroup Pyrogenes. The results suggest that synanthropic rodents might play an important role in leptospiral infection among wildlife and domestic species in the archipelago.

Seroprevalence of Leptospira spp. Infection in Cattle from Central and Northern Madagascar

Leptospirosis is a zoonotic disease of global importance, especially in tropical countries. The current Leptospira spp. seroprevalence in cattle from central and northern Madagascar is unknown. Thus, the aim of this study was to determine the seroprevalence resulting from infections with pathogenic Leptospira spp. in zebu cattle from these areas. Serum samples from 194 animals were tested by microscopic agglutination test (MAT) using a panel of 12 serovars as antigens. Samples with a titer of ≥1:100 were considered positive. The overall seroprevalence was 59.3% (95% CI; 52.0–66.2%) with titers ranging from 1:100 to 1:1600. Among the seropositive animals, the most frequent antibody reactions were against serovar L. Tarassovi (serogroup L. Tarassovi) with 40.2% (33.3–47.5%), followed by L. Hardjo (L. Sejroe) with 13.9% (9.5–19.8%), L. Grippotyphosa (L. Grippotyphosa) with 9.8% (6.2–15.1%), L. Pomona (L. Pomona) with 7.7% (4.5–12.7%) and L. Autumnalis (L. Autumnalis) with 5.2% (2.6–9.5%). Less than 5% of the samples reacted positively against the remaining serovars. These results indicate a very high exposure of Malagasy cattle to Leptospira spp. which, consequently, poses a definite risk for people working with cattle acquiring this zoonotic infection.

The prevalence of Leptospira among invasive small mammals on Puerto Rican cattle farms

Leptospirosis, an emerging infectious disease caused by bacteria of the genus Leptospira, is thought to be the most widespread zoonotic disease in the world. A first step in preventing the spread of Leptospira is delineating the animal reservoirs that maintain and disperse the bacteria. Quantitative PCR (qPCR) methods targeting the LipL32 gene were used to analyze kidney samples from 124 House mice (Mus musculus), 94 Black rats (Rattus rattus), 5 Norway rats (R. norvegicus), and 89 small Indian mongooses (Herpestes auropunctatus) from five cattle farms in Puerto Rico. Renal carriage of Leptospira was found in 38% of the sampled individuals, with 59% of the sampled mice, 34% of Black rats, 20% of Norway rats, and 13% of the mongooses. A heterogeneous distribution of prevalence was also found among sites, with the highest prevalence of Leptospira-positive samples at 52% and the lowest at 30%. Comparative sequence analysis of the LipL32 gene from positive samples revealed the presence of two species of Leptospira, L. borgpetersenii and L. interrogans in mice, detected in similar percentages in samples from four farms, while samples from the fifth farm almost exclusively harbored L. interrogans. In rats, both Leptospira species were found, while mongooses only harbored L. interrogans. Numbers tested for both animals, however, were too small (n = 7 each) to relate prevalence of Leptospira species to location. Significant associations of Leptospira prevalence with anthropogenic landscape features were observed at farms in Naguabo and Sabana Grande, where infected individuals were closer to human dwellings, milking barns, and ponds than were uninfected individuals. These results show that rural areas of Puerto Rico are in need of management and longitudinal surveillance of Leptospira in order to prevent continued infection of focal susceptible species (i.e. humans and cattle).

Study on causes of fever in primary healthcare center uncovers pathogens of public health concern in Madagascar

BACKGROUND

The increasing use of malaria diagnostic tests reveals a growing proportion of patients with fever but no malaria. Clinicians and health care workers in low-income countries have few tests to diagnose causes of fever other than malaria although several diseases share common symptoms. We propose here to assess etiologies of fever in Madagascar to ultimately improve management of febrile cases.

METHODOLOGY

Consenting febrile outpatients aged 6 months and older were recruited in 21 selected sentinel sites throughout Madagascar from April 2014 to September 2015. Standard clinical examinations were performed, and blood and upper respiratory specimens were taken for rapid diagnostic tests and molecular assays for 36 pathogens of interest for Madagascar in terms of public health, regardless of clinical status.

PRINCIPAL FINDINGS

A total of 682 febrile patients were enrolled. We detected at least one pathogen in 40.5% (276/682) of patients and 6.2% (42/682) with co-infections. Among all tested patients, 26.5% (181/682) had at least one viral infection, 17.0% (116/682) had malaria and 1.0% (7/682) presented a bacterial or a mycobacterial infection. None or very few of the highly prevalent infectious agents in Eastern Africa and Asia were detected in this study, such as zoonotic bacteria or arboviral infections.

CONCLUSIONS

These results raise questions about etiologies of fever in Malagasy communities. Nevertheless, we noted that viral infections and malaria still represent a significant proportion of causes of febrile illnesses. Interestingly our study allowed the detection of pathogens of public health interest such as Rift Valley Fever Virus but also the first case of laboratory-confirmed leptospirosis infection in Madagascar.

Biogeography of Leptospira in wild animal communities inhabiting the insular ecosystem of the western Indian Ocean islands and neighboring Africa

Understanding the processes driving parasite assemblages is particularly important in the context of zoonotic infectious diseases. Leptospirosis is a widespread zoonotic bacterial infection caused by pathogenic species of the genus Leptospira. Despite a wide range of animal hosts, information is still lacking on the factors shaping Leptospira diversity in wild animal communities, especially in regions, such as tropical insular ecosystems, with high host species richness and complex biogeographical patterns. Using a large dataset (34 mammal species) and a multilocus approach at a regional scale, we analyzed the role of both host species diversity and geography in Leptospira genetic diversity in terrestrial small mammals (rodents, tenrecs, and shrews) and bats from 10 different islands/countries in the western Indian Ocean (WIO) and neighboring Africa. At least four Leptospira spp. (L. interrogans, L. borgpetersenii, L. kirschneri, and L. mayottensis) and several yet-unidentified genetic clades contributed to a remarkable regional Leptospira diversity, which was generally related to the local occurrence of the host species rather than the geography. In addition, the genetic structure patterns varied between Leptospira spp., suggesting different evolutionary histories in the region, which might reflect both in situ diversification of native mammals (for L. borgpetersenii) and the more recent introduction of non-native host species (for L. interrogans). Our data also suggested that host shifts occurred between bats and rodents, but further investigations are needed to determine how host ecology may influence these events.

Presence of Borrelia spp. DNA in ticks, but absence of Borrelia spp. and of Leptospira spp. DNA in blood of fever patients in Madagascar

The occurrence of tick-borne relapsing fever and leptospirosis in humans in Madagascar remains unclear despite the presence of their potential vectors and reservoir hosts. We screened 255 Amblyomma variegatum ticks and 148 Rhipicephalus microplus ticks from Zebu cattle in Madagascar for Borrelia-specific DNA. Borrelia spp. DNA was detected in 21 Amblyomma variegatum ticks and 2 Rhipicephalus microplus ticks. One Borrelia found in one Rhipicephalus microplus showed close relationship to Borrelia theileri based on genetic distance and phylogenetic analyses on 16S rRNA and flaB sequences. The borreliae from Amblyomma variegatum could not be identified due to very low quantities of present DNA reflected by high cycle threshold values in real-time-PCR. It is uncertain whether these low numbers of Borrelia spp. are sufficient for transmission of infection from ticks to humans. In order to determine whether spirochaete infections are relevant in humans, blood samples of 1009 patients from the highlands of Madagascar with fever of unknown origin were screened for Borrelia spp. - and in addition for Leptospira spp. - by real-time PCR. No target DNA was detected, indicating a limited relevance of these pathogens for humans in the highlands of Madagascar.

Human leptospirosis in Seychelles: A prospective study confirms the heavy burden of the disease but suggests that rats are not the main reservoir

Background

Leptospirosis is a bacterial zoonosis caused by pathogenic Leptospira for which rats are considered as the main reservoir. Disease incidence is higher in tropical countries, especially in insular ecosystems. Our objectives were to determine the current burden of leptospirosis in Seychelles, a country ranking first worldwide according to historical data, to establish epidemiological links between animal reservoirs and human disease, and to identify drivers of transmission.

Methods

A total of 223 patients with acute febrile symptoms of unknown origin were enrolled in a 12-months prospective study and tested for leptospirosis through real-time PCR, IgM ELISA and MAT. In addition, 739 rats trapped throughout the main island were investigated for Leptospira renal carriage. All molecularly confirmed positive samples were further genotyped.

Results

A total of 51 patients fulfilled the biological criteria of acute leptospirosis, corresponding to an annual incidence of 54.6 (95% CI 40.7–71.8) per 100,000 inhabitants. Leptospira carriage in Rattus spp. was overall low (7.7%) but dramatically higher in Rattus norvegicus (52.9%) than in Rattus rattus (4.4%). Leptospira interrogans was the only detected species in both humans and rats, and was represented by three distinct Sequence Types (STs). Two were novel STs identified in two thirds of acute human cases while noteworthily absent from rats.

Conclusions

This study shows that human leptospirosis still represents a heavy disease burden in Seychelles. Genotype data suggests that rats are actually not the main reservoir for human disease. We highlight a rather limited efficacy of preventive measures so far implemented in Seychelles. This could result from ineffective control measures of excreting animal populations, possibly due to a misidentification of the main contaminating reservoir(s). Altogether, presented data stimulate the exploration of alternative reservoir animal hosts.

Leptospirosis is an emerging environmental infectious disease caused by corkscrew shaped bacteria called Leptospira. Humans usually get infected during recreational or work-related outdoor activities through contact with urine excreted by animal reservoirs. As a zoonotic disease, leptospirosis is a good example of the One Health concept for it links humans, animals and ecosystems in a web of pathogen maintenance and transmission. This zoonosis is highly prevalent in the tropics and especially in tropical islands. Seychelles archipelago has been reported as the country with highest human incidence worldwide, although figures are based on dated studies and/or poorly specific tests. The presented investigation aimed at providing an updated information on human leptospirosis burden in Seychelles and exploring the transmission chains in their environmental aspects. Presented data confirms that the disease still heavily impacts the country. Genotyping of pathogenic Leptospira in human acute cases reveals that three distinct Sequence Types (STs) are involved in the disease. However, rats typically considered as the main reservoir in Seychelles, harbor only one of these STs, found only in a minority of human cases. Hence, it appears that rats are likely not the main reservoir of leptospirosis in Seychelles, which has important consequences in terms of preventive measures to be implemented for a better control of human leptospirosis.

[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.

Simultaneous detection of chikungunya virus, dengue virus and human pathogenic Leptospira genomes using a multiplex TaqMan® assay

Background

In 2005–2006 a major epidemics of Chikungunya disease occurred in South-West Indian Ocean islands. In Reunion Island, the magnitude of Chikungunya infection related symptoms was high and with over 38% of serological prevalence in the population. This epidemics illustrated the potential threat of emerging arboviral diseases for inhabitants of Reunion Island and elsewhere since vectors are worldwide distributed. A sentinel surveillance network was set-up to detect emerging pathogens associated with fever over 38 °C and in the absence of known etiologic causes. Leptospirosis is caused by a pathogenic spirochete of the Leptospira genus and is an endemic and recurrent seasonal disease of great concern in Reunion Island. To accurately diagnose potentially infected patients and to advise Health authorities on the presence of emerging pathogens, a rapid diagnostic test was needed that could differentiate between these 3 pathogens.

Methods

A one-step multiplex real-time PCR assay was developed that can simultaneously detect RNA of Chikungunya and Dengue viruses and leptospiral DNA with good performance for a routine diagnostic use.

Results

Simplex protocols already published were used with key modifications to implement a triplex assay which was set-up with a small reaction volume to improve cost efficiency.

Conclusions

This approach has enabled greater diagnostic capacity in our laboratory. We established a multiplex approach validated and valuable for cost savings, and with the concurrent detection of 3 pathogens of public health concern.

Four years into the Indian ocean field epidemiology training programme

INTRODUCTION

Following the 2005-6 chikungunya outbreak, a project to strengthen regional Public Health preparedness in the Indian Ocean was implemented. It includes the Comoros, Madagascar, Mauritius, Reunion (France) and Seychelles. A Field Epidemiology Training Programme (FETP-OI) was started in 2011 to develop a pool of well-trained intervention epidemiologists.

METHODS

The FETP-OI consists of two years of supervised, learning-by-doing, on-the-job training at national sites involved in disease surveillance and response. It includes work placements at the Madagascar Pasteur Institute and the French regional epidemiology unit in Reunion and up to three training courses per year. Training objectives include epidemiological surveillance, outbreak investigations, research studies, scientific communication and transfer of competencies.

RESULTS

In four years, two cohorts of in total 15 fellows originating from four countries followed the FETP-OI. They led 42 surveillance projects (71% routine management, 14% evaluations, 12% setup, 3% other) and investigated 36 outbreak alerts, 58% of them in Madagascar; most investigations (72%) concerned foodborne pathogens, plague or malaria. Fellows performed 18 studies (44% descriptive analyses, 22% disease risk factors, and 34% on other subjects), and presented results during regional and international conferences through 26 oral and 15 poster presentations. Four articles were published in regional Public Health bulletins and several scientific manuscripts are in process.

CONCLUSION

The FETP-OI has created a regional force of intervention consisting of field epidemiologists and trained supervisors using the same technical language and epidemiological methods. The third cohort is now ongoing. Technically and financially sustainable FETP-OI projects help addressing public health priorities of the Indian Ocean.

Human Leptospirosis on Reunion Island, Indian Ocean: Are Rodents the (Only) Ones to Blame?

BACKGROUND

Although leptospirosis is a zoonosis of major concern on tropical islands, the molecular epidemiology of the disease aiming at linking human cases to specific animal reservoirs has been rarely explored within these peculiar ecosystems.

METHODOLOGY/PRINCIPAL FINDINGS

Five species of wild small mammals (n = 995) as well as domestic animals (n = 101) were screened for Leptospira infection on Reunion Island; positive samples were subsequently genotyped and compared to Leptospira from clinical cases diagnosed in 2012-2013 (n = 66), using MLST analysis. We identified two pathogenic species in human cases, namely Leptospira interrogans and Leptospira borgpetersenii. Leptospira interrogans was by far dominant both in clinical samples (96.6%) and in infected animal samples (95.8%), with Rattus spp and dogs being its exclusive carriers. The genetic diversity within L. interrogans was apparently limited to two sequence types (STs): ST02, identified among most clinical samples and in all rats with complete MLST, and ST34, identified in six humans, but not in rats. Noteworthy, L. interrogans detected in two stray dogs partially matched with ST02 and ST34. Leptospira borgpetersenii was identified in two clinical samples only (3.4%), as well as in cows and mice; four haplotypes were identified, of which two seemingly identical in clinical and animal samples. Leptospira borgpetersenii haplotypes detected in human cases were clearly distinct from the lineage detected so far in the endemic bat species Mormopterus francoismoutoui, thus excluding a role for this volant mammal in the local human epidemiology of the disease.

CONCLUSIONS/SIGNIFICANCE

Our data confirm rats as a major reservoir of Leptospira on Reunion Island, but also pinpoint a possible role of dogs, cows and mice in the local epidemiology of human leptospirosis. This study shows that a comprehensive molecular characterization of pathogenic Leptospira in both clinical and animal samples helps to gaining insight into leptospirosis epidemiology within a specific environmental setting.

An Unprecedented High Incidence of Leptospirosis in Futuna, South Pacific, 2004 - 2014, Evidenced by Retrospective Analysis of Surveillance Data

Futuna is a small Polynesian island in the South Pacific with a population of 3,612 in 2013. The first human leptospirosis case was confirmed in 1997. Active surveillance started in 2004. Cases were confirmed by PCR or real time PCR, or by serology using MAT or a combination of IgM-ELISA and MAT. A retrospective analysis of surveillance data shows that the disease was endemic with a mean annual incidence of 844 cases per 100,000 over an 11-year period from 2004 to 2014. An epidemic peak as high as 1,945 cases per 100,000 occurred in 2008. Serogroup Australis was predominant until 2007, Icterohaemorrhagiae was dominant afterwards. Cluster analysis revealed different hot spots over time. Lifestyle habits, such as walking barefoot in irrigated taro fields or pig pens probably contributed to contamination from the swine and rodent reservoirs to humans. Severe forms were rare, and the case fatality rate was 0.5%. The medical community and general population were aware of leptospirosis and rapid treatment with amoxycillin was the main treatment, probably contributing to this low fatality rate.

Epidemiology of Leptospirosis in Africa: A Systematic Review of a Neglected Zoonosis and a Paradigm for 'One Health' in Africa

BACKGROUND

Leptospirosis is an important but neglected bacterial zoonosis that has been largely overlooked in Africa. In this systematic review, we aimed to summarise and compare current knowledge of: (1) the geographic distribution, prevalence, incidence and diversity of acute human leptospirosis in Africa; and (2) the geographic distribution, host range, prevalence and diversity of Leptospira spp. infection in animal hosts in Africa.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we searched for studies that described (1) acute human leptospirosis and (2) pathogenic Leptospira spp. infection in animals. We performed a literature search using eight international and regional databases for English and non-English articles published between January 1930 to October 2014 that met out pre-defined inclusion criteria and strict case definitions.

RESULTS AND DISCUSSION

We identified 97 studies that described acute human leptospirosis (n = 46) or animal Leptospira infection (n = 51) in 26 African countries. The prevalence of acute human leptospirosis ranged from 2 3% to 19 8% (n = 11) in hospital patients with febrile illness. Incidence estimates were largely restricted to the Indian Ocean islands (3 to 101 cases per 100,000 per year (n = 6)). Data from Tanzania indicate that human disease incidence is also high in mainland Africa (75 to 102 cases per 100,000 per year). Three major species (Leptospira borgpetersenii, L. interrogans and L. kirschneri) are predominant in reports from Africa and isolates from a diverse range of serogroups have been reported in human and animal infections. Cattle appear to be important hosts of a large number of Leptospira serogroups in Africa, but few data are available to allow comparison of Leptospira infection in linked human and animal populations. We advocate a 'One Health' approach to promote multidisciplinary research efforts to improve understanding of the animal to human transmission of leptospirosis on the African continent.

Use of a New High Resolution Melting Method for Genotyping Pathogenic Leptospira spp

BACKGROUND

Leptospirosis is a worldwide zoonosis that is endemic in tropical areas, such as Reunion Island. The species Leptospira interrogans is the primary agent in human infections, but other pathogenic species, such as L. kirschner and L. borgpetersenii, are also associated with human leptospirosis.

METHODS AND FINDINGS

In this study, a melting curve analysis of the products that were amplified with the primer pairs lfb1 F/R and G1/G2 facilitated an accurate species classification of Leptospira reference strains. Next, we combined an unsupervised high resolution melting (HRM) method with a new statistical approach using primers to amplify a two variable-number tandem-repeat (VNTR) for typing at the subspecies level. The HRM analysis, which was performed with ScreenClust Software, enabled the identification of genotypes at the serovar level with high resolution power (Hunter-Gaston index 0.984). This method was also applied to Leptospira DNA from blood samples that were obtained from Reunion Island after 1998. We were able to identify a unique genotype that is identical to that of the L. interrogans serovars Copenhageni and Icterohaemorrhagiae, suggesting that this genotype is the major cause of leptospirosis on Reunion Island.

CONCLUSIONS

Our simple, rapid, and robust genotyping method enables the identification of Leptospira strains at the species and subspecies levels and supports the direct genotyping of Leptospira in biological samples without requiring cultures.

Has Madagascar lost its exceptional leptospirosis free-like status?

BACKGROUND

Leptospirosis is a widespread but underreported cause of morbidity and mortality. It has rarely been reported in either humans or animals in Madagascar.

METHODS

We conducted a cross-sectional survey of the inhabitants in Moramanga, Madagascar, in June 2011, to estimate the prevalence of human infection using the microscopic agglutination test (MAT). This activity was carried out as part of a workshop implemented by the Pasteur Institute of Madagascar, focusing on surveillance with a one week field study and targeting the health staff of the district level.

RESULTS

In total, we sampled 678 inhabitants from 263 households. The sex ratio (M/F) was 0.65 and the mean age 26.7 years. We obtained a value of 2.9% for the first recorded seroprevalence of this disease in the human community of Moramanga. Questionnaire responses revealed frequent contacts between humans and rodents in Moramanga. However, activities involving cattle were identified as a risk factor significantly associated with seropositivity (OR=3).

CONCLUSION

Leptospirosis remains a neglected disease in Madagascar. This study highlights the need to quantify the public health impact of this neglected disease in a more large scale, in all the country and to establish point-of-care laboratories in remote areas.

Leptospirosis after a stay in Madagascar

We report a case of polymerase chain reaction (PCR)-confirmed leptospirosis in a patient who recently traveled to Madagascar, a country where only two cases have been reported since 1955. Although laboratory and clinical presentations were atypical and despite leptospirosis not being a documented disease in Madagascar, blood and urine tests for leptospirosis enabled retrospective confirmation of the diagnosis.

Diseases of livestock in the Pacific Islands region: setting priorities for food animal biosecurity

Most Pacific Island countries and territories (PICTs) have developing economies and face a critical shortage of veterinarians with limited financial resources allocated to their animal disease surveillance programmes. Thus, animal health authorities have to set priorities for better focusing their scarce resources. The main objective of this study was to identify animal diseases perceived to be of importance by decision makers within selected PICTs, at the regional and national levels, to ensure better targeting of animal health resources. A second objective was to investigate whether the targeted surveillance programmes resulting from this rationalized approach would also benefit the local communities engaged in livestock production. A multi-criteria prioritization process was developed, involving local experts, to score and rank 132 animal diseases based on their priority at the regional and national levels for four PICTs: Fiji, Papua New Guinea, Solomon Islands, and Vanuatu, which form part of a regional Food Animal Biosecurity Network. In parallel interviews with farmers and field animal health and production workers were conducted to assess their perception of animal diseases. The list of the top-twenty ranked diseases for the Pacific Islands region shows a mix of endemic zoonotic diseases (such as leptospirosis ranked first; brucellosis third; tuberculosis sixth; and endoparasites and ectoparasites, respectively eleventh and thirteenth) with exotic diseases (such as HPAI ranked second, FMD fifth, and rabies ninth). There were different disease ranking lists for each of the four targeted PICTs, confirming different strategies of disease prevention and control may be required for each country, rather than a regional approach. Interviewed animal health and production workers were unfamiliar with most of the prioritized diseases and a majority acknowledged that they would not be able to recognize clinical signs if outbreaks were to occur in their area. Leptospirosis, which is endemic and identified as the top priority disease at the regional level, was never mentioned by any interviewed farmer. Farmers did not name any emerging infectious diseases as priorities. Instead, they identified endemic diseases (parasites, flu, coccidiosis, and scabies) as the most important. While animal disease priorities appear to differ widely between the targeted regions and countries, it also varies significantly between experts and farmers. Better targeted surveillance programmes may thus result in more rational and transparent allocation of resources, and thus enhanced food security, but may not directly match the needs of the local communities.

Leptospirosis in Sub-Saharan Africa: a systematic review

BACKGROUND

Leptospirosis is an emerging zoonotic infection worldwide, possibly due to climate change and demographic shifts. It is regarded as endemic in Sub-Saharan Africa; however, for most countries scarce epidemiological data, if any, exist. The primary objectives were to describe the prevalence of leptospirosis in countries in Sub-Saharan Africa, and to develop options for prevention and control in the future.

METHODS

A systematic review was conducted to determine the prevalence of leptospirosis in Sub-Saharan Africa; the PRISMA guidelines were followed. Medline/PubMed, Embase, The Cochrane Library, Web of Science, BIOSIS Previews, the African Index Medicus, AJOL, and Google Scholar were searched.

RESULTS

Information about the prevalence and incidence of leptospirosis in humans is available, but remains scarce for many countries. Data are unavailable or outdated for many countries, particularly those in Central Africa. Most data are available from animals, probably due to the economic losses caused by leptospirosis in livestock. In humans, leptospirosis is an important cause of febrile illness in Sub-Saharan Africa. It concerns numerous serogroups, harboured by many different animal carriers.

DISCUSSION

A wide variety of data was identified. Prevalence rates vary throughout the continent and more research, especially in humans, is needed to reliably gauge the extent of the problem. Preventive measures need to be reconsidered to control outbreaks in the future.

Diversification of an emerging pathogen in a biodiversity hotspot: Leptospira in endemic small mammals of Madagascar

Biodiversity hotspots and associated endemism are ideal systems for the study of parasite diversity within host communities. Here, we investigated the ecological and evolutionary forces acting on the diversification of an emerging bacterial pathogen, Leptospira spp., in communities of endemic Malagasy small mammals. We determined the infection rate with pathogenic Leptospira in 20 species of sympatric rodents (subfamily Nesomyinae) and tenrecids (family Tenrecidae) at two eastern humid forest localities. A multilocus genotyping analysis allowed the characterization of bacterial diversity within small mammals and gave insights into their genetic relationships with Leptospira infecting endemic Malagasy bats (family Miniopteridae and Vespertilionidae). We report for the first time the presence of pathogenic Leptospira in Malagasy endemic small mammals, with an overall prevalence of 13%. In addition, these hosts harbour species of Leptospira (L. kirschneri, L. borgpetersenii and L. borgpetersenii group B) which are different from those reported in introduced rats (L. interrogans) on Madagascar. The diversification of Leptospira on Madagascar can be traced millions of years into evolutionary history, resulting in the divergence of endemic lineages and strong host specificity. These observations are discussed in relation to the relative roles of endemic vs. introduced mammal species in the evolution and epidemiology of Leptospira on Madagascar, specifically how biodiversity and biogeographical processes can shape community ecology of an emerging pathogen and lead to its diversification within native animal communities.