Geographical distribution and relative risk of Anjozorobe virus (Thailand orthohantavirus) infection in black rats (Rattus rattus) in Madagascar

Acknowledgements We thank those who facilitated the survey: householders, heads of fokontany, local administration and health authorities from Ministry of Health. We would like to express our gratitude to the staff of the Plague Central Laboratory Unit, Institut Pasteur de Madagascar: Dr. Minoarisoa Rajerison who facilitated this study; Corinne Rahaingosoamamitiana and Soanandrasana Rahelinirina for helping to conduct and organize the field work. We would also like to thank Dr. Fanjasoa Rakotomanana and Dr. Lalaina Arivony Nomenjanahary assistance in the field trips and technical and field support. Funding This work was supported by the Institut Pasteur de Madagascar (Internal Project through ZORA: Zoonoses, Rodent and Arboviruses) and Wellcome Trust Fellowships to ST (#081705, #095171). VR was also supported though Girard’s fellowship undergraduate program from the Institut Pasteur de Madagascar. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Reemergence of Recombinant Vaccine–derived Polioviruses in Healthy Children, Madagascar

International audiencePoliomyelitis outbreaks caused by pathogenic vaccine-derived polioviruses (VDPVs) are primarily a result of low polio vaccine coverage. Low coverage enables interhuman circulation of polioviruses (PVs) from the oral polio vaccine (OPV), and it enables genetic drift of the viruses and their subsequent reversion to neurovirulent phenotypes. Polio outbreaks associated with type 2 or 3 VDPVs (VDPV2s or VDPV3s) were reported in 2001-2002 and 2005 in Toliara Province in southern Madagascar. These VDPVs were found in patients with acute flaccid paralysis (AFP) and in healthy children who were contacts of the patients with AFP. The genomes of these VDPVs belong to several independent, complex mosaic recombinant lineages composed of sequences derived from vaccine polioviruses and other co-circulating species C human enteroviruses (human EV-C). The 2001-2002 and 2005 outbreaks in Toliara Province were stopped after rapid and efficient OPV vaccination campaigns

Dried-Blood Spots: A Cost-Effective Field Method for the Detection of Chikungunya Virus Circulation in Remote Areas

<div><p>Background</p><p>In 2005, there were outbreaks of febrile polyarthritis due to Chikungunya virus (CHIKV) in the Comoros Islands. CHIKV then spread to other islands in the Indian Ocean: La Réunion, Mauritius, Seychelles and Madagascar. These outbreaks revealed the lack of surveillance and preparedness of Madagascar and other countries. Thus, it was decided in 2007 to establish a syndrome-based surveillance network to monitor dengue-like illness.</p><p>Objective</p><p>This study aims to evaluate the use of capillary blood samples blotted on filter papers for molecular diagnosis of CHIKV infection. Venous blood samples can be difficult to obtain and the shipment of serum in appropriate temperature conditions is too costly for most developing countries.</p><p>Methodology and principal findings</p><p>Venous blood and dried-blood blotted on filter paper (DBFP) were collected during the last CHIKV outbreak in Madagascar (2010) and as part of our routine surveillance of dengue-like illness. All samples were tested by real-time RT-PCR and results with serum and DBFP samples were compared for each patient. The sensitivity and specificity of tests performed with DBFP, relative to those with venous samples (defined as 100%) were 93.1% (95% CI:[84.7–97.7]) and 94.4% (95% CI:[88.3–97.7]), respectively. The Kappa coefficient 0.87 (95% CI:[0.80–0.94]) was excellent.</p><p>Conclusion</p><p>This study shows that DBFP specimens can be used as a cost-effective alternative sampling method for the surveillance and monitoring of CHIKV circulation and emergence in developing countries, and probably also for other arboviruses. The loss of sensitivity is insignificant and involved a very small number of patients, all with low viral loads. Whether viruses can be isolated from dried blood spots remains to be determined.</p></div

Ct Differences in RNA amplification from 15 µl aliquots of whole blood and DBFP.

<p>Ct Differences in RNA amplification from 15 µl aliquots of whole blood and DBFP.</p

Primers and probes used in amplification of Chikungunya RNA as previously described by Laurent et al. 2007 [28] (modifications of primers are indicated in bold).

<p>Primers and probes used in amplification of Chikungunya RNA as previously described by Laurent et al. 2007 <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002339#pntd.0002339-Laurent1" target="_blank">[28]</a> (modifications of primers are indicated in bold).</p

Sensitivity and specificity of test performed on DBFP for the diagnosis of Chikungunya virus infection^a.

a<p>Sensitivity, 93.1% (68/73, (95% CI:[84.7–97.7]); specificity, 94.4% (102/108, (95% CI:[88.3–97.7]); Kappa coefficient, 0.87 (95% CI:[0.80–0.94]).</p

High permissiveness for genetic exchanges between enteroviruses of species A, including enterovirus 71, favours evolution through intertypic recombination in Madagascar

International audienceHuman enteroviruses of species A (EV-A) are the leading cause of hand-foot-and-mouth disease (HFMD). EV-A71 is frequently implicated in HFMD outbreaks and can also cause severe neurological manifestations. We investigated the molecular epidemiological processes at work and the contribution of genetic recombination to the evolutionary history of EV-A in Madagascar, focusing on the recently described EV-A71 genogroup F in particular. Twenty-three EV-A isolates, collected mostly in 2011 from healthy children living in various districts of Madagascar, were characterized by whole-genome sequencing. Eight different types were identified, highlighting the local circulation and diversity of EV-A. Comparative genome analysis revealed evidence of frequent recent intra- and intertypic genetic exchanges between the noncapsid sequences of Madagascan EV-A isolates. The three EV-A71 isolates had different evolutionary histories in terms of recombination, with one isolate displaying a mosaic genome resulting from recent genetic exchanges with Madagascan coxsackieviruses A7 and possibly A5 and A10 or common ancestors. The engineering and characterization of recombinants generated from progenitors belonging to different EV-A types or EV-A71 genogroups with distantly related nonstructural sequences indicated a high level of permissiveness for intertypic genetic exchange in EV-A. This permissiveness suggests that the primary viral functions associated with the nonstructural sequences have been highly conserved through the diversification and evolution of the EV-A species. No outbreak of disease due to EV-A has yet been reported in Madagascar, but the diversity, circulation, and evolution of these viruses justify surveillance of EV-A circulation and HFMD cases to prevent possible outbreaks due to emerging strains.IMPORTANCE Human enteroviruses of species A (EV-A), including EV-A71, are the leading cause of hand-foot-and-mouth disease (HFMD) and may also cause severe neurological manifestations. We investigated the circulation and molecular evolution of EV-A in Madagascar, focusing particularly on the recently described EV-A71 genogroup F. Eight different types, collected mostly in 2011, were identified, highlighting the local circulation and diversity of EV-A. Comparative genome analysis revealed evidence of frequent genetic exchanges between the different types of isolates. The three EV-A71 isolates had different evolutionary histories in terms of recombination. The engineering and characterization of recombinants involving progenitors belonging to different EV-A types indicated a high degree of permissiveness for genetic exchange in EV-A. No outbreak of disease due to EV-A has yet been reported in Madagascar, but the diversity, circulation, and evolution of these viruses justify the surveillance of EV-A circulation to prevent possible HFMD outbreaks due to emerging strains

Prevalence of chronic hepatitis B virus infection and infrastructure for its diagnosis in Madagascar: implication for the WHO’s elimination strategy

Abstract Background WHO developed a global strategy to eliminate hepatitis B by 2030 and set target to treat 80% of people with chronic hepatitis B virus (HBV) infection eligible for antiviral treatment. As a first step to achieve this goal, it is essential to conduct a situation analysis that is fundamental to designing national hepatitis plans. We therefore estimated the prevalence of chronic HBV infection, and described the existing infrastructure for HBV diagnosis in Madagascar. Methods We conducted a stratified multi-stage serosurvey of hepatitis B surface antigen (HBsAg) in adults aged ≥18 years using 28 sentinel surveillance sites located throughout the country. We obtained the list of facilities performing HBV testing from the Ministry of Health, and contacted the person responsible at each facility. Results A total of 1778 adults were recruited from the 28 study areas. The overall weighted seroprevalence of HBsAg was 6.9% (95% CI: 5.6–8.6). Populations with a low socio-economic status and those living in rural areas had a significantly higher seroprevalence of HBsAg. The ratio of facilities equipped to perform HBsAg tests per 100,000 inhabitants was 1.02 in the capital city of Antananarivo and 0.21 outside the capital. There were no facilities with the capacity to perform HBV DNA testing or transient elastography to measure liver fibrosis. There are only five hepatologists in Madagascar. Conclusion Madagascar has a high-intermediate level of endemicity for HBV infection with a severely limited capacity for its diagnosis and treatment. Higher HBsAg prevalence in rural or underprivileged populations underlines the importance of a public health approach to decentralize the management of chronic HBV carriers in Madagascar by using simple and low-cost diagnostic tools

Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar

International audienceBackground: Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008–2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts.Methodology/Principal Findings: First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001). Areas with high cattle density were at risk (p<0.01; OR = 2.6). Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6). Finally, our study highlighted the easterncoast, western and north-western parts as high-risk areas for RVF transmission in cattle.Conclusions/Significance: Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution of vectorial or direct transmissions could be further assessed by mathematic modelling