Detection of new genetic variants of Betacoronaviruses in Endemic Frugivorous Bats of Madagascar.

BACKGROUND: Bats are amongst the natural reservoirs of many coronaviruses (CoVs) of which some can lead to severe infection in human. African bats are known to harbor a range of pathogens (e.g., Ebola and Marburg viruses) that can infect humans and cause disease outbreaks. A recent study in South Africa isolated a genetic variant closely related to MERS-CoV from an insectivorous bat. Though Madagascar is home to 44 bat species (41 insectivorous and 3 frugivorous) of which 34 are endemic, no data exists concerning the circulation of CoVs in the island's chiropteran fauna. Certain Malagasy bats can be frequently found in close contact with humans and frugivorous bats feed in the same trees where people collect and consume fruits and are hunted and consumed as bush meat. The purpose of our study is to detect and identify CoVs from frugivorous bats in Madagascar to evaluate the risk of human infection from infected bats. METHODS: Frugivorous bats belonging to three species were captured in four different regions of Madagascar. We analyzed fecal and throat swabs to detect the presence of virus through amplification of the RNA-dependent RNA polymerase (RdRp) gene, which is highly conserved in all known coronaviruses. Phylogenetic analyses were performed from positive specimens. RESULTS: From 351 frugivorous bats, we detected 14 coronaviruses from two endemic bats species, of which 13 viruses were identified from Pteropus rufus and one from Eidolon dupreanum, giving an overall prevalence of 4.5%. Phylogenetic analysis revealed that the Malagasy strains belong to the genus Betacoronavirus but form three distinct clusters, which seem to represent previously undescribed genetic lineages. CONCLUSIONS: Our findings suggest that CoVs circulate in frugivorous bats of Madagascar, demonstrating the needs to evaluate spillover risk to human populations especially for individuals that hunt and consume infected bats. Possible dispersal mechanisms as to how coronaviruses arrived on Madagascar are discussed.

Rabies surveillance in Madagascar from 2011 to 2021: can we reach the target?

Rabies is endemic in Madagascar and a neglected disease. The aim of this study was to summarize human and animal rabies surveillance activities in Madagascar from 2011 to 2021. Samples from terrestrial mammals and humans were tested for rabies virus infection using direct fluorescent antibody, RT-PCR and virus isolation by the National Reference Laboratory (NRL) for rabies at the Institut Pasteur de Madagascar. Among 964 animal and 47 human samples tested, 66.7 and 70.2% were positive, respectively. The NRL received these suspect rabies samples from 48 of 114 districts of Madagascar. Most of them were submitted from the district of the capital city Antananarivo (26.3%) and mainly from its region Analamanga (68.9%). Animal samples were mainly from dogs (83%), cats (9.5%) and cattle (5.8%). Pigs, lemurs, goats accounted for less than 1%. During the 11 years of surveillance, 48 human skin and/or brain biopsy samples were received from 20 districts, mainly from Antananarivo and its surroundings (N = 13), Toamasina and its surroundings (N = 8) and Moramanga (N = 6). The high positivity rate for all species and the non-homogeneous spatial distribution of samples suggests substantial underreporting of rabies cases. There is a clear need to better understand the reasons for underreporting and prioritize rabies surveillance, prevention and control in Madagascar, with improvements in budget, education and infrastructure. A joint animal and human health rabies control program including vaccination of at least 70% of the dog population, is needed to achieve the goal of eliminating dog-transmitted human rabies by 2030 from Madagascar.

Enabling animal rabies diagnostic in low-access areas: Sensitivity and specificity of a molecular diagnostic test from cerebral tissue dried on filter paper.

Rabies is a lethal zoonotic encephalomyelitis that causes an estimated 59,000 human deaths yearly worldwide. Although developing countries of Asia and Africa bear the heaviest burden, surveillance and disease detection in these countries is often hampered by the absence of local laboratories able to diagnose rabies and/or the difficulties of sample shipment from low-access areas to national reference laboratories. Filter papers offer a convenient cost-effective alternative for the sampling, shipment, and storage of biological materials for the diagnosis of many pathogens including rabies virus, yet the properties of diagnostic tests using this support have not been evaluated thoroughly. Sensitivity and specificity of molecular diagnosis of rabies infection using a reverse transcription followed by a hemi-nested polymerase chain reaction (RT-hn-PCR) either directly on brain tissue or using brain tissue dried on filter paper were assessed on 113 suspected field animal samples in comparison to the direct fluorescent antibody test (FAT) recommended by the World Health Organization as one of the reference tests for rabies diagnosis. Impact of the duration of the storage was also evaluated. The sensitivity and the specificity of RT-hn-PCR i) on brain tissue were 96.6% (95% CI: [88.1-99.6]) and 92.7% (95% CI: [82.4-98.0]) respectively and ii) on brain tissue dried on filter paper 100% (95% CI: [93.8-100.0]) and 90.9% (95% CI: [80.0-97.0]) respectively. No loss of sensitivity of RT-hn-PCR on samples of brain tissue dried on filter paper left 7 days at ambient temperature was detected indicating that this method would enable analyzing impregnated filter papers sent to the national reference laboratory at ambient temperature within a 1-week shipment time. It could therefore be an effective alternative to facilitate storage and shipment of samples from low-access areas to enhance and expand rabies surveillance.

How could an African swine fever outbreak evolve in an enzootic context? The case of Imerintsiatosika, Madagascar in 2015.

African swine fever (ASF) is a haemorrhagic contagious pig disease generally causing high mortality. ASF is enzootic in Madagascar with outbreaks reported each year. An ASF outbreak occurred in May 2015 in the municipality of Imerintsiatosika in Madagascar. We investigated the outbreak to describe it and to identify risk factors in order to propose control measures, and to document evidence of an ASF outbreak in an enzootic country. We took biological samples from very sick and dying pigs, sold by the farmer to the butcher, for PCR analysis. An active search for all possible farm-cases was carried out. A definition of suspected farm-case was established and we implemented a descriptive survey and a retrospective cohort study. Laboratory results confirmed ASF virus infection. Suspected farm-cases represented 81 farms out of 922. Out of 3081 pigs of infected farms, 44% (95% CI: 42-46%) were sick, of which 47% were sold or slaughtered. Case fatality was 60% (95% CI: 56-63%) while 21% (95% CI: 19-24%) of the diseased pigs recovered. The outbreak duration was nine months and half of the infected farms' pig population remained after the outbreak. Compared to the exotic breed, local pigs had twice the risk of infection. It is the first detailed report of an ASF outbreak in an enzootic situation. The disease still has a large impact with 50% animals lost. However, the case fatality is lower than expected that suggests the possibility of resistance and subclinical cases. Proximity to road and increased number of farms are risk factors so biosecurity measures are needed. Further studies are needed to understand why pigs of local breed are more affected. Finally, an acceptable alternative to the sale of sick animals should be found as this currently is the breeders' means to reducing economic loss.

Challenges of rabies surveillance in Madagascar based on a mixed method survey amongst veterinary health officers.

Introduction: In Madagascar, rabies is endemic and a notifiable disease. The objective of this mixed study was to understand the challenges faced by the Veterinary Health Officers (VHOs) in the current rabies surveillance system in Madagascar. Methods: A survey was conducted from mid-April to the end of July 2021 during which all officially-listed VHOs (N = 150) were contacted by phone at least twice. Participants, representative of the 22 regions of Madagascar, were interviewed by phone based on a semi-structured questionnaire on (1) their knowledge of rabies epidemiology in their area of activities, (2) the occurrence of human and animal rabies and the species affected in the region where they work, (3) the factors that might influence rabies surveillance depending on (a) their activities and area of operation, (b) the socio-cultural aspects of local communities, and (c) the general organization of animal rabies surveillance. Results: The majority (80/90) of VHOs declared having been informed of at least one suspected or confirmed case of human and/or animal rabies in their area of activity during their work as VHOs: at least once a month for 11 of them, at least once a year for 40 and with undetermined frequency for 29. Several obstacles hinder the surveillance of rabies resulting in under-reporting. The lack of funds to access suspect animals, collect, pack and ship samples in compliance with biosecurity measures and the cold chain, was mentioned as a major obstacle to surveillance. The second barrier is socio-cultural: in many large coastal regions, dogs are taboo and VHOs fear rejection by the community if they treat dogs. Discussion and conclusion: While the general population requires information on the rabies situation in Madagascar and on how to proceed in the event of a bite, veterinarians and decision-makers need to be fully aware of an evidence-based approach to rabies surveillance, prevention and control. Communication between the human and animal health sectors should be improved. Politicians need to be persuaded of the importance of funding to eliminate rabies in Madagascar. The adoption, in early 2023, of a national strategic plan for rabies control is a first step in this direction.

Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling.

The force of infection (FOI) is one of the key parameters describing the dynamics of transmission of vector-borne diseases. Following the occurrence of two major outbreaks of Rift Valley fever (RVF) in Madagascar in 1990-91 and 2008-09, recent studies suggest that the pattern of RVF virus (RVFV) transmission differed among the four main eco-regions (East, Highlands, North-West and South-West). Using Bayesian hierarchical models fitted to serological data from cattle of known age collected during two surveys (2008 and 2014), we estimated RVF FOI and described its variations over time and space in Madagascar. We show that the patterns of RVFV transmission strongly differed among the eco-regions. In the North-West and Highlands regions, these patterns were synchronous with a high intensity in mid-2007/mid-2008. In the East and South-West, the peaks of transmission were later, between mid-2008 and mid-2010. In the warm and humid northwestern eco-region favorable to mosquito populations, RVFV is probably transmitted all year-long at low-level during inter-epizootic period allowing its maintenance and being regularly introduced in the Highlands through ruminant trade. The RVF surveillance of animals of the northwestern region could be used as an early warning indicator of an increased risk of RVF outbreak in Madagascar.

[Ovarian pregnancy: about 3 cases and review of the literature]. / Grossesse ovarienne: à propos de 3 cas et une revue de la literature.

Ovarian pregnancy is a rare event among women with ectopic pregnancy in whom the ovary is the site of implantation. Its diagnosis requires a well codified approach. The peculiarities of the determining factors, of the histopathological and evolutionary features typical of ovarian pregnancies led us to focus on this form of ectopic pregnancy. We report 3 cases of ovarian pregnancy diagnosed in our Department. The three women were between 30 and 42 years, at 13 to 37 weeks of amenorrhea. All women had abdominal pain of varying intensity associated with shock. Anatomopathological examination of the right annex, normal site of implantation of ovarian pregnancies, confirmed the diagnosis. All women had juxtaposition ovarian cortical pregnancy. Ovarian pregnancy is a rare event among women with ectopic pregnancy, having specific peculiarities. Its diagnosis is difficult and is based on preoperative findings. The identification of the ovarian implantation on histopathological examination is ideal for confirming the diagnosis. Currently, it is assumed that ovarian pregnancy is the form of ectopic pregnancy which can develop to term or even result in a live birth.