Diversity, distribution, and drivers of Polychromophilus infection in Malagasy bats.

BACKGROUND: Numerous studies have been undertaken to advance knowledge of apicomplexan parasites infecting vertebrates, including humans. Of these parasites, the genus Plasmodium has been most extensively studied because of the socio-economic and public health impacts of malaria. In non-human vertebrates, studies on malaria or malaria-like parasite groups have been conducted but information is far from complete. In Madagascar, recent studies on bat blood parasites indicate that three chiropteran families (Miniopteridae, Rhinonycteridae, and Vespertilionidae) are infected by the genus Polychromophilus with pronounced host specificity: Miniopterus spp. (Miniopteridae) harbour Polychromophilus melanipherus and Myotis goudoti (Vespertilionidae) is infected by Polychromophilus murinus. However, most of the individuals analysed in previous studies were sampled on the western and central portions of the island. The aims of this study are (1) to add new information on bat blood parasites in eastern Madagascar, and (2) to highlight biotic and abiotic variables driving prevalence across the island. METHODS: Fieldworks were undertaken from 2014 to 2016 in four sites in the eastern portion of Madagascar to capture bats and collect biological samples. Morphological and molecular techniques were used to identify the presence of haemosporidian parasites. Further, a MaxEnt modelling was undertaken using data from Polychromophilus melanipherus to identify variables influencing the presence of this parasite RESULTS: In total, 222 individual bats belonging to 17 species and seven families were analysed. Polychromophilus infections were identified in two families: Miniopteridae and Vespertilionidae. Molecular data showed that Polychromophilus spp. parasitizing Malagasy bats form a monophyletic group composed of three distinct clades displaying marked host specificity. In addition to P. melanipherus and P. murinus, hosted by Miniopterus spp. and Myotis goudoti, respectively, a novel Polychromophilus lineage was identified from a single individual of Scotophilus robustus. Based on the present study and the literature, different biotic and abiotic factors are shown to influence Polychromophilus infection in bats, which are correlated based on MaxEnt modelling. CONCLUSIONS: The present study improves current knowledge on Polychromophilus blood parasites infecting Malagasy bats and confirms the existence of a novel Polychromophilus lineage in Scotophilus bats. Additional studies are needed to obtain additional material of this novel lineage to resolve its taxonomic relationship with known members of the genus. Further, the transmission mode of Polychromophilus in bats as well as its potential effect on bat populations should be investigated to complement the results provided by MaxEnt modelling and eventually provide a comprehensive picture of the biology of host-parasite interactions.

Local-scale diversity of Yersinia pestis: A case study from Ambohitromby, Ankazobe District, Madagascar.

Plague is a re-emerging zoonotic disease and a major public health concern in several portions of the world, especially in Madagascar. We report on the presence of different subtypes of Yersinia pestis co-occurring in the same locality. After confirmation of a human plague case in Ambohitromby Commune (Ankazobe District) via isolation of Y. pestis, we undertook small mammal trapping to identify the circulation of Y. pestis amongst rodents in this locality; blood samples were collected from rodents for seroprevalence analysis. Of the 60 individuals of Rattus rattus captured, one yielded an isolate of Y. pestis, 13 others were positive for F1 antigen of Y. pestis using a rapid diagnostic test, and 4 were PCR positive targeting the caf1 and pla genes; 28/60 (46.7%) of the captured R. rattus were seropositive for Y. pestis. Whole-genome SNP analyses revealed that the two isolates obtained from the human case, and the R. rattus belonged to two different subtypes of Y. pestis (s05 and s13, respectively) that were circulating concurrently in Ambohitromby in 2016. Three Y. pestis subtypes (s03, s05 and s13) have now been isolated from Ambohitromby. Subtype s05 had been persisting there for >10 years but one or both of the other subtypes may have been introduced from the Central Highlands region as they were not observed in previous years (s13) or only observed once previously (s03). High seroprevalence against Y. pestis in R. rattus suggests that a portion of the local murine population may have acquired resistance to Y. pestis. Future research should focus on genomically characterizing Y. pestis strains circulating in Ankazobe District and other plague-endemic regions of Madagascar to better understand the overall phylogeography of Y. pestis.