Avian malaria on Madagascar: delimiting local species using an integrative approach combining genetic, morphological and host specificity data

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Avian malaria is a disease caused by unicellular blood parasites of the order Haemosporida (subphylum: Apicomplexa). The parasites life cycles are obligate heteroxenous, meaning the parasites need two different hosts (intermediate and definitive host) to successfully fulfill their life cycles. In case of avian haemosporidian parasites, birds are the intermediate host and blood-sucking dipterans are the vectors (definitive hosts). There are three different haemosporidian genera infecting birds: Plasmodium, Haemoproteus and Leucocytozoon. So far, molecular studies have identified nearly 4,000 unique avian haemosporidian lineages i.e. haplotypes worldwide, detected in over 1,800 bird species and 350 vectors. In contrast, however, there are only 103 morphologically described species, to which 228 of the nearly 4000 lineages can be assigned (MalAvi, http://mbio-serv2.mbioekol.lu.se/Malavi; as of November 2019). This shortcoming is due to the fact that there have been no clear rules for species descriptions in the field of avian Haemosporida. The latest and most promising method for species identification is an integrative approach that brings together molecular, morphological and ecological data (Galen et al. 2018).In the requested project approximately 1700 blood samples of a Malagasy bird population, collected between 2003 - 2021 in the Maromizaha rainforest on Madagascar, will be examined for possible Leucocytozoon infection. The targeted examination of the genus Leucocytozoon should provide a meaningful statement about the actual prevalence in the Malagasy bird population and complete the data set of previous studies. Due to the high number of endemic bird species, it is expected that a high diversity of Leucocytozoon lineages will be found. The examination of more than 800 blood smears of the same bird population will clarify which parasites detected by PCR method (during this project and in our previous study (Musa et al. 2019)) can reproduce in the bird host and in which cases an abortive infection was detected. Moreover, the morphological detection and measurements of the gametocytes will be the basis for further analyses. At least 12 new haemosporidian parasite species, proposed in our latest study (Musa et al., 2019), along with a still unknown number of Leucocytozoon species (data will be obtained during this project) exist on Madagascar. These species will be described using an integrative approach that combines morphological data, molecular data of various genetic markers and ecological data such as host specificity (following Galen et al. 2018).