The evolutionary host switches of Polychromophilus : a multi-gene phylogeny of the bat malaria genus suggests a second invasion of mammals by a haemosporidian parasite

• Published in: Malaria Journal
• Main Authors: Witsenburg Fardo, Salamin Nicolas, Christe Philippe
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2012
• Subjects: Polychromophilus; Malaria; Haemosporida; Chiroptera; Plasmodium; Host switch; Phylogenetic analysis; Outgroup selection; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/1475-2875-11-53; https://doaj.org/article/4526759013f944c3bbf5995ba727630c

Abstract Background The majority of Haemosporida species infect birds or reptiles, but many important genera, including Plasmodium , infect mammals. Dipteran vectors shared by avian, reptilian and mammalian Haemosporida, suggest multiple invasions of Mammalia during haemosporidian evolution; yet, phylogenetic analyses have detected only a single invasion event. Until now, several important mammal-infecting genera have been absent in these analyses. This study focuses on the evolutionary origin of Polychromophilus , a unique malaria genus that only infects bats (Microchiroptera) and is transmitted by bat flies (Nycteribiidae). Methods Two species of Polychromophilus were obtained from wild bats caught in Switzerland. These were molecularly characterized using four genes ( asl, clpc, coI, cytb ) from the three different genomes (nucleus, apicoplast, mitochondrion). These data were then combined with data of 60 taxa of Haemosporida available in GenBank. Bayesian inference, maximum likelihood and a range of rooting methods were used to test specific hypotheses concerning the phylogenetic relationships between Polychromophilus and the other haemosporidian genera. Results The Polychromophilus melanipherus and Polychromophilus murinus samples show genetically distinct patterns and group according to species. The Bayesian tree topology suggests that the monophyletic clade of Polychromophilus falls within the avian/saurian clade of Plasmodium and directed hypothesis testing confirms the Plasmodium origin. Conclusion Polychromophilus ' ancestor was most likely a bird- or reptile-infecting Plasmodium before it switched to bats. The invasion of mammals as hosts has, therefore, not been a unique event in the evolutionary history of Haemosporida, despite the suspected costs of adapting to a new host. This was, moreover, accompanied by a switch in dipteran host.