Avian malaria in a forest specialist bird in the extremes of the species distribution in Chile

Avian malaria is a vector-borne disease caused by related parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon, which are globally distributed in most birds. Latitudinal gradients are good tools to explain... [ view full abstract ]

Avian malaria is a vector-borne disease caused by related parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon, which are globally distributed in most birds. Latitudinal gradients are good tools to explain transmission dynamics of vector-borne parasites and therefore the host susceptibility in distinct geographical regions. In this context, we assess the prevalence patterns of avian malaria parasites in a forest specialist passerine, the Thorn-tailed Rayadito (Aphrastura spinicauda). As a part of a long-term study, we have monitored two populations in Chile: (i) Fray Jorge National Park (FJ) the northernmost (low latitude) population, a relict and highly isolated forest immersed in a semiarid matrix and (ii) Navarino Island (NI) the southernmost (high latitude) population. Nestlings and adults individuals were captured, marked and recaptured during five reproductive seasons (2010-2014). We evaluated the infection status of 105 individuals from FJ and 67 individuals from NI by nested-PCR using the primers HaemNR3-HaemNFI as the first step and HaemF-HaemR2 to amplify 480 bp for Plasmodium-Haemoproteus and HaemFL-HaemR2L to amplify 478 pb for Leucocytozoon of the mtDNA cytochrome b gene. Overall, the population in the low latitude showed low prevalence of infection for Plasmodium-Haemoproteus (0.95%) and Leucocytozoon (3.80%). The population in the high latitude showed high prevalence of infection for Leucocytozoon (64.17%) and low prevalence for Plasmodium-Haemoproteus (4.47%). Additionally, we observed association between age and malaria parasites, none nestling was infected with malaria. Differences in prevalence patterns of avian malaria among parasite genera through latitudinal gradients could be explained by differences in vector-host-parasite interactions. Besides, the low prevalence in low latitude population could be explained by the fact that FJ is immersed in a semiarid matrix where probably there are less vectors for avian malaria transmission.