Mining increases the prevalence of avian haemosporidian parasites in Northeast Amazonia.

Studies contrasting parasite prevalence and host-parasite community structure between pristine and disturbed environments will improve our understanding of how deforestation affects disease transmission and parasite extinction. To determine how infection rates of a common and diverse group of avian blood parasites (Plasmodium and Haemoproteus) respond to changes in avian host composition after mining, we surveyed 25 bird communities from pristine forests (two forest types: plateau and hillside) and reforested sites in Northeast Amazonia. Infection rates and both parasite and avian host community structure exhibited considerable variation across the deforestation gradient. In opposition to the emerging pattern of lower avian haemosporidian prevalence in disturbed tropical forests in Africa, we show that secondary forests had higher haemosporidian prevalence in one of the largest mining areas of Amazonia. The dissimilarity displayed by bird communities may explain, in part, the higher prevalence of Haemoproteus in reforested areas owing to the tolerance of some bird species to open-canopy forest habitat. On the other hand, deforestation may cause local extinction of Plasmodium parasites due to the loss of their avian hosts that depend on closed-canopy primary forest habitats. Our results demonstrate that forest loss induced by anthropogenic changes can affect a host-parasite system and disturb both parasite transmission and diversity.