Spatial and seasonal variation of avian malaria infections in five different land use types within a Neotropical montane forest matrix

Seasonality as well as habitat destruction can alter host-parasite interactions. The montane cloud forest of Veracruz State in Mexico has been transformed into agro-ecosystems and cities. The aim of this study was to determine how ecological parameters of avian malaria parasites responded to five different land use types (i.e., well-preserved cloud forest, periurban forest, urban forest, coffee plantation, and cattle field) and to seasonality. We used microscopy and PCR methods to determine prevalence, parasitaemia, and aggregation of haemosporidians infecting the widespread chestnut-capped brush finch (Arremon brunneinucha). We performed PCA and cluster analyses to determine vegetation structure and similarity, and to investigate how relevant vegetation variables are associated with parasitological parameters. All haemosporidian infections in chestnut-capped brush finches belonged to Haemoproteus and Plasmodium species. Prevalence and parasitaemia of avian malaria were higher during the rainy season, while aggregation remained similar. Both prevalence and parasitaemia were higher in the urban forest. Prevalence was lower in the well-preserved cloud forest during the dry season. Parasitaemia was negatively associated to bush cover. Our results suggest that an increase in land use intensity reduces seasonal fluctuations in parasite transmission, and that infections are more frequent and more severe for birds inhabiting urban environments.