Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Final Activity Report Summary - AVIAN MALARIA (Conservation and Evolutionary Genetics of Avian Malaria with reference to South Pacific Islands)

Birds do not leave their parasites behind when they migrate from their wintering to their breeding grounds and back. The role of migratory birds to spread diseases between regions has been widely documented; however, the extent to which the parasite diversity and transmission varies between migrant and non-migrant host species has not been adequately explored across an altitudinal gradients. Many migrants move between altitudes or to the plains, and thereby encounter different faunas of parasites and pathogens compared with resident species. In plains the resident birds may act as reservoirs for blood parasites, increasing the risk of migrants to become infected with new parasites in wintering ground. Given that suitable vectors are present to transmit and maintain the infection, such migrants can form effective bridge for parasites between wintering and breeding grounds. Hence, the risk of infection to naïve resident birds in high-altitude is increased.

The one-year study aimed to explore the degree to which:
1. migrant and resident avian hosts were infected with two vector-borne parasites across altitudes in the western Himalayas;
2. vector communities were expanded or contracted in geographical or altitudinal ranges and the consequent risks of parasite transmission in malaria-free zones.

The western Himalayas are a rich in species mountainous system where species turnover was associated with altitudinal variation in habitat, as well as with temperature-dependent variation in species’ composition along the range, e.g. in mosquitoes. It therefore provided an ideal system to explore temperature-dependent range expansion in vectors and their interaction with host-parasite systems with changing climatic conditions. The project drew many parallels with the human malaria model where increase in temperature in highland areas led to increase in malaria cases. In addition, the project determined the resonance with the avian malaria model of the Hawaiian system where the temperature threshold restricted the parasite transmission to mid-elevation forests.

This multi-tiered host-parasite-vector system had important worldwide implications for deriving general predictions relating to climate change. It is important to undertake such basic studies of disease transmission and vector populations in order to understand the general conditions that could promote host switching and emergence of novel pathogens.

Reported by

See on map