Between 1986 and 1993, we studied a breeding colony of Purple Martins (Progne subis) in Maryland that were chronically infected with two blood parasites: Haemoproteus prognei, a haematozoan, and an unidentified filarial nematode. We assessed whether cross-infections are more severe than single infections by comparing the return rates of birds infected with either or both parasites and the return rates of uninfected controls. Birds were captured every year and banded, and blood smears were taken for parasite screening. Average prevalence of filaria among the 400 birds screened during this period was 22%. Birds usually became infected by their second year (SY), and infected SY birds had significantly lower return rates than older birds. Cross-infections were rare (8%) and were fatal in 90% of cases. With one exception, birds infected with H. prognei acquired filaria as a second infection, which suggests that although both blood parasites are relatively benign for older Purple Martins, co-infection with a second parasite (in this case, H. prognei) almost always results in death.
Est-ce que les Infections Multiples Sont Plus Sévères que les Infections Simples chez Progne subis?