Population differences in susceptibility to Plasmodium relictum in zebra finches Taeniopygia guttata

Domesticated Australian and Timor zebra finches (Taeniopygia guttata castanotis, and T. guttata guttata, respectively) were inoculated with canary (Serinus canaria) blood containing a Hawaiian isolate of Plasmodium relictum (lineage GRW04), a hemoparasite that causes avian malaria. In two experimental trials, Timor, but not Australian zebra finches developed parasitemia that was detected by microscopic examination of blood smears. In the second trial, in which molecular detection methods were used, a single Australian zebra finch and 5 of 6 challenged Timor birds were positive for the parasite. Additionally, P. relictum DNA was detected in multiple blood samples obtained from Timor birds over the 28 days following challenge. Timor zebra finches may provide a useful, easily maintained, laboratory model for the study of arbovirus/Plasmodium interactions in passerines, but are still inferior to canaries, the traditionally used model of avian malaria infection, in terms of supporting high parasitemia infections.