A survey on blood parasites of birds in Chiang Mai province

Abstract

Blood parasites are one of the most remarkable bird parasitism. Though these agents may not the main cause of death in avian species, they interfere with vital organs normal functions. This study was aimed to survey and provide the occurrence of blood parasites in birds within Chiang Mai. Blood samples were collected from 111 birds composed of red-backed sea eagles (n=2), rock doves (n=52), red junglefowls (n=14), spotted wood-owl (n=1), pheasants (n=13), peafowls (n=2), purple swamphen (n=1), spotted dove (n=1), common mynas (n=3), tree sparrows (n=6), red-whiskered bulbuls (n=13), and Asian barred owlets (n=3). Blood was drawn from brachial wing veins then stored in capillary tubes and EDTA microcentrifuge tubes. Blood samples were centrifuged to evaluate packed cell volume (PCV) and Woo’s technique was performed to identify Trypanosoma spp. To identify other blood parasites, thin blood smears were made by dying with Giemsa’s stain and observed under 40x, 100x ,400x, 1000x microscopic magnifications. From 111 samples, 54 samples gave blood parasite positive results (48.65%). Further investigation showed 18 samples were positive with more than one parasite species. Four major group of blood parasites were detected, including Microfilaria 35.14%, Haemoproteus spp. 17.12%, Leucocytozoon spp. 8.11%, and Trypanosoma spp. 4.50%. Bird that positive to blood parasites can show normal or low PCV values and may appear to be as healthy as normal birds while act as a vector.