Response of leukocytes in chickens infected with the avian schistosome Austrobilharzia variglandis (Trematoda).

Leukocyte levels were monitored weekly in chickens infected with the avian schistosome Austrobilharzia variglandis. Changes in relative and absolute numbers of leukocytes were recorded over a 7-week period beginning 1 week before exposure. There was a significant increase (P less than 0.001) in total leukocytes, peaking at 5.8 X 10(4) cells/mm3 on day 21 postexposure; controls had 2.4 X 10(4) cells/mm3 on that day. The leukocyte count declined over the next 3 weeks, returning to nearly normal levels by day 42 postexposure. With the exception of eosinophils, which peaked 35 days postexposure, all leukocyte subpopulations peaked in number on day 21. Increases in heterophils and monocytes were related to the schistosome egg burden.