Susceptibility of pekin and muscovy ducks to Haemoproteus nettionis.

Domestic muscovy (Caririna moschata) and pekin (Anas platyrhynchos) ducklings were exposed to or injected with homogenates of Culicoides flies collected at White Pine, Michigan. Gametocytes of Haemoproteus nettionis were detected in both species of ducks at 16 days post-exposure. Culicoides downesi was indicated as a vector of H. nettionis in northern Michigan. Blood infections occurred with a higher prevalence and reached a higher intensity in muscovy ducks. Endogenous tissue stages of H. nettionis were located in endothelial cells of the lung and occasionally in the heart and spleen. Attempts to infect domestic ducklings by blood or tissue inoculations from wood ducks (Aix sponsa) infected with H. nettionis were not successful, even though schizonts of H. nettionis were seen in these wood ducks at necropsy. No morbidity or mortality was observed in any ducks infected with H. nettionis.