HEMATOZOA OF WOOD DUCKS (AIX SPONSA) IN MISSOURI

We examined 371 wood ducks (Air sponsa) for hematozoa from two localit ies in Missouri (USA) in 1989 and 1990. Thirty-seven (10%) harbored on e or more species of blood parasites. Haemoproteus nettionis was the m ost common parasite, occurring in 36 (10%) of the birds. Leucocytozoon simondi was found in two (0.5%) and microfilaria occurred in five (1% ) of the wood ducks examined. Infections were more prevalent in adults (18%) than in immature birds (2%). There was no difference in prevale nce between sex, location, or year. Based on seasonal prevalence, tran smission probably did not occur at either location in the summer. Incr eased prevalence in the winter samples occurred after northern wood du cks migrated into the sample areas.