April 27, 2012

In the Spotlight: Past Wildlife Disease Investigation from WDA Newsletter

Nordic Section Quarterly Report of Wildlife Disease Investigation Cases
Wildlife Disease Association (WDA) Newsletter

New development in Trichomonas gallinae epidemic in Finland
By Marja Isomursu, Finnish Food Safety Authority

The avian protozoan parasite, Trichomonas gallinae, first emerged in finch populations of Finland, Sweden and Norway in 2008. The parasite quickly spread in Finland and has caused large-scale morbidity and mortality among greenfinches (Carduelis chloris).

So far, trichomonosis in other passerine species has apparently been rare. In January 2012, first reports of trichomonosis-like illness in yellowhammers (Emberiza citrinella) were received and soon after that, first cases were confirmed by necropsy and isolation of the parasite from the crop.

Courtesy of Wikipedia
Nine new outbreaks were confirmed during the following winter months from different parts of the country. All outbreaks were seen in feeding places visited by flocks of yellowhammers.

The reason behind this new epidemiological development could be climatic: December 2011 was the warmest since the emergence of trichomonosis allowing the horizontal spread of freeze-intolerant T. gallinae at feeding places. Yellowhammers form large flocks and visit feeding places in Finland only in winter. This behavior has probably protected the population from the disease up to now. Interestingly, no cases were seen in greenfinches while yellowhammers were dying. The last cases in greenfinches were confirmed in the warm December 2011.

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