Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 1999
Publication Date: N/A
Interpretive Summary: Toxoplasma gondii is a single-celled parasite of livestock and humans. It can cause mortality in most warm blooded animals. The Hawaiian crow, Corvus hawaiiensis is an endangered species. The U.S. Department of Interior has a program to save these animals. Scientists at the Beltsville Agricultural Research Center and the U.S. Department of Interior have found dthat toxoplasmosis is killing these crows in the wild. They found that infected crows can be treated with an anticoccidial, diclazuril. These findings will be of great interest to wildlife biologists, parasitologists and veterinarians.
The 'Alala (Corvus hawaiiensis) is the most endangered corvid in the world, and intensive efforts are being made to reintroduce it to its former native range in Hawaii. We diagnosed Toxoplasma gondii infection in five free-ranging 'Alala. One 'Alala, recaptured from the wild because it was underweight and depressed was treated with diclazuril (10 mg/kg) orally for rten days Antibodies were measured before and after treatment by the modified agglutination test (MAT) using whole formalinized T. gondii tachyzoites and mercaptoethanol The MAT titer decreased four-fold from an initial, titer of 1:1,600 with remarkable improvement in physical condition Lesions of toxoplasmosis were also seen in two partially scavenged carcasses in a third fresh intact carcass. Toxoplasma gondii was confirmed immunohistochemically by using anti-T gondii specific serum The organism was also cultured by bioassay in mice from tissues of one of these birds and the brain of a fifth 'Alala that did not exhibit lesions. This is the first record of toxoplasmosis in 'Alala, and the parasite appears to pose a significant threat and management challenge to re-introduction programs for 'Alala in Hawaii.