Submitted to: International Journal for Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/15/2002
Publication Date: 6/15/2002
Citation: Dubey, J.P., Lindsay, D.S., Rosenthal, B.M., Sreekumar, C., Hill, D.E., Shen, S.K., Kwok, O.C., Rickard, L.G., Black, S.S., Rashmir-Raven, A. 2002. Establishment of besnoitia darlingi from opossums (didelphis virginiana) in experimental intermediate and definitive hosts, propagation in cell culture, and description of ultrastructural and genetic characteristics. International Journal for Parasitology 32:1053-1064. Interpretive Summary: Parasites of the genus Besnoitia are single celled parasites of animals. Some species cause mortality and economic losses in animals. Besnoitia darlingi is a parasite of opossums and cats. Little is known of its life cycle and biology. Scientists at the Beltsville Agricultural Research Center and the Mississippi State University report life cycle and its biology. The results will be of interest to wildlife biologists, parasitologists, veterinarians and pathologists.
Technical Abstract: Besnoitia darlingi from naturally infected opossums (Didelphis virginiana) from Mississippi, USA, was propagated experimentally in mice, cats, and cell culture and was characterised according to ultrastructural, genetic, and life-history characteristics. Cats fed tissue cysts from opossums shed oocysts with a prepatent period of nine or 11 days. Oocysts, bradyzoites, or tachyzoites were infective to outbred and interferon gamma gene knockout mice. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey cells and revived after an 18 month storage in liquid nitrogen. Schizonts were seen in the small intestinal lamina propria of cats fed experimentally-infected mouse tissues. These schizonts measured up to 45 x 25 m and contained many merozoites. A few schizonts were present in mesenteric lymph nodes and livers of cats fed tissue cysts. Ultrastructurally, tachyzoites and bradyzoites of B. darlingi were similar to other species of Besnoitia. A close relationship to B. besnoiti and an even closer relationship to B. jellisoni was indicated for B. darlingi on the basis of the small subunit and ITS-1 portions of nuclear ribosomal DNA.