title: Prevalence and tissue distribution of Besnoitia darlingi cysts in the Virginia opossum (Didelphis virginiana) in Michigan.
abstract: Specimens of Virginia opossums (Didelphis virginiana) in Michigan were examined over 1 year to document the presence of Besnoitia darlingi cysts. Cyst morphology, prevalence, seasonal variation, and tissue sites of isolation were studied. Histology and ultrastructural features of the detected cysts and bradyzoites were consistent with B. darlingi. In the opossums, B. darlingi had intracellular tissue cysts. Tissue cysts had a mean diameter of 560 microm and were separated from the host tissue by a thick (5-20 microm) cyst wall. Overall prevalence of B. darlingi cysts in opossums was 10.9% (15/137). Variations in the prevalence were detected during spring (3/17; 17.6%), summer (10/34; 29.4%), and fall (2/60; 3.3%). No cysts were detected in the specimens examined during winter (0/26; 0%). Numerous B. darlingi cysts were detected in ears, conjunctiva, tongue, abdominal muscles, diaphragm, stomach, heart, liver, kidney, lung, and spleen. Cysts were detected mainly in adult female opossums that were debilitated. Ear was the most frequent organ from which the cysts were reported (10/15; 66.7%) when compared individually with other body tissues (P<0.05).
authors.affiliation: Molecular Epidemiology Laboratory, National Food Safety and Toxicology Center, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Hany M
authors.initials: HM
authors.lastname: Elsheikha
authors.forename: Linda S
authors.initials: LS
authors.lastname: Mansfield
authors.forename: Scott D
authors.initials: SD
authors.lastname: Fitzgerald
authors.forename: Mahdi A
authors.initials: MA
authors.lastname: Saeed
mesh_terms: D000818:Animals; D003048:Coccidiosis / Q000453:epidemiology / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D003560:Cysts / Q000469:parasitology / Q000662:veterinary; D005260:Female; D008168:Lung / Q000469:parasitology / Q000473:pathology; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008854:Microscopy, Electron / Q000662:veterinary; D008857:Microscopy, Interference / Q000662:veterinary; D009893:Opossums / Q000469:parasitology*; D015995:Prevalence; D021745:Sarcocystidae / Q000254:growth & development*