Atoxoplasmosis in tanagers.

Atoxoplasma spp. (extraintestinal Isospora spp.) are coccidian parasites that infect a variety of passerine species. Atoxoplasmosis has been difficult to diagnose using buffy coat and organ impression smear examinations or histopathologic examination of tissues at necropsy. The prevalence of this parasite was studied in the tanager collection of a zoological park after the death of several tanagers from confirmed and suspected infections. A polymerase chain reaction assay was used to test blood, feces, or tissue samples (or all) from 88 individuals representing 18 species. Twenty-three of 60 (38.3%) blood samples from clinically healthy birds tested positive for Atoxoplasma, and one of six fecal samples was positive. Nineteen of 32 (59.4%) tissue samples from deceased tanagers tested positive. A total of 57 other institutions were also queried regarding the presence of Atoxoplasma. The high number of Atoxoplasma-positive clinically healthy birds suggests that the parasite is prevalent subclinically within tanager collections, with young birds and stressed adults being the most likely to develop clinical disease. Thorough disinfection of enclosures, consideration of enclosure designs, and preventing fecal contamination of food and water are important methods of decreasing transmission. Selective breeding programs and regular screening of breeding pairs may be recommended to decrease transmission to susceptible offspring. Care should also be taken when housing tanagers in mixed species or in outdoor enclosures because the transmission risks between species have not been well established.

Molecular analysis of SV-40-CAL, a new slow growing SV-40 strain from the kidney of a caged New World monkey with fatal renal disease.

A decline of the Callimico goeldii population in American zoos is presently occurring due to glomerulonephritis of unknown etiology. We hypothesized that this emerging idiopathic fatal renal disease (IFRD) was caused by a virus. We therefore attempted to isolate virus from the kidneys three C. goeldi in Illinois that had IFRD. Along with other viruses, Simian virus 40 (SV-40) strain CAL was isolated. SV-40-CAL is currently the slowest-growing natural isolate of SV-40 in CV-1 cells. Inefficient SV-40-CAL growth in CV-1 cells stems from two features: a suboptimal protoarchetypal regulatory region, and a Large tumor antigen gene sequence like that of SV-40 strain T302, previously considered the slow-growing natural isolate of SV-40. To our knowledge, this is the first documented isolation of SV-40 from a New World monkey outside of a laboratory setting. Though SV-40 is renaltropic, the role of SV-40-CAL in IFRD is uncertain. Transmission of SV-40 to C. goeldii through anthropogenic activity is suspected.