Toxoplasma gondii cysts in placentas of experimentally infected sheep
Dubey, J.P.
American Journal of Veterinary Research 48(3): 352-353
1987
ISSN/ISBN: 0002-9645 PMID: 3565888 Document Number: 291995
To determine the presence of tissue cysts in ovine placentas, 6 ewes were inoculated orally with 10,000 Toxoplasma gondii oocytes at 60 days of gestation. The ewes were euthanatized and necropsied 21, 52, 56, 57, 57, and 62 days after T. gondii inoculation, and placental cotyledons from each ewe were collected and homogenized. To distinguish between the presence of tachyzoites that are killed by acid pepsin solution and bradyzoite (from cysts) unaffected by this solution, a portion of each homogenate was inoculated into mice and another portion was inoculated into mice after digestion in acid pepsin solution. Toxoplasma gondii was isolated in 26 of 34 (76.4%) of mice inoculated with nondigested placentas of all 6 ewes and in 16 of 34 (47%) mice inoculated with digested placenta of 5 of 6 ewes. Seemingly, cysts do occur in placental tissue, but the digestion method was inferior, compared with the nondigestion method for recovery of T. gondii from placenta.