Studies on congenital toxoplasmosis in canines

The purpose of the study was to determine the influence of Toxoplasma gondii infection on reproductive failures in dogs, foxes and racoon dogs as well as to find the optimal method for diagnosing congenital toxoplasmosis in canines. The studies were performed on farmed silver and polar foxes, racoon dogs and dogs. 52 females from 20 farms and 4 bitches which had miscarried or lost their litters in the first 3 days after whelping were serologically examined using the latex agglutination test. 20 out of 42 seropositive females were chosen for detailed serologic examination performed by the immunofluorescent antibody test. The T. gondii specific IFA IgG antibodies were found in titres ranging from 1:80 to 1:2560 and IgM in titres from 1:20 to 1:1280, respectively. IN 4 females with low IgG titres a twofold increase in titres was found after 3 weeks. Miscarried foetuses and dead neonates were examined for T. gondii infection using the following methods: immunofluorescence, cytology, histopathology, PCR and mouse inoculation. A total of 35 samples of organs (liver, lungs, brain) wee examined. T. gondii was detected in 32 samples by PCR, in 4 by using impression smears stained cytologically, and in 11 examined by the immunofluorescent test. Interstitial pneumonia and non-purulent encephalitis were observed in the histology preparations as well, and T. gondii cysts were found in 5 liver samples. Only 2 organ samples (of the 14 examined) were positive by mouse inoculation. T. gondii infection is a realistic cause of reproductive failures in canines. Sensitivity to PCR is most efficient method used to detect T. gondii in miscarried foetuses and dead neonates of canines.