Histopathological and molecular study of Neospora caninum infection in bovine aborted fetuses

Objective: To estimate the extent to which abortion in dairy cows was associated with of Neospora caninum (N. caninum) and to determine the risk factors of neosporosis in dairy farms from 9 provinces in Iran. Methods: Polymerase chain reaction (PCR) test was used to detect Neospora infection in the brain of 395 bovine aborted fetuses from 9 provinces of Iran. In addition, the brains of aborted fetuses were taken for histopathological examination. To identify the risk factors associated with neosporosis, data analysis was performed by SAS. Results: N. caninum was detected in 179 (45%) out of 395 fetal brain samples of bovine aborted fetuses using PCR. Among the PCR-positive brain samples, only 56 samples were suited for histopathological examination. The characteristic lesions of Neospora infection including non-suppurative encephalitis were found in 16 (28%) of PCR-positive samples. The risk factors including season, parity of dam, history of bovine virus diarrhea and infectious bovine rhinotracheitis infection in herd, cow's milk production, herd size and fetal appearance did not show association with the infection. This study showed that Neospora caused abortion was significantly more in the second trimester of pregnancy than other periods. In addition, a significant association was observed between Neospora infection and stillbirth. Conclusions: The results showed N. caninum infection was detected in high percentage of aborted fetuses. In addition, at least one fourth of abortions caused by Neospora infection. These results indicate increasing number of abortions associated with the protozoa more than reported before in Iran.

Pathological description and immunohistochemical demonstration of ovine abortion associated with Toxoplasma gondii in Iran / 대한수의학회지

The obligatory intracellular protozoan parasite Toxoplasma gondii is a major world wide cause of infectious ovine abortion. In some different diagnostic techniques that are being used to detect this pathogen in ovine fetuses, immunohistochemistry (IHC) is a very sensitive and expensive one. Histopathology is not truly a specific and sensitive test for Toxoplasma infection but it can be helpful to choose some suspected tissues for IHC. In this study 9.5% of 200 samples (aborted ovine fetuses internal organs such as brain, liver, heart, lung, kidney, spleen) (4.6~14.4% with 95% CI) were positive in IHC with a very good logical agreement among different diagnostic techniques (kappa = 0.73, 0.8) and with no significant difference among different fetal age groups (p > 0.05).