A Serological and Molecular study on Toxoplasma gondii infection in sheep and goat in Tabriz



Toxoplasmosis is an important zoonotic diseases in human and animals. The disease caused by the
protozoan Toxoplasma gondii. To determine the infection rate of toxoplasmosis in sheep and goats in east
Azarbaijan province of Iran a total of 186 sera, 13 fetal brains, 13 cotyledons and 34 whole blood samples
were collected from sheep and goats in Tabriz abattoir during the year 2010. Serum samples were tested for
IgG antibodies against Toxoplasma gondii by Enzyme Linked Immunosorbent Assay (ELISA). This test is
used in conjunction with direct and nested PCR techniques for detection of T. gondii DNA in blood,
cotyledon and brain of fetuses, using 4 pairs of universal and specific primers, 18SrRNA, ITS-1, (Tg1,Tg2)
and (Tg3,Tg4). Antibodies against T. gondii were found in 18.3% serum samples. DNA of T. gondii was
detected in 69% of fetal brains, 23% of cotyledons and 14.7% of blood samples. The prevalence rate of T.
gondii in sheep was 24.8% and in goats was 10.6% and the significant difference was observed between
sheep and goats groups (p≤0.05). The prevalence of toxoplasmosis antibodies was significantly higher in
adult sheep and goats than younger animals. There was significant difference between male (10.5%) and
female (19.2%) sheep and goat was observed (p≤0.05). Detection of T. gondii DNA using PCR minimizes
the problems which the researcher may face when using serological methods and facilitates diagnosis in
complex cases. The presence of T. gondii in blood, fetal tissues and neonatal specimens strongly suggests
active and or congenital infection.