An investigation of the concurrency of anti- antibody and parasitemia in water buffalo () in northwest of Iran.

is an obligate intracellular parasite causing abortion and reproductive failure in ruminants. Here, the seroprevalence of DNA and anti- antibodies and the correlation between the DNA and the antibody using polymerase chain reaction (PCR) and a new developed whole cell-based enzyme-linked immunosorbent assay (ELISA) in water buffalo () were investigated. To determine the level of anti- antibody, 83 serum samples were collected from buffaloes in the northwest of Iran. Plates were coated with 2 × 10 whole tachyzoites and the anti- antibody level was determined by calculating the ratio of sample/positive control (S/P) optical densities (ODs) in the ELISA. All samples with the ration of 0.50 or above were accounted as positive. To confirm the presence of DNA, the serum samples were directly subjected to PCR and nested PCR for detection of NC5 gene without the DNA isolation process. A total number of 83 buffalo serum samples were examined for the presence of anti- immunoglobulin G and DNA. All samples with the S/P ratio of 0.50 or above (16 samples, 19.27%) were also positive for DNA. All samples with OD less than 0.50 (34 samples, 40.96%) were negative for DNA. However, 33 samples with the S/P ratio of bellow 0.50 (39.75%) showed a significant level of antibody. A 100% correlation was observed between high levels of the anti- antibody and DNA in the serum of water buffalo, and the whole tachyzoites have the potency to be used as antigens for detection of the parasite in ELISA.