In vitro culture of Toxoplasma gondii in HeLa, Vero, RBK and A549 cell lines.

Toxoplasma gondii is a protozoan parasite which can be grown in vivo and in vitro. Various cell lines are used for T. gondii culture in vitro. In this study, four cell lines of HeLa, Vero, RBK and A549 were compared with each other for T. gondii tachyzoites culture. The four cell lines were cultured and infected with 5,000,000 tachyzoites, respectively. The number of tachyzoites and viable host cells and pH of the media were assessed in each culture. The highest tachyzoite yield was seen in HeLa cell culture. The lowest number of viable host cells and the lowest pH were seen in HeLa cell line culture. The lowest tachyzoite yield, the highest viable cell and the highest pH were observed in Vero cell line culture. HeLa and Vero cell lines are thus appropriate for rapid and long-term propagations of T. gondii tachyzoites, respectively.

Seroprevalence of bovine leukemia virus (BLV) infection in dairy cattle in Isfahan Province, Iran.

Bovine leukemia virus (BLV), the causative agent of enzootic bovine leukosis (EBL) is an exogenous C-type oncovirus in the Retroviridae family. It causes significant economic losses associated with the costs of control and eradication programs due to carcass condemnation at slaughter and restrictions of export of cattle and semen to importing countries. The main objective of this research was to determine the seroprevalence of BLV infection in cattle herds in central region of Iran (Isfahan province) using a commercial enzyme-linked immunosorbent assay (ELISA) to detect serum antibodies against BLV. Samples of blood serum were collected from 403 female dairy cattle (Holstein-Friesian) from 21 livestock farms and 303 animals (81.9%) were BLV seropositive. A significant association was found between age as a potential risk factor and BVL seroprevalence with animals ≥ 4 years (86.6%) having a significantly (χ(2) = 35.6, p < 0.001) higher seroprevalence compared to those < 4 years (54.2%). We found no significant statistical association between seroprevalence and pregnancy, lactation status and farming systems as potential risk factors in this study (p > 0.1). It is concluded that BLV infection is a very common problem in the study area. Hence, control measures should be instituted to combat the disease and further studies are required to investigate the impact of this disease on dairy production in the country.