Bluetongue (BT) is a serious hemorrhagic disease of ruminants caused by bluetongue virus (BTV). Inactive BTV vaccines have been successful in field trials in some areas, and inactivated vaccines are considered safer. ...Bluetongue (BT) is a serious hemorrhagic disease of ruminants caused by bluetongue virus (BTV). Inactive BTV vaccines have been successful in field trials in some areas, and inactivated vaccines are considered safer. However, information about the effect of the viral antigen level on the serological response and efficiency of the inactive BTV-16 vaccine is lacking. In the present study, the serological response and efficiency of the viral antigen concentration in the binary ethylenimine-inactivated Chinese BTV serotype-16 vaccine were investigated. The viral antigens in the viral suspension (VS) were quantified using a modified BTV AC-ELISA method. Four batches of vaccine containing 1, 5, 10, and 50 μg/ml of viral antigen were generated from the VS. Four groups of naive Chinese sheep were vaccinated with the different vaccine batches, and the serological response and vaccine efficiency were investigated before and after challenge infection. The vaccines containing 10 and 50 μg/ml of viral antigen induced significant ELISA and neutralizing antibody titers 14 days after vaccination, whereas the vaccines containing 1 and 5 μg/ml of viral antigen did not have these effects. A booster immunization at 21 days enhanced all groups’ antibody titers;however, the increased titer was related to the viral antigen level. In contrast to the serological response, the viral antigen level of the vaccines did not have a significant effect on the vaccine efficiency. With the exception of one sheep from the 5 μg/ml viral antigen group, all vaccinated sheep from the four antigen level groups showed strong resistance to infection based on their clinical symptoms, rectal temperatures and viremia. Collectively, these data suggested that viral antigen levels from 1 to 50 μg/ml had a significant effect on the serological response of the animals but a limited effect on the vaccine efficiency. The BTV-16 vaccine containing 1 μg/ml of viral antigen was sufficient to achieve high efficiency, but only the vaccines with more than 10 μg/展开更多
The aim of the present study was to estimate the seroprevalence of antibodies to bluetongue virus (BTV) among domestic ruminants of Grenada. Sera samples from cattle (133), goat (314) and sheep (481) were tested using...The aim of the present study was to estimate the seroprevalence of antibodies to bluetongue virus (BTV) among domestic ruminants of Grenada. Sera samples from cattle (133), goat (314) and sheep (481) were tested using competitive Enzyme-linked immunosorbent assay (c-ELISA). Of the total of 928 samples tested, the overall BTV seroprevalence was 78.4% (95% confidence interval (CI ± 2.65). The seropositivity of ovine, caprine and bovine was found to be 71.7% (95% CI, 67.67% to 75.73%), 80.2% (95% CI, 75.79% to 84.61%) and 98.5% (95% CI, 96.43% to 100.57%), respectively. There was statistical significance in the seroprevalence of BTV among bovine, caprine and ovine (p < 0.05). It is evident from this study that blue tongue virus is endemic in Grenada.展开更多
文摘Bluetongue (BT) is a serious hemorrhagic disease of ruminants caused by bluetongue virus (BTV). Inactive BTV vaccines have been successful in field trials in some areas, and inactivated vaccines are considered safer. However, information about the effect of the viral antigen level on the serological response and efficiency of the inactive BTV-16 vaccine is lacking. In the present study, the serological response and efficiency of the viral antigen concentration in the binary ethylenimine-inactivated Chinese BTV serotype-16 vaccine were investigated. The viral antigens in the viral suspension (VS) were quantified using a modified BTV AC-ELISA method. Four batches of vaccine containing 1, 5, 10, and 50 μg/ml of viral antigen were generated from the VS. Four groups of naive Chinese sheep were vaccinated with the different vaccine batches, and the serological response and vaccine efficiency were investigated before and after challenge infection. The vaccines containing 10 and 50 μg/ml of viral antigen induced significant ELISA and neutralizing antibody titers 14 days after vaccination, whereas the vaccines containing 1 and 5 μg/ml of viral antigen did not have these effects. A booster immunization at 21 days enhanced all groups’ antibody titers;however, the increased titer was related to the viral antigen level. In contrast to the serological response, the viral antigen level of the vaccines did not have a significant effect on the vaccine efficiency. With the exception of one sheep from the 5 μg/ml viral antigen group, all vaccinated sheep from the four antigen level groups showed strong resistance to infection based on their clinical symptoms, rectal temperatures and viremia. Collectively, these data suggested that viral antigen levels from 1 to 50 μg/ml had a significant effect on the serological response of the animals but a limited effect on the vaccine efficiency. The BTV-16 vaccine containing 1 μg/ml of viral antigen was sufficient to achieve high efficiency, but only the vaccines with more than 10 μg/
文摘The aim of the present study was to estimate the seroprevalence of antibodies to bluetongue virus (BTV) among domestic ruminants of Grenada. Sera samples from cattle (133), goat (314) and sheep (481) were tested using competitive Enzyme-linked immunosorbent assay (c-ELISA). Of the total of 928 samples tested, the overall BTV seroprevalence was 78.4% (95% confidence interval (CI ± 2.65). The seropositivity of ovine, caprine and bovine was found to be 71.7% (95% CI, 67.67% to 75.73%), 80.2% (95% CI, 75.79% to 84.61%) and 98.5% (95% CI, 96.43% to 100.57%), respectively. There was statistical significance in the seroprevalence of BTV among bovine, caprine and ovine (p < 0.05). It is evident from this study that blue tongue virus is endemic in Grenada.
