Serological response of foals to polyvalent and monovalent live-attenuated African horse sickness virus vaccines.
African horse sickness (AHS) is typically a highly fatal disease in susceptible horses and vaccination is currently used to prevent the occurrence of disease in endemic areas. Similarly, vaccination has been central to the control of incursions of African horse sickness virus (AHSV) into previously unaffected areas and will likely play a significant role in any future incursions. Horses in the AHSV-infected area in South Africa are vaccinated annually with a live-attenuated (modified-live virus [MLV]) vaccine, which includes a cocktail of serotypes 1, 3, 4 (bottle 1) and 2, 6-8 (bottle 2) delivered in two separate doses at least 21 days apart. In this study, the neutralising antibody response of foals immunized with this polyvalent MLV AHSV vaccine was evaluated and compared to the response elicited to monovalent MLV AHSV serotypes. Naïve foals were immunized with either the polyvalent MLV AHSV vaccine, or a combination of monovalent MLV vaccines containing individual AHSV serotypes 1, 4, 7 or 8. There was a marked and consistent difference in the immunogenicity of individual virus serotypes contained in the MLV vaccines. Specifically, foals most consistently seroconverted to AHSV-1 and responses to other serotypes were highly variable, and often weak or not detected. The serotype-specific responses of foals given the monovalent MLV vaccines were similar to those of foals given the polyvalent MLV preparation suggesting that there is no obvious enhanced immune response through the administration of a monovalent vaccine as opposed to the polyvalent vaccine.
['Crafford|J E|JE|', 'Lourens|C W|CW|', 'Smit|T K|TK|', 'Gardner|I A|IA|', 'MacLachlan|N J|NJ|', 'Guthrie|A J|AJ|']
D000355:African Horse Sickness D000356:African Horse Sickness Virus D000818:Animals D057134:Antibodies, Neutralizing D000914:Antibodies, Viral D006736:Horses D056724:Immunity, Humoral D009500:Neutralization Tests D011897:Random Allocation D012703:Serotyping D013019:South Africa D014613:Vaccines, Attenuated D014765:Viral Vaccines
African horse sickness virus Vaccination Modified-live virus vaccine Neutralizing antibody