Therapeutic and Prophylactic Potential of FMD Virus-specific Polyvalent Immunoglobulins during an FMD Outbreak in Cattle

Abstract

Foot and mouth disease (FMD) is a highly contagious and economically devastating disease of cloven-hoofed animals worldwide. In the present study the therapeutic and prophylactic potential of polyclonal, polyvalent FMD virus-specific bovine antibodies has been investigated as a possible approach for rapid control, lessening of the severity of clinical signs and prophylactic protection of susceptible animals during FMD outbreaks. The prepared FMD virus-specific polyvalent immunoglobulins were concentrated, purified, filter sterilized (0.22nm) and its titer against the FMD virus serotypes, A, O and SAT2, was adjusted to 2.15, 2.25 and 2.10 log10 TCID50/ml, respectively. In an experimental FMDV induced infection, the immunoglobulin therapy was given 4 days post experimental infection. The effect of different doses of immunoglobulins (4, 6 and 8ml) the severity of the clinical signs, healing of lesions and virus shedding was determined. A dose of 8 ml (2.0 log10 TCID50/ml) of the prepared FMD virus-specific antibodies proved highly effective in reducing the severity of the clinical signs and inducing recovery within 48 - 96hrs post therapy, as compared with the control non-treated infected calves. A dose related recovery rate was recorded. Field trial was conducted and evaluated during the FMD outbreak in Egypt during 2016/2017. Significant reduction of the morbidity of the disease and 100% reduction of mortality were recorded. The prepared FMD virus-specific bovine polyvalent antibodies proved to be a drug of choice during FMD outbreaks protecting susceptible animals and inducing rapid recovery of diseased one associated with reducing clinical signs severity and reducing virus shedding.