The Serological Response in Cattle following Administration of a Heterologous Sheep Pox Virus Strain Vaccine for Protection from Lumpy Skin Disease; Current Situation in Armenia

SIMPLE SUMMARY: Lumpy skin disease (LSD) is an economically important viral disease of cattle caused by the lumpy skin disease virus (LSDV) of the Poxviridae family. It was first reported in Armenia in 2015 when the disease was rapidly identified with no further spread from the initial outbreak. This was followed by a vaccination campaign to help keep the disease from returning. Vaccination can be a powerful tool for preventing the spread of transboundary diseases, but there is currently no single vaccine that protects cattle from all strains of LSD, with many vaccines providing various results. We sought to assess the quality of vaccination currently used in Armenia by evaluating the antibody response of a dry culture sheep pox virus-based vaccine against LSD in cattle. Cattle were able to produce protective antibodies >80%, which should protect against lumpy skin disease, based on previous observations, but suggests more work is needed. We have also observed no adverse side-effects in cattle following vaccination. In an area that is not suffering from continuous outbreaks, we suggest this vaccine could be a safe alternative for protection from LSD in cattle. ABSTRACT: Lumpy skin disease (LSD) is a highly infectious viral disease of cattle caused by LSD virus (LSDV), which was first reported in Armenia in late 2015. It was identified in pasture-raised cattle near the border with Iran. Currently, vaccination plays a key role in preventing further incursion of disease in high-risk areas. The purpose of this work was to assess the quality of vaccination currently used in Armenia by determining the immune response of the heterologous dry culture sheep pox virus-based vaccine against LSD in cattle. Seroprevalence and seroconversion testing was carried out using an ELISA to detect specific antibodies against LSD before and 30 days after vaccination in three adjacent regions of Armenia (Ararat, Armavir, Gegharkunik). Ixodes ticks were also examined for the presence of LSDV via real-time PCR. We found that the heterologous vaccine used in Armenia creates a high level of population immunity of 86.09% (83.83–87.97%) and no adverse side effects were observed in cattle. Of the 6 types of Ixodes ticks identified and tested, we found no evidence of LSDV circulating in these vectors. These results suggest that regular serological monitoring via ELISA and heterologous vaccination should continue in areas of Armenia at high risk for incursion of LSD to reduce the spread of this highly infectious transboundary disease.