Virology
Immunomodulation by the gammaherpesvirus of Malignant Catarrhal
fever
Haig, D
SEERAD funded
Malignant Catarrhal Fever (MCF) is a fatal disease of cattle and other susceptible species such as deer and bison, caused by a family of gamma-herpesviruses including Alcelaphine herpsesvirus-1 (AlHV-1), which persistently infects wildebeest and causes MCF in cattle in East Africa, and Ovine herpesvirus-2 (OvHV-2), a widespread, persistent virus of sheep, which is the cause of sheep-associated MCF worldwide.
In the natural (reservoir) host, MCF virus infection is persistent and does not cause any overt disease. In contrast, infection of a susceptible host species causes MCF, with clinical signs similar to other important cattle diseases such as FMD, BVD and rinderpest. Early diagnosis is currently not possible as MCF is recognised only in the acute stages when the infected animal is near death. The route of infection is also not understood though the virus is assumed to be passed through close contact or via aerosol from the nasal/oral secretions of the reservoir host. The disease is sporadic but has serious consequences, since most animals showing clinical MCF either die or are culled. However, surveillance of this disease is difficult with traditional diagnostic tools due to the ability of the virus to persist for the lifetime of the reservoir host with little detectable virus or viral antigen.
MCF research at Moredun has three main goals:
• to improve the diagnostic tools available for MCF
• to understand how the virus causes disease in cattle
• to devise appropriate means for treatment and prevention
This project will analyse the immune pathology of MCF in order to help researchers understand the host-virus interactions that contribute to the disease process and immunity. Central to this research is the recent sequencing of the entire OvHV-2 genome by a consortium including Moredun . This allows us to look at the expression of both host and viral genes in MCF-affected animals and improve our understanding of the immune dysregulation that appears to be central to MCF. This project will also analyse the factors required for protection from herpesvirus infection with the aim of developing potential vaccines against this infection. Initial results are promising and importantly they have potential for application to a wider range of herpesvirus infections of livestock.
It is hoped that this research will also provide information that may be used to improve current viral surveillance and to advise end-users on best practise to reduce the occurrence of disease.