Bovine viral diseases: the role of host genetics.

Abstract

Abstract This chapter explores the major viral diseases of cattle and identifies those that are likely to be amenable to control assisted by host genetic selection, using either known polymorphisms in disease resistance genes or whole-genome approaches. Candidate genes for viral resistance include host receptors, pathogen recognition receptors, genes in the type I interferon pathway, restriction factors, cytokines, genes associated with viral and infected cell destruction, natural killer (NK) cell receptors and ligands, and genes in the major histocompatibility complex. Considerable evidence exists for the role of polymorphisms in genes in each of these categories in resistance to various viral diseases. However, attention is increasingly turning to the potential use of whole genome scans to find markers that may either be used to assist in the identification of causal mutations or to breed for resistance. Cattle viral diseases where host genetic variation has been quantified, or significant genetic marker associations demonstrated, include bovine leukaemia, various bovine respiratory diseases, bovine herpesvirus 1 (BHV-1) and, anecdotally in cattle, foot and mouth disease. Breed or species-level variation in resistance to rinderpest, malignant catarrhal fever (MCF) and lumpy skin disease has also been reported. Overwhelming evidence suggests that genetics could provide new approaches to disease control in the rapidly changing environment faced by cattle breeders, both in developed and developing countries. However, many obstacles and difficulties lie ahead if we are to achieve these goals, with bridging the phenotype gap and fully understanding the mechanisms of disease resistance being major challenges.