Arthrogenic Alphaviruses and Inflammatory Myopathies

Abstract

There is increasing evidence to suggest that viruses have aetiological roles in the idiopathic inflammatory myopathies. Arthrogenic alphaviruses (such as chikungunya virus, Ross River virus and sindbis virus) are known to cause outbreaks of polyarthritis worldwide. The clinical presentation of alphavirus infection includes fever, rash, arthralgia, and arthritis, however, one of the most predominant features of alphaviral disease are symptoms of myalgia with corresponding myositis. The recent outbreaks of chikungunya virus in several countries surrounding the Indian Ocean has seen millions of people affected, with case reports indicating a high incidence of myalgia and skeletal muscle involvement in the aetiology of this disease. The mechanisms of how alphaviruses cause musculoskeletal disease are slowly being unraveled with evidence to suggest that the viral induced inflammation can result in damage to the skeletal muscle tissues, possibly explaining the symptoms of myalgia. In recent years, the use of small animal models for alphavirus-induced myositis has furthered our understanding of the idiopathic inflammatory myopathies caused by these viruses. This chapter will discuss the role of alphaviruses as an often-overlooked cause of myositis, including how small animal models are being used to dissect the pathobiology of disease and identify potential drug candidates to ameliorate disease.