Alphavirus and Its Vertebrate Hosts
from: Bats and Viruses: Current Research and Future Trends (Edited by: Eugenia Corrales-Aguilar and Martin Schwemmle). Caister Academic Press, U.K. (2020) Pages: 27-34.
Alphaviruses are positive-sense single-stranded RNA arthropod-borne zoonotic arboviruses, which belong to the family Togaviridae. Geographically, alphaviruses have a near worldwide distribution and around 30 species have been described. Antigenic and evolutionary patterns classify alphaviruses into ten antigenic complexes and show association with reservoir and human disease. Clinically, alphaviruses are associated with a range of diseases, including mild febrile disease, rash and encephalitis, but sometimes results are fatal. Recent studies of 'dengue-like' illness in Latin America have revealed that many alphaviruses such as Venezuelan equine encephalitis, Madariaga, Mayaro and chikungunya viruses are misdiagnosed as dengue; diagnosis based on only signs and symptoms is even more complicated in areas where these viruses circulate simultaneously. In nature, alphaviruses are maintained in enzootic sylvatic cycles that involve a vertebrate host and enzootic vectors. However, altered host and mosquito ranges have been reported during alphavirus emergence and major epidemics. Epidemiological and serological evidence suggest that several species of mammals could serve as enzootic reservoirs and potential amplifiers of alphaviruses in nature. This chapter describes the current state of alphavirus reservoirs, with a focus on major alphaviruses, namely VEEV, MADV, EEEV and CHIKV, and future implication of alphavirus ecological studies for outbreak investigation and control read more ...