Characterization of Chikungunya Virus: Emergence and Responses to Outbreaks

Abstract

Chikungunya (CHIKV) is a re-emerging mosquito-borne alphavirus of the Togaviridae family that causes acute febrile arthralgia. The virus contains a 12kb single-stranded, positive sense RNA genome, circulates in zoonotic and urban cycles, and is transmitted by mosquitos of the Aedes species. Over the past ten years, a convergence of factors including a mutation in the E1 envelope glycoprotein have facilitated the geographic expansion of CHIKV infection to more than fifty countries, affecting over 2 million persons in the Indian Ocean, Pacific Ocean, and Caribbean regions. This thesis examines current knowledge on CHIKV including its phylogeny, structure, and pathogenesis. It has been found that CHIKV encodes four nonstructural proteins that participate in the replication cycle of the virus as the replicase complex and capsid and envelope structural glycoproteins with antigenic properties. Examination of the Alanine to Valine mutation in the IOL CHIKV strain also offered further insight into the emergence of this virus via Ae. albopictus transmission. This work considers the potential for various control strategies against CHIKV in light of these known viral properties. Promising antiviral candidates include broad spectrum drugs, or those previously licensed against other viruses, and vaccine candidates reflect modern vaccine technologies for delivery of the defined CHIKV antigens. In the absence of CHIKV treatment and prophylaxis, novel species-specific approaches to vector control that utilize bacterial endosymbionts to block pathogen transmission and DNA technology to genetically modify mosquitos may rapidly curtail the spread of not only CHIKV, but other mosquito-borne infections that are constantly emerging or re-emerging as global pathogens.