Making hosts smell tastier: How mosquito‐borne viruses take the initiative in viral transmission

Abstract

There are hundreds of mosquito-borne viruses in nature that can be carried and transmitted by mosquitoes to human and animal hosts, causing serious diseases such as viral encephalitis, meningitis and haemorrhagic fever. Over the past two decades, emerging and re-emerging mosquito-borne viruses, including dengue virus, Zika virus, chikungunya virus and West Nile virus, have become a public health challenge worldwide, causing billions of infections and hundreds of thousands of deaths each year. 1 For instance, approximately 2.5 billion people in the world live in areas where dengue virus is endemic. Each year, approximately 390 million people become infected or reinfected with dengue virus, leading to 500 000-1 million hospital admissions, and dengue fever epidemics have occurred in more than 100 countries and regions worldwide. 2 Mosquito-borne viruses are transmitted from mosquitoes to hosts. In the virus transmission cycle, mosquitoes need to find, locate and bite an infected person or animal to feed on the blood that carries the virus. Subsequently , mosquitoes are able to carry and rapidly transmit the virus. 3 If a mosquito bites an uninfected person, it cannot become infected, and the virus transmission cycle is interrupted. At the beginning of a mosquito-borne viral epidemic, the proportion of infected individuals in the population is not high. Instead, mosquitoes are able to select infected individuals in the population to bite, thus accelerating the spread of the virus and causing an epidemic outbreak. How effectively the mosquito locates the infected host and acquires the virus is the main rate-limiting step in the 'host-virus-mosquito' transmission cycle. How do mosquitoes locate their infectors, and what are the reasons for the rapid spread of mosquito-borne viruses in nature? In a recent study published in Cell, Zhang et al. identified a previously unknown role of dengue and Zika viruses in regulating the host to promote viral transmission. 4 The authors built two classical behavioural devices (a three-cage olfactometry device and a two-arm olfactometry device) and found that mice infected with dengue and Zika viruses were significantly more attractive to Aedes aegypti and Aedes albopictus. The authors then analysed the body temperature, carbon Clin. Transl. Med. 2023;13:e1168. wileyonlinelibrary.com/journal/ctm2 1 of 3 https://doi.