Mosquitoes that transmit Zika virus could spread other viruses
A new study led by Colorado State University, United States (US), researchers found that Aedes aegypti, the primary mosquito that carries Zika virus, might also transmit chikungunya and dengue viruses with one bite. The findings shed new light on what’s known as a coinfection, which scientists said is not yet fully understood and may be fairly common in areas experiencing outbreaks.
“A mosquito, in theory, could give you multiple viruses at once,” said Claudia Ruckert, post-doctoral researcher in CSU’s Arthropod-borne and Infectious Diseases Laboratory.
The research team’s paper was published May 19 in Nature Communications. The CSU team infected mosquitoes in the lab with multiple kinds of viruses to learn more about the transmission of more than one infection from a single mosquito bite. While they described the lab results as surprising, researchers said there’s no reason to believe that these coinfections are more severe than being infected with one virus at a time. Existing research on coinfections is sparse, and the findings are contradictory.
One, two, three viruses in one mosquito, Chikungunya, dengue and Zika viruses are transmitted to humans by Aedes aegypti mosquitoes, which live in tropical, subtropical, and in some temperate climates. As the viruses continue to emerge into new regions, the likelihood of co-infection by multiple viruses may be increasing. At the same time, the frequency of co-infection and its clinical and epidemiologic implications are poorly understood.
The first report of chikungunya and dengue virus co-infection occurred in 1967, according to the study. More recently, co-infections of Zika and dengue viruses, Zika and chikungunya, and all three viruses have been reported during various outbreaks, including the recent outbreak of Zika virus in North and South America.
Ruckert said the research team found that mosquitoes in the lab can transmit all three viruses simultaneously, although this is likely to be extremely rare in nature.
“Dual infections in humans, however, are fairly common, or more common than we would have thought,” she said.
CSU researchers had expected to find that one virus would prove to be dominant and outcompete the others in the mid-gut of the mosquito where the infections establish and replicate before being transmitted to humans.