Mosquitoes have the ability to transmit more than one virus in single bite, according to study

Aedes aegypti mosquitoes may also transmit other flaviviruses like Zika virus, chikungunya, and dengue fever within the course of one bite in a process called coinfection, according to a recent study conducted by researchers at Colorado State University (CSU).

Aedes aegypti mosquitoes are known to be the most-common species for flavivirus transmission in the Americas.

The study centers on CSU researchers infecting mosquitoes with multiple types of viruses to learn in greater detail about the transmission of more than one infection from a single bite. Although coinfections of two viruses are fairly common, the researchers found that coinfections of three or more viruses are only appear in extremely rare circumstances in nature.

The researchers said they expected to observe that one virus would become more dominant than others in the midgut area of the mosquito, which is where viruses begin to replicate before being passed to humans.

“It’s interesting that all three replicate in a really small area in the mosquito’s body,” Claudia Ruckert, a CSU post-doctoral researcher, said. “When these mosquitoes get infected with two or three different viruses, there’s almost no effect that the viruses have on each other in the same mosquito.”

Over the course of the study the researchers came to the conclusion that there was no evidence that coinfection of humans resulted in infections that were clinically more severe. The team said, however, it was also likely that coinfections in humans are significantly under-diagnosed.

“Depending on what diagnostics are used, and depending on what the clinicians think, they might not notice there’s another virus,” Ruckert said. “It could definitely lead to misinterpretation of disease severity.”

Ruckert said the next step for her team was to examine how coinfections affect the evolution of viruses within mosquitoes and how it differs from mosquitoes infected with only one virus. The CSU team also said they were interested in adding a fourth virus, yellow fever, to the mix to determine what interactions may occur.