Chikungunya and dengue viruses may be transmitted with even one bite of Aedes aegypti, which is the primary mosquito that carries Zika virus.
The findings shed new light on what is known as a co-infection, which scientists say 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 at Colorado State University (CSU) in the US.
The 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.
The researchers found that mosquitoes in the lab can transmit all three viruses simultaneously, although this is likely to be extremely rare in nature.
While they described the lab results as surprising, researchers said there is no reason to believe that these co-infections are more severe than being infected with one virus at a time.
“Dual infections in humans, however, are fairly common, or more common than we would have thought,” Ruckert said.
The researchers had expected to find that one virus would prove to be dominant and outcompete the others in the midgut of the mosquito where the infections establish and replicate before being transmitted to humans.
“It is interesting that all three replicate in a really small area in the mosquito’s body,” Ruckert said.
“When these mosquitoes get infected with two or three different viruses, there is almost no effect that the viruses have on each other in the same mosquito,” she said.
The first report of chikungunya and dengue virus co-infection occurred in 1967, researchers said.
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.
The research was published in the journal Nature Communications.