A new study reports that Aedes aegypti mosquitoes that carry Zika can also transmit dengue and chikungunya in the same bite.
“A mosquito, in theory, could give you multiple viruses at once,” said Claudia Ruckert, a post-doctoral researcher at Colorado State University in the U.S.
In the study, the research 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.
They found that saliva samples from the mosquito tested positive for all three viruses 14 days after the insects were exposed. Another saliva samples tested positive 21 days after exposure.
While not all the insects had the virus in the saliva, the researchers pointed out that the virus’ presence in the saliva occurs only after the infection has traveled through the body. As a result, the other mosquitoes that tested positive may still have been able to transmit the disease in the future even if the virus was not found in the saliva.
The results showed that mosquitoes in the lab could 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,” Ms. Ruckert added.
One virus proved to be dominant and out-competed the others in the midgut of the mosquito where the infections establish and replicate before being transmitted to humans.
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.
The researchers published their findings in the journal Nature Communications.