Yellow fever mosquitos can carry both the Zika virus and the chikungunya virus in their saliva, which implies that people can be infected with both viruses in a single bite. Scientists from Wageningen University & Research are publishing these findings this week in the Open Access magazine PLoS Neglected Tropical Diseases.
Since 2015 there has been a major outbreak of Zika virus and chikungunya virus in Central and South America and the Caribbean. Both the local population and tourists in these areas can contract the diseases after being bitten by infected mosquitoes.
There is still no vaccine to protect people against these viruses. While a Zika infection usually causes mild symptoms, for pregnant women it can result in serious damage to the brain of her unborn child. An infection with the chikungunya virus causes severe fever, skin rash and serious joint pain which may become chronic. Infections with both of these viruses in patients is being reported increasingly often.
To gain more insight into the speed in which the viruses can spread worldwide, virologists and entomologists from Wageningen University & Research studied whether a single bite by a mosquito could actually transmit Zika and chikungunya at the same time.
In a Wageningen facility with special precautions - a so-called biosafety level 3 [SK1] laboratory - the scientists infected yellow fever mosquitoes (Aedes aegypti) in three different ways: with the Zika virus, with the chikungunya virus, and with both viruses at once. In doing so they hoped to find out whether the viruses would impede or stimulate each other during the infection of the mosquito.
The research showed that both viruses easily multiplied in the mosquito body. In the case of at least 12% of the co-infected mosquitoes , both viruses were present in the mosquito saliva. This implies that a single mosquito bite can simultaneously transmit both Zika and chikungunya to people.
This study into viruses that can be transmitted to humans by mosquitoes is an excellent example of the research being carried out within Wageningen University & Research's Global One Health programme. The programme is aimed at managing the risks of new and endemic infectious diseases, an issue of major importance in terms of global heath and food security. A better insight into the role of the mosquito as a disease transmitter can lead to more specific mosquito control and disease prevention.
Article: Mosquito co-infection with Zika and chikungunya virus allows simultaneous transmission without affecting vector competence of Aedes aegypti, Giel P. Göertz, Chantal B. F. Vogels, Corinne Geertsema, Constantianus J. M. Koenraadt, Gorben P. Pijlman, PLoS Neglected Tropical Diseases, doi: 10.1371/journal.pntd.0005654, published 1 June 2017.