As winter melts away, the Aedes mosquito population rises with the temperature. When these mosquitoes puncture host skin to feed with their needle-like probosces, they often transmit pathogens like the Zika virus into the wound.
While Zika virus usually results in a mild infection, it can lead to severe birth defects if contracted during pregnancy. Despite having caused disease outbreaks in 89 countries globally, researchers do not fully understand the factors that drive viral transmission success.
Noushin Emami, an infectious biologist at the Liverpool School of Tropical Medicine, studies how pathogens manipulate their hosts and vectors to promote transmission.
Noushin Emami
Now, scientists found that Zika virus infection manipulates human skin cells to emit chemical signals that attract mosquitoes to further its spread.1 The results, published in Communications Biology, offer insights on how viruses may influence vector behavior to improve their transmission success.
“Basically, [the virus] is very sneaky,” said Noushin Emami, an infectious biologist at the Liverpool School of Tropical Medicine and study coauthor. “[It] doesn't have any organs, but gets our organs and shakes hands, writes a contract with them, and says, ‘okay, now you're working for me.’”
Emami had previously shown that the malarial parasite manipulates its host to make it more attractive to insect vectors, and wondered whether viruses would exhibit similar properties.2 Other researchers had previously found that viruses can manipulate the host skin microbiota to produce mosquito-attracting odors, but the role of infected skin cells in this process remained poorly understood.3
Joining forces with Gisa Gerold, a virologist at the Medical University of Innsbruck, Emami and her team investigated how fibroblasts in the dermis of the skin, where the first viral amplification usually occurs, react to Zika virus infection.
On running the volatiles extracted from Zika infected cultured human dermal fibroblasts, the team noted increased emission of 14 volatile organic compounds (VOCs). The researchers found that these VOC profiles specifically attracted female Aedes aegypti mosquitoes that transmit Zika virus, but not Anopheles gambiae mosquitoes that do not transmit Zika virus.
The team also found that bloodmeal placed near the VOC blend attracted more mosquitoes compared to one placed next to a control. “We were hoping to see [such an effect],” said Gerold. “But we were actually really excited to see that.”
Gisa Gerold, a virologist at the Medical University of Innsbruck, studies how viruses interact with host cells.
Gisa Gerold
According to Emami, scientists often think that the transmission of viruses is passive because viruses simply consist of encapsulated genetic material, so the virus using human system for their benefit was surprising. “It was our hypothesis, but when it was confirmed, I was very happy.”
Finally, the researchers sought to understand the mechanism by which the virus altered VOC production from skin fibroblasts. Transcriptomic and proteomic analyses, including those from previously published studies, revealed increased expression of genes and enzymes associated with antiviral mechanisms and lipoprotein metabolism in Zika-infected fibroblasts.
“We tried really hard to find the exact metabolic pathway that is manipulated by viruses to make these compounds,” said Gerold. But researchers have never found the skin to release the VOCs they identified, making it difficult to identify the underlying mechanism, she explained. The team intends to study human skin explants and mice to further investigate the mechanism.
“It's a good lead, good observation. But this is only a starting point,” said Shashank Tripathi, a virologist at the Indian Institute of Science, who was not involved in the study. Further studies must investigate this effect in animal models and humans. He added, “A single bite in a large individual—is that enough to produce volatile molecules to attract mosquitoes? There's so much more that remains to be explored and proven.”
- Mozūraitis R, et al. Zika virus modulates human fibroblasts to enhance transmission success in a controlled lab-setting. Commun Biol. 2025;8(1):139.
- Emami SN, et al. A key malaria metabolite modulates vector blood seeking, feeding, and susceptibility to infection. Science. 2017;355(6329):1076-1080.
- Zhang H, et al. A volatile from the skin microbiota of flavivirus-infected hosts promotes mosquito attractiveness. Cell. 2022;185(14):2510-2522.e16.
