No volunteer attracted all three disease-carrying species, a finding with practical value as Florida logs its largest local dengue outbreak in decades

Why do some people get bitten more than others? A Florida International University (FIU) study suggests the answer depends on which mosquito is doing the biting. Among 119 volunteers, three disease-carrying species each favored a different group of people, and not one person ranked as highly attractive to all three, according to the study in iScience.

The species were Aedes aegypti, the main dengue mosquito; Aedes albopictus, the Asian tiger mosquito; and Culex quinquefasciatus, the southern house mosquito that spreads West Nile virus. Together they carry dengue, Zika, yellow fever, and West Nile.

The research, first published this summer and highlighted again this week on ScienceDaily, lands as Florida battles a dengue surge. The state health department counted 425 locally acquired dengue cases in 2026 from 11 counties through its Oct. 11 to 17 report, compared with 62 in all of 2025, Medical Economics reported.

Three Species, Three Different Favorite Targets

Volunteers placed an arm inside a device called an olfactometer, which let mosquitoes smell them but not bite. Researchers counted how many mosquitoes of each species moved toward each person.

The daytime-biting Aedes aegypti favored people who were not wearing added fragrance and whose skin gave off lower levels of certain compounds. It also showed a slight preference for men over women. The Asian tiger mosquito, also a daytime biter, was drawn to people whose skin released more ketones and plant-like volatile compounds.

The night-biting Culex quinquefasciatus appeared most sensitive to the skin microbiome. Certain bacterial families were linked to higher attraction, while others seemed to discourage biting.

There was only weak overlap between the people the two Aedes species preferred, and some volunteers attracted few mosquitoes of one species but many of another. In practical terms, being a poor target for one mosquito offered no guarantee of protection from the others.

"We didn't expect the species to prefer different people," said lead author Kaylee Marrero, a Ph.D. student at FIU, according to the university's announcement.

Swabs, Odor Samples and a Microbial Signature

Alongside the attraction tests, the team collected odor samples and swabbed each volunteer's skin. Odor compounds were profiled with gas chromatography-mass spectrometry, and skin bacteria were identified through microbiome profiling. Human skin releases more than 1,000 volatile compounds, many produced or altered by bacteria, which is why odor and microbes were studied together.

The team then compared the most and least attractive people for each species. Bacterial signatures differed between those groups, and the bacteria tied to attraction were not the same across species. That suggests each mosquito evolved its own way of decoding human scent.

Matthew DeGennaro, the FIU neurogeneticist who leads the lab, said the results show that skin microbes help define each person's odor signature. That idea opens the door to repellents that target the cues a specific species relies on, or even to approaches that shift the skin microbiome.

Limits of a Lab Study With 119 Miami Volunteers

This was a controlled laboratory study, not a field trial. It measured attraction, not actual bites or infections, and it involved 119 people recruited in Miami. The authors caution that more work is needed to identify exactly which compounds and bacteria drive each species' choices.

The study shows associations between odor, microbes, and attraction. It does not prove that changing one compound would protect anyone. Species-specific repellents remain a future possibility — not a product — and current guidance on mosquito protection has not changed.

Practical Protection Where Dengue and West Nile Overlap

For households, the most useful takeaway is that a person who rarely gets bitten in the evening may still be a favored target during the day, and the reverse. Aedes mosquitoes bite mainly in daytime, while Culex mosquitoes are most active from dusk to dawn, so protection should cover both periods — morning, afternoon, and evening.

Tampa Bay residents face the highest current dengue risk in Florida, with Hillsborough County accounting for most local cases. Older adults and people with chronic illness face higher risk of severe West Nile disease, which has no vaccine or specific treatment.

Federal health officials recommend EPA-registered repellents, long sleeves where practical, and emptying standing water from planters, buckets, and gutters each week. Aedes mosquitoes breed in small containers around homes, so yard cleanup matters most for dengue. People who develop fever, severe headache, rash, or joint pain after mosquito exposure should contact a doctor and mention where they have been.

Florida's outbreak shows why species matters. Of 395 locally acquired cases typed by PCR testing, 393 were dengue virus serotype 2, and the same Aedes mosquitoes can also carry chikungunya, according to Medical Economics. Florida has logged 88 travel-associated chikungunya cases and one locally acquired case this year. West Nile, spread mainly by Culex mosquitoes, had its earliest U.S. start in more than two decades this year, Nature World News previously reported. Because the two diseases depend on different mosquitoes with different habits, a repellent tuned to one species might help in Tampa but matter less in Phoenix or rural Texas, where Culex drives most risk.

Florida publishes weekly arbovirus surveillance reports, the next place to watch for updated dengue counts. The FIU team plans to focus on the skin bacteria linked to each species, work that could one day support repellents tailored to the mosquito that matters most in a given region.

What Readers Want to Know

What did the study find? Three mosquito species each preferred a different group of people, and no volunteer was highly attractive to all three.

Which mosquitoes were tested? Aedes aegypti (dengue), Aedes albopictus (Asian tiger mosquito), and Culex quinquefasciatus (West Nile).

What makes someone attractive to them? Skin odor compounds and skin bacteria. Each species responded to a different mix of chemical and microbial cues.

Can I buy a species-specific repellent? Not yet. The study points toward future products. EPA-registered repellents remain the recommended protection.

How big is Florida's dengue outbreak? The state counted 425 locally acquired cases in 2026 through mid-October, compared with 62 in all of 2025.

When are these mosquitoes most active? Aedes species bite mainly during the day. Culex mosquitoes are most active from dusk to dawn.