Mosquitos can carry some dangerous diseases, including malaria, recently rediscovered in Florida.
Whether you are a target of those pesky insects may depend on an odd array of factors including your your blood type, your body scent, your metabolism, and what you wear.
"Some people are more prone to bites than others," said Eva Buckner, Assistant Professor & State Extension Specialist at the UF/IFAS Florida Medical Entomology Laboratory in Vero Beach. "If you are one of these people you need to protect yourself this summer."
Mosquito season in the state started earlier than usual this year, in mid-April, and the extreme heat and rain are triggering higher mosquito levels.
"In Florida we get mosquitoes year-round but the numbers are highest in the warm summer months," Buckner said. "We are in the middle of mosquito season and it's hot and we are getting lots of rain this year and those two things are promoting more production of mosquitoes."
What makes you a magnet
Scientists estimate that 20% of people are more likely to attract mosquitoes and thus get bitten more often. Here is why you may be one of them:
- Your blood type: If you have type O blood, you will attract more mosquitoes than people with all other blood groups. Type A is the next most popular for mosquitoes, followed by Type B, according to research published by the US National Library of Medicine.
- Your scent: A new study found that people who are most attractive to mosquitoes produce a lot of certain chemicals on their skin that are tied to smell. Researchers at New York's Rockefeller University designed an experiment pitting people's scents against each other, and discovered people who are mosquito magnets had high levels of certain acids on their skin. Those people who attract mosquitos based on smell tend to get bitten over and over. Scientists don't yet know why mosquitoes prefer certain body scents, just that they do.
- Your metabolism: Mosquitoes can detect carbon dioxide from a distance of up to 50 meters. The faster your metabolism, the more carbon dioxide you exhale. So those people who have a faster metabolism are more likely to be victims of bites. Mosquitoes also prefer pregnant women because they have a higher metabolic rate and tend to exhale more CO2.
- Your clothing choices: Mosquitoes are attracted to heat, and dark colors hold in heat more than light colors do. Colored clothing, such as black, navy, blue or red may make it easier for these insects to find you. Light-colored clothing tends to reflect heat. This means mosquitoes are less likely to notice you in a white or pale yellow garment. While you have the most protection when when your arms and legs are covered by pants and long sleeve shirts, those pesky insects can pierce fabrics like leggings that are thin and tightfitting as easily as they do skin.
- Your drink selection: Several studies have shown mosquitoes are more attracted to people after they drink beer. It could be that people breathe a little harder afterward or their skin is a little warmer. Or, the ethanol you give off in your sweat when you have been drinking could be what lure the mosquitoes.
What if a disease carrying mosquito bites you
More than 80 species of mosquitos circulate in Florida, however only certain types bite humans. Some bite at night, others during the day, and often they come out at dawn and dusk. Some mosquito species are leg and ankle biters and are attracted to the stinky smell of bacteria on your feet. Other species prefer the head, neck and arms, possibly because of the scents emitted by your skin and closeness to carbon dioxide released by your mouth.
The majority of mosquito bites are annoying rather than harmful. About a dozen types can pass on diseases to humans, including chikungunya, dengue, Zika and West Nile viruses.
The Anopheles mosquitos were just linked to cases of malaria in Florida. The Florida Department of Health issued a statewide mosquito-borne illness advisory after four locally contracted cases of malaria were reported along the Gulf Coast south of Tampa. Malaria, caused by a parasite that spreads through bites from Anopheles mosquitoes, has symptoms that include fever, chills, sweats, nausea and vomiting, and headaches.
Buckner said most likely, someone in the area traveled to a foreign country where they contracted malaria. That person then got bit by a mosquito locally, and it went on to bite other people.
Most mosquitoes have flight ranges of only 1 to 3 miles.
"These cases are very localized," Buckner said. "These type of mosquitoes are not as great vectors as others that carry mosquito-borne pathogens like dengue fever." The four residents in Sarasota County who contracted malaria from a mosquito have received treatment and have recovered, according to the state's Department of Health advisory.
"This mosquito-borne malaria in Florida is a different subtype than the African one. It is not associated with fatal disease," said Michaela Gack, Ph.D., scientific director of Cleveland Clinic's Florida Research and Innovation Center.
Diseases such as dengue fever, chikungunya, and Zika are spread by Aedes aegypti mosquitoes, an aggressive biter. Miami-Dade County issued a dengue alert in April.
Adriana Toro with Broward County Mosquito Control said the county has stepped up spraying for mosquitoes and is doing pre-treatment on larvae. However, anyone who is experiencing mosquito problems at their home can request service by calling 311 or by completing a Mosquito Service Request Form. "If you are having problems with mosquitoes, notify us and we will check the area during the day, and if confirmed, we will send our trucks at night," Toro said.
The Palm Beach County Division of Mosquito Control also has increased its aerial spraying in response to increased mosquito levels and the potential of vector-borne disease threats.
Experts warn that summer travel can put you in contact with disease-carrying mosquitoes, so take precautions.
European Union officials recently cautioned that there is a growing risk this summer of mosquito-borne viral diseases in Europe due to climate change. Because summers are getting longer and warmer, conditions are more favorable "for invasive mosquito species such as Aedes albopictus and Aedes aegypti," the European Center for Disease Prevention and Control said.
In other parts of the world, the Zika virus still looms. And Peru is currently grappling with the worst outbreak of mosquito-borne dengue fever on record.
"In the Caribbean and South America, in certain areas, there is a lot of rain and risk for malaria, dengue, chikungunya, and Zika," Gack said. "It doesn't mean they are everywhere, just in the areas that are more swamp-like. With diseases like dengue, there a range of symptoms, but most of the time they are mild."
What works and what doesn't to prevent bites
Experts say the best defense against mosquitoes remains traditional repellents with ingredients like DEET, Picaridin and IR 3535. The higher the concentration, the longer it lasts.
"These are not 100% protection," Gack said. "It's about how much you apply and how often."
Natural repellents like lemon eucalyptus oil can also work, but they must be reapplied more often. If you are outside, don't count on citronella for protection. According to the American Mosquito Control Association, citronella candles have only a mild repellent effect.
What does seem to work are fans. Mosquitoes are notoriously weak fliers, so circulating air can stop the bugs from reaching you.
Researchers like Leslie Vosshall, the chief scientific officer at the Howard Hughes Medical Institute, said the future lies in studying people who are mosquito magnets and figuring out how to "manipulate" the odors that originate from their skin. She believes scientists may be able to develop a cream that interferes with or reduces the levels of certain byproducts on the skin, which could make a person less attractive to mosquitoes.
Sun Sentinel health reporter Cindy Goodman can be reached at cgoodman@sunsentinel.com.
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