Every few months, I examine a patient with malaria; I see patients with dengue fever maybe twice a year. As an infectious disease specialist, I expect to examine a patient with Zika virus at some point as well.
Zika, first identified in humans in 1952, is getting a lot of attention this year, but much older mosquito-borne infections including malaria, dengue and others are also still around — and some have even been a problem in the U.S. Modern transportation, environmental changes and global travel have increased the potential for mosquito-borne diseases to strike in the United States. In fact, the patients I examined are ones who brought the disease here after contracting it when visiting other countries.
Besides being annoying pests, mosquitos can be dangerous insects to humans. They are responsible for 1 in every 6 infections worldwide and kill many people (725,000 annually, according to one estimate). Three mosquito species are especially threatening in the U.S. Here are descriptions of each, followed by my advice on avoiding contracting a mosquito-borne illness from any of them, and how to help stem the spread of disease. While the U.S. government and other public officials are preparing to aggressively fight Zika, there’s a lot you can do as well.
[See: How to Avoid Summer Pest Risks — From West Nile to Chikungunya Virus.]
Species
Mosquitos have been on earth for thousands of years. They now number more than 3,500 species worldwide, and about 150 can infect humans. Only females can transmit infections, because only females bite. They drink our blood for a protein they need to reproduce, unwittingly transmitting harmful viruses that they carry. Mosquitos are attracted to our sweat and carbon dioxide from air we expel. They are fast, with some tracking us from hundreds of yards away.
Culex pipiens, Aedes aegypti and Aedes albopictus are the three most threatening species in North America.
— Culex pipiens, the common house mosquito, can transmit West Nile Virus or its close cousin, Japanese encephalitis. The female Culex prefers to feed after mating, usually in the evening. It reproduces by laying larvae in stagnant water — think water in flowerpot trays or old tires.
— About half of the mosquitos in the U.S. belong to the Aedes genera, including the aegypti and albopictus species. Aedes mosquitos transmit yellow fever, chikungunya, dengue and Zika. Females lay eggs at waterlines or on dry ground, hatching in small amounts of water such as water found in tires or downspouts.
— Aedes aegypti, out of Africa, are now thriving in the southeastern U.S. They often bite in the morning or afternoon, preferring humans to other animals.
— Aedes albopictus, nicknamed the Asian Tiger mosquito because of their white stripes and origin, have now spread around the eastern and Midwestern U.S. They were first detected in the U.S. in 1985 and bite anytime.
All of these mosquitoes live only about a month and can produce millions of offspring each season. But they have different life cycles, including reproduction patterns — making them especially difficult to manage.
They all can transmit multiple diseases, feeding especially in impoverished, overcrowded areas where people do not take precautions to prevent bites. They have not transmitted viruses en masse in the U.S. in decades, with the exception of West Nile, which infected more than 2,000 people in 2014. Dengue virus also has been transmitted in Florida, Texas and Hawaii, but this is uncommon.
In recent years, weather changes due to La Niña have created more mosquito-friendly warmer climates in North America. The Centers for Disease Control and Prevention estimates that Aedes aegypti may have spread over the entire southern half of the U.S., and nearly the entire eastern half of the U.S. could now be home to the Aedes albopictus.
[See: Your Guide to Stylish Sun Protection.]
How to Protect Yourself
While the potential for the spread of mosquito-borne illnesses in the U.S. is concerning, you can take steps to not only protect yourself but also slow down the spread of the disease-carrying species.
To prevent being bitten by an infected mosquito, follow the CDC’s recommendations:
— Wear long-sleeved clothing, socks and pants, or clothes with insecticide (permethrin) built in.
— Apply mosquito repellant (containing DEET, Picardin or lemon eucalyptus oil) to intact skin, making sure not to spray it directly into your face or onto cuts. (To apply it to your face, spray it on your hands and pat gently.) If applying sunscreen as well, put on the sunscreen first, let it dry, and then apply the repellent. (I don’t recommend using combination products because you need to reapply sunscreen frequently).
— Keep screens on open windows and doors.
— Finally, wash often with soap to rid yourself of the odor attractive to mosquitoes.
If you travel to areas with high rates of mosquito-borne illness — such as Africa, Asia or South America — consult your medical provider beforehand about the proper vaccinations and medications to take. The CDC is concerned about travelers returning to the U.S. with mosquito-borne diseases.
To further counter mosquito spread, empty containers with standing water every day and use spatial repellents such as mosquito coils to take away their habitat. You may also try buying mosquito-eating fish if you have a pond. Most jurisdictions don’t recommend bombing yards with environmental sprays, in part because mosquitos can develop long-term resistance to these toxins.
If you are bitten, and develop a fever within a few days, contact your health care provider.
For now, those are the only measures I can suggest with near certainty for fighting mosquito-borne illnesses. Researchers are studying other macro options, including introducing genetically modified or infected species into the mating pool — or even killing off whole species. Evidence is only emerging about these tactics; we simply don’t know if they will influence virus transmission by mosquitoes outside the lab long term.
In the meantime, if you follow the established guidelines for preventing mosquito bites, and consult with your health care provider when necessary, you and your family will not likely suffer. Don’t let the Zika threat ruin your summer.
[See: 10 Classic Health and Safety Risks Among First-Time Campers.]
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Mosquitos 101: What to Know to Stay Healthy originally appeared on usnews.com
