Mosquitoes: Annoying insects that can spread disease

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Mosquitoes are pesky insects that can bite and leave your skin with red, itchy bumps. They are the reason why you might not enjoy a summer day at the pool or an evening walk in the park. What makes mosquitoes very important to humans is not just their annoyance but also their ability to spread disease. Mosquitoes are important vectors of disease. Vectors are organisms that transmit bacteria, viruses, and parasites from one infected person or animal to another. Other common vectors include ticks and fleas.

Worldwide, the most important disease spread by mosquitoes is malaria, which infects 2 million people every year and kills 500,000. While the majority of the diseases transmitted by mosquitoes occur in developing countries and in tropical and sub-tropical regions, infection and disease spread can be just a plane ride away or just around the corner. For example, the first case of West Nile Virus (WNV) in the US was identified in New York in 1999 apparently resulting from the arrival of an infected bird, human traveler, or mosquito. The virus has since spread rapidly and has infected about 40,000 people in the US. Of these, 17,000 became very ill and about 1600 died. Mosquitoes are also responsible for the spread of heartworm disease in pets.

Only female mosquitoes bite, because they need a blood meal to make eggs. Male mosquitoes feed only on nectar. Mosquitoes are experts at finding humans and animals to bite by sensing movement, color, temperature, moisture, and chemicals like carbon dioxide, which we release during normal breathing. This means we have to use several techniques to beat them at their game.

Fortunately, the majority of mosquito bites do not lead to disease. Even so, the best way to prevent infection is to prevent a bite. Here are important preventive tips:

• Limit mosquito breeding grounds. Mosquitoes breed in standing water; homeowners should remove sources of standing water (areas where water can collect after rainfall) around their home. A few examples are flowerpots, buckets, pet dishes, discarded tires, and birdbaths. If you have a swimming pool, perform adequate maintenance to prevent mosquito breeding. Report abandoned swimming pools to your local health department.

• Keep mosquitoes out of your home. Install and quickly repair screens on windows and cover gaps in doors and walls.

• Reduce your risk of a bite:
  

  • Use insect repellents and be sure to follow label directions for safe use. Use repellents that have been registered by the Environmental Protection Agency (EPA). EPA-registered repellents have been approved for safety and effectiveness. 

  • Use your clothing as a barrier by wearing long sleeves, pants, socks, and shoes.

  • Limit your time outdoors when mosquitoes are the most active, which is between dusk and dawn.

  • Use mosquito netting to cover infant carriers when outdoors.

If bitten by a mosquito: Immediately disinfect the area by washing it with soap and water.

Itching will likely follow, and the bite site will be swollen, warm, and tender to touch. This is your body’s natural response to the mosquito’s saliva. Try your best not to scratch. Scratching will only result in more skin irritation. To relieve the itching, you can apply a nonprescription corticosteroid, like hydrocortisone 1% cream.

Watch the site for signs of infection. Increased pain, swelling, redness or warmth, or oozing of fluid from the site are signs that indicate wound infection. Also watch for symptoms of mosquito-transmitted illnesses, such as fevers, body aches, headaches or neck stiffness. Seek immediate medical evaluation and treatment if any of these symptoms occur.

For treatment advice, use the webPOISONCONTROL online tool to get help, or call your poison center at 1-800-222-1222. Whether online or by phone, expert guidance is always free, confidential, and available 24 hours a day.