Physician Offers Tips for Protection from Mosquito-borne Illnesses

SPRINGFIELD — Mosquitoes are more than just a nuisance causing itchy, red welts; their bites can also transmit diseases, such as the West Nile virus and eastern equine encephalitis (EEE) in this area.

Already last week, the Massachusetts Department of Public Health (DPH) announced it detected West Nile virus and EEE in mosquito samples collected at the end of June in Carver and Quincy, and the region’s current spate of hot, humid, rainy weather has created premium mosquito-breeding conditions. The mosquito is ranked as the deadliest creature on earth due to the diseases it can carry, which worldwide also include malaria, dengue fever, and the Zika virus. That’s why prevention is key, as is an understanding of the symptoms that might indicate an infection.

“Not all mosquitoes carry disease, but the potential is there,” said Dr. Andrew Koslow, associate medical director of American Family Care for Massachusetts. “The types of illnesses mosquitoes transmit vary by geography, so it’s best to do a little research and take preventive steps whether you are home or traveling.”

Last summer, the Massachusetts DPH confirmed six human cases of the West Nile virus in the Commonwealth after eight cases in 2022. With regard to EEE, the DPH noted that outbreaks in the state tend to occur every 10 to 20 years and last two to three years. The most recent outbreak of EEE in Massachusetts began in 2019 and included 12 cases with 6 fatalities. In 2020, there were five cases with one fatality.

Koslow emphasized that using mosquito repellent with at least 30% DEET is one of the most effective tactics to deter bites. Other effective ingredients in mosquito repellents include permethrin, picaridin, or oil of lemon eucalyptus.

“Be sure to apply repellents according to the directions on the package,” he advised. “Use them especially when you are in higher-risk situations, such as being outside in an area with a high mosquito population, being near stagnant water, or being outside between dusk and dawn, when mosquitoes are most active.”

Additional tips to reduce the risk of mosquito bites include:

• Wearing loose-fitting, long-sleeved tops and long pants — although mosquitoes can bite through fabric, they prefer bare skin;

• Using mosquito-deterring plants, products, and environmental treatments for mosquito control in outdoor spaces;

• Eliminating standing water on one’s property as standing water provides an ideal breeding ground for mosquitoes; and

• Repairing any holes in window and door screens.

“Because a relatively small number of mosquitoes in our area carry disease, there is no need to panic if you are bitten,” Koslow said. “Wash the area with soap and water, and use an ice pack to help reduce swelling. A paste made of baking soda and water or an over-the-counter itch cream can help with itching. For multiple bites or more severe symptoms, you can take an oral antihistamine.”

Koslow also urged against scratching mosquito bites to prevent localized skin infections. “If the bitten area worsens over the following few days — such as increased redness, pain, heat, or a red streak extending from the bite — see a healthcare professional right away for evaluation and treatment,” he advised. “The bite may be infected, and it can be difficult on your own to tell the difference between a strong reaction or an infection. Severe allergic reactions are rare but possible.”

People infected with the West Nile virus often have no symptoms, but some experience fever, fatigue, head and body aches, nausea, vomiting, or a rash on the chest, back, and/or arms. The first symptoms of EEE, which is much rarer, appear within three to 10 days of a bite from an infected mosquito and can include a high fever, nausea and vomiting, stiff neck, headache, or fatigue.

“Both of these diseases, especially EEE, can progress to more serious symptoms, including brain infection and death, so see a medical professional right away if you experience any of these symptoms after a mosquito bite,” Koslow warned. “While there is no specific treatment for either infection, supportive care may be lifesaving.”