TThe deadliest animal in the world can be crushed with one blow: the mosquito.
The buzzing insects are more than just a nuisance – they spread disease. When they bite people or animals and drink blood from them, they can also pick up viruses or germs. Then, when they bite someone or something else, they leave the germs just under the skin.
In some areas of Massachusetts, people have been warned to stay home when mosquitoes are most active after a rare case of Eastern equine encephalomyelitis was discovered. And Dr. Anthony Fauci, the former top U.S. infectious disease expert, was recently hospitalized after contracting West Nile virus.
Both are serious diseases transmitted by mosquitoes. Fortunately, they are relatively rare.
Of course, the best way to prevent illness is to avoid bites. This can be done by using insect repellent, wearing long-sleeved clothing and long pants, and staying indoors when mosquitoes are around. Local health officials are also working to reduce mosquito numbers, for example by spraying entire neighborhoods with insecticides. Authorities in Massachusetts are using trucks and planes to spray at-risk areas this week.
Here’s a look at some common – and less common – mosquito-borne illnesses.
Eastern equine encephalomyelitis
Most people infected with Eastern equine encephalomyelitis do not develop symptoms, but some may develop fever or swelling of the brain, and about a third of those infected die. According to the U.S. Centers for Disease Control and Prevention, there have been three cases of Eastern equine encephalomyelitis in the U.S. this year, one each in Massachusetts, New Jersey and Vermont. The worst year for the disease was 2019, with 38 cases. It is caused by a virus and is not very common worldwide. The virus typically spreads in certain swamps, including red maple and white cedar swamps in Massachusetts.
West Nile virus
About 2 in 10 people infected with West Nile virus develop symptoms, including fever and swelling of the brain. About 1 in 10 people who develop severe symptoms die. There have been 216 West Nile cases so far this year. West Nile virus was first reported in the United States in New York in 1999. It gradually spread throughout the country. In 2003, there were nearly 10,000 cases.
malaria
Malaria infected nearly 250 million people worldwide in 2022 and killed more than 600,000, mostly children. The disease is caused by a mosquito-borne parasite and mainly affects people in tropical regions, especially Africa. A vaccination campaign has been launched in recent months that health authorities hope will help reduce the number of cases and deaths.
Dengue
Dengue fever, also known as “breakbone fever” because it can be so painful, is becoming increasingly common. The World Health Organization says about half the world’s population is at risk of contracting the disease, and there are 100 to 400 million infections each year. Not everyone shows symptoms, which can include fever, severe headaches and pain in muscles and joints. Most cases in the U.S. involve people who have traveled to other countries, although the CDC says there have been about 2,600 domestically transmitted cases so far this year.
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The Associated Press Health and Science Department receives support from the Science and Educational Media Group of the Howard Hughes Medical Institute. All content is the responsibility of the AP.
