Dr. Anthony Fauci’s recent diagnosis with a case of West Nile virus has brought renewed attention to the little-known illness that is the leading cause of mosquito-borne disease in the continental United States.
Fauci, 83, the former director of the National Institute of Allergy and Infectious Diseases, became a household name as one of the government’s leading experts during the COVID-19 pandemic. He was most likely bitten by an infected mosquito in his back yard, according to news reports. He experienced fever, chills, and severe fatigue, was hospitalized briefly, and is now believed to be recovering at his home.
Unlike the other mosquito-borne virus making news this summer — eastern equine encephalitis, which is a rare but a very serious illness with an approximately 30 percent fatality rate — West Nile virus is more common, and most people (8 out of 10) do not develop any symptoms when they are infected. One in 150 infected people with West Nile virus develop a serious, sometimes fatal illness.
According to the U.S. Centers for Disease Control and Prevention, West Nile virus is most commonly spread through the bite of an infected mosquito. People become infected after being bitten by mosquitoes that have fed on the blood of infected birds. Symptoms include fever, headache, body aches, vomiting, diarrhea, or rash.
Yale School of Public Health Associate Professor Nathan Grubaugh, an infectious disease epidemiologist, said the number of cases of West Nile virus nationally has stayed relatively stable over the past decade with about 1,000 to 3,000 cases per year. So far this year, the CDC has reported 216 cases in 33 states, but August and September are usually the months where the virus is most prevalent so it remains to be seen if this year will be different from those past.
The Connecticut Agricultural Experiment Station, which is responsible for testing and tracking mosquitos in the state, is reporting high levels of mosquitos infected with West Nile virus this year, Grubaugh said.
Climate change increasing mosquito days
Rainy weather and warm temperatures this spring may have contributed to the increase. Higher than usual rainfall can increase mosquito breeding especially if there is standing water due to flooding, according to the CDC. Climate scientists have warned that warmer and wetter seasons are extending the number of “mosquito days” in states around the country. The Northeast, according to reports, has warmed faster than the rest of the country. The region has experienced the biggest increase in mosquito days, which are defined by days with an average humidity of at least 42 percent and temperatures between 50- and 95-degrees Fahrenheit.
New York City began spraying pesticides to kill mosquitos and curtail transmission of West Nile virus on Aug. 26.
Prevention
The best way for people to prevent infection with the West Nile virus, according to the CDC , is to avoid being bitten by mosquitos. This can be done by limiting outside activities from dusk to dawn, using insect repellent, and wearing long-sleeved shirts and pants.
There are no vaccines to prevent West Nile virus, or medicines to treat it.
Additional information about protecting yourself from mosquito bites is available on the CDC website.