As the United States enters mosquito season, a prominent public health figure says his West Nile virus infection felt like he had been “hit by a truck.”
Dr. Anthony Fauci, former director of the National Institute of Allergy and Infectious Diseases and leader of the nation’s early response to the COVID-19 pandemic, made the comment after spending several days hospitalized with West Nile, a mosquito-borne virus.
On Saturday, Fauci’s spokesperson told media outlets including USA TODAY that the 83-year-old immunologist had contracted West Nile virus and spent six days in the hospital. He has since been recovering.
In an interview with STAT, a health news site, Fauci said he felt like he had been “hit by a truck.”
“I’ve never been this sick in my life. Ever,” he told the publication. “This is by far the worst situation I’ve ever been in with an illness.”
Fauci’s case is rare. Most people infected with West Nile virus by mosquitoes do not develop symptoms, although rare cases can lead to lasting neurological problems or even death.
When did West Nile virus appear?
West Nile virus became endemic in the United States 25 years ago in Fauci’s hometown of New York. Today, there are thousands of cases each year, though experts say these incidents are vastly underreported.
So far in 2024, the United States has reported 216 cases, 142 of which were in people who developed the severe neuroinvasive form of the disease, according to the Centers for Disease Control and Prevention.
“We’ve learned a lot, but we still have the same tools to prevent disease that we had back then,” Dr. Erin Staples, a medical epidemiologist in the CDC’s division of vector-borne diseases, told USA TODAY. “We need to do better.”
After all, she explained, mosquitoes are the deadliest animal in the world.
What is West Nile Virus?
According to the CDC, West Nile virus circulates primarily among birds that serve as vectors for mosquitoes. West Nile virus was first identified in the West Nile region of Uganda before spreading to Africa, Europe, Asia, Oceania and the Americas, the European Centre for Disease Prevention and Control said. In the United States, West Nile virus follows the mosquito season that begins in the summer months. Infections are typically identified in August and September.
Mosquitoes, usually of the genus Culex, bite birds, contract the disease, and then transmit it to humans. Humans do not develop high enough levels of the virus in their bloodstream for mosquitoes to contract it again and transmit it to other humans. In rare cases, West Nile virus has been transmitted between humans through blood transfusions, organ transplants, or from mother to baby.
There is no human vaccine to prevent West Nile virus, but there is a vaccine for horses.
How common is West Nile virus?
West Nile virus is the leading cause of mosquito-borne disease in the United States, according to the CDC. In August 1999, the first year it was introduced to the United States, there were 62 cases and several deaths.
In the following years, the virus began to spread through migratory birds that passed through the country. The United States saw a surge in human infections, starting with about 66 cases in 2001 and reaching over 4,100 recorded cases by 2002. There were 284 deaths from West Nile virus that same year. In 2003, 9,862 people were infected and 264 died in the United States. Cases are now most numerous in the central and western United States.
West Nile virus cases are vastly underreported, and many people don’t know they have the virus. The cases that are reported are typically the most severe infections. A blood test has traditionally been used to detect West Nile virus in patients, although spinal fluid samples have been used to look for the neurological form of the disease, the CDC’s Staples said.
What are the symptoms?
About 4 in 5 people who get West Nile virus have no symptoms. About 1 in 5 people who are infected develop the most common symptom, West Nile fever. Other common symptoms include headache, body or muscle aches, joint pain, vomiting, diarrhea and rash, according to the CDC. Symptoms typically appear 1 to 14 days after a person is bitten and can last three to six days, according to Penn Medicine, a hospital and medical school.
In rare cases, a more severe neuroinvasive form develops and can cause encephalitis or meningitis. Symptoms include muscle weakness, stiff neck, weakness in an arm or leg, confusion, loss of ability to think clearly, and loss of consciousness or coma.
About 10% of these severe cases result in death. In 2023, 182 people in the United States died from West Nile virus.
Anyone can develop severe disease, but older people, people with certain underlying medical conditions (cancer, cardiovascular problems, kidney disease), and organ transplant recipients are at higher risk. Most people infected with West Nile virus are protected from future infections.
How to Prevent West Nile Virus
The best way to prevent West Nile virus is to limit areas where mosquitoes can breed and bite people. Here are some recommended measures:
- Use an insect repellent approved by the Environmental Protection Agency.
- Wear loose-fitting, long-sleeved shirts and pants when outdoors.
- Eliminate mosquito breeding grounds, such as standing water where mosquitoes can lay eggs, around homes. Install screens on windows and doors and repair holes in screens.
- If possible, use air conditioning instead of leaving windows and doors open on hot days.
