The Centers for Disease Control (CDC) reported that cases of West Nile virus rose by 550 last year to a total of 2,647. 167 people died from the mosquito-borne disease in 2018, according to the report. In its most severe form, West Nile Virus causes inflammation of the brain.
“I think [the report] confirms and says again that this is a significant problem in the U.S., that we have a couple thousand people getting very serious neurologic infections,” director of the division of infectious diseases and immunology at the NYU Langone School of Medicine Dr. Mark Mulligan said.
No vaccine exists for the disease, which is spread from infected birds to humans through mosquitos. Only about one in 150 develop the severe form of the disease, and many who are infected don’t develop any symptoms but do gain immunity against any future infection.
Immunity may be why some states that historically had higher rates of infection have lowered this year, like New York, Arizona, and California. Other states like Nebraska and the Dakotas had higher rates last year.
Avoiding Infection
Additionally, places with high rates of infection are taking steps to control mosquito populations that other states may not take. “In places where it first popped up, it’s now part of the surveillance and control efforts, so we know when to detect it, people know to spray themselves and dump their water,” Sadie Ryan, an associate professor of medical geography at the University of Florida, said.
Experts advise covering exposed skin and using bug spray. People can also avoid being outdoors at dusk when mosquitoes are most likely to bite.
Symptoms of a more mild infection include headache, fever, body aches, skin rash, and swollen lymph nodes. Severe infections may cause convulsions, tremors, stiff neck, sleepiness or coma, and paralysis.
The severe form of West Nile causes encephalitis, an inflammation of the brain. Most encephalitis cases occur in people over age 50. Some with encephalitis do recover but may still have memory loss, confusion, muscle weakness, joint pain, fatigue, vomiting, diarrhea, and insomnia.
Symptoms usually occur within five to 15 days of a mosquito bite. A rash over a large area of the body may also occur.
CDC Concerns
While last year’s numbers were higher than the previous year, they were only about as high as some other recent years, the CDC noted. “There have been some years within those past years that have been this high, so I think there’s fluctuation year-to-year,” Mulligan said.
West Nile Virus is the most common neuroinvasive disease in the U.S. Another mosquito-borne illness, La Crosse virus, became the most common neuroinvasive disease for children with 86 cases in 2018.
“More La Crosse virus disease cases were actually reported in the 2018 data than in any year since 2011, and it’s the most common cause of neuroinvasive arboviral disease in children,” said Ryan. “People who are scared about their kids getting nasty diseases should be thinking about La Crosse.”
No comments: