What you need to know about West Nile virus

Wednesday, June 28, 2017

mosquito

As Southeast Michigan heads into peak mosquito season, it’s important to know how to recognize and prevent West Nile virus.

Although up to 80 percent of persons infected with WNV experience no symptoms, said Christopher Carpenter, M.D., section head, Infectious Disease and International Medicine, Beaumont Hospital, Royal Oak, it can occasionally cause a severe and sometimes fatal, neurologic disease.

Approximately 20 percent of those infected with the virus, Dr. Carpenter said, develop fever, muscles aches, headache, rash, nausea, vomiting diarrhea and abdominal pain. Interestingly presence of rash reduces the risk for more severe disease.

One in 150 people develop serious disease, including severe weakness or paralysis, vision loss, meningitis and encephalitis. People over the age of 50 are at the greatest risk for encephalitis; children are at the greatest risk for meningitis.

People typically develop symptoms between three and 14 days after being bitten by an infected mosquito.

The easiest and most effective way to prevent West Nile virus is by preventing mosquito bites, according to Beaumont Hospital, Royal Oak, infectious disease specialist, Paul Johnson, M.D.

  • Many mosquitos are most active from dusk to dawn. Always use insect repellent and wear long sleeves and pants during these times.
  • Use insect repellents that contain at least 20 percent DEET or picaridin. Follow package directions when applying.
  • Make sure screens on windows and doors are fully functioning and intact.
  • Eliminate mosquito breeding grounds by emptying standing water from flower pots, buckets and barrels. Change water in pet dishes and replace water in bird baths on a weekly basis. Drill holes in tire swings so water doesn’t collect. Empty plastic wading pools and store on their sides when not in use.

How does West Nile virus spread?

West Nile is primarily spread by the bite of an infected mosquito, Dr. Johnson said. Mosquitos become infected when they feed on infected birds. Infected mosquitoes spread WNV to humans and other animals when they bite.

What should I do if I think I’m infected?

Mild cases generally resolve on their own, while severe cases require hospitalization. If you develop symptoms of severe WNV illness, such as severe headaches or confusion, seek medical attention immediately, Dr. Johnson said. Pregnant women and nursing moms should talk to their medical provider if they develop symptoms.

What should I do if I find a dead bird?

Do not handle the bird with your bare hands. Contact your local health department for instructions on reporting and disposal.

The first West Nile virus activity for Michigan in 2017 was confirmed in May in three birds from around the state, including one turkey in Barry County, and two crows, one from Kalamazoo County and one from Saginaw County.

In 2016, there were 42 serious illnesses and three deaths related to West Nile virus in Michigan. Nationally, there were 2,038 human cases of the virus and 94 deaths were reported to the Centers for Disease Control and Prevention.