The first case of human West Nile virus infection for the 2018 season has been identified in Los Angeles County. Last month, a San Gabriel Valley resident was hospitalized with the disease, which is spread by the bite of an infected mosquito. West Nile virus (WNV) survives in nature through several types of birds. Mosquitoes that feed on infected birds then carry the virus. While not all mosquitoes carry the virus, the type of mosquito that spreads WNV is found throughout LA County.

Since WNV’s first Los Angeles County appearance in 2004, there have been increased levels of West Nile virus activity for the past five years. The Los Angeles County Department of Public Health collaborates with local vector control agencies to target areas for mosquito control activities as well as educate people on how to protect themselves.

As Los Angeles enters mosquito season, here’s what you need to know about West Nile virus:

  • WNV infects roughly 10,000 people a year in LA County, but most never show symptoms or only experience mild illness
  • Most mosquitoes do not carry the virus, and it cannot be spread from person-to-person
  • Those over the age of 50 or who have chronic medical problems are at higher risk of developing more serious health issues
  • On average, Los Angeles County receives 221 cases of West Nile virus per year
  • Last year’s WNV season was the longest season on record for LA County, extending until mid-December

To decrease the risk of infection:

  • Apply mosquito repellents containing DEET, picaridin, oil of lemon eucalyptus
  • Consider wearing long-sleeved shirts and long pants when outdoors, particularly when mosquitoes are present (at dawn and dusk)
  • Ensure your window and door screens are free of holes
  • Mosquitos breed in water. Take a few minutes to remove any standing water from your yard (flower pots, old tires, bird baths, pet bowls)
  • Stock garden ponds with goldfish or other mosquito-eating fish

Recovery from West Nile virus can take months or years. There is no vaccine or treatment to cure the illness once an individual becomes sick. The best way to lower the risk of WNV is to prevent breeding sources and protect against mosquito bites.

Click here to learn more about West Nile virus activity in Los Angeles County