The California Department of Public Health announced Friday that three state residents have died after contracting the West Nile virus. The three deaths mark the first conformed fatalities from the virus this year.
The deceased persons were residents of Kern, Los Angeles and San Bernardino counties.
As of Friday, the CDPH has reported 87 human cases of WNV from 13 California counties this year. Additionally, 239 dead birds from 30 counties have tested positive for WNV in 2017, and 2,284 mosquito samples from 24 counties have also tested positive for WNV this year.
The Stanislaus County Health Services Agency announced in mid-August that two area residents had been confirmed to have contracted West Nile virus. The 53-year-old female and a 64-year-old male are the first confirmed human West Nile Virus infections in Stanislaus County this year. In both cases the two patients have developed the more serious neurologic disease. As of Friday, the county has now had six confirmed cases of West Nile virus in humans.
Stanislaus County has had three dead birds and 130 mosquito samples test positive for West Nile virus. All three of the dead birds were located within the Turlock Mosquito Abatement District.
“West Nile virus can cause a deadly infection in humans, and the elderly are particularly susceptible,” said CDPH Director and State Health Officer Dr. Karen Smith. “August and September are peak periods of West Nile virus transmission in the state so we urge everyone to take every possible precaution to protect themselves against mosquito bites.”
The numbers of WNV positive dead birds and mosquito samples are below those at this same time last year, but the number of positive mosquito samples exceeds the state’s most recent five year average, according to the CDPH.
West Nile virus is influenced by many factors, including climate, the number and types of birds and mosquitoes in an area, and the level of WNV immunity in birds. West Nile virus is transmitted to humans and animals by the bite of an infected mosquito.
Approximately 1 in 5 people who are infected with West Nile virus will develop symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Less than 1 percent will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). About 10 percent of people who develop neurologic infection due to West Nile virus will die, according to the Centers for Disease Control and Prevention. People over 50 years of age and those with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and organ transplants, are at greater risk for serious illness.
There are no medications to treat or vaccines to prevent West Nile Virus infection. People with milder illnesses typically recover on their own, although symptoms may last for several weeks or months. In the neuroinvasive forms, patients can suffer severe and sometimes long-term symptoms.
CDPH recommends that individuals protect against mosquito bites and WNV by practicing the “Three Ds”:
1. DEET – Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR3535 according to label instructions. Repellents keep the mosquitoes from biting you. Insect repellents should not be used on children under two months of age.
2. DAWN AND DUSK – Mosquitoes that transmit West Nile Virus usually bite in the early morning and evening so it is important to wear proper clothing and repellent if outside during these times. Make sure your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens that have tears or holes.
3. DRAIN – Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property by emptying flower pots, old car tires, buckets, and other containers. If you know of a swimming pool that is not being properly maintained, please contact your local mosquito and vector control agency.