Tulare County health officials issued a warning Friday morning that the West Nile virus has been detected in mosquito samples and urged residents to take safety precautions to avoid contracting both West Nile and the St. Louis Encephalitis virus.

The viruses are transmitted from mosquitoes to humans, and there is no vaccine or medication to treat them. Most infected with West Nile and St. Louis viruses will show no symptoms, but one in five people infected with West Nile will develop a fever with other symptoms within 10 days of being infected. The most common symptoms are fever and headache similar to a mild flu.

Severe cases can affect the central nervous system, resulting in meningitis or encephalitis, and can result in long-term disability or death.

Ryan McNeil, manager of the Fresno County Mosquito and Vector Control District, said that no West Nile-laden mosquitoes have been found so far in the county.

“It’s a little early,” he said.

McNeil had good news and bad news about the forecast for this year’s mosquito season: Expect more mosquitoes thanks to the record winter rains that have refilled ponds, ditches, and other water basins, but also expect lower rates of infection. While that might seem counterintuitive, he said, it’s because when animals have more water sources to gather at, they will be more spread out and less likely to share any infections.

While there is no vaccine for humans, there is a vaccine for horses, which are particularly susceptible to West Nile virus. Horse owners should vaccinate their equines annually.

How to Stay Safe

Watch out for potential breeding grounds, not just on your own property but also at homes that are unoccupied or in foreclosure that may have unattended pools or backyard ponds where mosquitoes can breed. To avoid being bitten and becoming infected with either West Nile or St. Louis virus, residents should:

• Use an EPA-registered insect repellant such as DEET.
• Wear pants and shirts with long sleeves at dawn and dusk and in areas where mosquitoes are active.
• Drain standing water.
• Repair or replace door and window screens that have holes or tears.

How to Report

If you see areas of standing water that may be a breeding area for mosquitoes, contact your local abatement districts:

• Fresno County Mosquito and Vector Control District, (559) 268-6565, https://www.fresnomosquito.org
• Delta Vector Control (northern Tulare County), (559) 732-8606, http://www.deltavcd.com
• Tulare Mosquito Abatement District (western Tulare County), (559) 686-6628, https://www.tularemosquito.com
• Delano Mosquito Abatement District (southern Tulare County), (661) 725-3114, https://delanomosquito.com
• Madera County Mosquito and Vector Control District, (559) 662-8880, http://www.maderamosq.org
• Kings Mosquito Abatement District, (559) 584-3326, https://kingsmosquito.net/wordpress/?page_id=144