Mosquitoes Test Positive for West Nile Virus

Maricopa County Department of Public Health
March 2005

PHOENIX — A mosquito sample collected by Maricopa County Vector Control Officers in the North Mesa area has tested positive for West Nile Virus (WNV).

The Maricopa County Environmental Services Department (MCESD) is blanketing the area with inspectors to notify local residents of the finding, trying to locate potential breeding sites and larviciding where necessary. City of Mesa authorities have been contacted. “This is an early indication that West Nile Virus is back this season and every Maricopa County resident needs to take the proper precautions to prevent mosquito breeding,” said Supervisor Don Stapley. “We all need to take part to ‘Fight the Bite’. We’re all in this together.” Arizona Department of Health Services (ADHS) is taking part with the County to quickly confirm any positive mosquito samples and is encouraging all residents to do what they can to protect themselves and their families. “We knew it was a matter of when, not if, we would see West Nile this year,” said Catherine Eden, state health director. “Arizonans should continue to enjoy our beautiful outdoors, but it is important we all take steps to protect ourselves from mosquitoes.”

Due to proactive surveillance efforts by the county, identification of infected WNV mosquitoes has occurred more than a month earlier than the typical mosquito-breeding season. Mosquito traps have been set since February. The turnaround time for identifying infected mosquitoes is much quicker due to implementation of an in-house rapid test. “This finding tells us that our surveillance is working and this will allow us to fight mosquitoes more specifically and aggressively,” said Al Brown, Director of the Environmental Services Department.

Using the Centers for Disease Control and Prevention (CDC) recommended treatment criteria in response to a mosquito carrying WNV, the County will fog that specific area where the infected mosquito was trapped. The fogging operation has been scheduled for Thursday night (March 10) to kill adult mosquito populations in the area bound to the North by McDowell Rd., 1.5 miles South to McLellan, and bound to the West by Mesa Drive and one mile East to Stapley.

There are several measures each individual can take to prevent mosquito breading that may lead to West Nile Virus infection:

• Eliminate mosquito-breeding sites around the home by removing standing water in potted plants, tires and other containers.
• Repair window and door screens to keep mosquitoes out of the home.
• Avoid outdoor activity before dawn and after dusk when mosquitoes are most active.
• When outdoors wear long sleeves and long pants to prevent mosquito bites.
• When outdoors wear a mosquito repellant containing DEET (follow label instructions, especially for use on children).
• Report dead birds to local authorities.

“Remember that prevention is the best tool we have,” said Dr. Doug Campos-Outcalt M.D., M.P.H., Maricopa County Chief Health Officer. “Our goal in all of these efforts is to prevent human disease.”

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