DoD officials monitor West Nile virus increase in mosquitoes
August 24, 2012
As summer winds down, Joint Base Myer-Henderson Hall's directorates of Environmental Management and Public Works continue to monitor the base mosquito population and its threat as a carrier of the West Nile Virus.
"We are continuing our regular surveillance program," said Greg Olmsted, DEM installation pest management coordinator, who said JBM-HH had not yet had any positive readings this year for the presence of West Nile virus in mosquitoes it collects and sends to Army Public Health Command-North at Fort Meade, Md., for analysis. The last positive reading was taken in August 2010 from the Fort McNair portion of JBM-HH.
"We will continue to monitor until the first freeze of the year," said Olmsted, who noted how that can occur as late as the end of October. Working with the Directorate of Public Works, DEM has set up nine mosquito Gravid Traps, designed by the U.S. Centers for Disease Control and Prevention, across JBM-HH.
The traps, which catch egg-laying female specimens, have been placed at various sites on base, including the caisson stables, commissary, officers club pools and the community gardens. According to Aug. 21 statistics compiled by the CDC, 47 states have reported West Nile virus infections in people, birds or mosquitoes this year. Nationally there have been 1,118 human cases of West Nile virus, including 41 deaths.
Virginia has reported one positive human case with an additional case pending, and Maryland has two reported cases. This is the highest number of cases reported to the CDC for this time of the year since the virus was first detected in the U.S. in 1999.
Five states -- Texas, Mississippi, Louisiana, South Dakota and Oklahoma -- report the largest number of cases, representing 75 percent of the total. The state of Texas alone has reported nearly half of the 1,118 cases. Last week the mayor of Dallas, Texas, declared a state of emergency with 465 reported cases of West Nile virus among its population, including 17 deaths. According to Army Public Health Command-North, at Fort Meade, Md., Brook Army Medical Center at Fort Sam Houston in San Antonio, Texas, reported one human case with an in-patient retiree at its hospital, with the installation having one additional suspected case.
An Aug. 13 report produced by Benedict Pagac, chief of the Entomological Sciences Branch of Army Public Health Command-North, documents an increased presence of the West Nile virus in mosquito samples taken from 12 military installations in the National Capital Area, including Joint Base Myer-Henderson Hall. "A total of 4,927 female mosquitoes were trapped at collaborating D.C. military sites during 261 trap nights," the report states.
"These mosquitoes were put in 365 pools and tested for West Nile virus. Of these, 35 pools tested positive." Joint Base Anacostia-Bolling in the District of Columbia had 33 positive readings, while the Bethesda National Military Medical Center in Maryland and Marine Corps Barracks at 8th and I in the District received one positive reading each. "Installation authorities [are] advised to enhance breeding site surveys, implement source reduction and larval control, and to notify the potentially effective human population to implement personal protection measures," the report urges.
To avoid contracting West Nile virus, "the goal is not to be bitten by a mosquito," said Olmsted. He advised base residents and employees to avoid being outdoors at dusk and dawn when mosquitoes are most active and to wear light-colored clothing with long-sleeved shirts, long pants and socks when you are outdoors. Olmsted recommended wearing a mosquito repellent.
He said there are several choices available -- from natural products to the chemical-based -- but what's important is choosing one that you feel comfortable applying to your skin. If you're active in sports and sweat, you may need to reapply repellent, he said. Mosquitoes are attracted to perspiration and the carbon dioxide in respiration.
Olmsted also advised eliminating the source of any standing pools of water around the home, such as bird baths, pet bowls and old tires. "It's important to maintain roofs and keep gutters clean," he said, adding, "Keep window screens in good condition so mosquitoes can't get in.
"It's the same message every year, but it's an important message," Olmsted emphasized. "You have to encourage people to protect themselves."