JOINT BASE SAN ANTONIO-RANDOLPH, Texas –
Public health officials at Joint Base San Antonio locations have not trapped any West Nile virus-positive mosquitoes so far this year, in contrast to a year ago.
Last year, West Nile-virus positive mosquitoes were identified at all four JBSA locations, starting with samples found at JBSA-Fort Sam Houston in mid-July.
However, ongoing surveillance has yielded nothing positive for West Nile virus at JBSA-Fort Sam Houston or JBSA-Camp Bullis in 2013, said Capt. Caesar Sarmiento, U.S. Army Medical Command/Brooke Army Medical Center entomologist.
He advised military members who venture into damp areas during training or exercises to "leave mosquito traps alone."
"Wear protective equipment, uniforms treated with DEET and use insect repellent on exposed skin," Sarmiento said. DEET, or diethyl toluamide, is a substance used in repellents.
At JBSA-Lackland, no positive samples for West Nile virus have been found, Jorge RodriguezCatalan, 559th Aerospace-Medicine Squadron Public Health Flight community health manager, said, "but that does not mean there are no mosquitoes carrying the virus.
"It just means we have not been able to catch any," he said. "Everyone should continue to use precautions such as using DEET; limiting activities during dusk and dawn, while mosquitoes are biting; wearing long sleeves and pants; and eliminating breeding sites."
RodriguezCatalan said mosquito activity at Lackland has been consistent for the last couple of years.
"This year is no exception," he said. "When it rains, expect mosquitoes as early as three days after a good rain."
Tyrone Toombs, 359th AMDS Public Health Flight technician, called the mosquito problem at JBSA-Randolph "worse than last year, but none of the mosquitoes we have trapped have been carriers of the West Nile virus."
This year, weekly mosquito monitoring at JBSA-Randolph, which consists of setting up traps at two high-risk locations, began April 2, nearly two weeks earlier than usual, Toombs said. Monitoring typically ends in early October.
"We started hitting the threshold breach of 50 mosquitoes per trap in May," Senior Airman Shannon Anderson, 359th AMDS Community Health Element preventive medicine technician, said. "The average in May was about 150, and the average in June was comparable."
Randolph "didn't go over the threshold at all last year," Toombs said, but the greater issue was that mosquitoes at all four locations tested positive for West Nile virus. Most people bitten by West Nile virus-infected mosquitoes have no symptoms, but others develop symptoms ranging from headache, nausea and vomiting to more serious conditions such as meningitis, encephalitis and paralysis.
RodriguezCatalan said Lackland's vector surveillance program typically runs from April through September, though it began in March this year.
"Climatic conditions determine the need to tweak our programs and geographical changes such as new construction, existing and new training sites or procedures, and customer complaints all factor into our decision to set out traps and where to set them," he said.
Sarmiento said mosquito surveillance at JBSA-Fort Sam Houston and JBSA-Camp Bullis occurs every week.
"At a minimum we put out two traps, but given our low capture results, I am increasing the number of traps I put out," he said.
Sarmiento said he chooses areas "where there is high potential for human contact," including training, housing and recreational areas.
Housing residents can help mitigate the mosquito problem by finding and eliminating breeding sites, public health officials said.
"Make sure you don't have standing water in your yard," Toombs said.
Possible breeding sites range from children's wading pools and plastic containers such as garbage cans and pet dishes to bird baths and boats.