An enlarged view of a mosquito known to spread the West Nile virus to humans. The West Nile virus was recently detected in Hancock County. (CDC PHOTO)
HANCOCK COUNTY — Samples from two mosquito pools collected in Fortville and McCordsville came back with positive test results for the West Nile virus (WNV).
Derek Adams, Environmental Health Specialist for Hancock County Health Department, shared he received the results of the July 25 tests after sending the tests to Indiana Department of Health’s (IDOH) Entomology Laboratory. Adams explained that they send the mosquitoes to the state to be tested because there is not a lab on site.
According to IDOH’s information page, the “West Nile virus (WNV) is an arthropod-borne virus (arbovirus) that is primarily transmitted in Indiana by mosquitoes in the genus Culex. WNV disease is the most commonly reported mosquito-borne disease in Indiana and in the United States.”
After receiving the results, Adams put the data into the Minimum Infectivity Rate (MIR) formula and calculated a value of 3.125, where the IDOH’s Entomology department says that MIR values “in the ballpark” of 4.0 are when human cases are seen to start.
As of Aug. 11 there are no reported cases of human WNV. WNV is only transmitted from mosquito to human and will not transmit from human to human.
Adams shared that he’ll set out six to nine traps per week, generally three traps at night for three nights, weather depending. Once mosquitoes are collected, he sorts through them by sex and species, looking for a specific species. After that process is completed, they are sent off for testing. If and when a positive is found in a certain area, Adams will increase the amount of surveillance of the area and reach out to local governments to let them know of the findings and share educational tools on how to protect themselves.
Adams said he has 15 days worth of samples he is waiting to hear back on from testing as of Aug 14.
“I do expect to see the WNV increase as the year goes on. Not only is that naturally how it works but also most of our county is still considered to be ‘abnormally dry’ by the U.S. Drought Monitor,” Adams said. “A common misconception is that mosquitoes are worse and disease is worse when it’s wet but actually the diseased mosquitoes that we are worried about thrive and have a higher effective rate when it’s dry and when it’s hot…”
As of Aug. 8, 88.4% of the county is listed as “abnormally dry.”
Hancock County Health Department shared that containers, even small bottle caps can be a potential mosquito breeding site.
In order to reduce the risk of exposure, the public is encouraged to take precautions in preventing mosquito breeding sites which include: discarding old tires, tin cans, ceramic pots or other containers that can hold stagnant water; repair failed septic systems; drill holes in the bottom of any recycling containers left outdoors, clean clogged roof gutters, particularly if leaves tend to plug up the drains; keep grass cut short and shrubbery trimmed; flush ornamental fountains and birdbaths periodically; aerate ornamental pools, or stock them with predatory fish; frequently replace the water in pet bowls; install or repair screens on windows and doors to keep mosquitoes out of the home.
The Hancock County Health Department recommends the following measures to prevent mosquito-borne diseases when venturing outside: avoid being outdoors when mosquitoes are active — late afternoon, dusk to dawn and early morning; apply an EPA-registered insect repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol to clothes and exposed skin; and cover exposed skin by wearing a hat, long sleeves and long pants in places where mosquitoes are especially active, such as wooded areas.
Cases where people are infected with the virus range from asymptomatic to neuroinvasive. One in four people who test positive will experience flu-like symptoms lasting three to 10 days, which include fever, headache, myalgia and loss of appetite. One in 230 people will experience severe symptoms.
Adams said that people spending more time outdoors also need to be more aware with flu season coming up.
“Now that flu season is starting to come around we want to be a little bit more diligent because WNV symptoms, if someone has them — which again only one in four people are going to have them — but if they do have them, they present almost identically to the flu,” Adams said. “So if people get treated for the flu or they get tested and are negative for the flu, then they might want to consider WNV.”
Hancock County Health Department shared that people older than 60 years and those with underlying health conditions are at higher risk of developing severe disease. Individuals who think they may have WNV should contact their healthcare provider.
For further information and questions, contact the Hancock County Health Department at 317-477-1125, or consult the Indiana Department of Health website at https://www.in.gov/health/idepd/.
