County health officials have confirmed 13 more human cases of West Nile virus in the past week, bringing the total number of cases in Denton County to 31.
Officials had been reporting about two new cases per week since the first human case of the year was reported at the end of May. Among those Denton County cases reported, the proportion of new cases classified as West Nile fever, versus the more severe West Nile neuro-invasive disease, remained about the same as previous cases.
This week, 17 Denton County residents were confirmed as having West Nile neuro-invasive disease. Symptoms move from high fever, severe headaches, stiff neck and stupor and numbness to muscle weakness, tremors or convulsions, vision loss, paralysis and coma. A total of 14 people have been confirmed as having West Nile fever.
At least two deaths have been reported — one in Texas and one in Arizona — according to the Centers for Disease Control and Prevention. Human cases of West Nile virus have been reported in 15 other states.
“Even though no deaths have been reported in Denton County, we do want residents to remain vigilant,” said Sarah McKinney, spokeswoman for the Denton County Health Department.
McKinney confirmed in an e-mail Friday that the department is working other possible cases.
“Right now we are receiving new reports almost daily, and we immediately start investigating to rule out West Nile,” McKinney wrote. “This is the same procedure for any notifiable condition, so this is something we do daily.”
Once a case is confirmed, county health officials contact the city where the person lives, and then update the online data, McKinney said.
James Kennedy, a University of North Texas biology professor supervising the city’s mosquito surveillance program, sees no sign of abatement in the virus.
“We get positive mosquitoes in every sample — as we did in that first sample in May — widespread, across the city,” Kennedy said.
Scattered rainfall and hot, but not scorching, temperatures have boosted mosquito habitat. The virus is transmitted between mosquitoes and birds each summer, eventually exposing and infecting humans, though usually not this early in the year, Kennedy said.
West Nile fever occurs in 20 percent of people bitten by a mosquito carrying the virus. The neuro-invasive disease occurs in less than 1 percent of those bitten by a mosquito carrying West Nile, McKinney said.
The city will be updating its map of locations of positive samples Monday, according to city spokeswoman Kara Roberson. The map is current through July 10. There have been more mosquitoes testing positive for West Nile in the past two weeks, Kennedy said.
West Nile-positive mosquitoes have been found close to both the UNT and Texas Woman’s University campuses, triggering concern about the well-being of returning students.
TWU spokeswoman Amanda Simpson said that students are expected back Aug. 22-23. The majority of TWU students are coming from counties where West Nile virus is already a problem, Simpson said, but the Office of Student Life is still deciding how to spread the word.
“They are monitoring the situation and have not decided what to do — that will come closer to move-in time,” Simpson said.
At UNT, officials have already issued an e-mail alert earlier this summer that provided details about the outbreak and what measures to take, spokesman Buddy Price said.
“The kids will be here in another three weeks, and we’ll definitely be looking at ways to educate them as much as possible,” Price said.
Researchers have developed a vaccine for horses, but the disease appears to pose little risk for dogs and cats — including little risk of communicating the virus, according to the CDC.
Currently, there is no vaccine for humans, but researchers are working on vaccines for West Nile virus and encephalitis.
The most people can do for now is try to limit their exposure, McKinney said.
Those tasks include draining standing water around homes and yards to reduce mosquito breeding grounds, dressing in pants and long sleeves when outdoors, applying insect repellent that contains DEET and staying indoors at dusk and dawn, when mosquitoes are most active.
PEGGY HEINKEL-WOLFE can be reached at 940-566-6881. Her e-mail address is pheinkel-wolfe@dentonrc.com.
BY THE NUMBERS
There have been 31 cases of West Nile virus reported across Denton County. Following is a breakdown by number and location:
Denton: 8
Carrollton: 6
Lewisville: 6
Unincorporated Denton County: 5
Flower Mound: 4
Highland Village: 1
The Colony: 1
For more information, call the Denton County Health Department’s West Nile virus hotline at 940-349-2907 or visit http://dentoncounty.com/heart/wnv
SOURCE: Denton County Health Department
