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Harris County public health officials reported Friday that there are seven positive cases of West Nile virus and a pool of more than 500 positive mosquito samples, nearly doubling since June 2024.
Of the seven infected individuals, six adults over the age of 50 have tested positive for the virus, as well as one infected minor under the age of 18, according to officials. Several of the infected adults over the age of 50 have been hospitalized, but no deaths have been reported at this time, according to officials.
“It’s important to understand that these mosquito infestations are affecting the entire county,” said Anna Zangeneh, senior manager of infectious and emerging diseases for the Department of Public Health, “which means that anyone, anywhere in the county, is at risk for infection.”
Public health officials report that 520 mosquito pools have tested positive for the virus. Each pool contains between one and 50 mosquitoes. On Wednesday, June 25, county officials reported that there were 235 positive pools at the time. Two weeks earlier, on June 12, officials counted 45 positive pools. Officials noted that the last peak year was 2014, with a total of 1,286 positive pools. In 2022, officials recorded 44 and 50 positive pools in 2023, respectively. These summers were faced with drought and very dry conditions.
Mosquito and Vector Control Division chief Max Vigilant explained that continued wet weather and hot weather are the reasons for the increase in mosquito populations across the county.
“We’re looking at the rainfall. Rain, humidity, temperature, then we have mosquitoes. Plus we’re getting flooding, wet conditions,” Vigilant said. “Flood mosquitoes lay their eggs in wet, salty water. They love those conditions. They love mud and grass. Within the next five to seven days, we’re going to have conditions where mosquitoes will start to emerge.”
Zangeneh also reported two human cases of dengue fever, which is also a mosquito-borne disease, in the county. Both cases involve people who traveled to areas where the virus is most prevalent, Zangeneh said.
Public health officials report that symptoms of West Nile virus include fever, headache, body aches, skin rash, and sometimes gastrointestinal symptoms such as vomiting and diarrhea.
Officials are urging the public to throw out containers that have accumulated water. Additionally, they recommend applying an EPA-approved mosquito repellent, especially DEET, to protect your family and pets. Vigilant says dogs can be infected with heartworm disease, so they should be given a monthly heartworm preventative in addition to a safe mosquito repellent.
“You need to protect your pets. Don’t leave them to be attacked by mosquitoes,” Vigilant says. “Strongly scented products will keep mosquitoes away for a period of time. They act on the mosquito’s liver and sensory organs, repelling them. There are several things people can use, including guinea grass, burning eucalyptus and candles. Do your research and make sure they are EPA approved products.”
