A sample of mosquitoes collected from Evanston at the end of June tested positive for the West Nile virus, according to the city. These are the first reports of the virus in Evanston this year.

Tests ordered by the North Shore Mosquito Abatement District, a local group that aims to protect communities from mosquito-borne illnesses, initially came back negative on July 3. When the same mosquito pool was tested again at the lab of the Illinois Natural History Survey, a division of the Prairie Research Institute at the University of Illinois at Urbana-Champaign, results indicated that the sample tested positive for West Nile virus.

The West Nile virus is most commonly transmitted through the bite of mosquitoes that were infected from feeding on diseased birds. Although 70 to 80 percent of people infected will not show any symptoms, some may have minor symptoms two to 14 days after being bitten, including body pains, rashes and headaches, according to the Center of Disease Control and Prevention. In less than one percent of cases, the virus can result in serious illnesses and death.

Evanston will continue to provide education to its residents on precautions they should take against the virus through the city’s website and social media, Evanston Health Department Director Evonda Thomas-Smith said.

The city provided a set of precautions for residents to follow earlier this week. The city advised people to avoid being outdoors between dusk and dawn when mosquitoes are most active, to use insect repellents and ensure screens on doors and windows are not broken.

As of Thursday, 29 cases of West Nile virus had been reported in the United States in 2014, with no reported cases in Illinois, according to a disease map from the U.S. Geological Survey.

The NSMAB will be carrying out operations in areas of Evanston on Monday that aim to control the amount of adult mosquitoes in the city, according to its website.