(NEW YORK) -- Health officials in several states are raising concerns about West Nile virus after detecting cases among residents, including some deaths.
Counties in Georgia, Maryland and Texas have detected their first infections this year. Kansas is putting nearly the entire state on high alert.
The Maryland Department of Health announced this week that an adult living in the Eastern Shore region, part of the Delmarva Peninsula, was positive for the virus.
"We are in the season when the West Nile virus can spread in Maryland," Deputy Secretary for Public Health Services Dr. Nilesh Kalyanaraman said in a statement. "We urge people to be vigilant and take steps to avoid infection and eliminate standing pools of water where mosquitoes can breed. Our teams are continuing to monitor mosquito activity across the state."
Similarly, in Atlanta, the DeKalb County Board of Heath said it's investigating three cases of the virus, including one among a man in his 20s. The Galveston County Health District in Texas confirmed a case in a woman in her 60s.
Dekalb County's board said crews are applying larvicide, an insecticide that targets the larval stage life of a mosquito, in low-lying areas and storms drains.
"Larvicide keeps young mosquitoes from becoming flying, biting adults," the board said.
Meanwhile, the Kansas Department of Health has put five of the state's six regions in the high-risk category, meaning residents have high odds of being bitten by an infected mosquito.
Kansas has seen 22 cases this year, including 17 neuroinvasive cases -- meaning the virus has affected the nervous system. Three deaths have been reported.
"We're right in the middle of our peak timeframe for WNV transmission here in Kansas, and with more widespread virus activity this year than in the previous several years, it's important to take mosquito bite prevention measures to protect yourself, your family, and livestock against all mosquito-borne illnesses," Dr. Erin Petro, the state's public health veterinarian, said in a statement.
West Nile virus is the leading cause of mosquito-borne disease in the contiguous United States, according to the Centers for Disease Control and Prevention.
It was first introduced in the Western Hemisphere during the summer of 1999 after people were diagnosed in New York City.
Mosquitoes typically become infected with the virus after feeding on infected birds and then spread it to humans and other animals, the federal health agency said.
The majority of people with the virus do not have symptoms, but about one in five will experience fever along with headaches, body aches, joint pain, diarrhea, vomiting or a rash. Most symptoms disappear but weakness and fatigue may last for weeks or months.
About one in 150 will develop severe disease leading to encephalitis, which is inflammation of the brain, or meningitis, which is inflammation of the membranes that surround the brain and spinal cord -- both of which can lead to death.
There are currently no vaccines or specific treatments available for West Nile virus. The CDC recommends rest, fluids and over-the-counter medications. For those with severe illness, patients often need to be hospitalized and receive support treatments such as intravenous fluids.
To best protect yourself, the CDC suggests using insect repellant, wearing long-sleeved shirts and pants, treating clothing and gear and taking steps to control mosquitoes. This last step includes putting screens on windows and doors, using air conditioning and emptying out containers with still water.