A 58-year-old Frederick County resident is the first Marylander this year to be diagnosed with West Nile fever.
The unidentified woman did not require hospitalization, according to the state Department of Health and Mental Hygiene. Officials would release no further information on the case.
Last year, the state reported 36 cases of West Nile encephalitis or meningitis in people, the first on Aug. 23. Seven of the victims died.
Mosquitoes carrying the West Nile virus have been found this summer in eight Maryland jurisdictions.
Seven horses have been stricken, five fatally.
State health officials have urged all residents -- especially those over 50, or whose immune systems are weakened by age, illness or medical treatment -- to try to avoid mosquitoes, use insect repellant and rid their properties of standing water where the bugs breed.
Fewer than 1 percent of those infected with the West Nile virus develop serious illness.
Symptoms include headache, high fever, a stiff neck, disorientation, tremors, weakness and paralysis.
Nationally, the Centers for Disease Control and Prevention has reported 470 West Nile cases in 2003, more than half in Colorado.