According to Cy Lesser, the department's chief of mosquito control, agriculture officials have more than doubled mosquito trapping on the Lower Eastern Shore.
The state of urgency was brought about after the Department of Health and Mental Hygiene reported last week a human case of the virus. Officials are not talking much about the case except that it involves a resident of Worcester County.
"The report has not been confirmed," says Karen Black, Health Department spokeswoman. "That will take a couple of weeks."
This year, the mosquito population had been well below normal because of a drought. Yet this was undone a few weeks ago when a combination of rains and a new moon increased tidal flooding of several hundred thousand acres of Eastern Shore marshland.
The water activated the mosquito eggs that had lain scattered on the marshland mud for weeks, and they rapidly developed into adult mosquitoes. The situation was worsened by the destruction of minnows that normally feed on the mosquito larvae, by the previous drought.
"There were no predators around to control the mosquito population," says Lesser.
Still, the worst is yet to come, as September is traditionally marked by heavy mosquito activity."There is increased potential of mosquitoes carrying the virus," Lesser warns." We don't think people need to be unduly concerned, but they should take some efforts to reduce the threat."
Mosquito control is the key tool in the effort to ameliorate the risk of infection with all mosquito-borne diseases, opines Maryland Agriculture Secretary Roger L. Richardson.
As of now, the department is boosting efforts with additional surveillance and more aggressive control activities in the Lower Eastern Shore for the remainder to the mosquito season. Steps include an increase in flights of airplanes used to spray mosquito-killing chemicals.
More than 50,000 acres were sprayed last week, and more spraying will take place this week, informs Lesser.
The department is also using trucks to spray areas that could be reached from the road. Field workers have been meeting with residents to suggest ways to rid their yards of containers holding water and other mosquito breeding nests.
Since 2001, there have been 136 cases of West Nile virus in Maryland and 18 deaths, say health officials. Six cases were reported last year, one more than in 2005. The disease peaked here in 2003 when 73 cases resulted in eight fatalities.
Health Department officials inform that most mosquitoes do not pose a threat to public health because they are not infected with viruses or other pathogens. Generally, less then 1 percent of the people bitten by a mosquito carrying the West Nile virus become ill.
People most at risk for developing symptoms of the disease are those older than 50 and those with compromised immune systems. The most common symptoms are fever, headaches, weakness, and joint and muscle pain.