The summer of 2020 has been a quiet one for the West Nile Virus, perhaps in part because of COVID-19, but the disease remains a threat across our area.
The Pennsylvania Department of Environmental Protection has steadfastly, if somewhat quietly, maintained a close eye on mosquito populations throughout the state this summer. Jeff Carroll, the PA DEP’s vector borne disease control coordinator in Lehigh and Northampton counties, said in July that a sample collected in Northampton County tested positive for the virus. Meanwhile, Carroll’s Bucks County counterpart, Arthur Carlson, indicated five positive tests closer to the Philadelphia suburbs.
Carlson indicated that cases are “picking up” in his coverage area.
There are no vaccines to prevent or medications to treat West Nile Virus in humans, however most people infected with it never develop any symptoms. About one in five people who are infected will develop a fever and other symptoms, and 1 in 150 infected people will develop a potentially fatal illness.
The CDC’s West Nile Virus activity map shows that as of July 28, Pennsylvania was one of 19 states to have reported a positive test in a mosquito or other insect/animal, and one of 11 states to have reported a human case so far this year. A July 23 PA DEP news release indicated that the positive test was from a Potter County resident in the north-central part of the state. There was no information available related to the condition of the infected person.
Although Carlson and Carroll both indicated that this has not been a particularly active West Nile Virus season thus far in their respective coverage areas, they urged residents to do their part to reduce the mosquito population, in order to help control the potential spread of the disease. The PA Department of Health’s West Nile Virus Disease Fact Sheet provides the following list of suggestions:
- Regularly empty any outside containers of water, or drill drainage holes in them.
- Maintain the screens on your windows and doors to keep infected mosquitoes out.
- Turn over plastic wading pools and wheelbarrows when not in use.
- Clean clogged roof gutters that may allow for the pooling of rain water.
- Do not allow water to stagnate in either bird baths or ornamental ponds.
- Regularly clean and chlorinate swimming pools and remove standing water from pool covers.
- Use landscaping to help eliminate standing water that routinely collects on your property.
- Remove discarded tires as they make an excellent larva habitat.
- For standing water that can’t be eliminated, residents can buy either Bacillus thuringiensis israelensis (Bti) or Bacillus sphaericus (Bsp) tablets at any lawn and garden store. After either tablet is thrown into the water, the bacteria will infect and kill any mosquito larvae present, but the water will remain safe for people, pets, aquatic life and plants.
The state also does its part to help educate the public about mosquitoes that may transmit West Nile Virus with the DEP’s Pesticide Management Plan.
“The plan is 50 percent education of the public to identify problem areas on properties that can be better managed to eliminate mosquito breeding,” Carroll said. “Department officials also go door-to-door leaving door hangers where problem areas are observed.”
“We stop and talk to homeowners and discuss any community concerns,” noted Carlson. “We discuss with municipalities the need to regrade or drain certain problem areas, and investigate and have corrected commercial drainage issues, abandoned residential pools and other non-natural areas that are prime breeding grounds for mosquitoes.”
The PA DEP conducts its own physical mitigation efforts as well.
The second aspect of the program is larviciding,” said Carlson. “Areas that cannot be drained or corrected are treated with larvicide on municipal properties, and in some cases on private property with permission.”
Carlson also described Ultra Low Volume (ULV) sprays, in which adult mosquito populations are targeted.
“A mosquito ULV event is keyed to a specific area, and only when absolutely necessary,” he said. “All ULV events are conducted at night, so no bees or other beneficial insects are flying and which could be harmed. Furthermore, the department is in constant contact with the beekeepers of Bucks County and they are aware of all department-proposed spray events.”
He indicated that there have been no ULV spraying events needed in Bucks County thus far this season.
Carroll said there has been no spraying activity in Lehigh County, while in Northampton County “a small adult control application was conducted (in July).”
“It was not a truck-mounted spray” as ULV sprays typically are, he added.