The Asian tiger mosquito -- so named for its white striped legs and back -- arrived in Houston about 30 years ago in a tire shipment from Japan.
It has since spread from New York to Wisconsin to Southern California, and now county officials say the mosquito has reached Lawrenceville.
"It's such a nasty problem and a major nuisance," said Bill Todaro, an entomologist with the Allegheny County Health Department. "It bites in the morning, in the evening and at night."
The first local case of the invasion of the Asian tiger mosquito came three years ago in West Mifflin's Homeville neighborhood.
"We went door-to-door in the neighborhood and talked to people about the possible breeding grounds of the mosquitoes and how to prevent them," Mr. Todaro said.
Residents of Homeville were required to get rid of items that hold water, such as tires, buckets, flowerpots, junk piles and cans, and to clean out roof gutters, storm drains and birdbaths.
Pesticide was sprayed throughout West Mifflin, and trucks picked up old tires tossed aside in ravines.
"The mosquitoes are seeding in old tires like a Trojan horse," Mr. Todaro said.
What worries health officials is the mosquito's unusually aggressive disposition mixed with the potential to spread diseases that range from the West Nile virus to dengue fever, according to Joe Conlon, technical adviser and expert at the American Mosquito Control Association.
Symptoms of dengue include severe headache, pain behind the eyes, joint pain, muscle and bone pain, rash and mild bleeding.
Approximately four cases of the fever are diagnosed each year in Pennsylvania, either in persons who have traveled to an endemic area or in persons from those areas visiting the state, according to a state health department fact sheet.
The mosquito also carries the dog heartworm virus.
Still, Mr. Conlon thinks it's likely that the Asian tiger mosquito -- one of 53 species of mosquito in Pennsylvania -- has likely led to cases of West Nile virus, which can be difficult to identify because it presents with flu-like symptoms.
The mosquitoes also are nearly impossible to control. Anywhere there is standing water, even in a discarded bottle cap, their eggs will survive.
As a threat to public health, Mr. Conlon said there's reason to worry, but no one should be surprised the Asian tiger mosquito is cropping up again in Pittsburgh.
"Is it alarming? No, it's probably expected," Mr. Conlon said. "People should have the requisite concern about a type of a mosquito that is a vector for disease in other parts of the world in their midst."
The health department suggests that people empty and turn over plastic wading pools when not in use; drain water from plastic coverings on swimming pools and outdoor furniture; properly filter/chlorinate backyard swimming pools and dismantle those not in use; fill in depressions on the lawn to prevent accumulation of water; and repair leaky outdoor faucets that can create a pool of stagnant water.mobilehome - neigh_city - breaking - region
Kelton Brooks: firstname.lastname@example.org or 412-263-1601. Alex Zimmerman contributed. First Published July 30, 2013 2:15 PM