Human health risks associated with the American crow roost of 30,000 in the city can be reduced significantly just by using common sense, according to Kevin J. McGowan, an ornithologist at Cornell University in Ithaca.
Mr. McGowan said people should try to avoid the birds, but if they do come in contact with crows or crow droppings, they should always wash their hands.
It looks messy and looks scary, Mr. McGowan said, referring to crow droppings on walkways or in parking lots. If you deal with cleaning up feces, try not to (put your mouth to) your fingers; wash your hands.
Thousands of crows invade Watertown every winter, and the City Council on Monday night voted to authorize Loomacres Wildlife Management of Warnerville to use lethal means to help control the population. Some people are worried about health problems the droppings might cause; how soon a killing strategy might be devised hasnt been established.
A crow expert for 25 years, Mr. McGowan said hes handled thousands of the birds, and although crows have defecated on him, he hasnt gotten sick. He said he practices routine safe handling and frequent hand washing.
He called the Watertown roost modest, because more attention is drawn with roosts of 100,000 crows or more. Although diseases are possible, humans getting them from crows would be a stretch, he said.
According to the Center for Food Security and Public Health at Iowa State University, one possible disease is Avian chlamydiosis in crows, or whats known as psittacosis in humans, which can be transmitted between birds by the inhalation of infectious dust or airborne particles such as feathers, and by the ingestion of infectious material, including carcasses. Large quantities of this organism are excreted in feces and can become aerosolized when the fecal material dries, according to the center.
A document from the center states that humans may become infected with psittacosis after inhaling contaminated dust, feathers or aerosolized secretions and excretions. Direct contact with infected birds, including bites, can also spread the disease.
Dogs may get it if they eat dead crows infected with it.
Mr. McGowan said another possible disease is salmonellosis. According to the Centers for Disease Control and Prevention, about 42,000 cases in humans are reported in the nation each year. The CDC reported that salmonella is usually transmitted to humans by eating foods contaminated with animal feces, including from birds. While the bacteria can be killed by thorough cooking, Mr. McGowan said the basic preventive measure of washing hands helps decrease that risk.
Also, Mr. McGowan said, West Nile Virus in crows is nothing to be alarmed about because birds die from the disease; they dont harbor it.
Calls seeking comment from the state departments of Health and Environmental Conservation were not immediately returned to the Times.