Expert: Droppings, crow roosts not healthy
The annual pilgrimage of crows roosting may sound as light-hearted discussion for some, but a local infectious disease expert paints a darker picture related to a health risk from heavy crow droppings created by large roosting populations.
Dr. Rutul Dalal, medical director of infectious disease and chairman of Infection Prevention and Control at UPMC Susquehanna, said there are more than 60 diseases that birds and their droppings can carry.
“The problem is especially worrisome in residential areas, as many carry fungal diseases that become airborne and can be transferred to humans just by being around droppings,” Dalal said.
Those with compromised immune systems and existing health conditions may be at greater risk, he said.
Those individuals may include people seeking transplants and undergoing cancer treatment, he added.
The feces can cause a brain and/or lung infection, Dalal said.
Another concern is the spread of West Nile virus.
West Nile is a mosquito-based disease.
“What can happen is that an infected mosquito bites a bird, the bird becomes infected, and another mosquito bites the infected bird, and then passes it on to a human it bites after,” Dalal said.
Additionally, birds may carry e-coli on their bodies, he said.
“They come in contact with large animal manure, get the e-coli on their feathers and feet, and can spread the bacteria through contact,” he said.
Large bird roosts present some risk of disease to people nearby, Dalal said.
The most serious health risks arise from fungal organisms that can grow in the nutrient-rich accumulations of bird droppings, feathers and debris under a roost, particularly if roosts have been active for years, he said.
External parasites also may become a problem when infested birds leave roosts or nests, Dalal said.
The parasites may invade buildings and bite people, he said.
Although those parasites can bite and irritate, they are unlikely to transmit diseases to humans, he added.
Other pests can accompany bird mess. Droppings, feathers, food and dead birds under a roosting area can breed flies, carpet beetles, and other insects that may become major problems in the immediate area, Dalal said.
“These pests may fly through open windows or crawl through cracks to enter buildings,” he said.
“If birds are discouraged from roosting around buildings, most of the parasites associated with them will soon die,” he said.
“If the pests are a problem after birds have been excluded, the roost area may be treated with a residual insecticide appropriately labeled by the U.S. Environmental Protection Agency for control of fleas, ticks, mites and similar pests,” Dalal said.
Prevention is the key to control the spread of germs associated with the birds, Dalal noted.
Those with compromised immune systems should try to avoid contaminated areas and when in those locations wear a N-90 respirator, Dalal said.
Respirators are also recommended for anyone working in an enclosed area where birds have been roosting, such as attics and crawl spaces.
Anyone coming in contact with the birds, their droppings, or a surface contaminated by droppings should wash their hands with soap and water, he said.