Virus is suspected in crow die-off in N.Y.

A mysterious die-off of hundreds of crows throughout New York state has been linked to the avian reovirus, a pathogen that has threatened the poultry industry in the past, relentlessly sweeping through flocks, state wildlife officials said Thursday.

The virus is not likely to jump the species barrier to infect humans. However, state health officials are taking no chances, and scientists at Wadsworth Center, a division of the state Health Department, were studying the virus.

State wildlife pathologist Ward Stone, who was instrumental nearly a decade ago in identifying the pathogen that turned out to be the West Nile virus, said the sudden sweep of death among crows had caught scientists by surprise.

“Initially, I didn’t know what it was,” Stone told Newsday on Thursday. “You really don’t know until you do the post-mortem examinations,” which include preliminary viral typing, he said. Additional specimens are being sent to a federal wildlife laboratory in Madison, Wis., which is expected to provide further molecular details about the strain.

“It’s causing necrotizing enteritis,” Stone said, referring to a severe hemorrhagic intestinal disorder that leaves few survivors. The virus is feared by executives in the broiler chicken industry, which produces most of the poultry sold in the United States. Epidemics have swept through flocks, destroying potential profits.

Stone added that various reovirus strains have been identified in the United States and Canada in recent years but only a small number of crows in New York contracted the virus and died.

Now, a dramatic shift in viral spread, which became most noticeable shortly after Christmas, has all the makings of a bird epidemic. Crows not only have died but sometimes have succumbed in large groups. Stone suspects when temperatures warm as expected next week, causing snow to melt in many upstate communities, more dead crows will be found.

So far, dead crows have been found in Albany, Dutchess, Jefferson, Montgomery, Orange and Steuben counties. The largest number of dead birds -- about 100 -- have been found in Poughkeepsie.

Stone thinks it’s only a matter of time before dead crows are spotted on Long Island and in Queens and Manhattan. He also suspects the infection will sweep into Connecticut and Massachusetts.

Health officials on Long Island have not found anything suspicious. Wendy Ladd, spokeswoman for the Suffolk County Health Department, said communities were already aware that dead crows would be reported because of the summertime spread of West Nile disease.

“We have not seen any increase in dead crows,” Ladd said Thursday. “We have a bird hotline for people to call and we haven’t gotten any calls about it.”

Cynthia Brown, spokeswoman for the Nassau County Health Department, also reported silent hotlines. “I have not heard any unusual crow kill-offs,” she said.

Crows, Stone said, tend to live in large social groups in winter composed of smaller families and individual birds. Such clustering helps explain why so many crows are dying simultaneously. Crows tend to live in small families during other seasons.

No other types of birds have been affected, but state biologists were monitoring ravens, magpies and blue jays, which are closely related to crows and have similar nesting habits.