- Bird

In a Hopeful First, American Crows Survive West Nile Virus


close up of the head and shoulders of a crow
American Crow by Bryan Calk/Macaulay Library.

Cornell College has documented American Crows surviving the deadly West Nile virus illness for the primary time ever.

In analysis printed in Could within the Journal of Avian Drugs and Surgical procedure, scientists at Cornell’s Janet L. Swanson Wildlife Hospital documented the immune response of 5 crows from 2017 to 2018 that acquired remedy and have been efficiently launched again into the wild. Throughout their hospital stays the crows acquired supportive care, together with fluid remedy, B-vitamin supplementation, and antiparasitic remedy, amongst different remedies.

Prior to those recoveries, crows recognized to have contracted West Nile Virus had a 100% mortality price.

“[Crows with West Nile virus] get very sick in a short time and shut down. They often die inside 4 days of being contaminated,” says Kevin J. McGowan, a scientist and crow professional on the Cornell Lab of Ornithology. “That is the primary time any American Crow has survived [to my knowledge].”

McGowan is a course developer and teacher for the Cornell Lab’s Chook Academy, the place he leads a web based class entitled The Hidden Lifetime of the American Crow. Over greater than 30 years, he has studied, banded, and tracked greater than 3,000 crows round Ithaca, New York.

“The variety of crows dropping lifeless in 1999 was truly the rationale that we knew there was some sort of new illness occurring within the first place,” McGowan mentioned. “[In Ithaca] we’d get calls from locals on a regular basis about sick and lifeless crows of their backyards.”

a crow with a purple wing tag and colored bands on its legs, used for field studies
Kevin McGowan has banded and studied greater than 3,000 American Crows within the Ithaca, New York, space, for the reason that Nineties. Photograph by Kevin McGowan/Macaulay Library.

In line with McGowan, over half of the native American Crow inhabitants round Ithaca succumbed to the illness throughout a wave in 2002 (when he collected over 35 lifeless crows in his freezer, all of which have been banded birds from his research inhabitants). One other outbreak in 2012 once more killed about half of the native Ithaca crows, he mentioned. New York Metropolis notably misplaced virtually 6,000 crows in simply 4 months in 1999 when West Nile Virus first appeared in the US.

Greater than 250 hen species are inclined to West Nile virus, however it’s deadliest to corvids and raptors—together with jays, magpies, ravens, eagles, hawks, owls, and particularly American Crows. There’s a vaccine out there for birds, however widespread vaccination of untamed hen populations will not be possible. As an alternative, scientists hope the Cornell research proves that crows are able to overcoming West Nile virus, and that wildlife rehabilitation would possibly assist native crow populations turn out to be extra proof against the virus.

“Their most necessary safety will probably be no matter maternal immunity the crows can move to their offspring,” mentioned lead writer Cynthia Hopf-Dennis, a Cornell scientific assistant professor of zoological drugs. “My hope is that after we return crows to the wild after remedy and rehabilitation, they’re able to contribute to a stronger inhabitants that is ready to survive the virus and supply some degree of safety to their offspring.”

In line with McGowan, the recoveries may imply a brand new chapter for crows and West Nile virus.

“It’s been pure dying for 20 years,” he mentioned. “This can be a signal of sunshine and we’ll take it. We’re extraordinarily glad to have these crows survive and be capable to get again on the market, absolutely recovered.”

Meher Bhatia’s work on this story as a pupil editorial assistant was made doable by the Cornell Lab of Ornithology Science Communications Fund, with assist from Jay Branegan (Cornell ’72) and Stefania Pittaluga.

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