Birds become immune to influenza

Date:  June 30, 2017

Source:  Lund University

Summary:  An influenza infection in birds gives a good protection against other subtypes of the virus, like a natural vaccination, according to a new study.

An influenza infection in birds gives a good protection against other subtypes of the virus, like a natural vaccination, according to a new study.

Water birds, in particular mallards, are often carriers of low-pathogenic influenza A virus. Researchers previously believed that birds infected by one variant of the virus could not benefit from it by building up immunity against other virus subtypes. However, the recent study concludes that mallards infected with a low-pathogenic virus build up significant immunity and resistance to other variants of the same virus.

"It was previously thought that the birds were not particularly good at protecting themselves against subsequent infections, but in fact they manage quite well," says Neus Latorre-Margalef, a biologist at Lund University.

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Birds studied to understand trade-offs between reproduction, immunity

University of Delaware post-doctoral researcher Ian Stewart is conducting research to answer this question a bit more scientifically. His subjects – tree swallows – make human parents look like slouches. Both the mother and father tree swallow feed their hatchlings every five minutes, 12 hours a day.  (It should be noted, though, that their parenting gig is much shorter than ours—after 17 or 18 days the young leave the nest.) Stewart is studying these small, migratory birds to better understand the trade-offs they make between reproduction and immunity. His research could potentially help scientists who study human biology better understand our own immune system and its stressors. Stewart is part of a young but growing interdisciplinary field called ecoimmunology, which combines aspects of immunology with ecology, biology, physiology and evolution. He chose to focus his research on tree swallows and bluebirds because both are fairly tolerant of human interaction. "Some birds don't like being observed but tree swallows and bluebirds don't get stressed from being watched or handled," notes Stewart.  There's another very important benefit to working with these birds—since they nest in boxes, not up in the trees, they're a heck of lot easier to catch.  Throughout the breeding season, Stewart catches the parent birds, injects them with a harmless antigen and releases them. Then, he re-catches the same birds a few days later to take blood samples and assess each bird's immune response to the antigens.  "Some of the tree swallows work harder at parenting," notes Stewart. "It may be because the bird has four hatchlings to feed instead of just three. Other times, the bird is simply more energetic at taking care of its hatchlings, regardless of brood size." 

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 http://phys.org/news/2012-11-birds-trade-offs-reproduction-immunity.html#jCp