Sentences with phrase «virus than birds»

But in vaccinated birds, the opposite was true: Those infected with the most virulent strains shed more virus than birds infected with the least virulent strain.

Not exact matches

Such viruses have not been identified in any of the more than 100,000 wild birds tested since the flu surveillance sampling began 43 years ago, Webster said.

Once La Niña comes around, disparate bird populations start to mingle again, increasing the likelihood that a carrier is infected with more than one variety of the virus.

In California, which has seen 92 people infected with West Nile virus this year, birds seem to be surviving better than before, says William Reisen, an entomologist at the Center for Vectorborne Diseases at the University of California, Davis.

An unprecedented wintertime outbreak of West Nile virus has killed more than two dozen bald eagles in Utah and thousands of water birds around the Great Salt Lake, state wildlife officials said on Tuesday.

Pandemic flu occurs when flu strains from different species — birds and humans, or humans and pigs — genetically mix to make a new virus that spreads faster and makes people sicker than either strain alone.

But the virus has been found in more than 60 bird species and about a dozen mammals; in a little more than a year, it has spread to 11 states along the East Coast and the District of Columbia.

When the birds weren't vaccinated, infection with highly virulent strains killed them so fast that they shed very little virus — orders of magnitude less than when they were infected with less virulent strains.

According to the authors, it has been known for more than three decades that while Lassa virus can infect a broad range of cells from different species, it does not infect chickens — despite the fact that bird cells have the necessary receptor, or protein, that the virus uses to enter cells.

(Reuters)- An unprecedented wintertime outbreak of West Nile virus has killed more than two dozen bald eagles in Utah and thousands of water birds around the Great Salt Lake, state wildlife officials said on Tuesday.

Bird flu viruses are potentially highly lethal and pose a global threat, but relatively little is known about why certain strains spread more easily to humans than others.

The accusation that Capua and others set off a human epidemic made no sense, she said, because one mild flu case does not constitute an epidemic; moreover, the avian virus she allegedly spread was a different strain than the one that killed the birds in Italy.

The CDC also indicated that during the summer 2012 ``... outbreak likely resulted from many factors, including higher - than - normal temperatures that influenced mosquito and bird abundance, the replication of the virus in its host mosquitoes, and interactions of birds and mosquitoes in hard - hit areas.»

Pet birds are probably at greater risk to WN virus than dogs or cats.

The much greater danger is the wholesale spread of the virus between large flocks of birds, especially birds that come into frequent contact with humans — and that is taking place in more countries now than ever before.