More than 10,000 migrating birds died of avian cholera in southern Oregon and northern California this year because of low water levels in the wetlands at a popular bird rest area, according to media reports.

“Sometimes I have seen birds literally fall out of the sky,” biologist Dave Mauser told EarthFix. “It happens that quickly.”

A cut-off water supply may be to blame, the Oregonian reported. The U.S. Bureau of Reclamation stopped water to a popular refuge for birds, the Klamath Basin National Wildlife Refuge Complex, because of light snowfall last year.

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As a result, the wetlands have been flooded with about half the usual amount of water this year, Ron Cole, the refuge manager, told National Public Radio.

"You can look at a bird in the morning and it seems completely healthy and that bird may be dead in a couple of hours," Cole said.

Now volunteers are picking up dead bird carcasses to reduce bacteria in the water. Snow geese and northern pintails have been hardest hit.

The breakout began in February in Northern California and spread north to the state border.  Cole believes the outbreak is slowing and that the final death toll could reach 20,000 birds.

Humans are not at high risk for avian cholera, according to EarthFix, an environmental news group affiliated with Oregon Public Broadcasting.

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A newly published study shows that "bush meat" and other wild animal products intercepted on their way into the United States often bring with them pathogens that can be deadly to humans, wildlife and livestock.

The pilot study focused on wild animals and wild animal products coming from primates, rodents and bats from Africa that were imported for human consumption and confiscated, mainly at New York’s John F. Kennedy Airport. What researchers found was that viruses sometimes persisted in these products even when they were smoked or otherwise prepared to make them safe for eating.

"We know from studies and outbreaks in Africa that live animals and bush meat carry a range of pathogens," said wildlife veterinarian Kristine Smith of EcoHealth Alliance, a wildlife conservation and global health nonprofit group in New York City which led the study.

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Some of the viruses they found included foamy virus -- a relative of simian immunodeficiency virus, or SIV (elated to HIV), and herpes, including several new strains. Bush meat like that analyzed in the study has been known to carry Ebola and monkey pox, which remain a concern even though they did not show up in the initial samples.

The study, conducted with the Centers for Disease Control, was only a start for health and environment experts concerned about the global trade in wildlife products.

The imports sometimes are often confiscated from single travelers — often people traveling to the United States carrying products that may be traditional fare from back home in Africa or Asia.

But there are also commercial shipments, said Smith. "You get big boxes, covered up with smelly dried fish. Once you dig down through that disgustingness you find the primates."

The animal products were discovered in a wide variety of conditions, said Smith. There were parts of African cane rats completely covered in mold and oozing fluids. Another whole cane rat carcass arrived in a cooler, completely preserved and fresh.

"A lot of what we saw was bloody, moldy, raw,” said Smith. "Some of the… primates look very well smoked on the outside, but inside there was still red meat."

Although most of the samples were confiscated between 2008 and 2010 and tested immediately, one large shipment seized in 2006 by U.S. Fish and Wildlife was not analyzed until four years later -- and still carried multiple viruses. 

Normally, U.S. agencies that confiscate wildlife products — typically the CDC and U.S. Fish and Wildlife — destroy them by incineration, Smith said.

Testing them first provides a picture of what is likely making its way into the market, she said. Experts estimate that only about 10 percent of the illegal trade is halted by authorities.

The United States is the world’s largest importer of wildlife and wildlife products.

About 55 million pounds of wildlife products enters the United States each year — including foods, fashion, traditional Chinese medicines and hunting trophies. In addition, more than 1 billion live animals were also legally imported for agriculture, clinical research, education and exhibition, and the pet and aquarium industry, according to a 2011 report by the Government Accountability Office.

That report concluded that gaps in the system regulating wildlife imports — which falls under several different agencies — increase the risk of disease that spread between animals and humans, as well as to other animals.

Smith says this pilot study established two important findings — that viruses were traveling to the United States and that the U.S. agencies involved in managing wildlife imports could work together seamlessly.

"We now need to expand the work to other ports around the country, and expand to other products, not just what CDC regulates," she said.

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