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Vaccine urgency increases when virus devastates pigs in China



BEIJING (AP) – Scientists are working to develop a vaccine to help safeguard pig supplies worldwide, as a deadly virus ravages swine herds in Asia.

Farmers have long been restricted in its spread by quarantining and killing infected animals, but the devastating march in East Asia has been stepping up the search for another solution.

The virus was not considered a top priority for researchers until it appeared last year in China, home to half of the world's pig breed, probably through Eastern Europe and Russia. It has since spread to other Asian countries, including Vietnam, killing millions of pigs along the way. Although it does not hurt people, it is highly contagious and deadly to pigs.

"Today's situation where you have this global threat puts a lot more emphasis on this research," says Dr. Luis Rodriguez, who directs

One way to develop a vaccine is to kill a virus before it injected into an animal. The disabled virus does not make the animal sick but encourages the immune system to identify the virus and produce antibodies against it. However, this approach is not consistently effective in all viruses, including one that causes African swine fever.

This is why scientists are working on a different kind of vaccine made from a weakened virus than a dead one. With the African swine fever, the puzzle is figuring out how to pinch the virus.

In Vietnam, where the virus has killed 4 million pigs in six months, the government said it was testing vaccines this summer, but provided little details about its program. In China, the government said scientists are working on a vaccine that genetically alters the virus, an approach that American scientists are also pursuing.

Taiwan last week imposed new security checks on arriving air passengers carrying pigmeat in an attempt to quit. an epidemic, according to Taiwan News. Infected pig carcasses were found washed ashore on the beaches of Taiwan, but no island on the island.

Myanmar reported its first outbreak in early August, and North Korea reported an epidemic in May, according to the UN Food and Agriculture Ministry

The US Department of Agriculture said it had recently signed a confidential agreement with a vaccine manufacturer to further research and development on one of the three vaccine candidates. The candidates are made by genetically modifying the virus to delete certain genes.

But before the vaccine becomes available, it must be tested in a large number of pigs in secure facilities with insulating pens, waste incinerators and carcasses and staff deactivation showers, said Linda Dixon, a biologist at the Pirbright Institute in London. viral diseases in livestock. The process takes two to five years, she said.

Extensive testing is required to ensure that vaccines made from attenuated viruses have no undesirable side effects.

In the 1

960s, for example, Spain and Portugal tested such a vaccine after outbreaks of African swine fever. Initially, the treated pigs looked good, but then lesions exploded on their skin, arthritis locked their joints and the animals failed to fatten, said Jose Manuel Sanchez-Viscino Rodriguez, who runs a laboratory focused on African swine fever at the University of Swine in the University of Madrid.

In the end, both parties eliminate the disease by imposing strict sanitary protocols, quarantining and killing infected and pig carriers.

Even if vaccines become available, they may not work worldwide. Vaccines developed for the virus in China and Europe, for example, can do nothing in Sub-Saharan Africa, where the disease has been around for longer.

The vaccine may be the most desirable in places where the disease is widespread, said Daniel Rock, who previously headed the African swine fever program on Plum Island. Other countries may prefer the quarantine and murder method.

This may be the case in the United States, where health officials train pork producers how to spot and report potential symptoms, which may include bleeding, lethargy, and loss of appetite. The disease has made it possible for the vaccine to be a high priority in the United States

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according to Candice Choi of New York. Follow Sam McNeill on Twitter: @stmcneil

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The Associated Press Health and Science Division is supported by the Howard Hughes Institute of Science Education. AP is solely responsible for all content.


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