Pig Disease Epidemic In Vietnam

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Main Category: Veterinary
Article Date: 20 Aug 2007 - 1:00 PDT

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An epidemic of an unprecendented and severe pig disease has broken out in Vietnam which previously was mostly found in imported pigs according to the country's Department of Animal Health. The disease is called Porcine Reproductive and Respiratory Syndrome (PRRS), also known as blue ear pig disease, and is caused by a virus. PRRS was first reported in North America and Europe in 1987.

Veterinary officials in Vietnam have sent virus samples to labs in the United States for DNA testing. This will also establish if it is related to the PRRS strain that killed an estimated 1 million pigs in China last year. American experts have also arrived in Vietnam to help the Vietnamese authorities investigate the outbreak.

The current outbreak in Vietnam started in June this year, and by the end of July an estimated 28,000 pigs were infected of which 20 per cent have died according to an interview between Reuters and an official from Vietnam's Department of Animal Health.

PRRS belongs to a family of viruses that includes equine viral arteritis that affects horses and young foals.

According to the Merck Veterinary Manual, PRRS has two phases: reproductive failure in pregnant sows and respiratory diseases in young pigs after they have been weaned. Reproductive failure results in significant increases in stillborn piglets (up to 35 per cent), abortion (over 10 per cent), premature births, weak newborn piglets and mummified piglet fetuses. Sows in milk are also more likely to become anemic and up to 50 per cent more likely to die before piglets are weaned.

PRRS is passed from the pregnant sow to the unborn piglet and piglets born with the virus are infectious for around 100 days afterwards.

In pigs still being suckled, PRRS develops as a "characteristic thumping respiratory pattern" and lung tissue from dead piglets shows severe damage from "necrotizing interstitial pneumonia".

Visible symptoms of PRRS include high fever, loss of appetite, red skin and diarrhea.

An outbreak of the reproductive form of PRSS can last between 1 and 4 months, depending on the farm and the health of the pigs. However, once it has got into weaning piglets, PRRS can become chronic, resulting in above normal rate of deaths (up to 25 per cent) and increased risk of other diseases including E. coli, Salmonella and swine flu.

PRRS is estimated to cost the US pig industry 600 million dollars a year.

PRRS is now endemic in the UK.

The strain that has broken out in Vietnam is a more unusual form of PRRS, and is infecting adult pigs as well as young piglets.

The Vietnamese authorities said they were working with China on tackling the epidemic and a Chinese veterinary expert is to arrive in Vietnam soon. Although the PRRS symptoms in Vietnam are similar to those in China, only the DNA tests will show if the strain is the same.

In the meantime neighbouring Cambodia has stopped importing pigs and pig meat from its neighbours, Vietnam, Laos and Thailand, said Reuters.

Click here to learn more about PRRS (thepigsite.com)

Written by: Catharine Paddock
Copyright: Medical News Today
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