Unknown pig virus kills 117 people in Malaysia

By Angela Pagano
28 April 1999

In southern Malaysia, hundreds of pig farmers have lost their livelihood and livestock due to an unknown virus believed to be transmitted by pigs. Over the last six months, 117 people have died and 236 have been hospitalised. More than 11,000 people have fled or been forced out of the affected areas in the state of Perak, and the districts of Sikamat and Bukit Pelandok, in the state of Negeri Sembilan.

Pig breeder Tah Ep Pau, whose 700 pigs have been destroyed, said: "I'm lucky to be alive. Every family I knew had at least two members who came down with Japanese encephalitis. My friend, his wife and child all died."

As well as losing their income and friends, many of the refugees have been stigmatised and found it hard to find work in neighbouring areas. Yeng Teck Teck, 38, said: "Even though we have been lucky to escape the disease, people are afraid of us, not knowing if we will infect them."

The Malaysian government has sent in soldiers to destroy up to 500,000 pigs. Although farmers have been offered limited compensation of $US14 per pig killed, before the crisis each pig was worth between $80 to $150. Thailand and Singapore have banned imports of live pigs and the price of pork has plummeted by 70 percent.

The affected region was the largest pig raising area in Southeast Asia. The industry was worth $395 million, supported more than 300,000 people and accounted for one quarter of Malaysia's livestock.

The first outbreak of the virus occurred last October in the state of Perak where 15 pig farmers were reported to have died. Two months later the disease had spread to the southwest state of Negeri Sembilan. A similar illness afflicted 11 slaughterhouse workers in Singapore last month after they handled imported pigs from Malaysia. One of the workers died.

Despite the growing number of deaths, the response of the Malaysian government and health authorities has been slow. Health officials first identified the disease as Japanese encephalitis (JE), a virus carried by infected pigs and transmitted to humans by the bite of the Culex mosquito. The government initially imposed a ban on medical officers from making public statements on the disease.

As the death toll continued to rise, the authorities were finally forced to take further action--ordering the mass culling of pigs, the spraying of insecticides and disinfecting of farms. But these measures were based on the assumption the disease was an outbreak of Japanese encephalitis, which proved not to be the case.

On March 17, Malaysian virologists flew samples of the virus to the US Centre for Disease Control and Prevention in Atlanta (CDC) where it was shown to be a rare Hendra-like disease. The Hendra virus was first detected in Australia in 1994 when it killed a number of racehorses and three people. Little is known of the disease except that the symptoms are the similar to JE and Hendra--high fever, aches, eventual coma and death.

A spokesman for the CDC Tom Skinner explained the difficulties now facing health authorities: "This is a new, previously unrecognized virus found in humans. This virus has never been seen before. We don't know if it's highly infectious. We don't know how people are being infected. It doesn't appear, right now, that this is being transmitted from person to person, but we're still not going to rule that out. But it's not Hendra. It's a Hendra-like virus, and it has a high mortality rate."

Scientists from the US, Australia, Japan and Taiwan as well as Malaysia are now trying to determine the basic characteristics of the virus and the best means of combatting its spread.