Several Asian countries are battling to contain African swine fever. The highly contagious disease has already led to the culling of millions of pigs in China, Cambodia and Vietnam. Martin Lowe reports from the Cambodia-Vietnam border.

A remote area where Vietnam meets Cambodia. These men on motorbikes are trying to smuggle pigs across the border. Smuggling bypasses all disease control regulations and is one of the main reasons African swine fever is spreading. Cambodia is the 'front line' in a battle to halt the outbreak, which has ravaged pig herds across Asia causing shortages and pushing up the price of pork by almost 40 percent. On Cambodian TV, pictures of another smuggling attempt, this time at night, but police were waiting.

MARTIN LOWE CAMBODIA-VIETNAM BORDER "Cambodian authorities have had some success, but all too often the smugglers get through. It's likely bribes are paid. Smuggled meat is a big concern but the disease can also be carried by ordinary travelers and truck drivers on clothing or vehicles."

HENG PISETH, DIRECTOR DEPT. OF AGRICULTURE, TBONGKHMUM PROVINCE "We're sending out police patrols 24 hours a day to look for smugglers, when we catch them we test the pigs for disease."

RY DAVIN CHIEF VETERINARY OFFICER, TBONGKHMUM PROVINCE "It's hard to stop the smuggling because pigs sell at a higher price in Cambodia than Vietnam."

Some pig herds in Cambodia are now infected and the culling of thousands of animals has begun, already millions have had to be slaughtered in China and Vietnam, while cases have also been discovered in Mongolia, Hong Kong and the DPRK. Watching anxiously is Thailand, Asia's second-biggest pork producer, with an industry worth more than three billion U.S. dollars a year. The country has so far remained disease-free but is on high alert.

NIPAT NUANIM, VICE-PRESIDENT SWINE RAISERS' ASSOCIATION OF THAILAND "We are working with our neighbors to create buffer zones in Laos and Cambodia, constructing disinfectant stations at the borders to try to keep swine fever out."

The disease can't be passed to people so there's no human risk but for animals it's devastating. Pigs bleed internally until they die. There's no vaccine or cure.

Dr. WANTANEE KALPRAVIDH, REGIONAL MANAGER UN FOOD & AGRICULTURE ORGANIZATION "Banning the movement of pigs would be recommended but it would work only in principle because of the porous borders."

Officials in Bangkok seized more than 550 frozen pig carcasses on their way to restaurants, with no record of their origin or any health inspection. At the border, a pig lorry waits on the Vietnamese side, for the right moment to try to smuggle the animals across.