By Sybille de La Hamaide

PARIS (Reuters) – Tracking meat and meat products from pigs infected with African swine fever is key to fight the spread of the highly viral disease as it can survive in processed food, the Deputy head of the World Organisation for Animal Health (OIE) said on Monday.

African swine fever (ASF) has spread rapidly in eastern Europe and China, the world’s largest pork producer, where new cases are appearing every day and the disease is traveling vast distances.

“The scenario in China is very challenging because of the amount of spread that has already occurred and the significant degree of contamination of various meat products,” Matthew Stone, Deputy Director General of the Paris-based OIE, told Reuters in an interview.

Considerable numbers of pigs could have been reared at times when farms were not aware of the virus, he said. Pigs were then sent to slaughter, sending the virus into the meat supply chain and creating an ongoing risk of further exposure.

Pigs can be infected by ASF by direct contact with infected pigs or the ingestion of garbage containing meat and or meat products from infected pigs.

Stone called on governments to ensure tight border controls and inspection methods to manage the risk of spread.

The rapid spread of ASF in China has sent pork prices higher in the country, raised prospects of higher imports and pressured the price of soybeans, a key ingredient of pig feed.

African swine fever, which does not affect humans, is characterized by high fever, loss of appetite, hemorrhages and death in two to 10 days. Mortality rates may be as high as 100 percent. There is no vaccine nor treatment for it.

The question of transport will be key in the European Union which is trying to contain outbreaks which have already hit several countries in the central and eastern part of the bloc.

Romania, Poland, Hungary and recently Bulgaria were among the most hit, alarming governments and pig farmers due the pace at which it has spread.

In Romania, authorities reported that food transported by people was very likely to be the source of contamination in the country, Stone said, stressing the risk of migrating populations in the spread of the disease.

African swine fever has led to the culling of around 250,000 animals in Romania.

“The humanitarian crisis of migration creates new risks for Europe that people are very mindful of, but so do populations of migrant workers that are legally coming to countries, retain strong connections to their home country, involving visit time and typically returning with food,” he said.

“This is quite a typical scenario in many countries and a very challenging one to get on top of because it’s very hard to undertake appropriate screening across the borders for all the cars and trucks and people that move across the borders.”

Many workers in Romania and Bulgaria, the two last countries to have joined the 28-member bloc, cross their borders to work in other EU countries, attracted by higher salaries.

The United Nations’ food agency last week said ASF would “almost certainly” spread to other Asian countries, notably through products containing infected pork, a popular meat in the region.

(Reporting by Sybille de La Hamaide; editing by David Evans)