One molecule is enough to trigger African Swine Fever, and there can be up to 50 million molecules in one drop of blood from a highly infected pig, Chinese officials have found.
It’s why they banned the use of pig blood in rations as they tried to get control of the disease that has claimed about seven per cent of the country’s pigs and sent pork prices soaring.
But then some packing houses dumped blood into sewers and it contaminated the environment, possibly infecting the wild boar population.
Now China is again allowing blood to be marketed, but only after it has been heated sufficiently to kill the virus.
Another measure comes into effect in mid-May, requiring all pork packers to pick a representative sample from each farm supplier to test for the disease.
This must be done under third-party supervision and a veterinarian. It could force many small-scale, low-income packers to close because they can’t afford it.
It would be better to conduct the tests on farms, keeping it out of slaughterhouses that, if they become contaminated, are a source for people and vehicles to carry it back to farms.
However, testing pigs on 25 million hog-producing farms is deemed too difficult and expensive.
Studies of 68 outbreaks showed that almost half were caused by the spread of virus material on vehicles and on non-disinfected workers; a third were caused by feeding pigs contaminated swill or food scraps; and 19 per cent were due to the transportation of infected pigs and meat products across regions.