The Virus is a danger to the world

For the animal experts, the nightmare began at the 3. August 2018 – and since then, it was only going to get worse. On the day the first notification of an outbreak of African swine fever (ASF), appeared on a farm in China. It was a small operation with less than 400 animals, 47 of them had killed the Virus already. The sounds for laymen, first not of particular concern, however, the epidemiologist François Roger from the Agricultural Research centre for International Development in Montpellier, told the science journal "Science" shortly after the event: "This is a danger for the Rest of the world."

in the year before, the researchers had warned of such an outbreak. More than a Million pigs have been killed in China to prevent Spread of the disease, whose causative agent for the people's harmless. So far, in vain. Each week, the country reports with the world's biggest pig meat production of new cases.

half of all pigs in this world lives in China. In Asia, the pathogen spreads very quickly. This raises the question of whether there is a particularly nasty virus variant is rampant. In Europe, the pathogen has emerged already in the year 2014, but so far, pigs are predominantly wild died because of it. In the fattening or farming farms were so far affected less frequently. "The Virus in China is nothing Special," says Sandra Blome from the Friedrich-Loeffler-Institut. "The rapid spread is caused by human behavior."

High viral load in the blood

The Specialist vet for Virology was recently in China to train farmers and veterinarians in dealing with the pathogen. As the most important means of transmission of the Virus has identified the feeding of blood products, and food waste.

The blood products are obtained at the slaughterhouse and important protein sources for fattening. China has banned the feeding of these materials, in the meantime, after all. Also in the EU, for instance, dried blood will feed the plasma, says Blome, this is not an unusual practice. "Here, you can be quite sure that an animal brought to the slaughterhouse, is healthy. In China, this is not necessarily the case."

The reason for this is that it is not always clear whether, when farmers received a compensation for a as infected reported pig. Of the battle of travel-contaminated blood stations operated over long distances to the nearest mast, or over the land borders to Thailand or Vietnam.

Actually, the disease was first described in 1921 in Kenya by veterinarians is transmitted by tick bites between pigs. The blood of an infected pig poses a mass-virus. Meat, feces, and urine, however, are charged much lower. Because of the high viral load in the blood-derived feed additives are also dangerous when the virus take a different route in the body of your next victim as the one who are specialized in the you actually – about the mouth and the upper digestive tract, instead of bloodstream-to-bloodstream by ticks transfer. In one Experiment, American researchers were able to show some time ago that you need 140'000 Times as many pathogens to infect a pig by the oral route of Transmission, such as over the Blood path, for example, by injection under the skin or into the bloodstream.

Nonetheless can also be contaminated salami bread, if you hit on a very susceptible animal, or the contact is repeated often enough.

man can control

The massive spread of the pathogen so clearly by the people affected. The wild pigs that are hunted for months in Germany intensified in order to prevent the jump of the pathogen from the neighbouring countries Belgium and Poland, in which ASP has been already proved, are therefore mostly innocent victims. How should also get a tick that has sucked blood of an infected wild pig in a pigsty a fattening operation?

That the pathogen could be in the foreseeable future for people dangerous, do not believe Blome. She works with the virus in high-security laboratories, but only to prevent that they leave the laboratory. Yourself will not protect you, because from an evolutionary point of view, there for the Virus is absolutely no reason for people to adapt. "This doesn't mean that it can't happen in principle," says Blome, "I reckon, but over very long periods of time seen to."

the Faster it will go, hopefully, with a vaccine against the disease. There are already several drug candidates, but those that "are particularly effective, have serious side effects," says Blome. She believes, however, that there will be a usable vaccine against the ASP, as it already exists against Classical swine fever. Despite the similar Name, these two pathogens are not biologically closely related. However, in the case of Classical swine fever, also shows that a vaccine alone is not enough. "In addition to a good vaccine," says Blome, "it needs a very good Management."

(editing Tamedia)

Created: 13.05.2019, 17:42 PM