How biotech will end African swine fever

A devastating outbreak of African swine fever is sweeping through China. Thanks to biotech hope is at hand.

Prepare to pay more for your Christmas chipolatas. The price of pork is on the up and farmers and lawmakers around the world are fighting to reverse the trend.

The problem? African swine fever. A devastating outbreak is sweeping through China, home of half of the world’s pigs.

It started in Liaoning Province to the north of the country, where the Government has encouraged the building of pig farms to feed on local grain.

But they neglected to provide abattoirs meaning that condemned pigs have been loaded onto trucks and driven down south, taking African swine fever with them.

So much for central planning. Now the disease has been reported in twelve provinces all over China and tens of thousands of pigs have been slaughtered.

This has echoes of Mad Cow Disease. In the early 1990s six million cows in the UK were destroyed to eradicate Bovine Spongiform Encephalopathy, to give it its proper name.

In my mind today I can still see the bonfires of these docile creatures, the vast majority of which were entirely healthy.

The reason for such a wholesale extermination was that BSE can pass to humans, where it manifests itself as Variant Creutzfeldt–Jakob disease.

Quite such drastic measures have not yet been required for African swine fever. It does not pass to humans although, given that viruses evolve all the time, it could yet do so.

Nonetheless it is a major problem for animal welfare and the food supply. But thanks to the rapid advance of biotechnology hope is at hand.

Sleepless nights

Most investors quite wrongly equate biotechnology with early stage research into human medicine. This is far from the truth.

Biotechnology is all about engineering the living world and in that respect progress is far more advanced in the plant and animal worlds than in the human.

Animal researchers and plant scientists have been able to conduct experiments that would never be allowed on human subjects for obvious reasons.

Any biotechnology fund that is investing only in medical research (i.e. almost all of them) is not really a biotech fund at all.

But I digress. Let’s return to African swine fever. This is a viral disease that makes pigs seriously unwell and can often be fatal.

However, some pigs can carry a mild form of the virus without any outward signs, which presents a difficulty because these undetected carriers can transmit the disease to others.

It is also not exclusive to pigs. The virus affects wild boars and is carried by ticks of the Ornithodoros species. This creates a vicious circle so that in Africa, where the ticks are especially common, it is impossible to eliminate the disease.

Obviously pigs and wild boars cannot jump on aeroplanes and cross continents (although a sniffer dog at Atlanta Airport did recently uncover a pig’s head in one suitcase), but still the virus can travel.

It may attach itself to clothes and shoes, but a particular concern is that the virus remains alive and active in meat products.

Last month customs officials in Japan confiscated a pack of sausages from a Chinese traveller and found that they contained the African swine fever virus.

The virus is endemic in sub-Saharan Africa but has spread. In the 1960s it appeared in Spain and Portugal and took thirty years to eliminate.

In 2007 it was detected in the Caucasus and has since spread through Eastern Europe and Russia. Now wild boars in Belgium have been found with the disease, but the outbreak in China is the most serious yet.

Legislators are running scared.

The Chinese have banned the feeding of kitchen waste, which can contain tainted meat. The Americans have banned imports of Polish pork.

France is to build a fence along its Belgian border to keep out the wild boar, and Lithuania is doing the same on its border with Belarus.

Germany is taking a different approach by encouraging the hunting of wild boar, while Japan has tightened its quarantine checks.

Zoe Davis, head of the UK’s National Pig Association, admits to having sleepless nights at the sight of Polish lorry drivers barbecuing in a lay-by.

“If those drivers had thrown their leftovers over the hedge, to be eaten by pigs or boars, the consequences could have been disastrous,” she explained.

“We would lose our export market overnight. If the virus got into our feral pig population, it would become virtually impossible to prove disease freedom and it would be many years before exports could resume.”

These Government measures may prove enough to beat the virus but still it will have come at considerable cost and they do not get to the root of the problem.

Biotech is the answer

As people travel more and goods are globally traded, so viruses are moving more readily from country to country. This is very hard to control.

Farmers do not necessarily fess up to outbreaks of disease. They would rather kill the animals and quietly dispose of them or sell the meat into the notoriously dodgy food chain and say nothing.

As I said earlier, animals may harbour African swine fever without displaying any symptoms, while viruses have many other vehicles of travel including simply being blown on the wind.

When they land on farm animals they find a weakened target.

In the intense effort to produce more food from finite resources breeders have been extraordinarily successful in creating animals that grow faster, produce more lean meat and produce more milk.

The administration of the growth hormone porcine somatotropin has increased muscle growth by as much as 50%. But in the pursuit of these qualities, selective breeding has produced animals that are more vulnerable to disease.

Selective breeding continuously narrows the gene pool, making the problem progressively worse.

The cost of endemic diseases has been estimated at 17% of the turnover of livestock industries in the developed world and 35%-50% in the developing world.

What can be done?

Animals crammed together in modern factory farms are inevitably more likely to transmit diseases.

The use of antibiotics is discouraged because it furthers the alarming problem of antibiotic resistance, so the preference is for vaccines.

But a vaccine may not be effective against all strains of a virus, it may require repeated administration or there may simply be no known vaccine – as is the case for African swine fever.

Modern biotechnology can provide the answer. Rather than trying to fight the virus we can engineer animals for which it simply does not pose a threat.

The key is to understand the precise interaction between the animal and the viral cells, right down to their genetic signals, and thanks to gene mapping this can now be achieved. New approaches have become possible.

One is to identify genes that confer protection against a specific disease or give a general boost to the immune system, and breed only from animals that have those genes.

The problem here is that the other genes of these animals that enter the mix may not be so beneficial.

A second method is gene transfer that permits the direct insertion of genes into an animal, including those of an entirely different species.

For example, wild animals are typically more resistant to disease than their domesticated cousins and genes that confer resistance in the former can be transferred to the latter.

An even more accurate approach is gene editing. Here a gene within an animal is altered directly.

In the past this has relied upon unreliable delivery on the back of a viral vector. But with the advent of CRISPR, gene edits can be made much more easily and more accurately.

This method has been used to precisely alter those genes that render pigs liable to African swine fever, as well as Porcine Reproductive and Respiratory System, thus protecting them from these diseases and with no apparent side-effects.

As soon as regulators give the green light, businesses are lining up to bring these to the market.

Pigs that cannot get ill, healthy animals that do not have to be slaughtered and more meat for all. A revolution in farming is under way.

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