VTT Technical Research Centre of Finland has developed a vaccine – diluted into drinking water – to effectively treat diarrhoea on piglets being weaned. The vaccine reduces the global resistance problem caused by excessive antibiotic use.

 

The vaccine is a new type of product that can replace antimicrobial drugs, such as zinc oxide, used is pig production. Bacterial strains resistant to antibiotics have become a global health threat. Bacteria know no boundaries, and the problem of resistance continues to mount worldwide – even in Finland, a country that has made it standard practice to use antibiotics only in moderation when treating farm animals.

 

“The vaccine’s production method has proved to be very effective, and it can also be used in the development of other animal vaccines. The method may be available commercially already in the next few years,” says Principal Scientist Jussi Joensuu of VTT.

 

Before that, however, it must be shown in practice that the vaccine is effective and safe. The first animal test was carried out this summer in Belgium, and the results in terms of efficiency are promising.

 

How it works

 

“When administered in drinking water, the vaccine offers protection exactly where it is needed, namely in the intestine,” said Joensuu. “If the vaccine was injected, most of the antibodies would remain in the bloodstream.”

 

When still suckling, piglets get enough protection from the sow’s milk. The disease emerges when piglets go from liquids to solids, enabling harmful bacteria – usually E. coli – to attach to the intestine. At that stage, the piglet’s own antibody production is only starting, and pathogenic bacteria get a foothold in the small intestine leading to diarrhoea. The piglet suffers, its growth slows down and in extreme cases, the diarrhoea causes death. Known as ‘piglet scour’, the ailment is estimated to cause annual losses of up to €2 billion euros globally.

 

The vaccine is administered to piglets in drinking water after weaning. The piglet’s immune system will recognise the vaccine molecule and start creating antibodies against the bacteria. The antibodies will prevent bacteria from attaching to the receptors in the small intestine, thereby preventing diarrhoea.

 

Currently, porcine post weaning diarrhoea is prevented by means of, for example, diet, hygienic rearing conditions and antibiotics. Globally speaking, up to 70 per cent of antibiotics are used on animals, especially farm animals.

 

Developing the vaccine 

 

The background for this development lies in Joensuu’s dissertation in 2006 in which he proved the effectiveness of the vaccine molecule. At that time the idea was to produce the vaccine molecules in transgenic plants, but the method was not commercially viable.

 

The expression system chosen by VTT was filamentous fungus Trichoderma reesei. The vaccine is produced by means of the fermentation process in a closed bioreactor.

 

A serious health threat

 

According to the World Health Organization (WHO), resistance to antibiotics is a global health threat. Increasingly, antibiotics no longer have the same effectiveness, which raises the risk of human and animal illness and mortality, and increases healthcare costs. “A lack of effective antibiotics is as serious a security threat as a sudden and deadly disease outbreak,” according to Dr Tetros Adhanom Ghebreyesus, Director-General of WHO. Indeed, resistance to antibiotics has become one of the most serious threats to human medicine and veterinary medicine alike.