Discussion on a Selection of Key Scientific Articles

By John Atkinson,
Associate Director, Intergovernmental Veterinary Health
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Transboundary spread of pig diseases: the role of international trade and travel.
Beltran-Alcrudo, D., Falco, J.R., Raizman, E., Dietze, K. BMC Veterinary Research. 2019;15(1), art. no. 64.

Key Thoughts:

We have to realise that as humans we all have an important role to play in keeping animals around the world healthy. This is not just a task for veterinarians, farmers, governments, and others directly involved in livestock. However, those of us involved in livestock are well placed to help raise awareness about transboundary diseases, how easily they are spread, and what each and every one of us can do to try to prevent them.

Article Summary:

Transboundary animal diseases (TADs) such as African swine fever (ASF) and foot-and-mouth disease (FMD) have a significant impact on many countries, can easily spread to others, and require international cooperation for control. As the world is increasingly interconnected because of increased trade and cultural exchange, animal populations are increasingly at risk of such diseases.

Preventing these diseases requires a good understanding of the possible pathways for introduction and prompt detection, investigation, and control. Unfortunately, the sources and pathways of outbreaks in developing countries are often unknown because of limited veterinary resources and diagnostic capabilities.

Pork consumption is increasing globally, and production is split between large-scale and traditional small-scale systems. Pigs in the latter small holder or backyard settings are at particular risk of infection with, and onward spread of, TADs because of poor disease prevention and control measures. Human behaviour underlies the spread of TADs through live animal movements, the transportation of pig-derived products, and fomites.

TADs may be introduced by both formal and informal international trade, which are closely linked. The main challenges with formal trade include the movement of live animals (especially incubating animals and asymptomatic carriers) and pork products (which may include pathogens that remain infectious for long periods of time, such as ASF virus).

Informal international trade, particularly involving meat and meat products, is a much higher risk for the spread of diseases. Such illegal movements are either for commercial purposes (large quantities) or personal consumption (small quantities), but both can end up with pigs consuming the meat/meat products. The people involved may not realise that their actions risk introducing TADs, so emphasis must be placed on raising awareness.

Local movements of people and goods across borders due to border controls can create price differences between countries, which encourages movements. In addition, vehicles, clothing, and footwear are risk factors for spreading animal diseases.

Once diseases are introduced into a new area, then animals need to be exposed to the pathogen to trigger an outbreak. The risk of this increases with higher numbers of pigs, lower standards of biosecurity, and the presence of wild boar populations. The consumption of infected feed is a common means of infection, through meat products intended for both animal feed and human consumption. The prevention of swill feeding and the proper disposal of food waste are therefore important control measures.

Biosecurity on the premises where animals are kept is critically important alongside the reporting and investigation of suspected disease outbreaks. Farmers and veterinarians must therefore receive appropriate training, as must those involved in wildlife such as hunters.

Encouraging responsible dog ownership in Africa.
Mpolya, E.A. Veterinary Record. 2019;184(9):278-280.

Key Thoughts:

It is important to understand and recognize differences between regions when it comes to rabies to ensure control programmes are tailored accordingly. As most roaming dogs in Africa actually have owners, collaborative efforts are needed to change human behaviour, encourage responsible dog ownership, and achieve high coverage of rabies vaccination.

Article Summary:

The target for the elimination of dog-mediated rabies is set for 2030. Achieving this goal involves responsible dog ownership and the vaccination of a high proportion of dogs.

In many parts of Africa dogs are usually kept to guard homes or livestock, and in both situations dogs are free to roam at certain times of the day or night. Therefore, almost all dogs in this part of the world have owners. This means that encouraging responsible dog ownership has a direct impact on rabies control efforts.

Organisations such as Mbwa wa Africa, Tanzania, are playing an important role by educating owners and helping them access veterinary care, and by working with local government. Encouragingly, dog owners in such areas are now acting more responsibly.

Whilst poverty currently limits private vaccine uptake, progress towards the elimination of rabies can be helped significantly by a combination of subsidized rabies vaccination, availability of veterinary services, educational materials for dog owners, and compliance of dog owners with vaccination programmes.



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