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Trichinella in pig herds
Trichinella testing is a legal requirement for breeding herds – both boars and sows – and pigs that are raised in non-controlled housing. Find out more about preventing the disease and the testing requirements.
What is Trichinella?
Trichinella spiralis is a parasitic nematode worm that can infect a wide range of mammals (including humans) and some birds.
The parasite is transmitted through the consumption of meat containing the immature (larval) stage of the worm.
Natural infections are most likely in carnivores and omnivores, such as foxes, bears and rats, but can also occur in horses.
Trichinosis is one of the most widespread foodborne parasitic diseases and occurs in most countries of the European Union (EU).
There have been no human cases acquired from meat produced in the UK for over 40 years. However, occasional cases have occurred in the UK due to consumption of undercooked pig or horse meat sourced from abroad.
What are the clinical signs and how can it be prevented?
Animals infected with Trichinella generally show no obvious signs of disease unless the infestation is very severe.
For specific advice, consult with your vet in the first instance.
To reduce Trichinella infection, ensure there is secure feed storage and pest control in place.
What are the Trichinella testing requirements?
All pigs sent to slaughter must be classified as being from either ‘controlled’ or ‘non-controlled’ housing.
The criteria for controlled housing is set out in Annex IV of assimilated Regulation (EU) 2015/1375. Under this regulation, controlled housing is defined as:
“A type of animal husbandry where swine are kept at all times under conditions controlled by the food business operator with regard to feeding and housing”.
Where pigs have outdoor access, you must demonstrate due diligence to ensure that this does not pose a risk of Trichinella being introduced to the holding.
For more information on testing, visit the FSA website.
The table below provides guidance to assist in determining whether controlled housing conditions may be applicable, using definitions of production systems to inform your judgement.
| Production system 1 | Definition of production system | Subject to the requirements of Annex IV of Regulation 2015/1375: Which production systems are likely to qualify as controlled housing? |
|---|---|---|
| Fully housed | These pigs are born, reared and finished indoors | Yes |
| Outdoor bred | These pigs are born outside in fields, where they are kept until weaning | Yes |
| Outdoor reared | These pigs are born outside in fields, where they are reared for approximately half their life (until at least 30 kg) | Likely |
| Free-range and organic pigs2 | These pigs are born outside in fields and remain outside until they are sent for processing | Unlikely: 100% outdoor access cannot be considered as falling under controlled housing conditions |
1 Definitions from: porkprovenance.co.uk/productionmethods.asp#
2 The key difference with organic pigs is that the use of pharmaceuticals is heavily restricted
Risks to be managed (controlled housing)
- All practical precautions regarding building construction and maintenance to prevent rodents, any other kind of mammals and carnivorous birds from having access to buildings where animals are kept
- Pest-control programme in place, particularly for rodents, to prevent infestation; records of this must be kept
- All feed to be obtained from a legitimate facility; feed must be stored in closed silos or other containers that are impenetrable to rodents
- Feed supplies must be heat-treated or produced and stored adequately
- Dead animals are collected, identified and transported without undue delay
- If a rubbish dump is in the neighbourhood of the holding, the operator must inform the competent authority. Subsequently, the competent authority must assess the risks involved and decide whether the holding is to be recognised as applying controlled-housing conditions
- Piglets coming onto the holding from outside and pigs purchased are born and bred under controlled-housing conditions
- Traceability of pigs at all times
- New animals may be introduced onto a holding if they come from holdings also officially recognised as applying controlled-housing conditions