Regarding meat transmission of PRRS in the fresh meat market from PRRS positive farms: what protocol do countries follow when slaughtering PRRS positive pigs?
And how many pigs that are positive still have the antigen within the glands at age of slaughter of 23 weeks?
PRRS can be found in pig meat of positive pigs and could be transmitted to other naïve pigs if they eat infected meat. Under experimental conditions naive pigs become infected after eating infected frozen pig meat which was stored at -20 degrees for 15 weeks. Obviously, this occurred mainly with meat harboring the highest PRRSV RNA copies, in the range of 109 copies per 500 g of meat, with both wild type and vaccine-related strains.
In EU, where PRRS is present in most countries is strictly forbidden to use pig meat as a feed source for pigs. The reasons for that are not just the risk of PRRS transmission, but ASF and prion related diseases.
Regarding the possibility of having pigs carrying the virus at slaughter time this is highly variable as it depends on when those animals were infected. We know that pigs can carry the virus a variable length of time depending on the animal, but the carrier status can be as long as 7 months. Taking this into consideration it could be highly probable to have carriers at 23 weeks of age if pigs come from a positive source. In those long-term carriers, virus is often found at tonsil level.
If you want to know more about the risks posed by pork, read out the chapters “Do people who handle pork represent a risk for the spreading of PRRS or other diseases if they enter in a swine farm?” and “Is there any possibility of incursion and spreading of PRRSV through pork brought in by farmworkers?”
References
- Raymond P. et al. Porcine reproductive and respiratory syndrome virus (PRRSV) in pig meat. Can J Vet Res. 2017 Jul; 81(3): 162–170.
Marcovetgrup S.L. – Spain
