Roxana Dobre – 11 July 2023 18:11 Pig farm
PRRS – porcine reproductive and respiratory syndrome virus and the one that causes a disease that destroys farms in pigs, sows or piglets, has emerged in a new, highly pathogenic variant. Spain has been fighting this virus for about three years, and the serious situation seems unstoppable.
For more than 30 years, PRRS has been causing problems in pig farms around the world. It is known that the virus has different strains and variants and mutations appear again and again and the problems become more and more severe. One of the newest variants of PRRS is the highly pathogenic ‘Rosalia’ variant found in Spain, according to the publication agricultural today.
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The new PRRS variant leads to significant fertility problems in sows, including weaker or stillborn piglets (photo: agrarheute.com)
The PRRS Rosalia variant leads to high mortality rates in piglets
“The situation in Spain is serious,” pointed out Spanish researchers and veterinarians, according to the quoted source. They describe the new variant as highly pathogenic, with higher mortality and abortion rates in sows, more stillborn piglets, and higher piglet mortality rates than previous strains of PRRS.
“On farms we see 10 to 30 percent higher losses in weaned piglets. Mortality rates in sows are 5 to 10% higher,” the vets also reported.
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Farms are having a hard time recovering even after the virus is gone
In some areas, the proportion of holdings unstable due to PRRS increased from 12 to almost 40 percent. Normally, the situation on affected farms stabilizes a few months after an outbreak. With the new Rosalia strain, this only happens after six to 9 months. And even then there are still problems.
One of the most remarkable characteristics of the PRRS virus is its rapid spread. Long-distance airborne transport of PRRS virus can occur up to 9.1 km away.
How PRRS affects pigs, sows and piglets
PRRS virus attacks the respiratory tract and on the other hand leads to fertility disorders. It is characteristic of the latter that there are mainly late spontaneous abortions and weak piglets. The virus also damages the lungs’ defense system, opening the door to other respiratory pathogens such as mycoplasma or influenza viruses. Chronic respiratory diseases are sometimes the result of infection with this virus.
How to diagnose PRRS in pigs
Diagnosing PRRS is often difficult because there are numerous strains of the pathogen. Therefore, only laboratory tests can determine exactly which pathogenic strain it is.
The result can be used to combat PRRS on the farm. This also makes possible a better assessment of the course of infection and the development of vaccination concepts adapted to this.
How do we “recognise” the symptoms of PRRS?
Porcine reproductive and respiratory syndrome (PRRS) has two clinical forms, reproductive disorders and respiratory disorders in pigs of any age. In any case, the clinical manifestation of PRRS virus infection depends on the age, the gestational status of the infected sow/gilt, the specific immune status of the animal, and the virulence of the infecting strain.
The most common symptom in breeding flocks is reproductive disorder including:
– Late abortions.
– Premature births.
– An increased number of mummified piglets, stillborn, and non-viable piglets, which die soon after birth.
– The acute form of sows/gilts characterized by lethargy, reduced appetite and fever.
– Increase in pre-weaning mortality.
– Irregular estrus, returns to estrus.
In young and fattening pigs, PRRS infection is characterized by:
– Heavy or rapid breathing and/or respiratory failure.
– Insufficient development.
– Lethargy, loss of appetite and fever.
– Red spots on the skin (cutaneous erythema).
– Rough hair on the back.
– Increased incidence and severity of other secondary systemic respiratory infections, such as Haemophilus parasuis, Pasteurella multocida or Streptococcus suis.
At necropsy, pneumonia can be observed in pigs affected by PRRS. The lungs are slightly fibrotic and do not release air (like a wet sponge) and are marbled with a tan gray color rather than the normal pink. Secondary bacterial pneumonia is often present, complicating the lesions and making interpretation of the pathology more difficult. (source: msd-animal-health.ro)
2023-07-11 15:17:26
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