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Postweaning Multisystemic Wasting Syndrome (PMWS) update from U.S.

by 5m Editor
22 June 2006, at 12:00am

US - A preconference workshop focused on Postweaning Multisystemic Wasting Syndrome (PMWS) was held at the American Association of Swine Veterinarians’ annual meeting in Kansas City, Mo.

The presentations included in the workshop supported the following points:

  • PMWS is not a food safety or public health issue.

  • PMWS associated with Porcine Circovirus-2 (PCV-2) has been present in the U.S. since the 1990s.

  • A more severe form of the disease has recently been reported in eastern Canada since late 2004 and has also been reported in the U.S.

  • PCV-2 is widely spread across production and is present in operations that have experienced PMWS and also in those that have not. Because of this, searching for PCV-2 naïve breeding stock and semen sources would most likely be very difficult.

The following practices for control of PCV-2 associated diseases were recommended (adapted from Halbur, P., and Opriessnig, T., Practical Management of PCV2-Associated Diseases: The American Experience, 2006 Annual Meeting Proceedings of the American Association of Swine Veterinarians). Producers should discuss with their veterinarians how these points might apply to their operations.

  • Ensure an accurate diagnosis. PMWS can look like many other diseases. Producers should confirm that they have a PCV2-associated problem in their farm with the help of the herd’s veterinarian. The veterinarian has to examine the pigs, perform necropsies as necessary and obtain laboratory confirmation of the infection and the presence of PCV-2 associated lesions.

  • Identify concurrent infections at the farm, site or system. Good quality diagnostic submissions will aid the producer and veterinarian to determine what other infections are present and what the appropriate treatment should be.

  • Eliminate or minimize the effects of Porcine Reproductive and Respiratory Syndrome (PRRS). This can be achieved through breeding herd stabilization, pig flow changes and/or vaccination.

  • Eliminate or minimize the effects of swine influenza virus coinfection. This can be achieved with breeding herd and, possibly, pig vaccination.

  • Determine if porcine parvovirus is present. Consider implementing parvovirus vaccination of growing pigs if coinfection of parvovirus and PCV-2 is confirmed.

  • Minimize the effect of mycoplasmal pneumonia. Consider the use of vaccination and/or strategic pulse medication.

  • Evaluate the use and timing of vaccinations. If herd evidence suggests an association between vaccination practices and PCV2-associated disease, re-evaluate the necessity and timing of the vaccines in use. It may be beneficial to change the brand of vaccine used and/or the timing of administration of the vaccine. Vaccination of pigs 5 to 7 weeks before PCV-2 associated disease occurs is recommended. PCV-2 infection typically occurs at 10- 14 weeks of age.

  • Treat bacterial coinfections. Use the appropriate antimicrobials to target bacterial coinfections.

  • Consider vitamin E and selenium. The use of increased levels of vitamin E and selenium in diets of barns experiencing PCV-2 associated disease has been found beneficial.

  • Consider the use of enhanced diets. Diets with increased plasma protein can be used on pigs that are slow to respond.

  • Remove pigs that don’t respond to treatment.

  • Adhere to all-in-all-out pig flow rules.

  • Minimize mixing and moving of pigs whenever possible.

  • Decrease pig density.

  • Use disinfectants. Buildings and transport vehicles should be disinfected with products that have been demonstrated to be efficacious against PCV-2.

  • Investigate the health status of the source. If the problem occurs repeatedly, ask your veterinarian to investigate the health status of your pig source. There is increasing evidence of differences in host susceptibility to PCV-2 associated diseases.

  • Implement segregated early weaning practices and strict biosecurity.

ThePigSite News Desk

5m Editor