Researchers from Iowa State University’s CVM Field Epidemiology team are conducting an epidemiological study to track and benchmark the aspects and practices implemented in swine breeding herds following the Porcine Reproductive and Respiratory Syndrome (PRRS) outbreak.
To date, the POMP has 80+ herds enrolled. Enrollment is open for additional herds to continue capturing the diversity of practices implemented in response to outbreaks and their association with recovery parameters.
PRRS is a viral disease characterized by two overlapping clinical presentations, reproductive impairment or failure in breeding animals, and respiratory disease in pigs of any age. The PRRS virus is an enveloped RNA virus in the genus Arterivirus, classified in the virus family, Arteriviridae.
An important feature of the virus is its ability to persist in long-term carrier pigs (greater than 200 days). However, field observation suggests that most infected pigs eventually become immune, then cease to shed virus by 60 days post-infection. This is accompanied by a steady decline in antibody titers over a period of four to eight months after infection. Shedding carriers probably are the most common means of virus introduction to a herd or population of pigs.
The virus is highly infectious (infectious dose is as little as 10 virions) but not highly contagious. It is present in nasal secretions, urine, semen, mammary secretions and feces. With the advent of artificial insemination, semen became a major source of viral introduction. The virus spreads readily by direct contact. There is limited experimental evidence of aerosol spread between farms but anecdotal opinions suggest it occurs at least sporadically.
PRRS is the most economically significant disease to affect US swine production since the eradication of classical swine fever (CSF). PRRS is the most economically significant disease to affect US swine production since the eradication of classical swine fever (CSF). Although reported initially in only a few countries in the late 1980s, PRRS now occurs worldwide in most major swine-raising countries. PRRS is prevalent in the United States and exists both in epidemic and endemic forms.
This project will produce quarterly summary reports with aggregated data. Raw data from enrolled herds is not shared.
The eligibility criteria to enroll breeding herds into the project include:
- Breeding herd reporting PRRS outbreak, and working on a plan to control and/or eliminate the infection.
- Producer willing to share diagnostic results.
- Herd veterinarian committed to complete a short survey with information about the PRRS management plan following the outbreak, and revising the survey on a quarterly basis until herd achieved the desired status (i.e. stability).
- Share weekly production data for 52 weeks prior to the outbreak, and 52 weeks after the outbreak.
- Plan to monitor the affected herd by sampling over time, with either weekly processing fluids (1 bag/week) or tongue tips (1 bag of up to 100 samples per week).
- 10 family oral fluids/month or monthly suckling pig bleeding (n=30).
Sources: Iowa State University, American Association of Swine Veterinarians