This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.
This week, we are sharing a disease sheet on porcine astrovirus by Drs. Arruda and Schwartz.
- Further research is needed in all areas of the virus in order to better understand, treat, and prevent Astrovirus.
- Astrovirus is a public health concern in humans as it is implicated in foodborne illnesses and has zoonotic potential.
- Porcine Astrovirus may play a role in enteric disease, and has been associated with neurological disease.
Porcine Astrovirus (PoAstV) is a nonenveloped RNA virus with 5 different strains present in U.S herds. It has been detected in both healthy and diseased pigs, so more research is needed to determine the clinical implications of a PoAstV infection. Recently a U.S swine production system reported PoAstV-associated neurological disease. In the sow farm 100% of pigs affected with disease died, while in the growing-finishing farms case-mortality rate was 75%. Signs exhibited by affected animals included paralysis, ataxia, paresis, and knuckling, which eventually progressed into lateral recumbency.
Scientific publications relating to Porcine Astrovirus are rare. The majority of information, however, supports fecal-oral as the main route of transmission. Some reports have shown PoAstV to retain infectivity in ground water for extended periods of time and can survive up to 3 hours in water with a p.H of 4.0. There is currently no vaccine available for this disease. The large antigenic diversity and high mutation rate are the biggest challenge for vaccine development. Diagnosis is typically made via PCR.
The major concern with Astrovirus is the zoonotic potential. Human Astrovirus is easily transmitted through contaminated food and water and causes moderate gastroenteritis in infants. Human-to-pig transmission is suspected due to the detection of human-porcine recombinant viruses. Pig-to-human zoonosis has not been reported, but Astroviruses can rapidly mutate, so it may be only a matter of time before a zoonotic strain emerges.
Further research into pathogenesis and vaccine development is crucial to prepare for a possible zoonotic outbreak.
— Blog post written by Joseph Thurston.