Porcine sapoviruses were first reported in US swine in 1980 (1). The viruses have worldwide distribution, with endemic circulation among pigs and pig farms. Disease most often occurs when the virus is introduced into naive populations.
Etiology and Pathogenesis of Sapovirus Enteritis in Pigs
Porcine sapoviruses are single-stranded RNA viruses in the family Caliciviridae. Strains in genogroup III (GIII) are most frequently detected in pigs with diarrhea. Infection of enterocytes results in necrosis and cell sloughing, predominantly at the villus tips, and this results in villous atrophy and fusion with loss of absorptive surface area. As with most other enteric viral infections, a malabsorptive diarrhea ensues.
Clinical Findings of Sapovirus Enteritis in Pigs
Suckling pigs exhibit a pasty to semiliquid diarrhea around 10 days old (2). The diarrhea is often self-limiting; however, pigs can lose 1 or 2 pounds of expected weaning weight. Disease can also occur in naive weaned pigs.
Diagnosis of Sapovirus Enteritis in Pigs
Given that the virus is endemic in many pig populations, results of PCR assays are best interpreted in clinical context and in conjunction with histopathological lesions of atrophic enteritis. Direct visualization assays, such as in situ hybridization, provide the most definitive etiological confirmation. Other enteric viral infections should be excluded through diagnostic testing, and coinfections in a population can occur.
Treatment and Control of Sapovirus Enteritis in Pigs
Management of sapoviruses is similar to that of other enteric viruses, and, given that the majority of infections are in suckling pigs, farrowing house cleanliness and biosecurity are essential for preventing disease spread among litters. Because commercial vaccines are not available, autogenous products or custom RNA-based products may be considered.
Key Points
Sapoviruses produce diarrhea in suckling pigs that is clinically indistinguishable from that in several other enteric viral infections.
Viruses are endemic in many populations, so direct visualization assays have higher diagnostic specificity than PCR assays.
Custom vaccines can be of value for prevention of disease in affected herds.
For More Information
Knowles NJ, Reuter G. Caliciviruses. In: Zimmerman JJ, Burrough ER, Karriker LA, Schwartz KJ, Zhang J, eds. Diseases of Swine. 12th ed. John Wiley and Sons, Inc; 2026:517-525.
References
Saif LJ, Bohl EH, Theil KW, Cross RF, House JA. Rotavirus-like, calicivirus-like, and 23-nm virus-like particles associated with diarrhea in young pigs. J Clin Microbiol. 1980;12(1):105-111. doi:10.1128/jcm.12.1.105-111.1980
Shen H, Zhang J, Gauger PC, et al. Genetic characterization of porcine sapoviruses identified from pigs during a diarrhoea outbreak in Iowa, 2019. Transbound Emerg Dis. 2022;69(3):1246-1255. doi:10.1111/tbed.14087
