Rotaviral enteritis is a common disease of the small intestine of pigs. Pigs of all ages are susceptible to infection; however, diarrheal disease usually occurs in nursing piglets and weaned pigs, with decreasing severity up to 6 weeks old.
Etiology and Pathogenesis of Rotaviral Enteritis in Pigs
Rotaviruses infect and destroy villus enterocytes throughout the small intestine. Lesions are segmental and are commonly observed from mid-jejunum through the ileum. Loss of villus epithelium results in villous atrophy, malabsorption, and osmotic diarrhea. Rotavirus serogroups A, B, and C are associated with diarrhea in piglets worldwide, and minimal cross-protection exists within and across serogroups.
Rotaviruses are easily transmitted by direct contact. Healthy carrier sows can shed rotavirus in their feces during the periparturient period, thereby exposing their litters to infection. Recently weaned pigs are commonly exposed to rotaviruses that persist in nursery facilities and in other carrier pigs during commingling.
Clinical Findings of Rotaviral Enteritis in Pigs
If neonatal pigs do not receive protective levels of maternal antibody, they are likely to develop profuse watery diarrhea in 12–48 hours. More commonly, rotaviral enteritis is endemic in a herd, and sows have varying levels of antibody in colostrum and milk, which provide varying levels of passive protection to nursing pigs.
Diarrhea often begins in pigs 5 days to 3 weeks old or immediately after weaning. The feces of affected nursing pigs are typically yellow or gray and watery in the early stages, and they progress to gray and pasty after approximately 2 days. Diarrhea commonly persists for 2–5 days. Affected pigs become gaunt and rough-haired; however, the mortality rate is usually low. Weaned pigs may have watery feces that contain poorly digested feed.
Lesions of Rotaviral Enteritis in Pigs
The small intestine appears variably thin-walled and the cecum and colon contain watery feces. Microscopically, there is segmental villous atrophy with severity dependent upon level of immunity to the specific rotavirus encountered.
Diagnosis of Rotaviral Enteritis in Pigs
PCR assay
Histological evaluation
Laboratory analysis of patient specimens is required for diagnosis of rotaviral enteritis. Confirmation is based on a combination of histological demonstration of villous atrophy in the jejunum or ileum, PCR assay detection of rotavirus in feces (assays for groups A, B, and C are widely available), and immunodiagnostic procedures to demonstrate viral antigen in the intestinal mucosa. Direct examination of feces by electron microscopy can also be helpful to identify rotaviral particles. Sequencing of the VP4 and VP7 genes can be performed to determine the P and G serotypes, respectively.
Differential diagnosis should include coronaviral enteritis, sapovirus enteritis, coccidiosis, and enteric colibacillosis.
Treatment and Control of Rotaviral Enteritis in Pigs
Supportive care
Increased lactogenic immunity
No specific treatment exists for rotaviral enteritis in pigs. Minimizing heat loss and providing adequate water to maintain hydration of the patient are helpful. Concurrent infection by enterotoxigenic Escherichia coli is common; therefore, antimicrobial treatment may decrease deaths. Providing affected weaned pigs with a warm, dry, draft-free environment and frequent limited feedings helps prevent starvation, secondary diseases, and permanent stunting.
The vaccine for group A rotavirus appears beneficial when given to sows before farrowing and ideally when matched to the specific G serotype that is endemic on the farm. Commercial vaccines for groups B and C have not been developed because of difficulty in virus propagation; however, custom autogenous vaccines could be an option, ideally when matched to the specific G serotype on the farm.
Intentional exposure of gilts and sows to feces from affected piglets, known as feedback, could be of benefit in increasing lactogenic immunity.
Key Points
Rotaviruses are ubiquitous in swine production environments.
Nursing and recently weaned pigs are commonly affected.
Infection results in malabsorptive diarrhea.
For More Information
Vlasova AN, Amimo JO, Saif LJ. Porcine rotaviruses: epidemiology, immune responses, and control strategies. Viruses. 2017;9(3):48.
Vlasova AN, Amimo JO, Raev SA, Saif LJ. Rotaviruses and reoviruses. In: Zimmerman JJ, Burrough ER, Karriker LA, Schwartz KJ, Zhang J, eds. Diseases of Swine. 12th ed. John Wiley and Sons, Inc; 2026:797-811.
