Porcine Rotavirus Infection in Pigs: Causes of Scours and Dehydration

Porcine rotavirus infection, also called rotaviral enteritis, is a contagious viral disease of the small intestine in pigs. It is best known for causing scours, dehydration, and poor growth in piglets. Pigs of any age can be infected, but clinical disease is most common in nursing piglets and recently weaned pigs, with severity usually decreasing as pigs get older.

Rotavirus infects and destroys cells on the tips of the intestinal villi. That damage reduces the intestine's ability to absorb nutrients and fluid, which leads to malabsorption and osmotic diarrhea. In practical terms, that means affected piglets can lose water fast, become gaunt, and fall behind even if mortality stays low in milder outbreaks.

Several rotavirus groups can affect pigs, especially groups A, B, and C. The virus spreads easily through feces, contaminated pens, equipment, and close contact. Some healthy-looking sows can shed virus around farrowing, so litters may be exposed very early in life.

This condition can look similar to other causes of piglet diarrhea, including E. coli, coccidiosis, transmissible gastroenteritis, PEDV, and salmonellosis. That is why a veterinary diagnosis matters. The right plan depends on the pig's age, hydration status, and whether more than one pathogen is involved.

Porcine rotavirus infection is caused by rotaviruses in the Reoviridae family, most commonly groups A, B, and C in piglets. The virus is shed in feces and spreads mainly by the fecal-oral route. Piglets become infected when they ingest virus from contaminated udders, flooring, feeders, waterers, boots, hands, or equipment.

Outbreaks are more likely when piglets have limited passive immunity from colostrum and milk. Healthy carrier sows may shed virus around the time of farrowing, exposing newborn litters. Recently weaned pigs are also at risk because they lose maternal antibody protection, face stress from diet and environment changes, and may be mixed with other pigs carrying the virus.

The virus survives well enough in pig environments to keep cycling through farrowing and nursery areas if sanitation and flow are not tight. Overcrowding, wet pens, chilling, poor hygiene, and age mixing can all increase exposure pressure. In many herds, rotavirus is endemic, meaning it is present on an ongoing basis rather than appearing as a one-time event.

Rotavirus also commonly occurs alongside other enteric pathogens, especially enterotoxigenic E. coli. Mixed infections can make diarrhea more severe and may change what your vet recommends for testing, supportive care, and herd management.

Your vet will start with the age of affected pigs, timing of diarrhea, hydration status, and herd pattern. Rotavirus is often suspected when nursing piglets or newly weaned pigs develop scours, especially if several pigs are affected and the illness lasts a few days. Still, symptoms alone are not enough to confirm it because many piglet diarrhea diseases overlap.

A more confident diagnosis usually combines clinical history with laboratory testing. Common tests include PCR on feces or intestinal samples for rotavirus groups A, B, and C. Diagnostic labs may also test for other pathogens at the same time, which is helpful because finding rotavirus alone in feces does not always prove it is the only cause of disease.

In some cases, your vet may recommend submitting fresh intestine, intestinal contents, or tissues from acutely affected untreated pigs. Histopathology can show villous atrophy in the jejunum or ileum, and immunodiagnostic testing can detect viral antigen in intestinal tissue. Early sampling matters because virus shedding is often highest in the acute stage.

Because treatment decisions depend on the whole picture, your vet may also assess dehydration, body temperature, nursing behavior, and evidence of secondary bacterial infection. That helps guide whether care can stay on-farm or whether individual pigs need more intensive support.

Prevention focuses on reducing exposure and improving early immunity. Good colostrum intake matters because maternal antibodies help protect piglets during their most vulnerable period. In herds where rotavirus is a recurring problem, your vet may discuss whether prefarrow sow vaccination for group A rotavirus fits the herd's disease pattern and management plan.

Strong farrowing-house hygiene also helps. Clean, dry, warm pens reduce stress and lower the amount of virus piglets encounter. All-in/all-out flow, prompt manure removal, careful cleaning of feeders and waterers, and limiting age mixing can reduce ongoing circulation. Because rotavirus can persist in pig environments, prevention usually requires consistent routines rather than one-time cleanup.

Biosecurity matters within the farm too. Boots, hands, equipment, carts, and shared tools can move fecal material between litters and rooms. Handling healthy pigs before sick pigs, using dedicated supplies when possible, and cleaning contaminated surfaces can help contain outbreaks.

If diarrhea keeps returning, ask your vet about a herd-level prevention review. That may include colostrum management, sow immunity, pig flow, sanitation protocols, and diagnostic testing to identify coinfections that make rotavirus harder to control.