Rotavirus Infection in Swine

Rotavirus

• Rotavirus is a non-enveloped RNA virus with a double-layered capsid, allowing it to remain stable and infective in the environment for months.
• Four serogroups (A, B, C, and E) infect swine, with Type A being the most prevalent.
• Severity of disease decreases with age, and it is self-limiting.
• The virus infects and destroys villous enterocytes, leading to villous atrophy.
• Diagnosis can be confirmed by PCR, electron microscopy, or ELISA (for serogroup A).
• Treatment is supportive with oral rehydration solutions, and prevention is through ingestion of lactogenic virus-neutralizing antibody from the sow.

TGE (Transmissible Gastroenteritis)

• TGE is caused by a coronavirus (TGEv) that is heat labile and prone to desiccation and photosensitization.
• The epidemic form causes acute disease in all age groups, with high morbidity and mortality.
• The severity of disease is age-dependent, but all ages will develop diarrhea.
• Necropsy reveals a fluid-filled small intestine and colon, with thin intestinal walls and empty lacteals.
• Diagnosis can be confirmed by TGEv/PRCV differential ELISA.
• Prevention is by stimulating herd immunity through exposure to infected tissue.

PED (Porcine Epidemic Diarrhea)

• PED is caused by a coronavirus (PEDv) that is more environmentally resistant than TGEv.
• The disease has a high morbidity and mortality rate, especially in naive sow herds.
• Clinical signs appear within 12 hours, with watery, fetid diarrhea and vomiting.
• Diagnosis can be confirmed by TGEv/PEDv differential PCR.
• Prevention is by stimulating herd immunity through exposure to infected tissue and feces.

Porcine Coccidiosis

• Porcine coccidiosis is caused by Isospora suis.
• Age at infection rather than infectious dose has the greatest impact on severity.
• Morbidity is variable, and mortality is low.
• Clinical signs include pasty diarrhea, unthrifty to potbellied appearance, and below-average wean weight.
• Diagnosis can be made by fecal flotation and histopathology.
• Prevention is by oral administration of an anticoccidial.

Swine Dysentery

• Swine dysentery is caused by a spirochete of the genus Brachyspira.
• The disease is characterized by mucohemorrhagic diarrhea containing flakes of frank blood or appearing as a generalized brick red to rust color.
• Lesions are observed in the spiral colon, with epithelial sloughing and mucosal invasion.
• Diagnosis can be confirmed by PCR test.
• Prevention is by depopulation, medicated elimination, and aggressive rodent control.

E. coli

• E. coli is a gram-negative rod that infects all ages of swine.
• The bacteria must express virulence factors to cause diarrhea.
• Enterotoxigenic E. coli (ETEC) is subdivided by fimbria, toxin, and age of pig affected.
• Clinical signs include profuse diarrhea, rapid dehydration, and emaciation.
• Diagnosis can be made by isolation of large numbers of E. coli and histopathology.
• Prevention is by passively derived lactogenic immunoglobins from vaccinated females and selection of genetically resistant breeds.

Clostridium Perfringens

• Clostridium perfringens Type A (CpA) is a gram-positive bacillus.
• Sows are regarded as the source of neonatal infection.
• Morbidity is high, and mortality is low.
• Clinical signs include diarrhea and below-average weaning weights.
• Diagnosis can be confirmed by PCR and genotyping.
• Prevention is by vaccination of gestating females and ensuring piglets consume sufficient colostral antibodies.

Clostridium difficile

• Clostridium difficile is a gram-positive bacillus that easily sporulates.
• The disease leads to a 10-15% reduction in wean weights.
• Clinical signs include watery diarrhea in 1-7 day old piglets.
• Diagnosis can be confirmed by volcano lesions on histologic exam and confirmation of toxins in fecal contents.
• Prevention is by vaccination and administration of antibiotics.

Porcine Proliferative Enteropathy (PPE)

• PPE is caused by Lawsonia intracellularis.
• Seroprevalence in grow-finish herds can reach 100%.
• Clinical signs include diarrhea, ranging in color from normal to dark-red or black.
• Diagnosis can be confirmed by histopathology and IHC.
• Prevention is by administration of a commercially available modified-live oral vaccine.

Salmonellosis

• Salmonellosis is caused by Salmonella Typhimurium.
• The disease is significant to the pork industry due to the isolation of multidrug-resistant strains.
• Pathogenesis is similar to Salmonella cholerasuis.
• Clinical signs include watery, yellow diarrhea containing feed particles.
• Diagnosis can be confirmed by bacterial isolation and histopathology.
• Prevention is by rearing pigs on slatted floors, decreasing stocking density, and acidification of digesta.

Whipworm

• Whipworm infestations are caused by Trichuris suis infection.
• Pigs kept on pasture, in outdoor lots, or facilities with a history of T. suis diagnosis are at greatest risk.
• The prepatent period is 6-7 weeks.
• Clinical signs include depressed weight gain, increased feed conversion, bloody diarrhea, ill thrift, and death.
• Diagnosis can be made by finding adult worms imbedded in the ileum, cecum, or proximal colon.
• Treatment and control are synonymous and require administration of an effective anthelmintic.

This quiz covers the characteristics and types of Rotavirus, a nonenveloped RNA virus that infects swine. Learn about the different serogroups and their prevalence in pigs of different ages.