Gastrointestinal Pathology of Pigs. Jerome C. Nietfeld, DVM, MS, PhD Kansas State Veterinary Diagnostic Lab Department DMP Kansas State University

Gastrointestinal Pathology of Pigs Jerome C. Nietfeld, DVM, MS, PhD Kansas State Veterinary Diagnostic Lab Department DMP Kansas State University

Neonatal Diarrhea Likely the number 1 killer of neonatal pigs

Normal absorption of fat Chyle in lymphatics

No chyle Lack of absorption of fat

No chyle Lack of absorption of fat Important gross observation for nursing pigs Malabsorptive diarrhea in nursing pigs: TGEV PEDV Rotavirus Isospora suis

Porcine Enteric Coronaviruses Transmissible gastroenteritis (TGE) virus Porcine epidemic diarrhea (PED) virus Infect and lyse enterocytes covering length of villi Severe villous atrophy Malabsorptive diarrhea Loss of lactase associated with absorptive enterocytes Maldigestion Undigested lactose passes to large intestine Osmotic diarrhea Porcine delta coronavirus experimental evidence of diarrhea in neonatal pigs

Normal Small Intestine Neonatal Pig

Porcine Enteric Coronaviruses (TGE)

Porcine Enteric Coronaviruses TGE

TGE and PED Severe villous atrophy

IHC Staining TGEV PEDV

IHC Staining TGEV

Porcine Rotaviruses Three groups affect pigs A, B, C Group A most prevalent in humans and cattle Commercial tests and antibodies available for group A EM can ID all groups, but cannot separate PCR available for A, B, and C Infect enterocytes at and near tips of villi Not as severe as TGEV or PEDV Malabsorption Viral enterotoxin

Rotavirus IHC Staining

Rotavirus Villous atrophy and fusion

Escherichia coli Enterotoxigenic E. coli (ETEC) Most common type of E. coli Pilus antigen and enterotoxin necessary Pilus antigens F4 (K88) diarrhea in suckling and weaned pigs Sudden death in weaned pigs Susceptibility inherited F5(K99), F6(987P) first week of life F41 F18 weaned pigs, also associated with edema disease, susceptibility inherited Enterotoxins Heat labile toxin (LT) Heat stable toxins A and B (STa, STb)

Escherichia Coli Attaching and effacing E. coli (AEEC) Enteropathogenic E. coli (EPEC) Uncommon E. coli septicemia and polyserositis Nursing piglets usually first week of life Uncommon Minor importance Edema disease CNS disease in weaned pigs F18 pilus and Shiga toxin 2e Susceptibility inherited

Escherichia Coli ETEC

Enterotoxigenic E. coli (ETEC) Colonization of small intestinal enterocytes

Attaching and Effacing E. coli (Enteropathogenic E. coli)

E. coli septicemia & polyserositis

E. Coli edema disease

Coccidiosis Isospora suis Minimum of 5 days old 7-14 days prime Necrosis and loss of small intestinal enterocytes Lymphatics empty

Isospora suis Catarrhal enteritis

Isospora suis Fibrinonecrotic enteritis

Isospora suis

Clostridium perfringens type C Usually acute hemorrhagic diarrhea in first week Often first 24 hours Necrosis and hemorrhage in jejunum Blood throughout ileum and large intestine Chronic form pseudomembranes in small intestine

Clostridium perfringens type C

Clostridium difficile Neonatal usually 1 st week of life Mesocolonic edema consistently present Not specific-other unidentified causes Differentials: Edema disease weaned pigs only PRRS virus

Clostridium difficile

Clostridium difficile Multifocal neutrophilic colitis volcano lesion

Acute septicemia Salmonella choleraesuis var Kunzendorf Cyanosis of extremities Often found dead High case mortality Edematous lungs Slightly enlarged, dark blueblack spleen Enterocolitis S. typhimurium most important Diarrhea Subacute to chronic Necrotizing enterocolitis Salmonellosis

S. Choleraesuis var kunzendorf

Classical Swine Fever

Porcine Respiratory and Reproductive Syndrome (Blue Ear Disease)

Salmonellosis

Proliferative enteritis (Lawsonia intracellularis)

Swine Dysentery (Brachyspira hyodysenteriae) Cause: Brachyspira hyodysenteriae Clinical signs and lesions reproduced with B. suanatine B. hampsonii B. intermedia some strains All strongly β-hemolytic Light brown mucoid progressing to mucohemorrhagic diarrhea Affects only large intestine: cecum to rectum Mucosa covered by thin layer of mucus Flecks of blood in early stages Blood, fibrin, necrotic debris in later stages

Swine dysentery

Intestinal Spirochetosis Brachyspira pilosicoli Possibly other weakly β- hemolytic species B. intermedia B. murdochi Gross lesions subtle Bacteria attach on end to mucosal epithelium forming a fringe

Trichuris suis (Whipworms)

Ascrids (roundworms)

Ascrids Fibrous scars milk spots in liver Pulmonary edema from endocarditis

Ascrids Fibrous scars milk spots in liver Pig also has proliferative enteritis

Gastric Ulcers Nonglandular cardia of pig stomach Normal squamous epithelium is nonkeratinized and white

Gastric Hyperkeratosis Preulcerative lesion Keratin stains with bile Mucosa raised, rough and yellow

Gastric Ulcers--acute

Gastric Ulcers chronic

Intestinal Mesenteric Volvulus Hemorrhagic Bowel Syndrome

Intestinal Mesenteric Volvulus

Gastric Volvulus

Rectal Stricture (Atresia Ani)

Rectal Stricture