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

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

2 Neonatal Diarrhea Likely the number 1 killer of neonatal pigs

3 Normal absorption of fat Chyle in lymphatics

4 Normal absorption of fat Chyle in lymphatics

5 No chyle Lack of absorption of fat

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

7 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

8 Normal Small Intestine Neonatal Pig

9 Porcine Enteric Coronaviruses (TGE)

10 Porcine Enteric Coronaviruses TGE

11 TGE and PED Severe villous atrophy

12 IHC Staining TGEV PEDV

13 IHC Staining TGEV

14 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

15 Rotavirus IHC Staining

16 Rotavirus Villous atrophy and fusion

17 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)

18 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

19 Escherichia Coli ETEC

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

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

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

23 E. coli septicemia & polyserositis

24 E. coli septicemia & polyserositis

25 E. Coli edema disease

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

27 Isospora suis Catarrhal enteritis

28 Isospora suis Fibrinonecrotic enteritis

29 Isospora suis

30 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

31 Clostridium perfringens type C

32 Clostridium perfringens type C

33 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

34 Clostridium difficile

35 Clostridium difficile Multifocal neutrophilic colitis volcano lesion

36 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

37 S. Choleraesuis var kunzendorf

38 Classical Swine Fever

39 Porcine Respiratory and Reproductive Syndrome (Blue Ear Disease)

40 Salmonellosis

41 Salmonellosis

42 Proliferative enteritis (Lawsonia intracellularis)

43 Proliferative enteritis (Lawsonia intracellularis)

44 Proliferative enteritis (Lawsonia intracellularis)

45 Proliferative enteritis (Lawsonia intracellularis)

46 Proliferative enteritis (Lawsonia intracellularis)

47 Proliferative enteritis (Lawsonia intracellularis)

48 Proliferative enteritis (Lawsonia intracellularis)

49 Proliferative enteritis (Lawsonia intracellularis)

50 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

51 Swine dysentery

52 Swine dysentery

53 Swine dysentery

54 Swine dysentery

55 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

56 Trichuris suis (Whipworms)

57 Trichuris suis (Whipworms)

58 Ascrids (roundworms)

59 Ascrids Fibrous scars milk spots in liver Pulmonary edema from endocarditis

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

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

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

63 Gastric Ulcers--acute

64 Gastric Ulcers chronic

65 Intestinal Mesenteric Volvulus Hemorrhagic Bowel Syndrome

66 Intestinal Mesenteric Volvulus

67 Gastric Volvulus

68 Gastric Volvulus

69 Rectal Stricture (Atresia Ani)

70 Rectal Stricture

71 Rectal Stricture