Swine diseases

1. Swine diseases

2. Ages of pigs are important • Neonates 0-3 weeks (birth: 3-4 lbs) • <4 kg (8.8 lbs) • Weanlings/nursery 3-10 weeks (~ 25 lbs) • 4-25 kg (8.8 – 55 lbs) • Growers/finisher 10-26 weeks (~ 50 lbs) • 25-120 kg (55 – 264 lbs) • Breeders/adults >6-8 months (~ 220 - 240 lbs) • >120 kg (> 264 lbs)

3. Orderly thinking... • Multisystemic Diseases • Respiratory Diseases • Gastrointestinal Diseases • Neurologic Diseases • Musculoskeletal Diseases • Reproductive Diseases • Dermatology • Miscellaneous

4. Multisystemic diseases • Nutritional • Vitamin E / selenium deficiency • Infectious • Erysipelas (Erysipelothrix rhusiopathiae): gram + rod • Glasser’s disease (Haemophilus parasuis): gram - coccobacillus • Salmonella: gram negative • PRRS (arterivirus) • Pseudorabies virus (herpes virus)

5. Erysipelas • Erysipelothrix rhusiopathiae • Gram positive rod • Environmental contaminant • most herds have carriers • Septicemia • diamond skin, arthritis, endocarditis, necrosis

6. Erysipelas • chronic forms of infection include endocarditis and arthritis • acute septicemia • fever, prostration, anorexia, vomiting, reluctance to walk • Hemorrhages may be present in multiple organs throughout the body. • Mortality can be quite high.

7. Diamond skin disease • "Diamond skin disease" • erythematous skin lesions • These may be the classic diamond-shaped lesions or more diffuse edema and erythema. • The lesions are due to vasculitis and thromboembolism.

8. Valvular endocarditis

9. Erysipelas cont... • Treatment • Penicillin • Tetracyclins • Prevention and control • Sanitation • Vaccinate at weaning and then q6 months • Zoonotic: ‘erysipeloid’ • occupational diseases for people such as veterinarians, abattoir workers and fisherman • Direct contact

10. Treatment and prevention • Penicillin – first choice people and animals • cephalosporins and clindamycin -people. • Caution and hygiene are important to prevent infection when working with potentially infected animals or in potentially contaminated environments

11. Glasser’s disease (polyserositis) • Haemophilus parasuis • small, pleomorphic, and fastidious, Gram-negative rod (coccobacillus) • Endemic • 3wk – 3 month (have no active/passive immunity) • initiated by stress • weaning, changes in environment, commingling, or as coinfection with other disease agents • Also associated with PRRS or swine influenza

12. Glassers - HX • 1931 an organism, presumably the same one, was isolated from swine with influenza and named Haemophilus influenzae suis. • 1943 it was clear that the organism was a pathogen in its own right, not necessarily associated with swine influenza, and the name was shortened to Haemophilus suis. • 1976, definitive taxonomic studies resulted in the present name, Haemophilus parasuis

13. Glassers - CS • Initially: fever, anorexia, depression • Meningoencephalitis: • tremors, incoordination, posterior paresis or lateral recumbency • Polyserositis • Polyarthritis • Mortality at any age • Less common clinical signs: • rhinitis, dyspnea, reddening of the conjunctiva, cyanosis of the extremities and edema of the eyelids or ears

14. Glasser’s disease (polyserositis) • Serosal surfaces: peritoneum, pleura, pericardium, joints, meninges • Polyserositis (serous membrane inflammation with effusion, fibrinous), • Pleuritis • Pericarditis • Peritonitis Pig with Glässer’s disease. Noticeable presence of fibrin in the peritoneal cavity (fibrinous peritonitis) and pericardiac cavity (fibrinous pericarditis

15. red, multifocal, disseminated and suggestive of septicemia and hematogenous spread Glasser’s disease

16. Glasser’s cont... • Diagnosis • Culture is difficult (but try it) • Brain, visceral pleura and other serosal exudates are preferred culture sites • Go with suspicion from gross lesions • Molecular techniques for identifying H. parasuis (research) • Treatment: Antibiotics and sulphonamides • Penicillins • Tetracyclins • periodic evaluation of antibiograms is warranted. • Mass: medicate, through the water (same age group)

17. Glassers - Prevention • Prevention and control • Reduce stress • Control of other diseases: PRRSV • prophylactic antimicrobials • Vaccine at weaning then again 3-4 weeks later • against one serovar of H. parasuis may not assure good protection against all serovars. (21 serovars)

18. Salmonella sp. • 2000 serotypes: small, hardy, ubiquitous, Gram-negative bacilli • Salmonella cholerasuis: mostly only in swine • Salmonella typhimurium • Zoonotic • Contaminated pork products are not a primary source of food-borne salmonellosis outbreaks in people but efforts to reduce salmonellae in the pork food chain are a high priority for the swine industry • disease in both people and swine include Salmonella serotypes typhimurium, enteritidis, agonaand heidelberg

19. Salmonella Typhimurium “But S. Typhimurium’s success in swine isn’t just due to its increased motility when norepinephrine levels increase. It also has a mechanism for acquiring iron from its host to support its own growth and replication” 7/2009 Microbiologist Brad Bearson analyzes cultures for the presence of Salmonella enterica serovar Typhimurium in swine feces.

20. Salmonella - HX • In 1886 the organism now known as Salmonella serotype choleraesuis was erroneously reported to cause hog cholera

21. Salmonella – Signalment, CS • weaned or growing/finishing pigs • Low-level endemnicity, carriers • Septicemia • pyrexia, anorexia • purple discoloration of the ears (infarction) • Small or large intestinal diarrhea (button ulcers) • Pneumonia • Rectal strictures Pig, intestine. The intestinal lumen has reddened erosions and a fibrinonecrotic exudate. Credit: Dr. B. Inskeep, AFIP

22. Salmonella

23. Salmonella cont... • Diagnosis • Aerobic culture • Treatment • Neomycin in the feed/water for whole group • Naxcel (ceftiofur) for individual • Prevention and control • Sanitation: inactivated by chlorine, iodine and phenol-based disinfectants • All in - all out operation • Various vaccines (live avirulent) Pig, mesenteric lymph node. The mesenteric lymph node is enlarged and edematous. This lymph node is good for obtaining cultures. Credit: Dr. B. Inskeep, AFIP

24. PRRS • Porcine reproduction (sows and gilts) and respiratory syndrome (young growing pigs but also occurs in naïve finishing pigs and breeding stock) • Most important economic disease in USA (after eradication of classical swine fever) • Arterivirus: SS enveloped RNA Virus (high mutation rates) • persist in long-term carrier pigs (greater than 200 days) in reality stop shedding 60 days later

25. PRRS - HX • 1987-88 in North Carolina, Iowa and Minnesota • 1989 – 90: Several outbreaks in Indiana were reported • During the subsequent decade, PRRS spread rapidly, both in Europe and North America • By the end of 1992 the disease was reported in Canada, Great Britain and several European countries. • Two distinct strains of virus, one in Europe and one in the United States, were characterized as genetically different but are clinically similar in most respects. Both are now in the United States, along with a multitude of viral variants. • Old name: swine infertility and respiratory syndrome (SIRS)

26. PRRS • Transmission: direct contact (very infectious): It is present in nasal secretions, urine, semen, mammary secretions and feces. • Clinical signs – neonates • pulmonary intravascular macrophages (PIM) and pulmonary alveolar macrophages (PAM); • anorexia, lethargy, fever • cyanosis of the ears, respiratory distress • secondary bacterial pneumonia • delayed or abnormal estrus cycle with increased numbers of stillborns/mummies (3rd trimester)

27. PRRS Lung affected with interstitial pneumonia of a pig with PMWS and co-infected with porcine reproductive and respiratory syndrome virus (PRRSV). This “infectious combination” is relatively frequent at field level; macroscopically it is not possible to distinguish between these two infections, so laboratory studies are required to confirm the etiologic diagnosis. Abortions, mummies and weak pigs

28. PRRS cont... • Diagnosis • virus isolation (VI), detection of PRRS antigen by fluorescent antibody tests (FAT) or immunohistochemistry (IHC), or detection of PRRS virus genome by polymerase chain reaction (PCR) and be coupled with presence of typical lesions. • serology provides indirect evidence of infection but does not determine if there is actual disease caused by PRRS virus. • Supportive care, treat secondary bacteria • moderately resistant to environmental degradation, the virus is easily inactivated by phenol, formaldehyde, and most common disinfectants

29. PRRS CONTROL • closed herds: • replacements do not enter male or female replacements from PRRSv positive herds outside the pyramid • Enter only PRRSv free replacement seedstock into a production pyramid. • semen: • Do not use PRRSv positive semen from a stud outside the pyramid. • Assure any outside semen is from a stud that is confirmed PRRSv free before entering it into a production pyramid. • commercial modified live vaccines • Live vaccines pose a dilemma as vaccine virus may act as a foreign introduction • Change feed with mycotoxins

30. Pseudorabies • Aujesky’s disease • Type 1 Herpes virus: alphavirus • The disease was eradicated from the US commercial pig industry in 2004 but remains in some localized feral swine populations • Species: cattle, sheep, dogs, cats, and goats but not horses AND rats, mice, raccoons, opossums, rabbits, and several fur-bearing mammals • Close contact with infected swine • central nervous system (CNS), respiratory system or reproductive system • Not humans!

31. Pseudorabies • The disease is named after the Hungarian veterinarian Dr. Aladár Aujeszky who linked the disease in cattle, dogs, and cats in 1902. • Pseudorabies was not identified as a viral disease in swine until 1909 • Prior to 1960, the disease in swine was important in Eastern Europe but major outbreaks did not occur in the US until the mid-1970s • In 1989, the US embarked on a 5-stage Federal/State/Industry program for eradication of PRV in swine; eradication of PRV from the commercial industry was achieved in 2004

32. Pseudorabies cont... • Baby piglets • up to 100% mortality • high fever, depression, anorexia, tremors, incoordination, dog-sitting position, vomiting, foaming at the mouth, blindness, paddling, coma and convulsions • Weanling/growers • up to 60% mortality in weanlings, 0-15% in finishers • pneumonia impt, neurologic dz, vomiting, extreme pyrexia • Adults - often inapparent • can cause stillbirth/abortion

33. Pseudorabies Dead pigs (and a cat), a result of Pseudorabies

34. Pseudorabies

35. Pseudorabies cont... • Reportable disease! • Diagnosis • Necropsy - • histologic lesions in brain, ulcers in gi tract • Serum neutralization is standard test • ELISA can be used as a screening test • Treatment - none • Prevention • closed herd! quarantine! restrict wildlife • The virus can be destroyed by many disinfectants, including orthophenylphenol, quarternary ammonium or iodine compounds, and 5% sodium hydroxide • vaccination

36. Pseudorabies

37. Pseudorabies • Regulation • use of vaccine regulated by states • federal regulations for monitoring • all animals over 6mo old must be tested • 25% of herd tested q3months or... • 10% of herd tested q1month

38. White muscle disease / Mulberry heart disease • Nursery or grower pigs (few weeks – 4 months) • Vitamin E / Selenium deficiency • Feeds high in the concentration of polyunsaturated fatty acids, copper, vitamin A or mycotoxins can either destroy vitamin E or make it less bioavailable • Grains from soils deficient (midwest) in selenium, or selenium antagonists in mixed feeds, can result in feeds low in selenium. • Both vitamin E and selenium work as antioxidants.

39. Vit E / Selenium cont... • Clinical signs • acute death (mulberry heart disease) • muscle weakness (white muscle disease) • more common in lambs, calves and chickens rather than swine • Diagnosis • Necropsy - hydropericardium, fibrinous epicarditis, myocardial hemorrhage • Diffuse hepatic necrosis - hepatosis dietetica • Liver selenium < 0.5 ug/g

40. Mulberry heart disease The condition was named after the mottled appearance of the heart muscle in affected pigs. Typically, there are alternating areas of necrosis and hemorrhage throughout the myocardium.

41. Hepatosisdietetica Hepatosis dietetica consists in a degenerative lesion caused by vitamin E and selenium insufficiency.

42. Vit E/ Selenium • prevention or treatment of a deficiency, pigs can be injected with vitamin E and/or selenium and tissue levels will be increased rapidly. • supplementation of feed or drinking water • Sows injected in late gestation give birth to pigs with increased levels of both compounds. • MHD is more responsive to vitamin E; • HD more so to selenium

43. References • http://www.aphis.usda.gov/animal_health/animal_dis_spec/swine/ • http://www.ncsu.edu/project/swine_extension/ncporkconf/2002/roberts.htm • http://www.vetmed.wisc.edu/pbs/zoonoses/Erysipelas/erysipelasindex.html • http://vetmed.iastate.edu/vdpam/new-vdpam-employees/food-supply-veterinary-medicine/swine/swine-diseases/haemophilus-parasuis- • http://vetpath.wordpress.com/category/necropsy-cases/

44. References • http://www.fmv.utl.pt/atlas/figado/pages_us/figad015_ing.htm