Swine Diseases 1 Sources of Information on Swine Health - PowerPoint Presentation

1. Swine Diseases1

2. Sources of Information on Swine HealthDiseases of Swine, 10th ed., 2012; Straw, B., et.al.American Association of Swine VeterinariansJournal of Swine Health and ProductionAASV.org website; disease modulesSwine Disease Manual, 4rd edition 2009; Neumann, Ramirez, SchwartzAnnual meeting proceedings, 2000-16 www.AASV.org2

3. DefinitionsDisease (from “dis” “ease”) is any abnormal state detrimental to the pig. Infectious disease (ID) is due to microbes. Microbes, bacteria, viruses and parasites, may or may not cause disease. If they cause disease they are often called pathogens. The normal flora of the microbes literally covers every external and internal surface of the pig’s body. The pig is exposed to many more helpful microbes than harmful ones. Whether or not ID occurs depends on the causal agent(s), host factors, and environmental factors. These factors are variable and directly or indirectly influence the frequency or occurrence of disease. Presence of a potential pathogen is called infection but infection does not always result in disease. 3

4. Disease Overview4Poor Environment = StressTempHumidityAmmoniaFeed/Water AvailabilityImproved Pathogen ActivityAntibiotic ResistantVirulence GenesToxin GenesMutationImmunocompromisedConcurrent DiseaseStress (Fight or Flight)Poor Nutrition/DehydrationPopulation Density

5. Infectious Disease Overview5Epidemic DiseaseAll animals within a population are susceptibleVERY FEW pathogens are epidemicEnvironment and host factors dictate disease SEVERITYAll animals will become diseasedEndemic DiseaseAll animals within a population are infectedMOST pathogens are endemicEnvironment and host factors dictate disease PREVALENCEOnly animals with poor environment and/or immune function will become diseasedInfectious Dose vs Immunity

6. Importance of Health to PerformanceOf the primary factors that affect throughput, efficiency, variation and productivity, health is the most important. With health challenges: genetic potential will not be expressed the best nutrition formulation or ration will not produce top resultsthe best management will not shinethe perfect environment will not allow for great production6

7. Health Challenges OutlineRespiratory challenges“Suis-cide” challengesEnteric challengesOther health challengesSolutions for health challenges7

8. RespiratoryPorcine Respiratory Disease Complex (PRCD)Viral agentsPorcine Respiratory and Reproductive Syndrome (PRRS virus)Swine Influenza Virus (SIV)Mycoplasma hyopneumoniaeBacterial agentsPasteurella sp.Actinobacillus pleuropneumonia (App)8

9. Porcine Respiratory Disease Complex (PRDC)Just as the name implies…respiratory problems in growing pigs are nearly always a result of multiple bugs and insultsA “mixed” infectionOutside of the lab, rarely is respiratory disease the result of a single pathogen!Any type of stress can be the first insult that leads to a cascade of events that can end up with disease and death9

10. PRDCPRRS, SIV and Mycoplasma act as “door openers”Secondary bacteria such as Pasteurella sp. take advantage of the lowered defense mechanisms as a result of the “door openers”The lungs become more susceptible to the secondary invaders after becoming infected with virus or mycoplasmaGenerally, one pathogen intensifies the other10

11. Components of PRDCViralPRRS, SIV, and PCV2BacterialMycoplasma hyopneumoniaePasteurella multocidaStrep. suisHaemophilus parasuisActinobacillus pleuropneumoniaeActinobacillus suisSalmonella choleraesuis11

12. Clinical Signs FeverAnorexiaLethargy CoughingGauntnessLabored breathing “Thumping”12

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14. PRRS VirusRemains the number one “co-factor” for swine respiratory disease complexResearch shows that PRRS virus costs swine producers hundreds of millions of dollars per yearIt has been estimated that 70% of the cost of a PRRS break can be attributed to the post-weaning phase of production 14

15. PRRS VirusRecent research has demonstrated aerosol transmission of infectious PRRS virus for nearly 3 milesSome veterinarians believe we must control the respiratory form of PRRS in the growing pig before we hope to gain area controlSeveral production systems are immunizing pigs with the commercial PRRS MLV vaccine for control and reduction of virus in areas of concentrated swine production15

16. PRRS Virus Lung Lesions High VirulenceLow VirulenceSource: Dr. Pat Halbur, Iowa State University16

17. PRRS VirusMany boar studs and recently, some sow sites have installed air filtration equipment to prevent the introduction of aerosolized PRRS virus and other pathogens17

18. PRRS Virus“Rope” technology is being developed and tested for PRRS virus monitoring of populations18

19. Swine Influenza Virus (Flu)Flu is a common viral co-factor in PRDCUntil circa 1998, we dealt exclusively with the “classic swine flu” in pigs, a strain called H1N1In the late 90’s, a different strain, H3N2 began infecting swine, particularly sows.H1N1 tended to be a seasonal problem in growing pigs causing transient anorexia, fever and coughing H3N2 has become more of an endemic virus 19

20. Swine FluSow vaccination is common (either pre-farrow or twice a year to the entire herd)Autogenous vaccine is also common in attempt to keep up with the drift and changes in the virusSIV is an RNA virus (same type as PRRS) which means it changes frequently making it difficult to control with today’s vaccine technologySwine flu can be zoonotic so worker vaccination is recommended20

21. Acute Swine Influenza (SIV)High morbidity and low mortalityFever: 105 + degrees FOff feed and depressedLabored abdominal breathingNasal dischargeDeep barking coughPigs may be unable to rise21

22. Source: Dr. Marie Gramer, University of MinnesotaThey don’t always cough!22

23. SIV Clinical SignsDepends on age and immune status of the affected pigsMay vary depending on strain of SIV involvedRapid recovery in 3-7 days if infection is uncomplicated23

24. Swine Influenza Virus Infection TimelineExposurePeak VirusExcretionSeroconversion24 hPeakFever48 h192 h(~1 wk)Viral ClearanceCoughing ~ 2 weeks240 – 336 h(10 – 14 days)Sample CollectionSource: Dr. Marie Gramer, University of MinnesotaDr. Mike Senn24

25. Swine Influenza (SIV)Typical Lung Lesions25

26. Maternal Antibody “Passive Immunity”Passive antibody from the sow is generally protectiveCan last up to 8-12 weeks of age Passive immunity decay explains SIV-induced disease is most common in pigs older than 12 weeks of age 26

27. MycoplasmaMycoplasma hyopneumoniae is nearly ubiquitous in pig populations in the U.S.While elimination attempts are usually successful in sow populations, re-infection of the pigs in swine-dense areas make vaccination a necessary part of most commercial herdsMycoplasma spreads among the populations of growing pigs acting as a “door opener” for secondary bacteria27

28. Mycoplasma PathogenesisIncubation period: 10 - 16 daysConsiderable variability in durationOnset of disease dependent on intensity of infection (exposure rate)Disease is not evident in most pigs until 3-6 months of ageVaccines are effective at reducing severity of lesions, clinical signs, and affect on performance but do not prevent infection28

29. Mycoplasma Clinical SignsDescribed as a chronic disease withHigh morbidity (high infection rate)Low mortality (low death rate)Chronic, non-productive coughFever, usually low gradeGradual onsetNormal breathing unless severe lung damage or secondarily infected29

30. Mycoplasma Lung Lesions30

31. Secondary Bacterial InfectionsPasteurella, Actinobacillus, Haemophilus, Streptococcus, and Bordetella sps. are often resident in the populationWe have been blessed with some awesome new tools for treatment of bacterial pneumonia but…Early identification of sick pigs and treatment is the key to treatment success! 31

32. Pasteurella multocida, Mycoplasma and PRRS32

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34. “Suis-cide” ChallengesStreptococcus suis (Strep suis)Hemophilous parasuis (Polyserositis or “Glasser’s Disease”)Actinobacillus suis (A. suis)These bugs are present in nearly every populationImproving management/ reducing environmental stressors are the key to control34

35. “Suis-cide” ChallengesAll these bugs can cause “sudden” deathsOften mortality and morbidity are higher in “start-up” or repopulated herds.Strep suis: CNS, arthritis, or respiratory formsH. parasuis: polyserositisA. suis: respiratory, skin lesions, arthritis35

36. Endocarditis36

37. Polyserositis/pericarditis37

38. Enteric (gut) ChallengesNeonatal challengesE.coli (K88, F18, 987P)Clostridium perfringes type A and C. difficileCoccidiosisViral (PED, PDCoV, rotavirus, TGE)Nursery phase challengesE.coli, Salmonella sp., ileitis, Porcine Colonic Spirochetosis, Viral Finishing phase challengesHBS, Ileitis, Salmonella sp., Brachyspira, PCV238

39. CoronavirusesAlphacoronavirus (Cats – Feline Infectious Peritonitis):TGEVPEDVBetacoronoavirus (Humans – SARS, MERS)Deltacoronavirus:PDCoV Gammacoronavirus (Avian – infectious bronchitis)39

40. Porcine Epidemic DiarrheaMay 17, 2013 first confirmed case in USAPEDv is a coronavirus related to transmissible gastroenteritis virus -- similar lesions – little cross protectionEurope 1971 – Asia 1982Young >>>>Old100% mortality for 3-4 weeks40

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43. IleitisLawsonia intracellularis Confirmed in 1993Replicates within cytoplasm of epithelial cells of the ileum43

44. IleitisLawsonia intracellularisPorcine EnteritisPorcine Proliferative Enteritis Porcine EnteropathyPorcine Proliferative EnteropathyProliferative hemorrhagic enteropathy Intestinal AdenomatosisNecrotic enteritis“Garden-hose Gut”44

45. Ileitis Clinical SignsClinical signs of acute ileitis can vary from a mild, non-hemorrhagic diarrhea to severe, hemorrhagic, watery diarrhea with rapid onsetPigs chronically affected display looseness sometimes tinged with blood along with loss of body condition and fail to thriveSubclinical form of ileitis has also been identified which affects growth performance 45

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47. Lesions of ileitis are variableSource: Dr. Connie Gebhart, University of Minnesota47

48. Where is the ileum ? 48

49. Solutions for IleitisWe have several effective antimicrobials approved for ileitis and when pulse-dosed at critical periods are very effective in control of ileitisWe also have an approved and effective avirulent live vaccine that can be used to orally vaccinate for ileitisTiming and implementation are paramount regardless of the approach you take 49

50. Porcine Circovirus Associated Disease(PCVAD)First identified and diagnosed in Canada in mid 1990’s as PMWS (Post-weaning Multi-systemic Wasting Syndrome).Became a serious health problem with high mortalities in nursery pigs in UK and Europe in 2001 and beyond. Called PCVD in EuropeEmerged in the US in 2005-2006Substantial losses across U.S. industryInitially called PMWS and associated with PDNS50

51. Dr. Mattew Turner51

52. PCVAD“Race for a cure” yielded three commercially available and efficacious vaccinesVaccine has proven itself beyond doubt!Subclinical cases are now the focus as it has been found that vaccine in the absence of typical clinical PCVAD, has led to improved ADG and reduction in the number of light pigs at market time.52

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54. PCVAD can be subclinical or include one or more of the following clinical manifestations:Multi-systemic disease with weight loss (formerly known as PMWS) High mortality: Doubling of historical mortality rate without introduction of a new known additional pathogenRespiratory signs including pneumoniaPorcine Dermatitis and Nephropathy Syndrome (PDNS) Enteric signs including diarrhea and weight loss54

55. PCV2 associated diarrhea is often seen in the group prior to PCV2-associated PMWSBrown-red-black diarrheaPCVAD55

56. Porcine Dermatitis/Nephropathy Syndrome (PDNS)Skin DiscolorationEnlarged, discolored Kidneys56

57. Thickened small intestinal mucosa in a case of PCV2-associated enteritisEnlarged mesenteric lymph nodesPCV2 antigen in the intestine(abundant goblet cells: red arrow)57

58. Dr. Matt Turner58

59. Dr. Matt Turner59

60. Dr. Matt TurnerDr. John Waddell60

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62. Non-Infectious ChallengesHemorrhagic Bowel Syndrome (HBS)Gastric UlcersCannibalismHerniasKyphosis/Lordosis (hump-back)62

63. HBS / TorsionCause is unknownRisk FactorsFeed interruptionRapid ingestion of large amounts of feed / water“Binge” eatingOvercrowdingLimited feeder spaceGenetic susceptibility63

64. Gastric UlcersRisk FactorsStressCrowding FastingMixingVentilationFinely ground feedIntermittent FeedingDelivery / orderingDiseaseANY INTERUPTION IN FEED INTAKE !!!!64

65. CannibalismPrimarily “tail biting”“Vices” such as tail and ear biting are generally a result of stressors which make the pigs uncomfortable and restlessUniform tail length and pig comfort are essential in addressing these problems65

66. Kyphosis/LordosisStraw, et. al. 200866

67. Senecavirus A (SVA)SVA, Seneca Valley Virus, resembles Foreign Animal Disease (FAD) clinical signs which we are required by federal law to report to the state veterinarian.While SVA is not a FAD we cannot tell the difference by clinical signs. Early identification of FAD will minimize disease transmission and economic fallout to the U.S. swine industry.If SVA is spread throughout a system animal movements will stop until all FAD are ruled out.67

68. What To Look For:Sows and GiltsBlisters (vesicles) intact or ruptured on the snout or mouth (Photo 1 & 2)Sudden lameness with ulcers like lesions on or around hoof wall (Photo 3)Sows not eating all feed or off feedSome fevers up to 10568

69. What to Look For:PigletsSudden increase in PWM less than 7 days of ageAffected piglets will be observed shortly after birthCan be confused with PED or TGEShort lived clinical signs - Production can resume to normal in 4 to 7 days69

70. What to Look For:Growing PigsSudden and severe lamenessSigns include redness and ulcers around the top of hooves and the skin between hoovesBlisters (vesicles) intact or ruptured on the snout or mouth (Photo 1 & 2)70

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72. Novel PathogensMicrobe identification tools continue to improveRemember Koch’s PostulatesThe microorganism or other pathogen must be present in all cases of the diseaseThe pathogen can be isolated from the diseased host and grown in pure cultureThe pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible laboratory animalThe pathogen must be reisolated from the new host and shown to be the same as the originally inoculated pathogen72

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75. Solutions for Health ChallengesPreventionTreatmentElimination75

76. First, Know Thy Enemy!Diagnose! Find out what pathogens are in the population!Attempt to sort the wheat from the chaff!Which pathogens are primary? Secondary? Incidental?What stressors could be allowing expression? 76

77. Diagnose!Clinical signsRespiratory, enteric, lameness, CNS, ADR?HistoryMorbidity/MortalityResponse to therapy?Fever?Laboratory confirmation77

78. After the diagnosisEstimate the prevalence of the disease.Estimate the cost of the disease in mortality, performance and profitDetermine if there is an effective treatment or immunization tool availableCalculate a cost:benefit ratioImplement the toolAssess response78

79. TreatOne the diagnosis has been reached and the decision to treat is made:Use the right tool at the right animal at right time, in the right dose in the right route and in the right frequency Choosing the correct therapeutic tool is only a fraction of the processImplementation of the treatment plan is critical!79

80. PreventChoices abound for preventative options:FeedbackPlanned exposureAvirulent live, attenuated vaccinesBacterins or killed virus vaccinesAutogenous vaccinesProphylactic use of therapeuticsAs with other tools, proper implementation is essential to success80

81. If you can’t live with it…Eliminate it!Multiple options existDepopulation/repopulationAge segregated rearingMedicated early weaningTest and removeMass vaccination and unidirectional pig flowLoad/immunize/close81

82. In the end…It is always best to keep disease out!Biosecurity should be first on the listWe now have the knowledge to implement herd biosecurity that really works82

83. 83The days of the snake oil salesman are over!