Diagnostic Center for Population and Animal Health

Transcription

1 Diagnostic Center for Population and Animal Health

2 Trends of Swine Diseases in the USA Dr. med. vet. Matti Kiupel, BS, MS, PhD, DACVP Diagnostic Center for Population and Animal Health College of Veterinary Medicine, Michigan State University 4125 Beaumont Road Room 152A, Lansing, MI 48848, USA Tel.: ** ; Fax: ** ;

3 Pork Worldwide Market Share PORK MARKET SHARE WORLDWIDE PORK Other Meat

4 US Share - World Pork Production 10% USA 90%

5 Production Dynamics - 79 to 93 WORLD PORK PRODUCTION UP 42% CHINA PORK PRODUCTION UP 40% NORTH AMERICAN PRODUCTION UP 4% Economic Growth - China 12% USA 3%

6 World Population 1 in 5 people in the world are Chinese 2700 people added to world population during this presentation!

7 Daily Protein Consumption ASIA consumes 11 gms. Protein dpp. 800 Million people in India (only 12% Muslims) USA consumes 72 gms. Protein dpp. 270 Million people in US

8 Production Dynamics ,580 Swine Farms ,780 Swine Farms

9 Management Technologies Traditional Technologies: - small farms: sows, outside - group farrowing: 2-4 groups/year - weaning age: 4-8 weeks-of-age - continuous-flow rearing

10 Management Technologies Evolution in Management Technologies: - large farms: sows, inside - reduced weaning age: days-of-age - age-segregated rearing: AI/AO, SEW - site-segregated rearing: 2- or 3- site

11 Ages: Stages Conventional SEW Suckling < 3 weeks < 2 weeks Nursery 3-8 weeks 3-8 weeks Grower 2-6 months 2-5 months Breeding > 6 months > 6 months

12 Swine Practice Today & Future Swine Dr. related services Dispensed Med. OTC Medication Other Other DVM s 24.6% 55.6% 25.7% 20.6% 29.1% Client visits/wk 35 64

13 Responding to Industry Dynamics Help coordinate producers - shift sows within the practice Take more time with the breeding herd sites Spend more time at each production site Provide added services, training Increase diagnostic, health monitoring procedures Epidemiology Cooperate with other specialists

14 Swine 2000 Conducted by the United States Department of Agriculture's (USDA) National Animal Health Monitoring System (NAHMS) Last National Swine Survey conducted in 2000 Two previous National Swine Surveys were conducted by NAHMS in 1990 and 1995 Study of swine operations in the 17 leading pork-producing states Good overview of the health, productivity, and management practices in the US swine industry

15 Swine 2000 First part (Part I) released in August 2001 Describes swine health and management Based on data gathered from 2,499 swine production sites Represents 92 % of the swine herds in the US with >100 pigs

16 Swine 2000 Second part (Part II) released in March 2002 More detailed description of US swine health and health management Based on data collected from 895 of the previously interviewed swine production sites

17 Swine 2000 Breeding herd management practices based on site size Defined by the number of breeding females onsite: Small Site - less than 250 breeding females Medium Site to 499 breeding females Large Site or more breeding females

18 Breeding Management Artificial insemination: Most (85.3 %) sows on large sites Half (51.3 %) of sows on medium sites Only 14.9 % of sows on small sites Semen used for artificial insemination: 72.9 % purchased semen 17.1 % collected semen on-site, 20.8 % collected semen off-site (owned a boar stud)

19 Percent of Sites that Purchased Semen, by Region

20 Common Diseases Problems Most frequently reported health problems in breeding herds (regardless of herd size): Roundworms: 40.8 % of sites PRRS: 21.4 % of sites PRRS less frequent in small herds (15.1 % of sites) than in large herds (58.3 % of sites) Other common disease problems: Mycoplasma pneumonia (14.2 % of sites) Traditional swine influenza (H1N1; 11.2 % of sites) Both more frequently in larger herds

21 Top 12 Diseases Problems in US Breeding Herds Salmonella TGE APP Glasser s Disease Parvovirus New Flu (H3N2) Erysipelas Gastric Ulcers Traditional Flu (H1N1) M. pneumoniae PRRS Roundworms Per cent of Sites 40 50

22 Sow Longevity Removal of breeding females from the herd: 41.6 % through death loss and culling Rate increased with site size from: 35.0 % on small sites 46.6 % on larger sites Annual sow/gilt cull rate in 2000: 35 % Annual sow/gilt death loss: 5.0 % on small sites 7.4 % on larger sites

23 Reasons for Culling Breeding Females 9 Females (%) Age Reproductive Failure Lamness Performance Other Reasons

24 Sites that Isolate and Health Test New Breeding Gilts and Boars Size of Site Small Medium Large All Sites New breeding gilts Always isolate, % Sometimes isolate, % Closed herd (no new arrivals), % Time in isolation, days Health tested at least sometimes, % New breeding boars Always isolate, % Sometimes isolate, % Closed herd (no new arrivals), % Time in isolation, days Health tested at least sometimes, %

25 Percentage of Sites that Always/Sometimes Isolate and Health Test new Breeding Females Per cent of Sites Isolation/Quarantine Health Test

26 Percent Sites and Pigs Where Maximum Weaning Age Was 20 Days or Less and Pigs Were Moved to a Separate-site Nursery

27 Acclimation of New Breeding Stock Acclimation to viral and bacterial diseases on receiving farm: Main method: vaccination - 84 % of sites vaccinated isolated new breeding females exposure to cull females (49 % of sites), increased with site size from 43 % of small sites to 69 % of large sites feeding of feces from other pigs (25 % of sites) feeding of mummies, placenta, or stillborn pigs (11.3 % of sites) exposure to sick pigs (7.7 % of sites)

28 Routine Vaccinations for Sows and Gilts in 1990 Leptospira 70.2 Parvovirus 65 Erysipelas 61.4 E. Coli scours 45.9 Atrophic Rhinitis 38.3 TGE 24.3 Erysipelas 22.4 Pseudorabies 21.5 Other 18.1 Rotavirus 16.8 APP Per cent of Producers 80

29 Percent of Sites that Vaccinated Breeding Females for PRRS, Mycoplasma, or Influenza in 2000

30 Percent of Sites that Vaccinated Weaned Market Pigs for PRRS, Mycoplasma, or Influenza in 2000

31 Percent Sites Requiring Preventive Measures of Visitors Before Entry into Swine Facilities

32 Ascaris suum - Larval Migration Liver scars more sensitive indicator than adults in intestine Liver scars will persist up to 3 months Economic impact of heavy adult ascarid burdens minimal reduction of burden impacted ADG by 1% Impact of larval migration on pneumonia is difficult to quantitate

33 Ascaris suum Economic Impact Parasite Ascaris suum (roundworm) Prevalence of Per pig cost ($) of worm internal parasites damage at in Midwestern three levels of parasite hogs infestation % Pigs % infested Farms Light Moderate Heavy at infested slaughter 70% 60%

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37 Liver

38 Liver

39 Ascaris suum

40 Ascaris suum

41 Ascaris suum

42 Lung

43 Lung

44 PRRS Virus Emerged in 1986 Arterivirus Strain variation virulence antigenic Lelystad virus Europe (1999 in US) VR U.S. Incompletely neutralized by conv. sera

45 Diagnosis of PRRSV in Pigs Can be problematic Clinical diseases varies based on: Age, gestation period, individual susceptibility, strain virulence Some strains are difficult to isolate Attenuated virus persists in tissues of vaccinated pigs for months (PCR only 68%) Endemic infection is common based on serology: often no clinical signs moderate decrease in growth rate, feed efficiency, or reproductive performance

46 Clinical Signs of PRRS Enzootic Weanling - Grower pigs respiratory disease poor growth increased bacterial diseases Adult sporadic third trimester reproductive failure Epizootic - since severe herd-wide outbreak of reproductive failure and sow death sow abortion and mortality syndrome (SAMS) acute or atypical PRRS Fever (41 C), recumbency, inappetence

47 Pathogenesis of PRRSV in Pigs Enters herd through new animals or semen Replicates in monocytes / macrophages Prolonged viremia and infection Crosses placenta > in last trimester Viremia: begins at 24 hrs, lasts 4-6 weeks (by VI) virus can be present in tonsils up to 213 days Disease most severe in young pigs Interstitial pneumonia, begins 3 days, most severe 7-10 days and resolves days Nodular lymphoid hyperplasia Dyspnea, sneezing, drop-off, other diseases such as polyserositis, meningitis

48 Distribution of PRRS 1996/97 from 32 herds in 11 states: 72% herds positive 90% of herds with clinical signs positive only 36% of herds without clinical signs were positive Increased risk for PRRS infection: not isolating gilts after purchase higher number of sows purchasing semen for artificial insemination more gilts purchased

49 Diagnosis of PRRS Typical lesions Demonstration of PRRSV or antigens VI serum, lung, spleen IHC lung, tonsil RT-PCR Serology ELISA Strain differentiation Sequencing, ORF 4-5

50 PRRSV Induced Lesions Gross lesions Interstitial pneumonia: variable appearance Enlarged lymph nodes after 5 days Microscopic lesions Interstitial pneumonia +/- necrotic macrophages in alveoli No necrosis of airway epithelium Lymphoid necrosis - hyperplasia Nonsuppurative myocarditis and encephalitis

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63 Swine Influenza Replicates in: Epithelium of small airways, pneumocytes Epithelium of nasal cavity, trachea, alveoli Alveolar macrophages Type A H1N1 H3N2

64 SIV Induced Disease Rapid course incubation: hours shed in nasal secretions for 4-5 days recovery, if uncomplicated, in 7 days Symptoms coughing dyspnea, pyrexia, drop-off abortions

65 SIV Lesions Gross checkerboard cranioventral pattern diffuse interstitial pattern firm (proliferative) cranioventral pattern Microscopic necrotizing bronchiolitis proliferation of type II pneumocytes peribronchial and perivascular cuffing

66 Diagnosis of SIV Typical lesions Demonstration of SIV or antigens FA/IFA lung VI lung, nasal swabs IHC fixed lung ELISA nasal swabs, bronchial swabs Serology: paired samples HI

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75 Emergence of Clostridial diseases in Swine

76 Clostridium perfringens type C less than 1 week of age some pigs may survive initially, but tend to grow poorly and die by 2 3 weeks-of-age segmental transmural necrohemorrhagic enteritis with subserosal and intramural emphysema colonizes the surface of the small intestinal mucosa and secretes a protein exotoxin that diffuses into underlying tissues and induces necrosis and hemorrhage

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82 Clostridium difficile Neonates; startup herds, low parity dams High mortality Gross lesions ascities, subcutaneous edema mesocolonic edema, necrotizing colitis Microscopic lesions erosive colitis w/ volcanic exudation

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86 Clostridium perfringens type A 1-4 days of age High morbidity, low mortality Overgrowth of organisms in lumen Enterotoxin? Anaerobe 2(4): , 1996 No gross or microscopic lesions

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90 Diagnosis Clostridium perfringens/difficile Jejunum, ileum, colon, cecal/colonic contents tissues: tied off and chilled and in 10% NBF cecal/colonic contents: frozen ASAP Tests Anaerobic culture Clostridium toxin genotyping by PCR: alpha, beta, epsilon, iota, endotoxin, beta-2 C. difficile toxin by antigen-capture ELISA

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