Zoonotic mischief from cattle

Transcription

1 Zoonotic mischief from cattle Nigel French GPCME workshop 2014 photobucket Collaborating Centre GPCME, Rotorua June 2014

2 Livestock populations Barbara Binney In Campylobacter Ecology and Evolution. Eds Sheppard, Méric Cattle

3 Population biology and evolution of zoonotic pathogens in NZ Low diversity Some pathogens absent Q-fever Unique strain types Salmonella Population structure shaped by: Hitchhiking: people and animals Isolation, recent colonisation by man EID 7, 767

4 Zoonoses Reservoir/maintenance hosts Bridging hosts Spill-over hosts >60% of all human infectious diseases are zoonoses

5 Quiz Zoonoses associated with cattle? Globally? In New Zealand? Most recent experience of cattle associated zoonosis in a patient?

6 Cattle Zoonoses - quiz 6

7 Cattle-associated zoonoses in NZ Absent Q fever, brucellosis Endemic Parapox, milkers nodule Recent decline Leptospirosis Recently emerged and declined Salmonella DT160, Salmonella Brandenburg Become relatively more important Campylobacteriosis Become absolutely more important E. coli O157:H7 and other STECs

8 Emerging Issues Rural preschool children STEC, Campylobacter, Salmonella, Cryptosporidium spp. Surface and shallow groundwater contamination Drinking, recreation Raw milk Antimicrobial resistance

9 Cattleassociated zoonoses figure very prominently in New Zealand. Source: ESR Ltd

10 Pathways and pathogens Number of cases per year E. coli O157 ~ 150 cases Salmonella DT160 ~ 250 cases Campylobacter ~ 8,000 cases Giardia ~ 1000 cases Leptospira ~ 100 cases Cryptosporidium ~ 800 cases

11 Enteric pathogens

12 Waterborne zoonoses in NZ Water-borne infections include: Campylobacter Cryptosporidium Giardia Salmonella E. coli O157. others

13 Faecal outputs of cattle and humans Cattle: Number of defecations 9 16, average 12 per day Average 2kg per defaecation Total output of 25kg per cow per day. 9 million cattle in NZ 230,000 tonnes faecal material per day 84 million tonnes per year. Humans 800 tonnes per day Source Dr Brent Gilpin ESR Ltd

14 Dairy Industry Strategy All water leaving dairy farm will meet recreational water guidelines

15 Clean Streams Accord Signed 26 May 2003 by Fonterra, Ministers for Environment, Agriculture and regional councils Dairy cattle excluded from streams 50% of streams by 2007, 90% by 2012 Regular race crossing-points have bridges or culverts 50% of streams by 2007, 90% by 2012 Farm dairy effluent is appropriately treated and discharged

16 Non-audited Clean Streams Accord

17 Surface Run-off Riparian Buffers Run-Off a key source of contamination Effectiveness of riparian buffers depends on a range of factors: - slope, rainfall intensity, soil type etc Buffers - can be effective in light rain - less effective in heavy rain

18 Irrigation Management Irrigation can promote surface run off especially if soils are saturated - Important for effluent irrigation Avoid irrigation immediately after grazing Border dyke worse than overhead irrigation Match irrigation to soil type

19 Two species of Cryptosporidium From cattle and sheep From swimming and person to person Parvum Hominis

20 Cryptosporidium parvum most common subtypes Prevalent in Ireland Cattle, sheep. horses Cattle? Cattle

21 Recent prevalence study (Julanda AlMawly) Both highly prevalent Giardia mainly non-zoonotic strains

22 Giardia typing

23 Giardia typing More zoonotic transmission than originally thought?

24 Waterborne diseases Cryptosporidium cases and water flow Crypto: Flu-like symptoms, watery diarrhoea, loss of appetite, substantial loss of weight, bloating, increased gas, nausea Giardia Diarrhea, abdominal discomfort, bloating, and flatulence

25 Campylobacteriosis Source: Olsen et al Campylobacter. 3rd ed. Washington DC: ASM Press; 2008.

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27 Interventions in poultry industry demanded 2006 No imports or exports, large consumers of chicken. Rates increase with sale of fresh poultry 30 kg pp/year

28 Manawatu sentinel site Identify genotypes common to particular sources Modelling (reservoir attribution) >6000 samples

29 Unique pattern of genotypes isolates from the Manawatu Poultry STs River water STs 474 Ruminant STs N=3120 isolates Poultry A Poultry B

30 Ruminant associated Host associated strain types in NZ Poultry associated

31 Genotype ST 474 street-level pattern Poultry associated cases

32 Ruminantassociated human cases

33 Source of human cases From presentation made to Govt and industry in July 2007

34 Relationship between campylobacteriosis notifications and hospitalisations (A. Sears) $50-70M per annum saving to economy Data Sources: ESR Ltd notification data; NZHIS hospitalisation data (filtered)

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36 Changes in the source of campylobacteriosis over time

37 Proportion of cases Proportion of cases Campylobacteriosis in 2013 Rural Poultry Ruminants Water Other Urban Poultry Ruminants Water Other

38 Dramatic change in epidemiology: now highest rates in rural under 5 year olds

39 Why different epidemiology in rural areas? Models showed strong correlation with density of dairy cattle in rural areas 2012

40 7 6 Poultry intervention Urban Rural no cattle Rural high cattle

41 Seasonality and dairy density Urban High dairy rural Young children During calving season Direct contact Hand mouth behaviour Epidemiology changed Different set of policy and decision makers Different stakeholders

42 epiclustr : a tool for cluster detection Modelling case notifications to identify clusters/outbreaks Outbreak probability >80% 50-80% 10-<50% Water supply zones 61 events

43 Raw milk cluster

44 International food safety perspective Sale of raw milk illegal in many countries Virtually all food safety advisory/regulatory committees related to food safety strongly endorsed the principles of consuming only pasteurised milk and milk products (AVMA, WHO, AMA, IAFP). Based on scientific analysis of food safety risks and the benefits of pasteurisation.

45 Law in NZ Sale at retail outlets not permitted Under the Food Act 1981, purchase of up to 5L from farm gate Milk must be harvested and stored in accordance with approved Risk Management Programme (RMP) However, questionable whether these RMP adequately address risks associated with farm gate sales. Currently registered RMP only cover production of raw milk intended for further treatment (e.g. pasteurisation) and not the sale of raw milk for drinking.

46 Issues with law Issues with the interpretation and enforcement of current law likely to have contributed to an increase in the number of sales occurring outside the limits provided in the law internet sales and collection points Some raw milk suppliers report supplying increasingly large numbers of customers utilising retail pick-up points in urban areas openly admit to illegally selling up to 16 litres at one time.

47 Feelings run high brutality and oppression of farmers, along with the torture of raw dairy advocates Italian study of vending machines: 178/60,907 samples +ve for 4 pathogens 18 samples were positive for Salmonella 83 L. monocytogenes 24 E. coli O157:H7 53 Campylobacter jejuni Four-Year Monitoring of Foodborne Pathogens in Raw Milk Sold by Vending Machines in Italy. Federica et al 2013, Journal of Food Protection 1

48 Trends in consumption in NZ Estimated ~100,000 consumers of raw milk (3%, but higher in farming families). Increasing? Vending machines installed Of raw milk consumers that were diagnosed with enteric pathogen in Manawatu 56/78 Campylobacter cases 26/78 for health reasons, 19/78 produced on own farm 65/78 drank it fresh from bottle

49 Perceived health benefits Anecdotal stories from recent NZ article: "I was brought up on it [raw milk] and never got sick," "It's amazing when you hear the benefits of it," Improvements for Parkinsons, Alzheimer's, eczema and asthma sufferers. "People would not buy it if it wasn't working," "I've never tried it before, but it's on my bucket list," she said.

50 Evidence for positive health benefits Some, but not considered convincing by metanalysis Criticised for poor study design, confounded variables, lack of RCTs Farm milk? Raw or treated? Need for ongoing investigation HRC-funded programme (Massey, led by Jeroen Douwes)

51 Bulk milk in NZ: Methods MPI study Raw milk samples collected from 80 randomly selected dairy farms. 5 samples per farm, 25ml samples analysed

52 Methods Milk quality data also collected from the same 80 farms as part of routine testing 8680 samples: somatic cell counts (SCCs, n = 8510), total viable bacteria counts (TBCs using BactoScan, n = 1092) and coliform counts (n = 807).

53 Raw milk survey results

54 Milk quality from MPI study Estimated number of live bacteria in a milk sample. N=1092 Median = 6000/ml Maximum count 1.4M 3 zero counts, 0.27% (limit detection issue) Bactoscan counts (+1)/ml

55 Bimodal distribution in TBC Mixture distribution analysis High level events occur ~10% of the time, with a geometric mean count of ~6000/ml Dropped cluster? Low level events have a geometric mean log count of ~60/ml

56 Milk quality from MPI study - coliforms Estimated number of coliform bacteria in a milk sample /ml N=807 12% positive for coliforms Maximum count 30,000/ml Coliform counts/ml

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59 E. coli O157:H7 O157 in children

60 STEC: the movie P. Jaros

61 Recent trends in E. coli O157 in New Zealand E. coli mainly O157 Number of cases First case in 1993 Date

62 Waikato Investigation concluded: Auckland

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64 Results risk factors (multivariable logistic regression model) Age 0-4 family contact animals* Age 5-19 Age >19 Recreational water Interrupted water supply Animal manure Cattle in area * Excl pets

65 STEC O157 in New Zealand

66 Phylogeography: Human cases and cattle: inter-country scale Aus US PSI tree NZ

67 Intra-island: Local strains Based on PFGE N=519 Fst network Gisborne unusual cluster of SBI type

68 Salmonellosis: a complex epidemiology In NZ salmonellosis is the second most notified foodborne disease after campylobacteriosis. Non-typhoidal >15,000 cases From French et al Development and application of new tools for the analysis of Salmonella surveillance data Final report, SCIG-MAS-001 April 2011

69 Jan-97 Jun-97 Nov-97 Apr-98 Sep-98 Feb-99 Jul-99 Dec-99 May-00 Oct-00 Mar-01 Aug-01 Jan-02 Jun-02 Nov-02 Apr-03 Sep-03 Feb-04 Jul-04 Dec-04 May-05 Oct-05 Mar-06 Aug-06 Jan-07 Jun-07 Nov-07 Apr-08 Sep-08 Feb-09 Jul-09 Dec-09 May-10 Oct-10 Mar-11 Aug-11 Jan-12 Recent trends in notified cases 2500 Number of cases 2000 Campylobacter Campylobacter Salmonella 500 Salmonella 0 Date

70 DT 160 most prevalent until 2011 In 1998, Salmonella DT160 identified as a human pathogen in NZ Initial outbreak in Christchurch in humans and sparrows Subsequently isolated from farmed animals, including dairy cattle, and wild birds. After 2000, increased significantly progressing from the South to the North Island. Now 2 nd behind Typhimurium RDNC-May 06.

71 Epidemiology and Infection 2011

72 Salmonellosis in humans Blue=Brandenburg (sheep, direct contact) Purple=Typhimurium 156 (food, cattle) Green=Typhimurium 160 (wild birds, food)

73 Salmonellosis in humans Blue=Brandenburg (sheep, direct contact) Purple=Typhimurium 156 (food, cattle) Green=Typhimurium 160 (wild birds, food)

74 Salmonellosis Complex epidemiology Some wildlife, some livestock associated, some both... Food, water, environmental pathways. Dominant clone of DT160 persisting Control of wild bird pathways Supermarkets, cafes Roof water

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76 Pseudocowpox Milker s nodule, Papular stomatitis, Paravaccinia Agent: Parapox virus very similar to Orf virus DNA virus Family poxviridae Variants of same virus Not true cowpox not endemic in NZ 82

77 Disease in humans 83

78 Clinical signs Teats and udders of cattle Raised firm, erythematous lesions Necrotic centres Bleed if scabs removed Papular stomatitis Oral mucosa, lips, hard palate, dental pad, muzzle, nostrils, tongue and oesophagus Up to 2cm diameter 2 O infection candida, aspiration pneumonia 84

79 Clinical signs 85

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81 Leptospirosis Arrived? First confirmed in a calf in 1950 Late 1950s early vaccines Bivalent vaccine introduced in 1979 Improved diagnostics in 1980s The photophobic dairy farmer retiring to bed with aching muscles, fever and nausea is now almost a thing of the past. This must mark as one of the major recent advances in (veterinary) public health in New Zealand. Roger Marshall David Blackmore

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83 Known endemic serovars and maintenance hosts in NZ >180 serovars worldwide

84 What serovars do you find in?

85 Human lepto trends Increasing predominance of Ballum at expense of Hardjo-bovis and Pomona Relatively more farmers compared to meatworkers in recent years Data source: Thornley et al 2002 and ESR

86 N Livestock prevalence Previous: slaughter stock 44% lamb slaughter lines 85% deer slaughter lines 71% beef breeding herds Urine shedding at slaughter: 31% for sheep, 21% for cattle New data adult breeding stock (238 farms, 20 animals/mob): Dreyfus et al. unpublished 0 200

87 Dairy cattle prevalence Parramore et al. 2011, unpublished

88 Lepto in Context High endemic level in sheep, cattle and deer high human exposure Changing ecology shift in host serovar balance Little knowledge about wildlife reservoirs Uncertainties about vaccination of animals NZVA review of best practice recommendations Real impact on human disease underestimated Prevalence data required for farmers, vets etc identification of infection sources

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