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Department of Veterinary Science Pennsylvania State University

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1 Department of Veterinary Science Pennsylvania State University
Salmonella Bhushan Jayarao Extension Veterinarian Department of Veterinary Science Pennsylvania State University University Park, PA

2 Salmonella PART TOPIC ________________________________________
1 Case Study: The Hudson Farm 2 What Should You Know About Salmonella ? 3 Prevention and Control Strategies

3 PART ONE Hudson Farm: a Case Study

4 Hudson Farm

5 Meet the Hudsons ! Linda Fred Mary Susan John Jeff Dave

6 The Hudson Dairy Farm History Employees 1920 - Established
Upgraded New structures & equipment Employees Jeff Hudson, owner 1 farm worker 1 milker Dave, Linda, Fred Susan & John feed the calves Jeff Hudson Owner Since 1982

7 Hudson dairy farm layout
M&S Milk cow barn Dry cow & heifer barn Feed barn Holding area Calf barn B T R Milking parlor Tool shed Hudson home Grazing area Hudson dairy farm layout

Grade A milk lbs of milk per day No antibiotic residue violations BTMSCC: 200, ,000 last year. DAIRY CATTLE 12 calves 19 dry cows 20 heifers 87 cows in milk OTHER ANIMALS 4 stray cats dogs pony ducks and chickens

9 People with whom Jeff interacts …...
Milk Agent Farm Worker Cull Cow Farm Credit Dealer Agent Banker Salesmen County Ext. Agent Veterinarian

10 So goes the story !

11 October 1, 7.00 am ???? I’ take it ! Jeff, I have got a deal for you !
How about 3 calves for $ 90 ? IF you don’t, I have someone who will take it ! ???? I’ take it !

12 October 1, am

13 Milk cow barn Feed barn Calf barn Milking parlor Tool shed Hudson home
M&S Milk cow barn Dry cow & heifer barn Feed barn Holding area Calf barn B T R Milking parlor Tool shed Hudson home Grazing area There’s no one to tell him where to put the calves, so he leaves them in the calf barn !!!!!!

14 October 4 5.00 am 8.00 am 3 new calves, and 2 other calves have
high temp. and bloody diarrhea …! 8.00 am The Vet examines the herd. He also takes a swab sample for lab testing. He then treats the calves, and then tells Jeff …”You might have a serious problem”

15 October 4 8.00 p.m. 11.00 PM This has not been a good day for Jeff !
A total 7 out of 15 calves are now sick. He treats the sick calves. PM Jeff, has to take both and to the County Hospital emergency room --- abdominal cramps and high temperature. This has not been a good day for Jeff !

16 October 5 4.00 am 5.00 am 6.00 am Children admitted.
Dave volunteers to help 5.00 am 8 dead calves Dave loads the dead calves on the UNI-LOADER and takes them to the pit. 6.00 am The cows have just returned from milking, he quickly TURNS AROUND hoses down the uniloader, and picks up feed for feeding the cows

17 October 8 October 10 Nothing much happening on the farm.
The remaining sick calves nursed back to health. On October 8th, the children return home Diagnosis: Salmonellosis. October 10 The veterinarian calls to tell that Salmonella from his calves is a new type of Salmonella called DT104.

18 October 12 4.00 am 18 cows in milk are scouring ! 9.00 am
Sick cows are moved from the milk barn to the maternity /sick pen. 11.00 am The Vet examines the cows. Verdict: Salmonellosis. 12.00 noon Mr. Smith a neighbor, who buys raw milk tells Jeff that they are going to host 24 Boy Scouts over the weekend on his game farm.

19 October 14 9.00 am Jeff learns, 18 of 24 boy scouts are hospitalized & 2 in serious condition. 11.00 am The County Health Officer, the State Regulatory Veterinarian, The Milk Agent, his Veterinarian, FDA and USDA officials come to the farm. 11.30 am Herd is to be quarantined, till further notice.

20 All newspapers carry the outbreak story !
Milk makes kids sick ……… Salmonella outbreak traced to DAIRY farm …….. Milk contains bugs that makes people sick ………. Scientists say …….. Dairy farming Dairy cows ….. All infected with dangerous bugs Killer bug on the loose …… dairy cows responsible

21 How did Salmonella typhimurium DT104 get into raw milk ?

22 Date Event October 1 Apparently healthy calves brought
Apparently clean looking truck New calves mixed with other calves

23 Date Event October 1- 3 Incubation period for Salmonella
(Children probably infected) October Clinical symptoms in calves & children

24 October 5 Dead calves loaded onto uniloader
Date Event October 5 Dead calves loaded onto uniloader UNI- LOADER IS CONTAMINATED WITH SALMONELLA ! Uni-loader hosed down with water !!!!! Picks up feed FEED IS CONTAMINATED WITH SALMONELLA ! SALMONELLA

25 Date Event October 5 Cows infected with Salmonella Typhimurium DT104
October Salmonella Typhimurium DT Multiple antibiotic resistance: Ampicillin Chloramphenicol Streptomycin Sulfonamides Tetracycline Incidence increasing in the US 3 human outbreaks reported !

26 Date Event October Cows infected with Salmonella

27 Date Event October Infected cows contaminate milking stall, parlor and milk in bulk tank

28 Putting it all together !

29 PART TWO What should you know about Salmonella ?

30 What’s Salmonella ? Salmonella is a bacteria Rod shaped
Appears pink to red when stained with Gram’s stain (Gram-negative) Belongs to a family; Enterobacteriaceae (intestinal bacteria) Salmonella (genus) enterica ( species) serovar ( over 2200 serovars) Example: Salmonella enterica serovar Dublin S. Dublin Light Microscope Electron Microscope

31 Historical Perspective
One of the first veterinary students from Cornell University, and holder of the first D.V. M. degree (1876) DANIEL ELMER SALMON, D.V.M. ( ) Father of disease eradication Pioneer in public health practice and medical research Discoverer of salmonellae Experimental Immunologist, Epidemiologist, Administrator Bureau of Animal Health [ Veterinary Medicine and Human Health, C. W. Schwabe, 1969]

32 Where does Salmonella come from ?
Inhabitant of intestinal tract of animals birds reptiles insects Host adapted Human: S. Typhi Cattle: S. Dublin Poultry: S. Pullorum Pigs: S. Choleraesuis Non host adapted S. Typhimurium

33 YES ! What’s Salmonellosis ?
When Salmonella causes a physical illness in animals or human beings it is termed as Salmonellosis Is Salmonella communicable between animals and humans ? YES ! Human outbreaks of Salmonellosis in the United States are frequently associated with food products of animal origin including eggs, meat, milk and milk products 38 Outbreaks, 14 (37%) traced to products of bovine origin !

34 Bovine Salmonellosis Magnitude of the problem National survey
2.1% fecal samples from 7.4% of farms Cull dairy cows 4.6% of cull cows (Washington State) Neonatal calves Ohio- 4.8% farms; California- 16 % farms Missing information Estimates of economic losses calf and adult cattle milk production contaminated raw bulk tank milk Salmonella in raw milk Wisconsin % Tennessee % South Dakota - 6.1%

35 Bovine Salmonellosis Common serotypes isolated from cattle in the United States S. Dublin - ( group ‘D’) Most S. Typhimurium - ( group ‘B’) common S. Newport S. Muenster S. Saintpaul S. Anatum S. Kentucky S. Montevideo

36 How does Salmonella gain access to a farm ?
Most important sources of infection Replacement calves trucks heifer/ cows birds /pests feed water visitors

37 Other routes of entry

38 Salmonella & host interaction
Contaminated feed water feces colostrum / milk Salmonella & host interaction Animal Intestine OUTCOME ? Salmonella Environment Microscopic picture of small intestine

39 Outcome of an Salmonella infection ….
No Salmonella in feces and milk No clinical signs Salmonella infrequently present feces and or milk SYMPTOMLESS CARRIER Salmonella present in the body but not excreted recover LATENT CARRIER Fever, diarrhea, bloody stool, dehydration, anorexia/ emaciation rapid breathing, sloughing of skin from extremities Clinical symptoms Salmonella in feces and or milk ACTIVE CARRIER death

40 Salmonella carriers ? diagnosis prevention and control
Animals with Salmonella infection that appear healthy and show no signs of disease make detection diagnosis prevention and control one of the most difficult tasks to achieve and provide the greatest challenges to the animal health industry. ACTIVE CARRIER LATENT CARRIER SYMPTOMLESS CARRIER

41 How do healthy animals become infected ?
FECES AND DISCHARGE Sick Contamination of: 1. Barn/ manure 2. Water troughs 3. Feed 4. Run off waste 5. Uni-loader 6. Other equipment Sick but apparently look healthy Feces On farm newly purchased Milk Feces Direct colostrum Indirect Healthy calves Healthy cows

42 “Characteristics of Salmonella and Salmonellosis --- points to remember”*
ONE : Infection on a farm is maintained primarily by transmission of Salmonella from feces of infected animals ACTION: Break the links in the chain by minimizing opportunity for fecal contamination of feedstuffs, feeding surfaces, water troughs and equipment * Partly taken from: John M. Gay, Bovine Herd Salmonellosis / courses-jmgay/ fdiuherdsalmonella.htm

43 TWO: Salmonella infection & subsequent clinical disease is a result of :
ACTION: Maximize host resistance by paying careful attention to the transition of susceptible animals (periparturient cows newborn calves). Organism Animal * serotype * age * virulence * immunity * No. of organisms * nutrition * prior exposure * stress

44 THREE: Salmonella infects anything in the livestock environment that has an intestinal tract:
ACTION: Initiate control programs 1. Rodent proof and bird proof feed storage 2. Remove nesting and roosting opportunities

45 ICEBERG EFFECT FOUR: Majority of Salmonella infections in a herd over a period of time are symptomless Clinical infections are only the tip of the iceberg, even during clinical outbreaks of disease ACTION: in an outbreak handle all animals as if they were shedding not just the sick ones. Reduce water and feed contamination. Clinical Normal Subclinical

46 FIVE : Some symptomless animals shed Salmonella through saliva, nasal secretions, urine, milk and feces Such animals POSE THE GREATEST PROBLEM in controlling spread of Salmonella infection as they contaminate water bowls nipples oral treatment equipment (balling guns, esophageal feeders) human hands ACTION: Clean all equipment with Chlorhexidine ( 3 oz. / gal) and other items such as boots and mats with orthophenylphenol.

47 1. Normal Dry Matter Intake
2. Normal VFA level 3. No Growth of Salmonella in rumen 1. Lowered Dry Matter Intake 2. Lowered VFA level 3. Increase in number of Salmonella in rumen 1. Don’t have regular access to feed 2. During transport 3. Parturition 4. Subclinical ketosis 5. Hypocalcemia 6. Sudden ration changes 7. Ration maladaptation 8. Inadequate bunk space and pen space 9. Mixing submissive heifers with dominant cows at parturition SIX: Salmonella are usually killed by exposure to the volatile fatty acids of fully functional normal rumens ACTION: Maximize rumen function by maximizing a consistent dry matter intake in periparturient and early fresh cows

48 SEVEN: Salmonella survives for long periods under conditions common on the livestock farm
Colostrum 30 C, 2 to 5 weeks. 5 C to 11 C, for ~ 10 days, low pH will reduce the number of Salmonella Pasture and soil days Garden soil days Liquid manure days ( S. Dublin), days ( S. Anatum) Slurry to 250 days Infected feces stored in cans days ( S. Dublin)

49 EIGHT: People who are at risk of illness
Farm workers Expectant mothers handling sick animals Working with sick calves and cows Poor personal hygiene Consuming raw bulk tank milk Public Consuming raw milk, fresh cheese made of raw milk.

50 NINE: Personal hygiene practices on farm
Wash hands with soap and water A must before and after: 1. Attending sick calves and animals 2. Milking cows ( also wear gloves) 3. Manure handling Dress and boots 1. Change into farm boots on the farm 2. Wash farm boots regularly 3. Leave farm boots on the farm 4. Wash and disinfect farm clothes IF available: shower before leaving the farm Avoid drinking raw milk

51 Salmonella Typhimurium DT 104
Emerging foodborne pathogen Detected in several countries Why is DT 104 of concern ? Multiple antibiotic resistance Ampicillin Chloramphenicol Streptomycin Sulfonamides Tetracycline DT 104 has been isolated from; poultry, swine, cattle and wild animals

52 Outbreaks ( human) in the US:
United States Humans S. Typhimurium: (1990) (1996) S. Typhimurium DT 104: (1990) (1996) Cattle ( Northwest) DT 104: No isolations till 1986 13% to 1991 64% to 1996 Outbreaks ( human) in the US: 4 ( 3 - west coast, 1- east coast) ALL 4 OUTBREAKS LINKED TO UNPASTEURIZED DAIRY PRODUCTS SOURCE OF DT 104 IN TWO OUTBREAKS, TRACED TO DAIRY FARMS

53 No unique control methods available for S
No unique control methods available for S. Typhimurium DT 104 in animals. Control measures that are effective against other types of Salmonella will reduce the likelihood of transmission of S. Typhimurium DT 104.

54 Risk factors for Salmonella Typhimurium DT 104
Cattle in dealer premises were at increased risk of disease (Odds ratio 14.25) Introduction of newly purchased cattle ( 4 weeks after purchase) to the farm increases the risk of disease (OR 2.51) Purchase via dealers was at high risk as compared with purchasing stock directly from other farms (OR 3.90) Evans S., and R. Davies Case control study of multiple - resistant Salmonella typhimurium DT 104 infection of cattle in Great Britian. Vet. Rec. 139 :557:558.

55 Risk factors for Salmonella Typhimurium DT 104
Persistently contaminated buildings may be a source of infection (OR 2.48) Lack of isolation facilities for ill animals was associated with an increased risk of disease In particular; if cows calved in buildings that previously housed diseased stock (OR 1.51) A high population density of cats around the farm increased the risk of infection (OR 1.35) Evidence of access to cattle feed stores by wild birds was associated with an increased risk of disease (OR 1.67)

56 Risk factors for Salmonella Typhimurium DT 104
Risk factors over which the dairy producer can exert control: 1. Purchasing replacement stock from direct sources rather than a dealer 2. Quarantine of purchased cattle for a 4 week period 3. Housing sick animals in dedicated isolation areas 4. Preventing wild bird access to cattle feed stores 5. Vaccination

57 Typical Scenario-1 OUTBREAK
No of animals weeks OUTBREAK Newly assembled herd, animals from unknown source, or from a dealer High morbidity ( at least % in the herd infected) Drop in milk production, ~ 10 %, high risk of bulk tank milk contamination Typically observed with S. Typhimurium, last 2-4 weeks Samples taken during outbreak show extensive herd contamination Samples collected 4-6 weeks later, most of which test negative Subsequent outbreaks or infections may be sporadic, or may go unnoticed

58 Typical Scenario-2 Recurrent Salmonella infection in calves and cows
Cycling of Salmonella in a herd Typically seen with Salmonella group D and group E Presence of animal reservoir or extensive environmental contamination Hot spots: Maternity area, calf housing areas, watering troughs Identify carriers, massive environmental cleanup, put in place appropriate management practices.

59 Other Scenarios... Salmonella detected in milk filters and
bulk tank milk Pre-fresh and or fresh cows sick Family member diagnosed with Salmonellosis after drinking raw milk Calves and cows you recently sold caused Salmonellosis Recurrent diarrhea and loss of calves

60 PART THREE Strategies for Prevention and Control of Salmonellosis

61 Principles of Salmonella Control on Dairy Farms
Herd risk factors Larger herd size Freestalls Recycled-water flush system “Open” herds Lack of quarantine facilities Rendered-product use Concurrent diseases Inadequate calf-feeding utensil cleaning

62 Principles of Salmonella Control on Dairy Farms -2
Individual animal risk factors Age ( 3 to 6 week-old calves) Starvation/ nutritional deficiencies Concurrent diseases Poor immunoglobulin levels Transport and other stresses Manure access

63 Principles of Salmonella Control on Dairy Farms -3
Sources of Salmonella bacteria Contaminated feed Carrier animals Vectors (birds, wild animals, pet animals, rodents)

64 Principles of Salmonella Control on Dairy Farms -4
Control measures during a Salmonella outbreak Identify sick animals Isolate sick animals Identify source of bacteria, and if possible eliminate Prevent reintroduction of the bacteria Institute hygiene measures (fecal-oral spread) Vaccination ? Treatment of infected animals ?

65 Control measures during a Salmonella outbreak -2
Human health precautions during a Salmonella outbreak Avoid exposure of young, old, or immune compromised people Limit number of people handling sick animals Avoid having same people handle sick and well animals Hygienic measures foot bath handwash separate clothes/footwear for sick animal handling Prevent pet animal exposure to cattle DON’T DRINK RAW MILK FROM AFFECTED FARM

66 END

67 Whole herd outbreak 1 General
A Make sure all farm personnel are made aware of the outbreak B Discourage all farm visitations and visitors C Disinfect 1 All soiled work clothes in PPM of chlorine solution, rinse, wash and dry. 2 Boots, rinse with high pressure hose and soak overnight in orthophenylphenol.

68 Whole herd outbreak 2 Secure the milking facility
A Milker(s) clothes and boots B Disinfect boots before entering the milking facility C Do not milk cows with diarrhea D EXTRA PRECUATION DURING CLEANING OF UDDER AND TEATS E No visitors or other farm personnel

69 Whole herd outbreak 3 Restrict movement of animals A Minimize movement
B Retain animals within the same barn/ unit till laboratory tests tests are negative C No visitors

70 Whole herd outbreak 4 Equipment 5 Feed areas clean Clean equipment
Between operations; one unit to another Same equipment is used for different tasks 5 Feed areas Remove feed in the feeding alleys at the time of outbreak Disinfect the feeding alley Replenish with fresh feed

71 Whole herd outbreak Calving area and Calf house Remove manure
Scrap off dry manure and top soil Clean wall with sodium triphosphate (1 oz. / gal) Spray the floor with same Transfer all refuse to a marked area on the farm

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