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Infectious Disease. Johne’s Disease (Paratuberculosis). Causative agent: Mycobacterium paratuberculosis Extremely slow onset, chronic, progressive, incurable, fatal minimum 18 months to clinical status incubation period up to 10 years Prevalent in 20% of US herds

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Johne s disease paratuberculosis
Johne’s Disease (Paratuberculosis)

  • Causative agent: Mycobacterium paratuberculosis

  • Extremely slow onset, chronic, progressive, incurable, fatal

    • minimum 18 months to clinical status

    • incubation period up to 10 years

  • Prevalent in 20% of US herds

  • 5-20% of ALL dairy cattle infected

    • 25-30% of all herds

    • increasing in both dairy and beef

    • sheep, goats and deer also susceptible


International prevalence
International Prevalence

  • Denmark:

    • almost half of all herds test positive

  • Holland:

    • 50 –80% of herds infected?

  • New Zealand:

    • 16 – 50% of herds infected


History

“Johne’s disease is not at all widespread.

It does occur, however, and as the years go by it will become more and more common and will places a great tax on the cattle industry”

Beach and Hastings 1922


Johne s disease paratuberculosis1
Johne’s Disease (Paratuberculosis)

  • Following calfhood exposure there is no evidence of infection for six months to several years

    • Rate of progression dependent on age, genetic background, nutritional status, management, etc


Johne s symptoms
Johne’s symptoms

  • Clinical status after “high stress” period

    • Progressive and fatal

    • Non-treatable

  • Primarily affects intestine and associated lymph tissues

  • Causes proliferation of intestinal tissue

    • Malabsorption diarrhea

    • Animal loses condition

    • Displays diarrhea and constipation

    • Decreased milk, same feed intake (until late stages)


Fig 35-1. Cows with Johne's disease typically lose tremendous amounts of body weight, although feed consumption may be normal (Courtesy of Mark Kirkpatrick)


Johne s disease paratuberculosis2
Johne’s Disease (Paratuberculosis) tremendous amounts of body weight, although feed consumption may be normal (Courtesy of Mark Kirkpatrick)

  • Apparently healthy animals can spread the disease

    • Test at regular intervals of 3-6 months

    • Diagnostic testing is often inaccurate

    • Fecal culture is most accurate method in live animals

      • False negatives are still a problem

  • No treatment

    • Prevention through keeping infected animals isolated


Johne s transmission
Johne’s Transmission tremendous amounts of body weight, although feed consumption may be normal (Courtesy of Mark Kirkpatrick)

  • Fecal-oral

    • Organism remains viable in feces for 6-11 months

  • Transplacental transfer

  • Organism present in milk, colostrum

  • Severity of infection depends on level of infective dose

  • Age of exposure is critical

  • <5% of infected animals develop clinical symptoms


Age effects
Age Effects tremendous amounts of body weight, although feed consumption may be normal (Courtesy of Mark Kirkpatrick)

  • Newborn calf most susceptible

    • susceptibility decreases with age

    • not clinical - no shedding until > 9 mos.

  • Cows least susceptible

    • infection unlikely after 1 year of age

    • shedding rate highest in mature, clinically infected cows


Costs
Costs tremendous amounts of body weight, although feed consumption may be normal (Courtesy of Mark Kirkpatrick)

  • Lost milk costs

  • Lost cow value and slaughter value

  • Lost marketing ability of herd

  • Longer calving intervals

  • Increased mastitis

  • Increased vet costs

  • $250/cow (all cows, not just infected)

  • Infected 100 cow herd with average infection rate loses $25,000/year


Antibody tests
Antibody Tests tremendous amounts of body weight, although feed consumption may be normal (Courtesy of Mark Kirkpatrick)


Fig 35-2. Enzyme-linked immunosorbent assays (ELISA's) are a useful diagnostic tool for estimating the prevalence of Johne's disease in infected herds (Courtesy of Mark Kirkpatrick)


Testing
Testing useful diagnostic tool for estimating the prevalence of Johne's disease in infected herds (Courtesy of Mark Kirkpatrick)

  • ELISA’s and other antibody tests have high incidence of “false positives”

    • If ELISA or antibody test is positive, fecal culture should be used to confirm status

  • Fecal cultures take 16 weeks, very expensive

    • Negative result does not necessarily indicate uninfected cow, just non-shedding cow

    • Positive result is fairly accurate


Fig 35-3. To confirm infection with Johne's disease, tissues can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)


Johne s disease paratuberculosis3
Johne’s Disease (Paratuberculosis) can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • Control measures for infected herd

    • Reduce contamination by good sanitation

    • Do not spread manure on pasture land

    • Raise young stock in uncontaminated environment, separate from mature animals


Control program
Control Program can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • Prevent transmission

    • sanitary maternity barn

    • clean perineal area and udder

    • Remove calf from dam prior to nursing, wash udder well prior to milking

    • feed colostrum from test-negative cows

    • raise “shedders” separate from “susceptibles”

    • spread manure on crop ground, not pasture


Control program1
Control Program can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • Reduce incidence in herd

    • test mature animals every 6 months

    • remove test-positive animals immediately

    • cull any apparent clinicals

      • regardless of test results

    • purchase only from tested clean herds

    • vaccinate infected herds

      • not cost-effective in clean herds

      • does not prevent disease, only reduces severity

      • interferes with antibody tests


Is johnes a food safety issue
Is Johnes a Food Safety Issue? can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

Crohn’s disease is a bowel disease in humans

Overall incidence 5.6 cases per 100,000

Severe and very unpleasant condition

Cause unknown, maybe infectious agent like Mycoplasma

Johnes organism found in Crohn’s patients

No firm link established, the evidence is still inconclusive - but the issue is a source of concern to the dairy industry


Bovine virus diarrhea bvd
Bovine Virus Diarrhea (BVD) can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • Incubation period of 7-9 days

  • Characterized by

    • High temperature (105-107 F)

    • Nasal discharge

    • Rapid breathing

    • Loss of appetite

    • Diarrhea

  • Causes abortions in pregnant cows (3-6 weeks after infection)

  • Decrease in milk production in lactating cows


Bovine virus diarrhea bvd1
Bovine Virus Diarrhea (BVD) can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • Prevention

    • Avoid contact with infected animals

    • Keep away from contaminated feed and water

    • Isolate all incoming animals for 30 days

  • Treatment

    • Electrolytes

    • Antibiotics combat the secondary bacterial invaders


Bovine virus diarrhea bvd2
Bovine Virus Diarrhea (BVD) can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • If BVD is a constant problem, vaccinate animals

    • Intramuscular administration of modified live or inactivated vaccines

      • One vaccination should last a lifetime

      • DO NOT vaccinate pregnant cows

        • Causes abortions

      • DO NOT vaccinate calves under 6 months of age

        • Ineffective due to interference from maternal antibodies from colostrum

      • Replacement heifers should be vaccinated at 9-12 months of age


Bvd control
BVD control can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • Multiple strains exist (identify!)

  • Fecal-oral

    • Sanitation crucial

  • Vaccines highly effective

    • not 100%

  • BVD-PI (persistently infected) are exceptional situation


Bvd pi animals
BVD-PI animals can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • 1 in every 200 calves is PI

  • Infected in utero between 80 and 120 days

  • Infection from 120-150 days

    • congenital defects

    • weak calf syndrome

  • Infection after 150 days

    • immune response

    • abortion, mummification


Bvd pi calves
BVD-PI calves can be stained for the immunohistological detection of M. paratuberculosis (Courtesy of Mark Kirkpatrick)

  • No immune response

    • recognizes virus as “self” permanently

  • Virus replication unchecked

    • incredibly high shedding rates

    • potential threat to entire operation

  • Difficult to identify

    • Ab titers ineffective method

    • must directly test for presence of virus


Fig 35-4. Obtaining an ear notch tissue sample for immunohistochemical diagnosis of BVD infection (Courtesy of Mark Kirkpatrick)


Fig 35-5. Immunohistochemical techniques help veterinarians visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)


Salmonella
Salmonella visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Invasive coliform

    • fecal-oral transmission

    • penetrates gut lining

    • systemic infection common

  • Present on up to 75% of dairies

    • clinical expression after stress (shipping)

  • Highly rate of transmission

    • “herd epidemics” common

    • high shedding rate

    • high mortality rate


Salmonella1
Salmonella visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Pathogen associated with stress and immunocompromised animals

    • Calves and transition cows most susceptible

      • maternity barn sanitation

      • isolation of sick or recently purchased animals

  • Characterized by rapid onset and severe watery diarrhea

    • Weak and rapidly dehydrated

    • Often becomes systemic infection

  • Pathogen transmitted in feces

    • High sanitation standards are critical

  • Infected cattle should be isolated

    • Animals are responsive to antibiotics


Challenges
Challenges visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Some strains infect people

  • Carriers include pets and pests

  • Different strains present in different herds

    • S. typhimirium DT 104 is problem pathogen

      • multiple antibiotic resistance (cassette resistance)

      • resistant to ampicillin, florfenicol, streptomycin, sulphonamides, and tetracyclines

      • use of one antibiotic selects for the rest


Treatment
Treatment visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Identify early

  • Isolate infected animals

  • Extreme sanitary measures

    • cows AND people

  • Use appropriate antibiotic treatment

    • test for susceptibility

  • Supplemental fluids crucial

  • Use herd-specific vaccine if necessary


Drenching fluids
Drenching Fluids visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)


Hbs one syndrome with several names
HBS - One Syndrome with Several Names visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • HBS: Hemorrhagic bowel syndrome

  • JHS: Jejunal hemorrage syndrome

  • BBS: Bloody bowel syndrome


Hemorrhagic bowel syndrome
Hemorrhagic Bowel Syndrome visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Sporadic in morbidity

  • A typical case incidence rate is 2-3%, with some farms experiencing an outbreak form

  • Mortality may approach 85-100% of cases due to peracute nature


Clinical signs of hbs
Clinical Signs of “HBS” visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Short incubation period – hours rather than days

  • Severe sweats

  • Bruxism (teeth grinding)

  • Sternal recumbancy

  • Lethargy (extreme depression)

  • Enopthalmia (sunken eyes)


Clinical signs of hbs1
Clinical Signs of “HBS” visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Slight bloating may be evident

  • Pale mucous membranes

  • Fluid slosh in lower right abdomen

  • Distended gut loops per rectal palpation

  • SUDDEN DEATH


Post mortem findings
Post-Mortem Findings visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Severe segmental small intestinal inflammation

  • Segmental hemorrhaging and clotting forming a functional plug.

    • Necrosis +/-

    • Impaction


Diagnostics
Diagnostics visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Appearance of characteristic lesions and clinical signs

  • Isolation of Clostridium perfringens type A from the lesion site in high numbers. Overgrowth occurs fast.

  • Fecal cultures not diagnostic


Treatment efforts
Treatment Efforts visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Prognosis is extremely poor

  • Surgical intervention

    • Some areas of segmental clots may be massaged out to resolve the case

    • Intestinal resection & anastamosis is usually required to remove affected tissue

    • Success Rate ~ 5-10%


Are clostridial species involved
Are Clostridial species involved? visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • C. perfringens type A has to be present in the diet to cause disease

  • Readily fermentable carbohydrate is needed to support growth & sporulate

  • Partial slowdown or stoppage of ingesta flow allowing proliferation of C. perfringens.

  • Generation time = 8.8 min.


Field observations
Field Observations visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

Food Poisoning:

Is there a source of C. perfringens type A (human model)?

  • Model of Infection

Lamb Enterotoxemia:

Carbohydrate engorgement or presence in small intestine in high amounts.

Gut Physiology?

Rumen emptying rates, local hypomotility?

Serum Ca levels?


Herd breaks
Herd Breaks visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

  • Fermentable Carbohydrate

    • NFC levels in excess of 40%?

    • Which high moisture feeds are being used in the ration and at what levels?

    • How soluble are the starches?

Wet vs. Dry

Fermented

Fineness of Grind


Vaccination
Vaccination? visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

Commercial Vaccines:

Vaccination with a 7-way Clostridial bacterin/toxoid has shown little effect.

C. perfringens C&D toxoid may have some effects if the infection was mixed.


Summary

Carbohydrate availability visualize the BVD virus in ear tissue (Courtesy of Mark Kirkpatrick)

Acidosis?

Rumen Emptying Rate?

Summary

Feed Contamination

Poor fermentation

Contamination

Intestinal Motility

Ca Levels, DMI or Acidosis


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