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Biohazard Containment > Disease Agent Information PATHOGEN SAFETY DATA SHEET
BOVINE TUBERCULOSIS
SECTION I: DISEASE / INFECTIOUS AGENT
SYNONYM / CROSS REFERENCE: TB, tuberculosis, mycobacteriosis
ETIOLOGY / TAXONOMY :
Genus: Mycobacterium
Species: bovis
Other mycobacterial species such as tuberculosis, microti
and africanum may cause mycobacteriosis in animals.
ORGANISM CHARACTERISTICS: (1)
- acid-fast, gram positive, non-motile, obligate aerobes, pleomorphic rods 0.2- 0.6 µm in
diameter and 1.5- 3 µm in length
- slow growing (colonies appear on Lowenstein-Jensen culture medium in 2-8 weeks)
- hydrophobic with high lipid content in cell wall. Cell wall resists decolourization in
staining (acid fast). Ziehl-Neelsen or Kinyoun staining techniques with carbol fuchsin
most widely used.
SURVEILLANCE :
Bovine tuberculosis is a reportable disease in Canada. Animal owners, veterinarians and
laboratories are required to immediately report the presence of an animal that is
contaminated or suspected of being contaminated to a CFIA district veterinarian. Control or
eradication measures will be applied immediately
(http://laws.justice.gc.ca/en/H-3.3/fulltoc.html).
DISTRIBUTION :
Bovine tuberculosis is diagnosed worldwide with great variations in incidence between
regions and countries. (2) It has been eradicated from Canadian livestock
herds, except for a geographically restricted area in Manitoba where infected wild elk and
deer serve as a source of re-infection. Freedom of Canadian livestock from M. bovis is confirmed by slaughter house inspection surveillance.
SECTION II: ANIMAL HEALTH HAZARD AND EPIDEMIOLOGY
CLINICAL DISEASE / PATHOGENESIS :
Many infected animals can appear healthy but lesions may be found post mortem. (3)
Other possible signs are progressive emaciation, poor appetite, fluctuating temperature,
respiratory distress, pharyngeal obstruction, reproductive disorders and mastitis. (4)
- The infectious dose may be as low as a few organisms by inhalation in animals, but
exposure does not always result in disease. The risk of infection is greater in enclosed
areas such as barns or where animals congregate such as feeding areas.
- The incubation period is usually 2-6 months, however dormant infections can last a
lifetime in both humans and animals and may reactivate during periods of stress or in old
age. (1)
SOURCE / MODE OF TRANSMISSION / COMMUNICABILITY : (4)
- inhalation (aerosols or droplet nuclei)
- ingestion (infected milk, drinking water and feed)
- excretion (sputum, mucus, feces, milk, urine, vaginal and uterine discharges)
VECTORS : none
HOST RANGE : (4)
- all warm-blooded vertebrates (cattle, goats and pigs most susceptible; sheep and horses
show high natural resistance)
ZOONOTIC POTENTIAL : (5,6)
- M. bovis can be transmitted to humans.
- immunocompromised individuals are particularly at risk.
RESERVOIR : (4,5)
Maintenance reservoirs include deer, elk and bison (North America), buffalo (South
Africa), water buffalo (Australia), badger (Meles meles)
in the United Kingdom and brush-tail possum (Trichosurus vulpecula)
in New Zealand.
Section III: DIAGNOSIS
NECROPSY / HISTOPATHOLOGY FINDINGS : (4)
- Granulomatous lesions are most frequently found in lymph nodes (especially bronchial,
retropharyngeal and mediastinal), liver, spleen, lungs, pleura, kidney and uterus and
occasionally in myocardium, intestine, omentum, peritoneum, meninges, skin, mammary
glands, genital tract and bone marrow
- Lesions may appear encapsulated, creamy, caseous or calcified.
LABORATORY DIAGNOSIS : (5)
- in live cattle, tuberculin skin test (caudal tail fold) If positive, followed by the
Comparative Cervical Test (CCT)
- post mortem, culture (special growth requirements) of lesion and surrounding tissue
- DNA Probe/PCR
- formalin-fixed tissue samples for histological diagnosis
DRUG SUSCEPTIBILITY : (3,7)
Treatment of animals is rarely practical. Humans can be treated with a combination of
antimicrobials such as Rifampin, Isoniazid, Ethambutol and Pyrazinamide for at least 6-9
months.
DIFFERENTIAL DIAGNOSIS : (5)
The following diseases may show clinical similarity to bovine tuberculosis:
- lung abscess due to aspiration pneumonia
- pleurisy and pericarditis following traumatic reticulitis
- chronic contagious bovine pleuropneumonia
- upper respiratory disease
- actinobacillosis
- bovine leukosis
- lymphadenopathy
- other causes of mastitis
SECTION IV: DECONTAMINATION PROCEDURES
Select a registered disinfectant with a drug identification number (DIN). Use according
to label directions for concentration and contact time. Consider organic load and
temperature. It is recommended that laboratories evaluate the effectiveness of the
disinfectant using a validated method (eg. Quantitative Carrier Test). See table 1 to help
select a registered disinfectant for use against M. bovis.
Table 1: Active ingredients considered to be effective against M. bovis (8)
ACTIVE INGREDIENT |
CONCENTRATION |
CONTACT TIME |
Alcohols:
Ethanol |
70% (vol/vol)
(no organic load) |
10 minutes |
Synthetic Phenols:
Orthophenylphenol |
5, 000 ppm (1:200) |
10 minutes |
Oxidising agents:
Sodium Hypochlorite |
10,000 ppm (1%) |
10 minutes |
PHYSICAL INACTIVATION : (7)
- steam sterilization, incineration, ultraviolet radiation
SURVIVAL OUTSIDE OF HOST : (7)
M. bovis can survive in the environment and diagnostic
specimens for weeks (longer in cold, dark and moist conditions).
SECTION V: LABORATORY HAZARDS FOR HUMANS
LABORATORY-ACQUIRED INFECTIONS: (9)
Most references refer to human tuberculosis (fourth most frequently reported
laboratory-acquired infection) , not bovine tuberculosis. Low infectious dose and long
incubation period are of concern.
BIOSAFETY PRECAUTIONS : (7,9)
- inhalation of aerosols (created by infected animals, their bedding or excretions, from
aerosol generating procedures, handling heat-fixed smears or cultures, or preparation of
frozen sections, especially from undiagnosed cases).
- ingestion
- accidental injection
SECTION VI: PHYSICAL AND OPERATIONAL REQUIREMENTS
CONTAINMENT REQUIREMENTS :
Primary culture and identification of diagnostic specimens is to be performed at Level
2 physical containment provided that Level 3 operational requirements are carried out. All
other manipulations, including further identification and sensitivity testing, must be
carried out using Level 3 physical and operational requirements as per the Containment
Standards for Veterinary Facilities.
The Standards can be accessed at :
http://www.inspection.gc.ca/english/sci/lab/convet/convete.shtml
PERSONAL PROTECTIVE EQUIPMENT :
Laboratory :
- primary layer of dedicated laboratory clothing (e.g. scrubs and head cover) and
dedicated laboratory footwear should be worn.
- secondary layer of protective clothing (e.g. solid-front gowns with tight-fitting
wrists, 2 pairs of gloves) should be worn over laboratory clothing when directly handling
infectious materials.
- adequate respiratory protection should be worn when directly handling infectious
material outside BSC.
- when full body protective clothing is not worn a shower is required on exit; where a
known or suspected aerosol exposure has occurred a shower is required on exit.
Post Mortem :
- primary layer of dedicated laboratory clothing (e.g. scrubs and head cover) and
dedicated laboratory footwear should be worn.
- secondary layer of protective clothing should be worn over laboratory clothing when
directly handling infectious materials.
- cut resistant gloves, adequate respiratory protection, steel toed/steel shanked rubber
boots.
- a shower is required on exit
HANDLING INFORMATION :
Spills in laboratory :
Spill protocol must be in place and include the following scenarios:
- spills inside the Biological Safety Cabinet (BSC)
- spills outside the BSC
- spills while performing aerosol generating procedures
- Consider entry and exit procedure modifications if necessary, appropriate PPE,
disinfection of spill and surroundings including contact time, flow (pattern) of the clean
up and disposal of contaminated materials.
Refer to Table 1 for disinfectant selection.
STORAGE : All cultures and infected material should be stored in
leakproof, sealed containers that are accurately labeled and clearly identified as a
biohazard risk. The access to infectious material should be controlled at all times.
Records must be kept to describe the use, inventory and disposal of infectious material.
DISPOSAL : Decontaminate all infectious material prior to disposal.
Use steam sterilization, incineration or chemical disinfection.
REFERENCES:
- Thoen C, Williams D, Tuberculosis, Tuberculoidoses, and other Mycobacterial Infections
In: Beran GW, ed Handbook of Zoonoses, Second Edition, CRC Press, 1994:41-59
- Zoonoses and Communicable Diseases Common to Man and Animals, Second Edition, PAHO
publication # 503
- Bovine
Tuberculosis Fact Sheet, U.S. Department of Agriculture, updated August 2002,
http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahtb.html
- Radostits OM, Gay CG, Blood DC, Hinchcliff KW, Veterinary Medicine, Ninth Edition,W.B.
Saunders Company Ltd. 2003:909-934
- Bovine
Tuberculosis Fact Sheet, OIE Collaborating Center, Iowa State University College of
Veterinary Medicine, updated 2003-06-03,
http://www.cfsph.iastate.edu/Factsheets/pdfs/bovine_tuberculosis.pdf
- Bovine Tuberculosis Fact
Sheet, Animal Health CFIA, updated 2003-08-12,
http://www.inspection.gc.ca/english/anima/heasan/disemala/tuber/tbfse.shtml
- Mycobacterium
tuberculosis, Mycobacterium bovis, MSDS, Health Canada, updated 2001-05-15,
http://www.phac-aspc.gc.ca/msds-ftss/msds103e.html
- Lauzardo M, Rubin J, Mycobacterial Disinfection In: Block SS, ed. Disinfection,
Sterilization and Preservation, Fifth Edition, Lippincott Williams and Wilkins,
2001:513-528
- Collins CH, Laboratory-Acquired Infections, Third Edition, Butterworth-Heinemann Ltd.
1993
LAST UPDATED (DATE): May 9, 2005
PREPARED BY: The Biohazard Containment and Safety Unit, CFIA
Disclaimer: Although the information and recommendations in this
Pathogen Safety Data Sheet are compiled from reliable sources, there is no guarantee,
warranty or any assurance that the information and recommendations are correct, accurate,
sufficient, reliable or current and the Canadian Food Inspection Agency shall not be
responsible for any loss or damage resulting from or in connection with the use of or
reliance upon the information and recommendations.
The user assumes all risks and responsibility for and shall be liable for the use of
and any reliance on the information and recommendations and the results thereof and any
loss or damage resulting therefrom.
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