Felis ISSN 2398-2950

Tuberculosis

Contributor(s): Danielle Gunn-Moore, Severine Tasker, Ellie Mardell

Introduction

  • CauseTuberculous disease (characterized by tubercle formation and surrounding granulomatous inflammation) is caused by infection with Mycobacterium bovis  Mycobacterium bovis or M. microti(previously known as M. mycroti-like). Infection with other tuberculous Mycobacterial strains, eg M. tuberculosis  Mycobacterium tuberculosis is rare. Nontuberculous disease (granulomatous disease only without tubercles) is caused by members of the Mycobacterium avium complex (MAC), eg M. avium  Mycobacterium avium , M. intracellulare - less common. These organisms are all considered together as generally similar clinical signs can result from infection.
  • Signs: cutaneous lesions, weight loss, lymphadenopathy, respiratory or GI signs. 
  • Diagnosis: detection of acid fast organisms, culture, PCR.
  • Treatment: ethical question over treatment as potential zoonotic risk (especially M.bovisM.tuberculosis).
  • Prognosis: poor if systemic involvement.
    Print off the owner factsheet on Mycobacterial infections in cats  Mycobacterial infections in cats to give to your client.

Pathogenesis

Etiology

  • Infection with M. bovis  Mycobacterium bovis is usually due to contact with contaminated milk or meat products (including M. bovis-infected rodents; badgers may be involved also via infection of local small rodents).
  • True tuberculosis (due to M.tuberculosis) is rare and nearly always results from contact of cat with infected human Mycobacterium tuberculosis.
  • M. microti believed to be acquired from wildlife during hunting and ingestion of rodents.
  • M. avium infection can be acquired from wildlife during hunting or via contact with infected soil contaminated by bird carcasses or feces (NB. M. avium survives for up to 2 years in the environment).

Predisposing factors

General

  • Outdoor access.
  • Hunting.
  • Fighting; infection may gain entry via wound opportunistically, eg cat bite. Cat-to-cat transmission may occasionally occur via fighting.
  • Retrovirus infection is not implicated.

Specific

  • Contact with infected humans or cattle.

Pathophysiology

  • Infection usually occurs from cutaneous penetration, ingestion or inhalation.
  • Lesions develop in walls of GI tract and spreads through hematogenous or lymphatic routes to tonsils and other lymph nodes.
  • Pulmonary consolidation can develop.
  • Incubation very variable from 2 months to 1 year.

Timecourse

  • Months.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • O'Halloran C, Ioannidi O, Reed N et al (2019) Tuberculosis due to Mycobacterium bovis in pet cats associated with feeding a commercial raw food diet. J Fel Med Surg 1098612X19848455 PubMed.
  • Roberts T, O'Connor C, Nuñez-Garcia J et al (2014) Unusual cluster of Mycobacterium bovis infection in cats. Vet Rec 174 (13), 326 PubMed.
  • Lloret A, Hartmann K, Pennisi M G et al (2013) Mycobacterioses in cats: ABCD guidelines on prevention and management. J Feline Med Surg 15 (7), 591-597 PubMed.
  • Lalor S M, Mellanby R J, Friend E J et al (2012) Domesticated cats with active mycobacteria infections have low serum vitamin D (25(OH)D) concentrations. Transbound Emerg Dis 59 (3), 279-281 PubMed.
  • Gunn-Moore D A, Gaunt C & Shaw D J (2012) Incidence of myocbacterial infections in cats in Great Britain: estimate from feline tissue samples submitted to diagnostic laboratories. Transbound Emerg Dis 60 (4), 338-44 PubMed.
  • Gunn-Moore D A, McFarland S E, Brewer J I et al (2011) Mycobacterial disease in cats in Great Britain: I. Culture results, geographical distribution and clinical presentation of 339 cases. J Feline Med Surg 13 (12), 934-944 PubMed.
  • Gunn-Moore D A, McFarland S E, Schock A (2011) Mycobacterial disease in cats in Great Britain: II. Histopathology of 225 cases, and treatment and outcome of 184 cases. J Feline Med Surg 13 (12), 945-952 PubMed.
  • Gunn-Moore D A & Shaw S (1999) Mycobacterial disease in the cat. In Practice 19 (9), 493-501 InPractice.
  • Stevenson K, Howle F E, Low J C et al (1998) Feline skin granuloma associated with Mycobacterium avium. Vet Rec 143 (4), 109-110 PubMed.
  • Gunn-Moore D A, Jenkins P A & Lucke V M (1996) Feline tuberculosis - a literature review and discussion of 19 cases caused by an unusual mycobacterial variant. Vet Rec 138 (3), 53-58 PubMed.

Other sources of information

Organisation(s)

  • Regional Centre for Mycobacteriology (PHLS), Llandough Hospital, Penlan Road, Renarth, Cardiff CF64 2XX, UK.
  • Mycobacteria Unit, City Hospital, Edinburgh EH10 5SB, UK.
  • Mycobacteria Unit, St James Hospital, St James Street, Dublin 8, Ireland.


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