Kolkata, Mar 26: Zoonotic tuberculosis (TB) is a form of tuberculosis in people caused by Mycobacterium bovis, which belongs to the M. tuberculosis complex.
It often affects sites other than the lungs (extrapulmonary), but in many cases is clinically indistinguishable from TB caused by M. tuberculosis.
Within animal populations, M. bovis is the causative agent of bovine TB. It mainly affects cattle, which are the most important animal reservoir, and can become established in wildlife. The disease results in important economic losses and trade barriers with a major impact on the livelihoods of poor and marginalized communities.
While the most common route of transmission of M. bovis to humans is through contaminated food (mainly untreated dairy products or, less commonly, untreated meat products), airborne transmission also poses an occupational risk to people in contact with infected animals or animal products, including farmers, veterinarians, slaughterhouse workers and butchers.
The laboratory procedures most commonly used to diagnose TB do not differentiate M. tuberculosis from M. bovis. This leads to underdiagnosis of zoonotic TB.
Zoonotic TB poses challenges for patient treatment and recovery. M. bovis is naturally resistant to pyrazinamide, one of the four medications used in the standard first-line anti- TB treatment regimen. As most healthcare providers initiate treatment without drug susceptibility testing, patients with zoonotic TB may receive inadequate treatment.
Zoonotic TB in humans is often initially extrapulmonary and may be misdiagnosed, and therefore initiation of treatment can be delayed.UNI