Differences in Primary Sites of Infection between Zoonotic and Human Tuberculosis: Results from a Worldwide Systematic Review

Abstract

Tuberculosis (TB) is one of the most devastating infectious diseases worldwide. Whilst global burden estimates for M. tuberculosis infection (MtTB) are well established, accurate data on the contribution of zoonotic TB (zTB) caused by M. bovis or M. caprae to human TB are scarce. The association of M. bovis infection with extrapulmonary tuberculosis has been suggested repeatedly, though there is little scientific evidence available to support this relationship. The present study aimed to determine globally the occurrence of extrapulmonary TB and the primary site (i.e. primary body location affected) of zTB in comparison with MtTB, based on previously published reports. A systematic literature review was conducted in 32 different bibliographic databases, selecting reports on zTB written in English, French, German, Spanish or Portuguese. Data from 27 reports from Africa, America, Europe and the Western Pacific Region were extracted for analyses. Low income countries, in Africa and South-East Asia, were highly underrepresented in the dataset. The median proportion of extrapulmonary TB cases was significantly increased among zTB in comparison with data from registries of Europe and USA, reporting mainly MtTB cases (47% versus 22% in Europe, 73% versus 30% in the USA). These findings were confirmed by analyses of eight studies reporting on the proportions of extrapulmonary TB in comparable populations of zTB and MtTB cases (median 63% versus 22%). Also, disparities of primary sites of extrapulmonary TB between zTB and MtTB were detected. Our findings, based on global data, confirm the widely suggested association between zTB and extrapulmonary disease. Different disability weights for zTB and MtTB should be considered and we recommend separate burden estimates for the two diseases.

Open questions and recent advances in the control of a multi‐host infectious disease: animal tuberculosis

“…Zoonotic TB is the disease caused by non-Mycobacterium tuberculosis members of the MTC transmitted from animals to humans. It often causes extra-pulmonary disease in humans and is still a major public health concern in developing countries, often linked with the consumption of raw dairy products or close contact with infected livestock (Dürr et al 2013). In industrialized countries, the main reason for TB control is economic: cattle TB results in severe losses due to trade restrictions and slaughter compensations for test-positive animals (Amanfu 2006).…”

Mycobacterium bovis hip bursitis in a lung transplant recipient

“…The 2 published cases of M. bovis infection in solid organ transplant recipients are summarized in Table 1, along with the present case; both of these were in renal transplant recipients who acquired the infection via consumption of unpasteurized dairy products (10,11). (4,12,13). Our patient had an unusual presentation of extrapulmonary TB, localized to the hip bursa.…”

“…Likewise, M. bovis cases have a higher likelihood of human immunodeficiency virus infection (OR 2.63, 95% CI 1.23–5.63) . Most cases of extrapulmonary M. bovis present in the lymphatics, peritoneum, and genitourinary tract (owing to use of Bacille Calmette‐Guerin [BCG] for bladder cancer) . Our patient had an unusual presentation of extrapulmonary TB, localized to the hip bursa.…”

Zoonotic Tuberculosis: A Concern and Strategies to Combat

“…Current diagnostics for human TB are focused on pulmonary diseases associated with M. tuberculosis (sputum smears examination) but zoonotic tuberculosis in human beings is frequently associated with extra-pulmonary tuberculosis and therefore initiation of treatment can be delayed [53,54]. There is lack of testing to identify the Mycobacterium spp.…”