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Zoonotic Mycobacterium bovis-induced tuberculosis in humans.

Müller B, Dürr S, Alonso S, Hattendorf J, Laisse CJ, Parsons SD, van Helden PD, Zinsstag J - Emerging Infect. Dis. (2013)

Bottom Line: In regions outside Africa included in this study, overall median proportions of zoonotic TB of ≤1.4% in connection with overall TB incidence rates ≤71/100,000 population/year suggested low incidence rates.For countries of Africa included in the study, we multiplied the observed median proportion of zoonotic TB cases of 2.8% with the continental average overall TB incidence rate of 264/100,000 population/year, which resulted in a crude estimate of 7 zoonotic TB cases/100,000 population/year.These generally low incidence rates notwithstanding, available data indicated substantial consequences of this disease for some population groups and settings.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa. borna.mueller@gmail.com

ABSTRACT
We aimed to estimate the global occurrence of zoonotic tuberculosis (TB) caused by Mycobacterium bovis or M. caprae infections in humans by performing a multilingual, systematic review and analysis of relevant scientific literature of the last 2 decades. Although information from many parts of the world was not available, data from 61 countries suggested a low global disease incidence. In regions outside Africa included in this study, overall median proportions of zoonotic TB of ≤1.4% in connection with overall TB incidence rates ≤71/100,000 population/year suggested low incidence rates. For countries of Africa included in the study, we multiplied the observed median proportion of zoonotic TB cases of 2.8% with the continental average overall TB incidence rate of 264/100,000 population/year, which resulted in a crude estimate of 7 zoonotic TB cases/100,000 population/year. These generally low incidence rates notwithstanding, available data indicated substantial consequences of this disease for some population groups and settings.

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Proportion of zoonotic tuberculosis (TB) among all TB cases stratified by country: Americas. x-axis values are median proportions. Each circle represents a study with the circle diameter being proportional to the log10 of the number of isolates tested. A gray rhombus indicates that the number of samples tested was not reported or could not be inferred from the data available. The median proportion of all studies for a given country is indicated by X. Numbers on the right side of the figures indicate the number of studies included for any given country.
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Figure 4: Proportion of zoonotic tuberculosis (TB) among all TB cases stratified by country: Americas. x-axis values are median proportions. Each circle represents a study with the circle diameter being proportional to the log10 of the number of isolates tested. A gray rhombus indicates that the number of samples tested was not reported or could not be inferred from the data available. The median proportion of all studies for a given country is indicated by X. Numbers on the right side of the figures indicate the number of studies included for any given country.

Mentions: A median of 0.3% (range 0%–33.9%) of M. bovis infections among human TB cases was found for all reports included. For most countries, M. bovis accounted for a negligible percentage of the TB cases (Figure 2). Conversely, high proportions were reported for specific areas of Mexico and the United States (Figure 4). For Mexico, the median percentage of M. bovis cases was 7.6% (range 0%–31.6%); proportions >10% were detected in 3 independent studies (20–22). However, overall TB incidence in Mexico is relatively low, with a rate of 16/100,000 population/year (1). In the United States, TB caused by M. bovis is strongly linked to persons in Hispanic communities, mostly with origins in Mexico (Table 3). A study including data from 41 states of the United States suggested that ≈90% of all TB cases caused by M. bovis affect persons of Hispanic ethnicity (8). This association is attributed to the consumption of unpasteurized, contaminated cheese produced in Mexico. Moreover, when multivariate logistic regression analyses was used, several studies in the United States showed an independent association of TB caused by M. bovis with TB cases in children, HIV coinfection and extrapulmonary disease (8–12). Surveys in San Diego County, California indicated a steady increase in the incidence of TB caused by M. bovis and a decrease in TB incidence caused by M. tuberculosis infection (9,12). In this setting, the odds for TB patients infected with M. bovis to die during treatment was >2 times as high as for patients infected with M. tuberculosis (9,10,12). In San Diego County, during 1994–2003 and 2001–2005, respectively, M. bovis accounted for 25 and 19 deaths, corresponding to 27% and 17% of all TB deaths and a mortality rate of ≈0.1/100,000 population/year (9,10). The reasons for increased deaths among patients infected with zoonotic TB compared with those infected with M. tuberculosis remained unidentified, although health care inequality or treatment differences were stated as possible explanations (9). However, overall incidence rates of zoonotic TB in the United States are low, at a median of 0.7/100,000 population/year. Although zoonotic TB causes minor consequences of disease in the Americas, available data corroborate the finding that M. bovis infections can be a substantial cause of deaths from TB among humans in certain population groups and settings.


Zoonotic Mycobacterium bovis-induced tuberculosis in humans.

Müller B, Dürr S, Alonso S, Hattendorf J, Laisse CJ, Parsons SD, van Helden PD, Zinsstag J - Emerging Infect. Dis. (2013)

Proportion of zoonotic tuberculosis (TB) among all TB cases stratified by country: Americas. x-axis values are median proportions. Each circle represents a study with the circle diameter being proportional to the log10 of the number of isolates tested. A gray rhombus indicates that the number of samples tested was not reported or could not be inferred from the data available. The median proportion of all studies for a given country is indicated by X. Numbers on the right side of the figures indicate the number of studies included for any given country.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4816377&req=5

Figure 4: Proportion of zoonotic tuberculosis (TB) among all TB cases stratified by country: Americas. x-axis values are median proportions. Each circle represents a study with the circle diameter being proportional to the log10 of the number of isolates tested. A gray rhombus indicates that the number of samples tested was not reported or could not be inferred from the data available. The median proportion of all studies for a given country is indicated by X. Numbers on the right side of the figures indicate the number of studies included for any given country.
Mentions: A median of 0.3% (range 0%–33.9%) of M. bovis infections among human TB cases was found for all reports included. For most countries, M. bovis accounted for a negligible percentage of the TB cases (Figure 2). Conversely, high proportions were reported for specific areas of Mexico and the United States (Figure 4). For Mexico, the median percentage of M. bovis cases was 7.6% (range 0%–31.6%); proportions >10% were detected in 3 independent studies (20–22). However, overall TB incidence in Mexico is relatively low, with a rate of 16/100,000 population/year (1). In the United States, TB caused by M. bovis is strongly linked to persons in Hispanic communities, mostly with origins in Mexico (Table 3). A study including data from 41 states of the United States suggested that ≈90% of all TB cases caused by M. bovis affect persons of Hispanic ethnicity (8). This association is attributed to the consumption of unpasteurized, contaminated cheese produced in Mexico. Moreover, when multivariate logistic regression analyses was used, several studies in the United States showed an independent association of TB caused by M. bovis with TB cases in children, HIV coinfection and extrapulmonary disease (8–12). Surveys in San Diego County, California indicated a steady increase in the incidence of TB caused by M. bovis and a decrease in TB incidence caused by M. tuberculosis infection (9,12). In this setting, the odds for TB patients infected with M. bovis to die during treatment was >2 times as high as for patients infected with M. tuberculosis (9,10,12). In San Diego County, during 1994–2003 and 2001–2005, respectively, M. bovis accounted for 25 and 19 deaths, corresponding to 27% and 17% of all TB deaths and a mortality rate of ≈0.1/100,000 population/year (9,10). The reasons for increased deaths among patients infected with zoonotic TB compared with those infected with M. tuberculosis remained unidentified, although health care inequality or treatment differences were stated as possible explanations (9). However, overall incidence rates of zoonotic TB in the United States are low, at a median of 0.7/100,000 population/year. Although zoonotic TB causes minor consequences of disease in the Americas, available data corroborate the finding that M. bovis infections can be a substantial cause of deaths from TB among humans in certain population groups and settings.

Bottom Line: In regions outside Africa included in this study, overall median proportions of zoonotic TB of ≤1.4% in connection with overall TB incidence rates ≤71/100,000 population/year suggested low incidence rates.For countries of Africa included in the study, we multiplied the observed median proportion of zoonotic TB cases of 2.8% with the continental average overall TB incidence rate of 264/100,000 population/year, which resulted in a crude estimate of 7 zoonotic TB cases/100,000 population/year.These generally low incidence rates notwithstanding, available data indicated substantial consequences of this disease for some population groups and settings.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa. borna.mueller@gmail.com

ABSTRACT
We aimed to estimate the global occurrence of zoonotic tuberculosis (TB) caused by Mycobacterium bovis or M. caprae infections in humans by performing a multilingual, systematic review and analysis of relevant scientific literature of the last 2 decades. Although information from many parts of the world was not available, data from 61 countries suggested a low global disease incidence. In regions outside Africa included in this study, overall median proportions of zoonotic TB of ≤1.4% in connection with overall TB incidence rates ≤71/100,000 population/year suggested low incidence rates. For countries of Africa included in the study, we multiplied the observed median proportion of zoonotic TB cases of 2.8% with the continental average overall TB incidence rate of 264/100,000 population/year, which resulted in a crude estimate of 7 zoonotic TB cases/100,000 population/year. These generally low incidence rates notwithstanding, available data indicated substantial consequences of this disease for some population groups and settings.

Show MeSH
Related in: MedlinePlus