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Differences in primary sites of infection between zoonotic and human tuberculosis: results from a worldwide systematic review.

Dürr S, Müller B, Alonso S, Hattendorf J, Laisse CJ, van Helden PD, Zinsstag J - PLoS Negl Trop Dis (2013)

Bottom Line: 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).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.

View Article: PubMed Central - PubMed

Affiliation: Veterinary Public Health Institute, Vetsuisse Faculty, University of Berne, Berne, Switzerland. salomeduerr@gmx.ch

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.

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Selection procedure with inclusion and exclusion criteria for the 27 reports included in the study and their uses in analysis.
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pntd-0002399-g001: Selection procedure with inclusion and exclusion criteria for the 27 reports included in the study and their uses in analysis.

Mentions: A systematic multi-lingual literature search was performed according to Cochrane guidelines with certain modifications (http://cochrane-handbook.org/). Thirty-two different bibliographic databases were searched for potentially relevant reports on putative zTB cases (M. bovis or M. caprae infections) in humans published until March 2010 using a highly sensitive search syntax (Tables S1 and S2). We included all types of observational and interventional studies on zTB or M. bovis and M. caprae infections in humans, unless the study reported exclusively on cases with evident human-human transmission. Before and after removal of duplicated reports 18'485 and 12'176 records, respectively, were identified (Figure 1). Titles and abstracts were screened to exclude reports which were unlikely to contain information on zTB cases; 1'203 potentially relevant reports remained of which 447 (37%) were available online and assessed for eligibility. We focused on reports available online for convenience while this was an important factor to improve the efficiency of the work. Moreover, it can be assumed that reports available online are of higher quality and that most of the more recent reports were available. Eligible records were written either in English, French, German, Spanish or Portuguese. Additionally, studies had to report on either the occurrence of extrapulmonary TB, primary site or sequelae of the disease. They had to include at least 10 individuals with zTB. No restrictions were made on the year when the study was undertaken. Eligibility of the relevant reports was assessed independently by three operators on 100 randomly selected reports. Ambiguities and diverging judgements were examined in order to harmonize the selection procedure. The remaining records were randomly assigned to one operator only. Thirty-seven reports were considered eligible for data extraction. Data was extracted stratified by WHO region, sex, age group and HIV co-infection of the patients, where possible. Data were sought for 20 variables (Table S3). After harmonizing the procedure of data extraction done by three operators based on 15 reports, the remaining reports were randomly allocated to one operator only. If any of the included reports were referring to relevant accessible external data which were not included in the database during earlier steps, these data were included as well in the analysis. Data on more than one study setting (different geographical regions and study periods) were available from two reports which enlarged the database by five records. A total of 15 reports had to be excluded for different reasons (Figure 1). The final database included 27 records from 26 different reports. Within these reports, differentiation of M. bovis, M.caprae and M. tuberculosis was done by molecular (e.g. PCR, spoligotyping), biochemical or both methods, or was not further specified for six reports. Anonymized human medical data was used.


Differences in primary sites of infection between zoonotic and human tuberculosis: results from a worldwide systematic review.

Dürr S, Müller B, Alonso S, Hattendorf J, Laisse CJ, van Helden PD, Zinsstag J - PLoS Negl Trop Dis (2013)

Selection procedure with inclusion and exclusion criteria for the 27 reports included in the study and their uses in analysis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3757065&req=5

pntd-0002399-g001: Selection procedure with inclusion and exclusion criteria for the 27 reports included in the study and their uses in analysis.
Mentions: A systematic multi-lingual literature search was performed according to Cochrane guidelines with certain modifications (http://cochrane-handbook.org/). Thirty-two different bibliographic databases were searched for potentially relevant reports on putative zTB cases (M. bovis or M. caprae infections) in humans published until March 2010 using a highly sensitive search syntax (Tables S1 and S2). We included all types of observational and interventional studies on zTB or M. bovis and M. caprae infections in humans, unless the study reported exclusively on cases with evident human-human transmission. Before and after removal of duplicated reports 18'485 and 12'176 records, respectively, were identified (Figure 1). Titles and abstracts were screened to exclude reports which were unlikely to contain information on zTB cases; 1'203 potentially relevant reports remained of which 447 (37%) were available online and assessed for eligibility. We focused on reports available online for convenience while this was an important factor to improve the efficiency of the work. Moreover, it can be assumed that reports available online are of higher quality and that most of the more recent reports were available. Eligible records were written either in English, French, German, Spanish or Portuguese. Additionally, studies had to report on either the occurrence of extrapulmonary TB, primary site or sequelae of the disease. They had to include at least 10 individuals with zTB. No restrictions were made on the year when the study was undertaken. Eligibility of the relevant reports was assessed independently by three operators on 100 randomly selected reports. Ambiguities and diverging judgements were examined in order to harmonize the selection procedure. The remaining records were randomly assigned to one operator only. Thirty-seven reports were considered eligible for data extraction. Data was extracted stratified by WHO region, sex, age group and HIV co-infection of the patients, where possible. Data were sought for 20 variables (Table S3). After harmonizing the procedure of data extraction done by three operators based on 15 reports, the remaining reports were randomly allocated to one operator only. If any of the included reports were referring to relevant accessible external data which were not included in the database during earlier steps, these data were included as well in the analysis. Data on more than one study setting (different geographical regions and study periods) were available from two reports which enlarged the database by five records. A total of 15 reports had to be excluded for different reasons (Figure 1). The final database included 27 records from 26 different reports. Within these reports, differentiation of M. bovis, M.caprae and M. tuberculosis was done by molecular (e.g. PCR, spoligotyping), biochemical or both methods, or was not further specified for six reports. Anonymized human medical data was used.

Bottom Line: 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).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.

View Article: PubMed Central - PubMed

Affiliation: Veterinary Public Health Institute, Vetsuisse Faculty, University of Berne, Berne, Switzerland. salomeduerr@gmx.ch

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.

Show MeSH
Related in: MedlinePlus