Population-Based Geospatial and Molecular Epidemiologic Study of Tuberculosis Transmission Dynamics, Botswana, 2012–2016

Abstract

Tuberculosis (TB) elimination requires interrupting transmission of Mycobacterium tuberculosis . We used a multidisciplinary approach to describe TB transmission in 2 sociodemographically distinct districts in Botswana (Kopanyo Study). During August 2012–March 2016, all patients who had TB were enrolled, their sputum samples were cultured, and M. tuberculosis isolates were genotyped by using 24-locus mycobacterial interspersed repetitive units–variable number of tandem repeats. Of 5,515 TB patients, 4,331 (79%) were enrolled. Annualized TB incidence varied by geography (range 66–1,140 TB patients/100,000 persons). A total of 1,796 patient isolates had valid genotyping results and residential geocoordinates; 780 (41%) patients were involved in a localized TB transmission event. Residence in areas with a high burden of TB, age <24 years, being a current smoker, and unemployment were factors associated with localized transmission events. Patients with known HIV-positive status had lower odds of being involved in localized transmission.

Characterizing tuberculosis transmission dynamics in high-burden urban and rural settings

“…Fewer venues might concentrate a larger proportion of the population in these venues and result in a higher proportion of transmission relative to urban venues. Differences in social practices between populations may also provide insight; inhabitants of Ghanzi, like many populations in rural southern Africa, experience seasonal oscillating migration between their residence and towns and villages for employment and other economic and cultural reasons, often residing in temporary congregate lodging 29 . Such migration has been shown to increase the risk of both acquiring and transmitting TB in similar populations 43 – 45 .…”

“…We conducted a prospective, population-based molecular epidemiologic study aimed at identifying TB transmission networks within Botswana (the Kopanyo study, “people gathering together” in local Setswana language) 28 , 29 . Study participants were recruited from two geographically distinct districts of Botswana: the greater Gaborone district, which contains the City of Gaborone and its surrounding suburbs, and the rural Ghanzi district.…”

“…Study participants were recruited from two geographically distinct districts of Botswana: the greater Gaborone district, which contains the City of Gaborone and its surrounding suburbs, and the rural Ghanzi district. Gaborone is the political and economic capital and the most populated urban center of Botswana, with a population density of approximately 1400 people per square kilometer and a TB notification rate of approximately 440–470 cases per 100,000 population 29 . Ghanzi is a large, rural agricultural district in northwest Botswana with an estimated population density of 0.4 people per square kilometer and an estimated TB notification rate of 722 per 100,000 population 29 .…”

“…Gaborone is the political and economic capital and the most populated urban center of Botswana, with a population density of approximately 1400 people per square kilometer and a TB notification rate of approximately 440–470 cases per 100,000 population 29 . Ghanzi is a large, rural agricultural district in northwest Botswana with an estimated population density of 0.4 people per square kilometer and an estimated TB notification rate of 722 per 100,000 population 29 . The HIV prevalence in the general population in both regions at the start of the study timeframe was an estimated 17 percent 30 .…”

High-resolution characterization of recent tuberculosis transmission in Botswana using geospatial and genomic data – the Kopanyo Study

“…Botswana is a country in southern Africa with a high burden of TB and TB-HIV coinfection (1,5,14). Participants included men and women of all ages who were diagnosed with TB disease and sequentially enrolled in the study (5,14). Those who had already received TB treatment for 14 days or more, prisoners, and patients who declined to participate were excluded (5,14).…”