A tuberculosis nationwide prevalence survey in Gambia, 2012

Abstract

ObjectiveTo estimate the population prevalence of active pulmonary tuberculosis in Gambia.MethodsBetween December 2011 and January 2013, people aged ≥ 15 years participating in a nationwide, multistage cluster survey were screened for active pulmonary tuberculosis with chest radiography and for tuberculosis symptoms. For diagnostic confirmation, sputum samples were collected from those whose screening were positive and subjected to fluorescence microscopy and liquid tuberculosis cultures. Multiple imputation and inverse probability weighting were used to estimate tuberculosis prevalence.FindingsOf 100 678 people enumerated, 55 832 were eligible to participate and 43 100 (77.2%) of those participated. A majority of participants (42 942; 99.6%) were successfully screened for symptoms and by chest X-ray. Only 5948 (13.8%) were eligible for sputum examination, yielding 43 bacteriologically confirmed, 28 definite smear-positive and six probable smear-positive tuberculosis cases. Chest X-ray identified more tuberculosis cases (58/69) than did symptoms alone (43/71). The estimated prevalence of smear-positive and bacteriologically confirmed pulmonary tuberculosis were 90 (95% confidence interval, CI: 53–127) and 212 (95% CI: 152–272) per 100 000 population, respectively. Tuberculosis prevalence was higher in males (333; 95% CI: 233–433) and in the 35–54 year age group (355; 95% CI: 219–490).ConclusionThe burden of tuberculosis remains high in Gambia but lower than earlier estimates of 490 per 100 000 population in 2010. Less than half of all cases would have been identified based on smear microscopy results alone. Successful control efforts will require interventions targeting men, increased access to radiography and more accurate, rapid diagnostic tests.

Mycobacterium tuberculosis Infection in Close Childhood Contacts of Adults with Pulmonary Tuberculosis is Increased by Secondhand Exposure to Tobacco

“…The limitation may be mitigated by the fact that our study area is known to have the highest burden of active TB and M. tuberculosis infection in the whole country. 15,23 Our findings from this study are of public health importance because approximately 50% of the world's children experience secondhand tobacco exposure in their homes and many of them in settings like ours with poor tobacco regulation and high TB burden. [23][24][25] This does not include the additional risk of third-hand smoke contamination caused by secondhand tobacco exposure in homes and other locations.…”

“…15,23 Our findings from this study are of public health importance because approximately 50% of the world's children experience secondhand tobacco exposure in their homes and many of them in settings like ours with poor tobacco regulation and high TB burden. [23][24][25] This does not include the additional risk of third-hand smoke contamination caused by secondhand tobacco exposure in homes and other locations. 26,27 Our study contributes to the body of evidence on the association between secondhand tobacco exposure and M. tuberculosis infection in children exposed to TB cases.…”

Bringing state-of-the-art diagnostics to vulnerable populations: The use of a mobile screening unit in active case finding for tuberculosis in Palawan, the Philippines

“…School-based mass screening usually involves subjects from a specific age group, therefore an age-group specific prevalence rate from the national survey could represent expected yield in such screening activities. Although the prevalence in those with younger age varies depending on epidemiological profiles of countries, it is generally lower than that of general population in many countries [ 4 , 24 – 26 ] including the Philippines [ 23 ]. They are often categorized as a low risk group in which systematic screening for active TB is not recommended [ 9 ].…”

Population-Based Tuberculosis Disease Prevalence Survey in Ghana: The Role and Lessons Learnt from the Laboratory

“…The proportion of survey participants eligible for sputum collection was higher (13.4%) than what was reported in other African countries such as Ethiopia (13%) [5] and Nigeria (10.6%) [6], but lower than in Zambia (14.6%) [7] and Gambia (13.8%) [8]. The high sputum collection rate (98% for at least one specimen and 93% for both spot and morning specimen) was comparable to results from surveys in other countries [5] [7] [8].…”

“…The proportion of survey participants eligible for sputum collection was higher (13.4%) than what was reported in other African countries such as Ethiopia (13%) [5] and Nigeria (10.6%) [6], but lower than in Zambia (14.6%) [7] and Gambia (13.8%) [8]. The high sputum collection rate (98% for at least one specimen and 93% for both spot and morning specimen) was comparable to results from surveys in other countries [5] [7] [8]. In the case of Ghana, we can attribute this finding to factors such as effective community sensitization prior to commencement of the survey, professional skill of the survey team, supervision by field laboratory staff whereby in some instances, follow-up to residences of participants for specimen collection and the provision of digital chest X-ray examination.…”