Prevalence ofMycobacterium tuberculosisin Sputum and Reported Symptoms Among Clinic Attendees Compared With a Community Survey in Rural South Africa

Abstract

Background Tuberculosis (TB) case finding efforts typically target symptomatic people attending health facilities. We compared the prevalence of Mycobacterium tuberculosis (Mtb) sputum culture-positivity among adult clinic attendees in rural South Africa with a concurrent, community-based estimate from the surrounding demographic surveillance area (DSA). Methods Clinic: Randomly-selected adults (≥18 years) attending two primary healthcare clinics were interviewed and requested to give sputum for mycobacterial culture. HIV and antiretroviral therapy (ART) status were based on self-report and record review. Community: All adult (≥15 years) DSA residents were invited to a mobile clinic for health screening, including serological HIV testing; those with ≥1 TB symptom (cough, weight loss, night sweats, fever) or abnormal chest radiograph were asked for sputum. Results Clinic: 2,055 patients were enrolled (76.9% female, median age 36 years); 1,479 (72.0%) were classified HIV-positive (98.9% on ART) and 131 (6.4%) reported ≥1 TB symptom. Of 20/2,055 (1.0% [95% CI 0.6–1.5]) with Mtb culture-positive sputum, 14 (70%) reported no symptoms. Community: 10,320 residents were enrolled (68.3% female, median age 38 years); 3,105 (30.3%) tested HIV-positive (87.4% on ART) and 1,091 (10.6%) reported ≥1 TB symptom. Of 58/10,320 (0.6% [95% CI 0.4–0.7]) with Mtb culture-positive sputum, 45 (77.6%) reported no symptoms. In both surveys, sputum culture positivity was associated with male sex and reporting >1 TB symptom. Conclusions In both clinic and community settings, most participants with Mtb culture-positive sputum were asymptomatic. TB screening based only on symptoms will miss many people with active disease in both settings.

Acute Intrathoracic Tuberculosis in Children and Adolescents with Community-Acquired Pneumonia in an Area with an Intermediate Disease Burden

“…Our study did not find any symptoms/signs suggestive of TB [ 1 ] in patients with CAP and TB. With our findings, we also want to open a debate into whether it is time to change the clinical definitions of tuberculosis in children and adolescents, as it has been reported in adults that up to 77.6% of people with TB are asymptomatic [ 17 ]. Cavallazzi et al [ 18 ] reported 60 (0.86%) patients with TB in a study of 6976 adults with CAP.…”

“…In countries with an intermediate TB burden, M.tb should be included in the etiological differential diagnosis (as a cause or coinfection) of both severe and non-severe CAP in children and adolescents. We invite researchers and clinicians around the world to debate whether the current clinical definitions of TB in children may be a late approach to diagnosing TB as it has been documented in adults that up to 77.6% of people with TB are asymptomatic [ 17 ]. It is important to conduct more research in children with CAP that includes a systematic search for M.tb, including molecular testing, in countries with an intermediate TB burden as well as develop screening tools that allow identifying incipient and sub-clinical TB [ 22 ] in children.…”

Direct estimates of absolute ventilation in primary health care clinics in South Africa

“…For 'airborne precaution rooms' (small rooms for accommodating people who may be infectious) the recommended ventilation rate was 160 litres/second/person on average (576 m 3 /hr/person), with a minimum rate of 80 litres/second/person (288 m 3 /hr/person) when wind speed and direction are not favourable. In high burden settings, the transmission risk in general clinic spaces may be equivalent to that in 'airborne precaution rooms', given the high prevalence of undiagnosed TB [31].…”

Estimating the contribution of transmission in primary healthcare clinics to community-wide TB disease incidence, and the impact of infection prevention and control interventions, in KwaZulu-Natal, South Africa

“…Mean clinic contact time per month in the model varied by sex and HIV/ART status strata, and within those strata, by whether someone was assigned to a high or low clinic visiting group. Empirical data from TB prevalence surveys conducted among attendees at the two clinics and in the general population in the DSA found a 86% (95% CI 10% to 310%) higher prevalence of TB among the clinic attendees 10. Mean clinic contact time in the model could therefore also be higher in people with untreated TB disease, to allow the model to be fitted to the prevalence of TB in clinic attendees relative to the general population.…”

“…Empirical data from TB prevalence surveys conducted among attendees at the two clinics and in the general population in the DSA found a 86% (95% CI 10% to 310%) higher prevalence of TB among the clinic attendees. 10 Mean clinic contact time in the model could therefore also be higher in people with untreated TB disease, to allow the model to be fitted to the prevalence of TB in clinic attendees relative to the general population. Finally, contact time occurring in all other indoor locations (including transport) was simulated, varying by sex, age group and HIV/ART status.…”