Prevalence and clinical relevance of helminth co-infections among tuberculosis patients in urban Tanzania

Abstract

BackgroundHelminth infections can negatively affect the immunologic host control, which may increase the risk of progression from latent Mycobacterium tuberculosis infection to tuberculosis (TB) disease and alter the clinical presentation of TB. We assessed the prevalence and determined the clinical relevance of helminth co-infection among TB patients and household contact controls in urban Tanzania.MethodologyBetween November 2013 and October 2015, we enrolled adult (≥18 years) sputum smear-positive TB patients and household contact controls without TB during an ongoing TB cohort study in Dar es Salaam, Tanzania. We used Baermann, FLOTAC, Kato-Katz, point-of-care circulating cathodic antigen, and urine filtration to diagnose helminth infections. Multivariable logistic regression models with and without random effects for households were used to assess for associations between helminth infection and TB.Principal findingsA total of 597 TB patients and 375 household contact controls were included. The median age was 33 years and 60.2% (585/972) were men. The prevalence of any helminth infection among TB patients was 31.8% (190/597) and 25.9% (97/375) among controls. Strongyloides stercoralis was the predominant helminth species (16.6%, 161), followed by hookworm (9.0%, 87) and Schistosoma mansoni (5.7%, 55). An infection with any helminth was not associated with TB (adjusted odds ratio (aOR) 1.26, 95% confidence interval (CI): 0.88–1.80, p = 0.22), but S. mansoni infection was (aOR 2.15, 95% CI: 1.03–4.45, p = 0.040). Moreover, S. mansoni infection was associated with lower sputum bacterial load (aOR 2.63, 95% CI: 1.38–5.26, p = 0.004) and tended to have fewer lung cavitations (aOR 0.41, 95% CI: 0.12–1.16, p = 0.088).Conclusions/SignificanceS. mansoni infection was an independent risk factor for active TB and altered the clinical presentation in TB patients. These findings suggest a role for schistosomiasis in modulating the pathogenesis of human TB. Treatment of helminths should be considered in clinical management of TB and TB control programs.

Prevalence and clinical significance of respiratory viruses and bacteria detected in tuberculosis patients compared to household contact controls in Tanzania: a cohort study

“…This is a prospective cohort study conducted in the densely populated Temeke district of Dar es Salaam, Tanzania; it is a study within a previously described ongoing prospective cohort study of TB patients and household contact controls in Dar es Salaam (TB-DAR) [6]. Between November 2013 and October 2015, we recruited smear-positive TB patients diagnosed at Temeke district hospital and household contact controls who lived in the same household as the index TB cases [6].…”

“…HIV testing for TB patients and controls was done as per Tanzania HIV testing algorithms using an Alere Determine HIV (Alere, USA) and a Uni-Gold HIV (Trinity Biotech; Wicklow, Ireland) confirmatory test rapid tests [15]. CD4þ T cells and full blood-cell counts were obtained as previously described [6].…”

“…Clinical severity of TB was graded as per published clinical TB score [16], but modified to a set of 12 TB score parameters instead of 13, since tachycardia was not systematically measured as previously noted [6]. Diagnosis delay was defined as a cough duration of 3 weeks as previously published from the same cohort study [17].…”

“…In sub-Saharan Africa, HIV has been the most important risk factor driving the TB epidemic in recent decades [5]. The efforts towards understanding other risk factors in TBdsuch as respiratory viruses, helminths [6], and bacteria [7]dare becoming increasingly important [8]. Evidence from experimental mouse models suggests that respiratory viruses such as influenza viruses may play a pathogenic role in individuals with tuberculous disease by negatively affecting immunity against M. tuberculosis [9].…”

Incidental Finding of Microfilariae in Bone Marrow Aspirate of a Patient With Tuberculosis: A Case Report.

“…It has been postulated that it may be due to liberation of some toxic material by the growing microfilariae within the marrow. Mhimbira F et al studied prevalence of helminth infections in 597 tuberculosis patients and 375 household controls , this study described finding of Strongyloides Stercoralis as the predominant helminth followed by hook worms and Schistosoma mansoni , W. bancrofti was not described as a finding (15). This case has been reported as an instance of rare presentation of Filariasis.…”