Sociocultural factors that influence the prevention of malaria in Ohangwena region, Namibia.

BACKGROUND: Namibia is undergoing an epidemiological transition after decline in local transmission of malaria, and the country is now in a position to move towards eliminating local transmission by 2030. However, malaria prevalence cannot be adequately explained from medical and modern prevention points of view alone. The persistence of malaria might appear as a result of not recognising sociocultural factors that seem useful in the prevention of malaria, Hence, studies on sociocultural factors are limited. AIM: The aim of this study was to describe the sociocultural factors that influence the prevention of malaria in Ohangwena region. SETTING: The study was conducted in Ohangwena region of northern Namibia. METHODS: This study was a cross-sectional study and a mixed methods, convergent parallel design was employed. RESULTS: The major theme revealed that traditional prevention methods of malaria are widely available in rural communities. The best accepted traditional prevention methods include tumbleweed, bitter bush and animal dung. Quantitative findings indicated that 67.0% of participants felt that nets are expensive. Key barriers included the long distance to access health facilities (29.1%), long waiting times (25.8%) and the lack of money to pay for services and transport (22.5%). CONCLUSION: The limited access to and cost of Western prevention methods minimise protection because of priority and resource allocations, but it could be mitigated with the use of locally available traditional prevention practices used for many years in curbing malaria. There is a need to create awareness about socioculturally congruent malaria care.Contribution: This study has revealed the need to combine standard prevention with traditional prevention practices in the fight against malaria, and it intensified research focusing on interventions that address sociocultural factors for the prevention of malaria in endemic regions. In addition, part of the novelty of the study is establishing the need to test the efficacy of traditional practices used.

Validation and Optimization of Host Immunological Bio-Signatures for a Point-of-Care Test for TB Disease.

The development of a non-sputum-based, point-of-care diagnostic test for tuberculosis (TB) is a priority in the global effort to combat this disease, particularly in resource-constrained settings. Previous studies have identified host biomarker signatures which showed potential, but there is a need to validate and refine these for development as a test. We recruited 1,403 adults presenting with symptoms suggestive of pulmonary TB at primary healthcare clinics in six countries from West, East and Southern Africa. Of the study cohort, 326 were diagnosed with TB and 787 with other respiratory diseases, from whom we randomly selected 1005 participants. Using Luminex® technology, we measured the levels of 20 host biomarkers in serum samples which we used to evaluate the diagnostic accuracy of previously identified and novel bio-signatures. Our previously identified seven-marker bio-signature did not perform well (sensitivity: 89%, specificity: 60%). We also identified an optimal, two-marker bio-signature with a sensitivity of 94% and specificity of 69% in patients with no history of previous TB. This signature performed slightly better than C-reactive protein (CRP) alone. The cut-off value for a positive diagnosis differed for human immuno-deficiency virus (HIV)-positive and -negative individuals. Notably, we also found that no signature was able to diagnose TB adequately in patients with a prior history of the disease. We have identified a two-marker, pan-African bio-signature which is more robust than CRP alone and meets the World Health Organization (WHO) target product profile requirements for a triage test in both HIV-negative and HIV-positive individuals. This signature could be incorporated into a point-of-care device, greatly reducing the necessity for expensive confirmatory diagnostics and potentially reducing the number of cases currently lost to follow-up. It might also potentially be useful with individuals unable to provide sputum or with paucibacillary disease. We suggest that the performance of TB diagnostic signatures can be improved by incorporating the HIV-status of the patient. We further suggest that only patients who have never had TB be subjected to a triage test and that those with a history of previous TB be evaluated using more direct diagnostic techniques.

Africa-wide evaluation of host biomarkers in QuantiFERON supernatants for the diagnosis of pulmonary tuberculosis.

We investigated host-derived biomarkers that were previously identified in QuantiFERON supernatants, in a large pan-African study. We recruited individuals presenting with symptoms of pulmonary TB at seven peripheral healthcare facilities in six African countries, prior to assessment for TB disease. We then evaluated the concentrations of 12 biomarkers in stored QuantiFERON supernatants using the Luminex platform. Based on laboratory, clinical and radiological findings and a pre-established algorithm, participants were classified as TB disease or other respiratory diseases(ORD). Of the 514 individuals included in the study, 179(34.8%) had TB disease, 274(51.5%) had ORD and 61(11.5%) had an uncertain diagnosis. A biosignature comprising unstimulated IFN-γ, MIP-1ß, TGF-α and antigen-specific levels of TGF-α and VEGF, identified on a training sample set (n = 311), validated by diagnosing TB disease in the test set (n = 134) with an AUC of 0.81(95% CI, 0.76-0.86), corresponding to a sensitivity of 64.2%(95% CI, 49.7-76.5%) and specificity of 82.7%(95% CI, 72.4-89.9%). Host biomarkers detected in QuantiFERON supernatants can contribute to the diagnosis of active TB disease amongst people presenting with symptoms requiring investigation for TB disease, regardless of HIV status or ethnicity in Africa.