Performance of rapid rk39 tests for the diagnosis of visceral leishmaniasis in Ethiopia: a systematic review and meta-analysis

Background

Visceral Leishmaniasis (VL) is a severely neglected disease affecting millions of people with high mortality if left untreated. In Ethiopia, the primary laboratory diagnosis of VL is by using an antigen from a 39-amino acid sequence repeat of a kinesin-related (rK39) of leishmania donovani complex (L. donovani), rapid diagnostic tests (RDT). Different rk39 RDT brands are available with very variable performance and studies from Ethiopia showed a very wide range of sensitivity and specificity. Therefore, a systematic review and meta-analysis were conducted to determine the pooled sensitivity and specificity of rk39 RDT in Ethiopia.

Method

PUBMED, EMBASE, and other sources were searched using predefined search terms to retrieve all relevant articles from 2007 to 2020. Heterogeneity was assessed by visually inspecting summary receiver operating curves (SROC), Spearman correlation coefficient (r_s), Cochran Q test statistics, inconsistency square (I²) and subgroup analysis. The presence and statistical significance of publication bias were assessed by Egger's test at p < 0.05, and all the measurements showed the presence of considerable heterogeneity. Quality assessment of diagnostic accuracy studies (QUADAS-2) checklists was used to check the qualities of the study.

Results

A total of 664 articles were retrieved, and of this 12 articles were included in the meta-analysis. Overall pooled sensitivity and specificity of the rk39 RDT to diagnose VL in Ethiopia were 88.0% (95% CI 86.0% to 89.0%) and 84.0% (95% CI 82.0% to 86.0%), respectively. The sensitivity and specificity of the rk39 RDT commercial test kits were DiaMed: 86.9% (95% CI 84.3% to 89.1%) and 82.2% (95% CI 79.3% to 85.0%), and InBios: 80.0% (95% CI 77.0% to 82.8%) and 97.4% (95% CI 95.0% to 98.8%), respectively.

Conclusion

Referring to our result, rk39 RDT considered an essential rapid diagnostic test for VL diagnosis. Besides to the diagnostic accuracy, the features such as easy to perform, quick (10–20 min), cheap, equipment-free, electric and cold chain free, and result reproducibility, rk39 RDT is advisable to remains in practice as a diagnostic test at least in the remote VL endemic localities till a better test will come.

Identification and characterization of HIV positive Ethiopian elite controllers in both Africa and Israel

OBJECTIVES

HIV elite controllers (ECs) are a unique subgroup of HIV-positive patients who are long-term virologically suppressed in the absence of antiretroviral treatment (ART). The prevalence of this subgroup is estimated to be < 1%. Various cohorts of ECs have been described in developed countries, most of which have been demographically heterogeneous. The aim of this study was to identify ECs in two large African cohorts and to estimate their prevalence in a relatively genetically homogenous population.

METHODS

We screened two cohorts of HIV-positive Ethiopian patients. The first cohort resided in Mekelle, Ethiopia. The second was comprised of HIV-positive Ethiopian immigrants in Israel. In the Mekelle cohort, ART-naïve subjects with stable CD4 counts were prospectively screened using two measurements of viral load 6 months apart. Subjects were defined as ECs when both measurements were undetectable. In the Israeli cohort, subjects with consistently undetectable viral loads (mean of 17 viral load measurements/patient) and stable CD4 count > 500 cells/μL were defined as ECs.

RESULTS

In the Mekelle cohort, 16 of 9515 patients (0.16%) fitted the definition of EC, whereas seven of 1160 (0.6%) in the Israeli cohort were identified as ECs (P = 0.011).

CONCLUSIONS

This is the first large-scale screening for HIV-positive ECs to be performed in entirely African cohorts. The overall prevalence of ECs is within the range of that previously described in developing countries. The significant difference in prevalence between the two cohorts of similar genetic background is probably a consequence of selection bias but warrants further investigation into possible environmental factors which may underlie the EC state.

Adherence to anti-tuberculosis treatment in Tigray, Northern Ethiopia

SETTING

Tuberculosis (TB) patients in Mekelle Zone, Tigray Region, in Ethiopia.

OBJECTIVE

To investigate adherence to anti-tuberculosis treatment.

DESIGN

A cross-sectional study in health facilities providing anti-tuberculosis treatment was conducted. Adherence was measured in three ways: through self-reported missed doses, by visual analogue scale whereby patients rate their own adherence and by record review. A patient was considered to be adherent if 90% or more of the prescribed medication was taken.

RESULT

Of 278 TB patients included, 101 were in the intensive and 177 in the continuation phase. Respectively 67 (24.1%), 130 (46.8%) and 80 (28.8%) patients had smear-positive, smear-negative and extra-pulmonary TB. Self-report of missed doses and record review indicated adherence of respectively 273 (97.3%) and 271 (97.5%) patients. By visual analogue scale, 250 (91.6%) patients rated themselves as adherent. History of drug side effects (aOR 0.25, 95%CI 0.08-0.77) and knowledge about TB prevention (aOR 0.19, 95%CI 0.05-0.8) were independently associated with being adherent in this setting.

CONCLUSION

Adherence to anti-tuberculosis treatment was high in our study. Adherence support should be given to the poor, the elderly, patients co-infected with the human immunodeficiency virus, alcohol abusers and smokers. Health education on TB prevention should be given to all TB patients regularly.