Malaria overdiagnosis and subsequent overconsumption of antimalarial drugs in Angola: Consequences and effects on human health

Malaria in Angola: recent progress, challenges and future opportunities using parasite demography studies

Over the past two decades, a considerable expansion of malaria interventions has occurred at the national level in Angola, together with cross-border initiatives and regional efforts in southern Africa. Currently, Angola aims to consolidate malaria control and to accelerate the transition from control to pre-elimination, along with other country members of the Elimination 8 initiative. However, the tremendous heterogeneity in malaria prevalence among Angolan provinces, as well as internal population movements and migration across borders, represent major challenges for the Angolan National Malaria Control Programme. This review aims to contribute to the understanding of factors underlying the complex malaria situation in Angola and to encourage future research studies on transmission dynamics and population structure of Plasmodium falciparum, important areas to complement host epidemiological information and to help reenergize the goal of malaria elimination in the country.

A systematic review and meta-analysis of the epidemiology of Leptospirosis in HIV uninfected and in people living with HIV from the Southern African Development Community

BACKGROUND

Leptospirosis is an occupational, neglected febrile disease of bacterial origin transmitted between humans and animals. In this manuscript we summarize available data on Leptospira infection in HIV uninfected and in people living with HIV from the Southern African Development Community (SADC) countries, identifying gaps in knowledge and recommend future research priorities.

METHODOLOGY

Articles published between 1990 and 2021 were accessed by an online search of Google Scholar and Medline/PubMed performed between February 2020 and July 2022. The STATA program was used for the Meta-analysis. Pooled prevalence values with 95% confidence intervals and heterogeneity were determined.

RESULTS

Thirty studies from eight SADC countries, reporting the prevalence on Leptospira were reviewed. A pooled prevalence of 19% (CI: 13-25%), a heterogeneity level of 96% and index score ranging from 2 to 9 was determined. Only four (4) studies reported HIV co-infection status. Three species of Leptospira (Leptospira interrogans (4), L. kirschneri (3), Leptospira borgpetersenii (1) and 23 serogroups were identified. The most frequently reported serogroups were Icterohaemorrhagiae (13), Grippotyphosa and Australis (10) followed by Sejroe (8).

CONCLUSION

Studies on human leptospirosis in the SADC region are scarce, especially in people living with HIV. Additional studies aimed at determining the prevalence and the role of the pathogen in people living with HIV, including detailed clinical, molecular and demographic data are recommended.

Most common reasons for primary care visits in low- and middle-income countries: A systematic review

With the Covid-19 pandemic and the introduction of the WHO's Essential Diagnostics List (EDL), increasing global attention is focused on the crucial role of diagnostics in achieving universal health coverage. To create national EDLs and to aid health system planning, it is vital to understand the most common conditions with which people present at primary care health facilities. We undertook a systematic review of the most common reasons for primary care visits in low- and middle-income countries. Six databases were searched for articles published between January 2009 and December 2019, with the search updated on MEDLINE to January 2021. Data on the most common patient reasons for encounter (RFEs) and provider diagnoses were collected. 17 of 22,279 screened articles were included. Most studies used unvalidated diagnostic classification systems or presented provider diagnosis data grouped by organ system, rather than presenting specific diagnoses. No studies included data from low-income countries. Only four studies (from Brazil, India, Nigeria and South Africa) using the ICPC-2 classification system contained RFE and provider diagnosis data and could be pooled. The top five RFEs from the four studies were headache, fever, back or low back symptom, cough and pain general/multiple sites. The top five diagnoses were uncomplicated hypertension, upper respiratory tract infection, type 2 diabetes, malaria and health maintenance/prevention. No psychological symptoms were among the top 10 pooled RFEs. There was more variation in top diagnoses between studies than top RFEs, showing the importance of creating location-specific lists of essential diagnostics for primary care. Future studies should aim to sample primary care facilities from across their country of study and use ICPC-3 to report both patient RFEs and provider diagnoses.

Rationalization of the Laboratory Diagnosis for Good Management of Malaria: Lessons from Transitional Methods

Introduction

Malaria is an endemic disease in sub-Saharan Africa. In clinical practice, the main concern is the overdiagnosis of malaria leading to inappropriate drug prescription without laboratory confirmation.

Objective

This study aimed to evaluate clinical examination reliability compared with translational laboratory methods of malaria diagnosis.

Methods

The study was conducted in Goundi Hospital among hospitalized patients over a seven-month period. Patients were interviewed, and malaria tests done included the Giemsa-stained thick and thin blood smears. Diagnostic accuracy was analysed by calculating sensitivity, specificity, and predictive values.

Results

Among 1,874 participants, 674 (35.96%) patients had positive Giemsa-stained thick blood films. The rate of positivity is higher for patients under 5 years of age. The parasite densities were between 160 and 84.000 parasites/μL. The threshold pyrogen of the parasitic density was around 10.000 parasites/μL for patients between 0 and 11 months of age, between 1 and 4 years of age, and between 5 and 14 years of age. This threshold was lower for patients over 15 years of age. The study reported some issues in the findings: 60.88% (607/997) cases of fever without positivity of the blood thick smear and 40.13% (284/674) cases of positivity of the thick drop without fever. The positive predictive value of malaria was between 80 and 85% for patients under 5 years of age. This value is lower for patients between 5 and 14 years of age and patients over 15 years of age.

Conclusion

A presumptive diagnosis of malaria should be confirmed by the laboratory in all suspected cases in all possible scenarios. Every parasitemia should be followed by the calculation of parasitic density. However, for the children under 5 years of age in areas of high transmission, the presumptive diagnosis of malaria in certain circumstances could be considered.

A portable brightfield and fluorescence microscope toward automated malarial parasitemia quantification in thin blood smears

Malaria is often most endemic in remote regions where diagnostic microscopy services are unavailable. In such regions, the use of rapid diagnostic tests fails to quantify parasitemia measurements which reflect the concentration of Plasmodium parasites in the bloodstream. Thus, novel diagnostic and monitoring technologies capable of providing such information could improve the quality of treatment, monitoring, and eradication efforts. A low-cost, portable microscope for gathering quantitative parasitemia data from fluorescently stained thin blood smears is presented. The system employs bimodal imaging using components optimized for cost savings, system robustness, and optical performance. The microscope is novel for its use of monochromatic visible illumination paired with a long working distance singlet aspheric objective lens that can image both traditionally mounted and cartridge-based blood smears. Eight dilutions of red blood cells containing laboratory cultured wild-type P. falciparum were used to create thin smears which were stained with SYBR Green-1 fluorescent dye. Two subsequent images are captured for each field-of-view, with brightfield images providing cell counts and fluorescence images providing parasite localization data. Results indicate the successful resolution of sub-micron sized parasites, and parasitemia measurements from the prototype microscope display linear correlation with measurements from a benchtop microscope with a limit of detection of 0.18 parasites per 100 red blood cells.

Historical trends and new surveillance of Plasmodium falciparum drug resistance markers in Angola

BACKGROUND

Plasmodium falciparum resistance to chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) has historically posed a major threat to malaria control throughout the world. The country of Angola officially replaced CQ with artemisinin-based combination therapy (ACT) as a first-line treatment in 2006, but malaria cases and deaths have recently been rising. Many classic resistance mutations are relevant for the efficacy of currently available drugs, making it important to continue monitoring their frequency in Angola.

METHODS

Plasmodium falciparum DNA was sampled from the blood of 50 hospital patients in Cabinda, Angola from October-December of 2018. Each infection was genotyped for 13 alleles in the genes crt, mdr1, dhps, dhfr, and kelch13, which are collectively involved in resistance to six common anti-malarials. To compare frequency patterns over time, P. falciparum genotype data were also collated from studies published from across Angola in the last two decades.

RESULTS

The two most important alleles for CQ resistance, crt 76T and mdr1 86Y, were found at respective frequencies of 71.4% and 6.5%. Historical data suggest that mdr1 N86 has been steadily replacing 86Y throughout Angola in the last decade, while the frequency of crt 76T has been more variable across studies. Over a third of new samples from Cabinda were 'quintuple mutants' for SP resistance in dhfr/dhps, with a sixth mutation at dhps A581G present at 9.6% frequency. The markers dhfr 51I, dhfr 108N, and dhps 437G have been nearly fixed in Angola since the early 2000s, whereas dhfr 59R may have risen to high frequency more recently. Finally, no non-synonymous polymorphisms were detected in kelch13, which is involved in artemisinin resistance in Southeast Asia.

CONCLUSIONS

Genetic markers of P. falciparum resistance to CQ are likely declining in frequency in Angola, consistent with the official discontinuation of CQ in 2006. The high frequency of multiple genetic markers of SP resistance is consistent with the continued public and private use of SP. In the future, more complete haplotype data from mdr1, dhfr, and dhps will be critical for understanding the changing efficacy of multiple anti-malarial drugs. These data can be used to support effective drug policy decisions in Angola.

Malaria Test, Treat and Track policy implementation in Angola: a retrospective study to assess the progress achieved after 4 years of programme implementation

Background

Malaria is one of the main causes of death in Angola, particularly among children under 5 years of age. An essential means to improve the situation is with strong malaria case management; this includes diagnosing suspected patients with a confirmatory test, either with a rapid diagnostic test (RDT) or microscopy, prompt and correct treatment with artemisinin-based combination therapy (ACT), and proper case registration (track). In 2011, the United States President’s Malaria Initiative (PMI) launched a country-wide programme to improve malaria case management through the provision of regular training and supervision at different levels of health care provision. An evaluation of malaria testing, treatment and registration practices in eight provinces, and at health facilities of various capacities, across Angola was conducted to assess progress of the national programme implementation.

Methods

A retrospective assessment analysed data collected during supervision visits to health facilities conducted between 2012 and 2016 in 8 provinces in Angola. The supervision tool used data collected for malaria knowledge, testing, treatment and case registration practices among health workers as well as health facilities stock outs from different levels of health care delivery. Contingency tables with Pearson chi-squared (χ²) tests were used to identify factors associated with “knowledge”, “test”, “treat” and “track.” Multivariable logistic regression models were used to assess factors associated with the defined outcomes.

Results

A total of 7156 supervisions were conducted between September 2012 and July 2016. The overall knowledge, testing, treatment and tracking practices among health care workers (HCWs) increased significantly from 2013 to 2016. Health care workers in 2016 were 3.3 times (95% CI: 2.7–3.9) as likely to have a higher knowledge about malaria case management as in 2013 (p < 0.01), 7.4 (95% CI: 6.1–9.0) times as likely to test more suspected cases (p < 0.01), 10.9 (95% CI: 8.6–13.6) times as likely to treat more confirmed cases (p < 0.01) and 3.7 (95% CI: 3.2–4.4) times as likely to report more accurately in the same period (p < 0.01).

Discussion

Improvements demonstrated in knowledge about malaria case management, testing with RDT and treatment with artemisinin-based combinations among HCWs is likely associated with malaria case management trainings and supportive supervisions. Gaps in testing and treatment practices are associated with RDT and ACT medicines stock outs in health facilities. Tracking of malaria cases still poses a major challenge, despite training and supervision. Hospitals consistently performed better compared to other health facilities against all parameters assessed; likely due to a better profile of HCWs.

Conclusion

Significant progress in malaria case management in eight provinces Angola was achieved in the period of 2013–2016. Continued training and supportive supervision is essential to sustain gains and close existing gaps in malaria case management and reporting in Angola.

Evaluation of Routine Microscopy Performance for Malaria Diagnosis at Three Different Health Centers in Brazzaville, Republic of Congo

Background

In Republic of Congo, malaria diagnosis still widely relies on microscopy. We aimed to evaluate the performance of routine microscopy for malaria diagnosis at three different health centers in Brazzaville.

Methods

A total of 259, 416, and 131 patients with clinical signs of uncomplicated malaria were enrolled at the Hôpital de Mfilou, Centre de Santé Intégré "Maman Mboualé," and Laboratoire National de Santé Publique, respectively. Two thick blood smears were prepared for each patient, the first being examined by routine microscopists and the second by expert.

Results

At the Hôpital de Mfilou, sensitivity was 62.1% and specificity was 67.3%. Positive and negative predictive values were 55.6% and 72.9%, respectively. At the Centre de Santé Intégré "Maman Mboualé," sensitivity was 94.2% and specificity was 33.6%. Positive and negative predictive values were 50% and 89.1%, respectively. At the Laboratoire National de Santé Publique, sensitivity and specificity were high with 91.7% and 94.9%, respectively. Positive and negative predictive values were 64.7% and 99.1%, respectively.

Conclusion

The performance of routine malaria microscopy in Brazzaville remains inaccurate with large variations among different health centers. Therefore, repeated training including supervision and evaluation would improve routine malaria diagnosis for better management of malaria in Brazzaville, the Republic of Congo.