Efficacy of artemether-lumefantrine, artesunate-amodiaquine, and dihydroartemisinin-piperaquine for treatment of uncomplicated Plasmodium falciparum malaria in Angola, 2015.

BACKGROUND: Recent anti-malarial resistance monitoring in Angola has shown efficacy of artemether-lumefantrine (AL) in certain sites approaching the key 90% lower limit of efficacy recommended for artemisinin-based combination therapy. In addition, a controversial case of malaria unresponsive to artemisinins was reported in a patient infected in Lunda Sul Province in 2013. METHODS: During January-June 2015, investigators monitored the clinical and parasitological response of children with uncomplicated Plasmodium falciparum infection treated with AL, artesunate-amodiaquine (ASAQ), or dihydroartemisinin-piperaquine (DP). The study comprised two treatment arms in each of three provinces: Benguela (AL, ASAQ), Zaire (AL, DP), and Lunda Sul (ASAQ, DP). Samples from treatment failures were analysed for molecular markers of resistance for artemisinin (K13) and lumefantrine (pfmdr1). RESULTS: A total of 467 children reached a study endpoint. Fifty-four treatment failures were observed: four early treatment failures, 40 re-infections and ten recrudescences. Excluding re-infections, the 28-day microsatellite-corrected efficacy was 96.3% (95% CI 91-100) for AL in Benguela, 99.9% (95-100) for ASAQ in Benguela, 88.1% (81-95) for AL in Zaire, and 100% for ASAQ in Lunda Sul. For DP, the 42-day corrected efficacy was 98.8% (96-100) in Zaire and 100% in Lunda Sul. All treatment failures were wild type for K13, but all AL treatment failures had pfmdr1 haplotypes associated with decreased lumefantrine susceptibility. CONCLUSIONS: No evidence was found to corroborate the specific allegation of artemisinin resistance in Lunda Sul. The efficacy below 90% of AL in Zaire matches findings from 2013 from the same site. Further monitoring, particularly including measurement of lumefantrine blood levels, is recommended.

Evaluating malaria case management at public health facilities in two provinces in Angola.

BACKGROUND: Malaria accounts for the largest portion of healthcare demand in Angola. A pillar of malaria control in Angola is the appropriate management of malaria illness, including testing of suspect cases with rapid diagnostic tests (RDTs) and treatment of confirmed cases with artemisinin-based combination therapy (ACT). Periodic systematic evaluations of malaria case management are recommended to measure health facility readiness and adherence to national case management guidelines. METHODS: Cross-sectional health facility surveys were performed in low-transmission Huambo and high-transmission Uíge Provinces in early 2016. In each province, 45 health facilities were randomly selected from among all public health facilities stratified by level of care. Survey teams performed inventories of malaria commodities and conducted exit interviews and re-examinations, including RDT testing, of a random selection of all patients completing outpatient consultations. Key health facility readiness and case management indicators were calculated adjusting for the cluster sampling design and utilization. RESULTS: Availability of RDTs or microscopy on the day of the survey was 71% (54-83) in Huambo and 85% (67-94) in Uíge. At least one unit dose pack of one formulation of an ACT (usually artemether-lumefantrine) was available in 83% (66-92) of health facilities in Huambo and 79% (61-90) of health facilities in Uíge. Testing rates of suspect malaria cases in Huambo were 30% (23-38) versus 69% (53-81) in Uíge. Overall, 28% (13-49) of patients with uncomplicated malaria, as determined during the re-examination, were appropriately treated with an ACT with the correct dose in Huambo, compared to 60% (42-75) in Uíge. Incorrect case management of suspect malaria cases was associated with lack of healthcare worker training in Huambo and ACT stock-outs in Uíge. CONCLUSIONS: The results reveal important differences between provinces. Despite similar availability of testing and ACT, testing and treatment rates were lower in Huambo compared to Uíge. A majority of true malaria cases seeking care in health facilities in Huambo were not appropriately treated with anti-malarials, highlighting the importance of continued training and supervision of healthcare workers in malaria case management, particularly in areas with decreased malaria transmission.

Epidemiology of measles in Angola: Results from routine surveillance from 2015 to 2021.

Background: Measles, an acute infectious disease of extremely contagious viral aetiology, has been eliminated in some parts of the world. To the best of the authors' knowledge, this is the first study on the epidemiological pattern of the measles virus in Angola, and it was carried out through a review of 7 years of observational retrospective data from the national measles laboratory surveillance programme. Methods: A retrospective study using national databases on the laboratory surveillance of measles was performed. Patients of all ages with suspected measles from all provinces of Angola were included. Serum samples were used to detect IgM-type measles-virus-specific antibodies by enzyme-linked immunosorbent assay. Findings: In total, 3690 suspected measles samples were sent to the Instituto Nacional de Investigação em Saúde. There were 962 (26.1%) laboratory-confirmed cases, and the most affected age group was children aged 1-4 years. The highest incidence rate per 100,000 population was found in Benguela (17.9%), followed by Huambo (16.7%) and Cuanza Sul (13.6%). Of the study years, the incidence rate per 1,000,000 population was highest in 2020 (11.9%). The most common complication was diarrhoea (n=406, 42.2%). Of the confirmed cases, 209 (21.7%) were vaccinated, 633 (65.8%) were unvaccinated, and 120 (12.5%) had unknown vaccination status. For all study years, vaccination coverage was <70%. Interpretation: Measles continues to be a serious problem in Angola, and more efforts are needed to increase measles surveillance and achieve a high percentage of vaccination coverage.