Efficacy of artemisinin-lumefantrine for treatment of uncomplicated malaria after more than a decade of its use in Kenya

Prevalence of mutations in the cysteine desulfurase IscS (Pfnfs1) gene in recurrent Plasmodium falciparum infections following artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) treatment in Matayos, Western Kenya

BACKGROUND

Malaria remains a public health concern globally. Resistance to anti-malarial drugs has consistently threatened the gains in controlling the malaria parasites. Currently, artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) are the treatment regimens against Plasmodium falciparum infections in many African countries, including Kenya. Recurrent infections have been reported in patients treated with AL or DP, suggesting the possibility of reinfection or parasite recrudescence associated with the development of resistance against the two therapies. The Plasmodium falciparum cysteine desulfurase IscS (Pfnfs1) K65 selection marker has previously been associated with decreased lumefantrine susceptibility. This study evaluated the frequency of the Pfnfs1 K65 resistance marker and associated K65Q resistant allele in recurrent infections collected from P. falciparum-infected individuals living in Matayos, Busia County, in western Kenya.

METHODS

Archived dried blood spots (DBS) of patients with recurrent malaria infection on clinical follow-up days after treatment with either AL or DP were used in the study. After extraction of genomic DNA, PCR amplification and sequencing analysis were employed to determine the frequencies of the Pfnfs1 K65 resistance marker and K65Q mutant allele in the recurrent infections. Plasmodium falciparum msp1 and P. falciparum msp2 genetic markers were used to distinguish recrudescent infections from new infections.

RESULTS

The K65 wild-type allele was detected at a frequency of 41% while the K65Q mutant allele was detected at a frequency of 22% in the recurrent samples. 58% of the samples containing the K65 wild-type allele were AL treated samples and while 42% were DP treated samples. 79% of the samples with the K65Q mutation were AL treated samples and 21% were DP treated samples. The K65 wild-type allele was detected in three recrudescent infections (100%) identified from the AL treated samples. The K65 wild-type allele was detected in two recrudescent DP treated samples (67%) while the K65Q mutant allele was identified in one DP treated (33%) recrudescent sample.

CONCLUSIONS

The data demonstrate a higher frequency of the K65 resistance marker in patients with recurrent infection during the study period. The study underscores the need for consistent monitoring of molecular markers of resistance in regions of high malaria transmission.

Trend of Malaria Burden Among Residents of Kisii County, Kenya After More Than a Decade Usage of Artemisinin Combined Therapies, 11-Year Laboratory Based Retrospective Study

Background

Malaria remains a major vector borne disease globally, with the majority of the casualties reported in Africa. Despite this fact, there is drastic reduction in malaria infection using Artemisinin combined therapies (ACTs). Malaria is characterized by significant inconsistency in different geographical locations due to different confounding factors. There is need to identify zone-specific malaria trends and interventions to completely eliminate the disease. Thus the study was aimed at assessing the 11-year trend of microscopically confirmed malaria cases in Kisii County, Kenya, so as to devise area-specific evidence-based interventions, informed decisions, and to track the effectiveness of malaria control programs.

Methods

This was a retrospective study carried out to determine 11-year malaria trend rates centered on the admission and laboratory records from health facilities located at four Sub-Counties in Kisii County, Kenya. Parasitological positivity rates of malaria were determined by comparing with the register records in health facilities which recorded confirmed malaria cases with the total number of monthly admissions over the entire year. Data was analyzed by using descriptive tools and chi-square test.

Results

There were 36,946 suspect cases, with 8449 (22.8%) confirmed malaria cases reported in this study. The overall malaria slide positivity rate over the last 11 years in the study area was 22.6%. The months of April and August showed the largest number of malaria cases (63%). The age group of ≥18 years contained the most positive confirmed cases, having a prevalence rate of 2953 (35.45%). Out of the confirmed malaria cases, 2379 (28.1%) were males and 6070 (71.9%) were females The highest malaria prevalence rate was recorded in 2014, with Marani Sub-County recording the highest positivity rate of 37.94%.

Conclusion

From the observed trends, malaria prevalence and transmission still remains stable in the study area. Thus more interventions need to be scaled up.

Experience and confidence in health technologies: evidence from malaria testing and treatment in Western Kenya

Background

Low adoption of effective health technologies increases illness morbidity and mortality worldwide. In the case of malaria, effective tools such as malaria rapid diagnostic tests (RDTs) and artemisinin-combination therapies (ACTs) are both under-used and used inappropriately. Individuals’ confidence in RDTs and ACTs likely affects the uptake of these tools.

Methods

In a cohort of 36 households (280 individuals) in Western Kenya observed for 30 months starting in June 2017, we examined if experience with RDTs and ACTs changes people’s beliefs about these technologies and how those beliefs affect treatment behavior. Household members requested a free RDT from the study team any time they suspected a malaria illness, and positive RDT results were treated with a free ACT. We conducted annual, monthly, and sick visit surveys to elicit beliefs about the accuracy of malaria RDT results and the effectiveness of ACTs. Beliefs were elicited on a 5-point Likert scale from “very unlikely” to “very likely.”

Results

Over the study period, the percentage of survey respondents that said a hypothetical negative RDT result was “very likely” to be correct increased from approximately 55% to 75%. Controlling for initial beliefs, people who had been tested at least once with an RDT in the past year had 3.6 times higher odds (95% CI [1 1.718 7.679], P = 0.001) of saying a negative RDT was “very likely” to be correct. Confidence in testing was associated with treatment behavior: those who believed a negative RDT was “very likely” to be correct had 1.78 times higher odds (95% CI [1.079 2.934], P = 0.024) of adhering to a negative RDT result (by not taking ACTs) than those who were less certain about the accuracy of negative RDTs. Adherence to a negative test also affected subsequent beliefs: controlling for prior beliefs, those who had adhered to their previous test result had approximately twice the odds (OR = 2.19, 95% CI [1.661 2.904], P < 0.001) of saying that a hypothetical negative RDT was “very likely” to be correct compared to those who had not adhered.

Conclusions

Our results suggest that greater experience with RDTs can not only increase people’s confidence in their accuracy but also improve adherence to the test result.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14102-y.

Therapeutic efficacy of artemether-lumefantrine, artesunate-amodiaquine and dihydroartemisinin-piperaquine in the treatment of uncomplicated Plasmodium falciparum malaria in Sub-Saharan Africa: A systematic review and meta-analysis

Background

Sub-Saharan Africa has the highest burden of malaria in the world. Artemisinin-based combination therapies (ACTs) have been the cornerstone in the efforts to reduce the global burden of malaria. In the effort to facilitate early detection of resistance for artemisinin derivatives and partner drugs, WHO recommends monitoring of ACT’s efficacy in the malaria endemic countries. The present systematic meta-analysis study summarises the evidence of therapeutic efficacy of the commonly used artemisinin-based combinations for the treatment of uncomplicated P. falciparum malaria in Sub-Saharan Africa after more than a decade since the introduction of the drugs.

Methods

Fifty two studies carried out from 2010 to 2020 on the efficacy of artemether-lumefantrine or dihydro-artemisinin piperaquine or artesunate amodiaquine in patients with uncomplicated P. falciparum malaria in Sub-Saharan Africa were searched for using the Google Scholar, Cochrane Central Register of controlled trials (CENTRAL), PubMed, Medline, LILACS, and EMBASE online data bases. Data was extracted by two independent reviewers. Random analysis effect was performed in STATA 13. Heterogeneity was established using I² statistics.

Results

Based on per protocol analysis, unadjusted cure rates in malaria infected patients treated with artemether-lumefantrine (ALU), artesunate-amodiaquine (ASAQ) and dihydroartemisinin-piperaquine (DHP) were 89%, 94% and 91% respectively. However, the cure rates after PCR correction were 98% for ALU, 99% for ASAQ and 99% for DHP.

Conclusion

The present meta-analysis reports the overall high malaria treatment success for artemether-lumefantrine, artesunate-amodiaquine and dihydroartemisinin-piperaquine above the WHO threshold value in Sub-Saharan Africa.