Dataset Information

In vitro reduction of Plasmodium falciparum gametocytes: Artemisia spp. tea infusions vs. artemisinin.

ABSTRACT:

Ethnopharmacological relevance

Artemisia annua has a long history of use in Southeast Asia where it was used to treat "fever", and A. afra has a similar history in southern Africa. Since their discovery, A. annua use, in particular, has expanded globally with millions of people using the plant in therapeutic tea infusions, mainly to treat malaria.

Aim of the study

In this study, we used in vitro studies to query if and how A. annua and A. afra tea infusions being used across the globe affect asexual Plasmodium falciparum parasites, and their sexual gametocytes.

Materials and methods

P. falciparumstrain NF54 was grown in vitro, synchronized, and induced to form gametocytes using N-acetylglucosamine. Cultures during asexual, early, and late stage gametocytogenesis were treated with artemisinin, methylene blue, and A. annua and A. afra tea infusions (5 g DW/L) using cultivars that contained 0-283 μM artemisinin. Asexual parasitemia and gametocytemia were analyzed microscopically. Gametocyte morphology also was scored. Markers of early (PfGEXP5) and late stage (Pfs25) gametocyte gene expression also were measured using RT-qPCR.

Results

Both A. annua and A. afra tea infusions reduced gametocytemia in vitro, and the effect was mainly artemisinin dependent. Expression levels of both marker genes were reduced and also occurred with the effect mainly attributed to artemisinin content of four tested Artemisia cultivars. Tea infusions of both species also inhibited asexual parasitemia and although mainly artemisinin dependent, there was a weak antiparasitic effect from artemisinin-deficient A. afra.

Conclusions

These results showed that A. annua and to a lesser extent, A. afra, inhibited parasitemia and gametocytemia in vitro.

SUBMITTER: Snider D

PROVIDER: S-EPMC7855472 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Publications

In vitro reduction of Plasmodium falciparum gametocytes: Artemisia spp. tea infusions vs. artemisinin.

Snider Danielle D Weathers Pamela J PJ

Journal of ethnopharmacology 20201130

<h4>Ethnopharmacological relevance</h4>Artemisia annua has a long history of use in Southeast Asia where it was used to treat "fever", and A. afra has a similar history in southern Africa. Since their discovery, A. annua use, in particular, has expanded globally with millions of people using the plant in therapeutic tea infusions, mainly to treat malaria.<h4>Aim of the study</h4>In this study, we used in vitro studies to query if and how A. annua and A. afra tea infusions being used across the g ...[more]

PMID: 33271239

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Project description:Background and objectivePrior small-scale clinical trials showed that Artemisia annua and Artemisia afra infusions, decoctions, capsules, or tablets were low cost, easy to use, and efficient in curing malaria infections. In a larger-scale trial in Kalima district, Democratic Republic of Congo, we aimed to show A. annua and/or A. afra infusions were superior or at least equivalent to artesunate-amodiaquine (ASAQ) against malaria.MethodsA double blind, randomized clinical trial with 957 malaria-infected patients had two treatment arms: 472 patients for ASAQ and 471 for Artemisia (248 A. annua, 223 A. afra) remained at end of the trial. ASAQ-treated patients were treated per manufacturer posology, and Artemisia-treated patients received 1 l/d of dry leaf/twig infusions for 7 d; both arms had 28 d follow-up. Parasitemia and gametocytes were measured microscopically with results statistically compared among arms for age and gender.ResultsArtemisinin content of A. afra was negligible, but therapeutic responses of patients were similar to A. annua-treated patients; trophozoites cleared after 24  h, but took up to 14 d to clear in ASAQ-treated patients. D28 cure rates defined as absence of parasitemia were for pediatrics 82, 91, and 50% for A. afra, A. annua and ASAQ; while for adults cure rates were 91, 100, and 30%, respectively. Fever clearance took 48  h for ASAQ, but 24  h for Artemisia. From D14-28 no Artemisia-treated patients had microscopically detectable gametocytes, while 10 ASAQ-treated patients remained gametocyte carriers at D28. More females than males were gametocyte carriers in the ASAQ arm but were unaffected in the Artemisia arms. Hemoglobin remained constant at 11 g/dl for A. afra after D1, while for A. annua and ASAQ it decreased to 9-9.5  g/dl. Only 5.0% of Artemisia-treated patients reported adverse effects, vs. 42.8% for ASAQ.ConclusionA. annua and A. afra infusions are polytherapies with better outcomes than ASAQ against malaria. In contrast to ASAQ, both Artemisias appeared to break the cycle of malaria by eliminating gametocytes. This study merits further investigation for possible inclusion of Artemisia tea infusions as an alternative for fighting and eradicating malaria.

Project description:BackgroundIn some settings, sensitive field diagnostic tools may be needed to achieve elimination of falciparum malaria. To this end, rapid diagnostic tests (RDTs) based on the detection of the Plasmodium falciparum protein HRP-2 are being developed with increasingly lower limits of detection. However, it is currently unclear how parasite stages that are unaffected by standard drug treatments may contribute to HRP-2 detectability and potentially confound RDT results even after clearance of blood stage infection. This study assessed the detectability of HRP-2 in periods of post-treatment residual gametocytaemia.MethodsA cohort of 100 P. falciparum infected, gametocyte positive individuals were treated with or without the gametocytocidal drug primaquine (PQ), alongside standard artemisinin-based combination therapy (ACT), in the context of a randomised clinical trial in Ouelessebougou, Mali. A quantitative ELISA was used to measure levels of HRP-2, and compared time to test negativity using a standard and ultra-sensitive RDT (uRDT) between residual gametocyte positive and negative groups.ResultsTime to test negativity was longest by uRDT, followed by ELISA and then standard RDT. No significant difference in time to negativity was found between the treatment groups with and without residual gametocytes: uRDT (HR 0.79 [95% CI 0.52-1.21], p = 0.28), RDT (HR 0.77 [95% CI 0.51-1.15], p = 0.20) or ELISA (HR 0.88 [95% CI 0.59-1.32], p = 0.53). Similarly, no difference was observed when adjusting for baseline asexual parasite density. Quantified levels of HRP-2 over time were similar between groups, with differences attributable to asexual parasite densities. Furthermore, no difference in levels of HRP-2 was found between individuals who were or were not infectious to mosquitoes (OR 1.19 [95% CI 0.98-1.46], p = 0.077).ConclusionsSurviving sexual stage parasites after standard ACT treatment do not contribute to the persistence of HRP-2 antigenaemia, and appear to have little impact on RDT results.

Project description:BackgroundUnderstanding the dynamics of gametocyte production in polyclonal Plasmodium falciparum infections requires a genotyping method that detects distinct gametocyte clones and estimates their relative frequencies. Here, a marker was identified and evaluated to genotype P. falciparum mature gametocytes using amplicon deep sequencing.MethodsA data set of polymorphic regions of the P. falciparum genome was mined to identify a gametocyte genotyping marker. To assess marker resolution, the number of unique haplotypes in the marker region was estimated from 95 Malawian P. falciparum whole genome sequences. Specificity of the marker for detection of mature gametocytes was evaluated using reverse transcription-polymerase chain reaction of RNA extracted from NF54 mature gametocytes and rings from a non-gametocyte-producing strain of P. falciparum. Amplicon deep sequencing was performed on experimental mixtures of mature gametocytes from two distinct parasite clones, as well as gametocyte-positive P. falciparum field isolates to evaluate the quantitative ability and determine the limit of detection of the genotyping approach.ResultsA 400 bp region of the pfs230 gene was identified as a gametocyte genotyping marker. A larger number of unique haplotypes was observed at the pfs230 marker (34) compared to the sera-2 (18) and ama-1 (14) markers in field isolates from Malawi. RNA and DNA genotyping accurately estimated gametocyte and total parasite clone frequencies when evaluating agreement between expected and observed haplotype frequencies in gametocyte mixtures, with concordance correlation coefficients of 0.97 [95% CI: 0.92-0.99] and 0.92 [95% CI: 0.83-0.97], respectively. The detection limit of the genotyping method for male gametocytes was 0.41 pfmget transcripts/µl [95% CI: 0.28-0.72] and for female gametocytes was 1.98 ccp4 transcripts/µl [95% CI: 1.35-3.68].ConclusionsA region of the pfs230 gene was identified as a marker to genotype P. falciparum gametocytes. Amplicon deep sequencing of this marker can be used to estimate the number and relative frequency of parasite clones among mature gametocytes within P. falciparum infections. This gametocyte genotyping marker will be an important tool for studies aimed at understanding dynamics of gametocyte production in polyclonal P. falciparum infections.

Project description:Background and objectiveSchistosomiasis (bilharzia), a serious neglected tropical disease affecting millions, has few cost-effective treatments, so two Artemisia wormwood species, A. annua and A. afra, were compared with the current standard praziquantel (PZQ) treatment in an 800 patient clinical trial, August-November of 2015.MethodsThe double blind, randomized, superiority clinical trial had three treatment arms: 400 for PZQ, 200 for A. annua, and 200 for A. afra. PZQ-treated patients followed manufacturer posology. Artemisia-treated patients received 1 l/d of dry leaf/twig tea infusions divided into 3 aliquots daily, for 7 days with 28-day follow-up.ResultsOf 800 enrolled patients having an average of >700 Schistosoma mansoni eggs per fecal sample, 780 completed the trial. Within 14 days of treatment, all Artemisia-treated patients had no detectable eggs in fecal smears, a result sustained 28 days post treatment. Eggs in fecal smears of PZQ-treated patients were undetectable after D21. More males than females who entered the trial had melena, but both genders responded equally well to treatment; by D28 melena disappeared in all patients. In all arms, eosinophil levels declined by about 27% from D0 to D28. From D0 to D28 hemoglobin increases were greater in PZQ and A. afra-treated patients than in A. annua-treated patients. Hematocrit increases were greater from D0 to D28 for patients treated with either PZQ or A. annua compared to those treated with A. afra. Gender comparison showed that A. afra-treated males had significantly greater hemoglobin and hematocrit increases by D28 than either PZQ or A. annua-treated males. In contrast, PZQ and A. afra-treated females had greater hemoglobin and hematocrit increases than A. annua-treated females. Both adults and pediatric patients treated with A. annua responded better compared to PZQ treatment.ConclusionBoth A. annua and A. afra provided faster effective treatment of schistosomiasis and should be considered for implementation on a global scale.

Dataset Information

In vitro reduction of Plasmodium falciparum gametocytes: Artemisia spp. tea infusions vs. artemisinin.

Ethnopharmacological relevance

Aim of the study

Materials and methods

Results

Conclusions

Publications

In vitro reduction of Plasmodium falciparum gametocytes: Artemisia spp. tea infusions vs. artemisinin.

Similar Datasets

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