Efficacy and Safety of Albendazole in Hookworm-infected Preschool-aged Children, School-aged Children, and Adults in Côte d'Ivoire: A Phase 2 Randomized, Controlled Dose-finding Trial

The effect of single dose albendazole (400 mg) treatment on the human gut microbiome of hookworm-infected Ghanaian individuals

Microbes play a key role in human gut homeostasis, metabolic, immunologic and physiopathology of the body. A longitudinal study conducted during 2018-2021 in the Kintampo North Municipality in Ghana demonstrated low hookworm infection cure rates following treatment with a single dose of 400 mg albendazole in some communities. To investigate associations between hookworm infection and the gut microbiome, we examined stool samples from consented participants who were either cured or remained infected after treatment. At each time point, stool was collected prior to and 10-14 days after albendazole treatment. We used 16S rRNA amplicon sequencing of DNA extracted from stool samples to investigate the composition and diversity of the gut microbiota and to identify potential microbial biomarkers associated with treatment outcomes. Hookworm infection was associated with increased species richness (p = 0.0093). Among treated individuals, there was also a significant variation in microbiota composition at 10-14 days following single-dose albendazole treatment. Individuals cured of hookworm infection after treatment showed a significant reduction in microbiota composition when compared to their pre-treatment state (ANOSIM; p = 0.02), whilst individuals who failed to clear the infection showed no change in microbiota composition (ANOSIM; p = 0.35). Uninfected individuals and those who were successfully treated were similar in their microbial composition and structure. We also found that the abundance of Clostridia spp. was increased in infected individuals pre- or post-treatment. Predictive functional profiling revealed the enrichment of two pyruvate ferredoxin oxidoreductase subunit pathways in individuals who remained infected after treatment (p < 0.05), alluding to an upturn of strictly anaerobic commensal bacteria such as Clostridia spp. This study suggests a relationship between human gut microbiome dysbiosis and albendazole therapy outcomes of hookworm infection. Future studies will further characterize specific biomarkers identified within this study to establish their potential for assessment of pharmacological responses to anthelminthic therapies, as well as explore the possibility of using probiotic supplementation as an adjunct treatment to increase albendazole effectiveness against hookworm.

Regular deworming and seasonality are potential challenges but also offer opportunities for hookworm elimination

The global health community has targeted the elimination of neglected tropical diseases (NTDs) including soil-transmitted helminthiasis by 2030. The elimination strategy has not changed from that of control using regular mass drug administration (MDA) with albendazole, WASH and education. Already doubts have been expressed about this achievement, principally because drugs do not interrupt transmission. We report here the findings of a cohort study aimed to identify host modifiable and environmental factors associated with hookworm infection and reinfection in rural communities in Kintampo North Municipality, Ghana. Faecal samples of 564 consented participants were screened for intestinal parasites at baseline, 9 months and 24 months using the Kato-Katz method. At each time point, positive cases were treated with a single dose of albendazole (400 mg) and their samples were again screened 10-14 days post-treatment to record treatment failures. The hookworm prevalence at the three-time points was 16.7%, 9.22% and 5.3% respectively, whilst treatment failure rates were 17.25%, 29.03% and 40.9% respectively. The intensities of hookworm infection (in eggs per gram) at the time points were 138.3, 40.5 and 135, which showed a likely association with wet and dry seasons. We posit that the very low intensity of hookworm infections in humans during the dry season offers a window of opportunity for any intervention that could drastically reduce the community worm burden before the rainy season.

Soil-Transmitted Helminth Infections among Antenatal Women in Primary Care Settings in Southern India: Prevalence, Associated Factors and Effect of Anti-Helminthic Treatment

Community-based studies from India on prevalence of soil-transmitted helminth (STH) infections have reported estimates as high as 50% in children. However, prevalence estimates during pregnancy in India are lacking. We aimed to describe the burden, associated factors of STH and cure rate after deworming in primary care settings. Pregnant women were recruited from four urban and five rural centers in Puducherry, South India, from December 2019 to April 2022. One stool sample was collected from each participant before deworming and one repeat sample was collected from STH positive woman after three weeks of deworming. The samples were processed with saline; iodine wet mount, and microscopic concentration techniques. Cure rate (CR) was assessed using Kato-Katz thick smear. Of 650 women included, 49 (7.5%, 95% CI 5.6-9.8) had one of the STH infections; the prevalence of Ascaris lumbricoides, hookworm and Strongyloides was 5.4%, 1.8% and 0.3%, respectively. The prevalence of any STH was higher among ages 26-30 years (9.1%), working women (8.3%), multigravida (8.3%), urban setting (8.3%), those who did not wash their hands before food (9%) and anemic women (8.9%), compared to their counterparts, but not statistically significant. The CR for hookworm was 100% and Ascaris lumbricoides was 88.6%. To conclude, the prevalence of STH was low among pregnant women compared to school aged children. Continued deworming activities along with improved sanitation could further reduce the burden.

Factors associated with variation in single-dose albendazole pharmacokinetics: A systematic review and modelling analysis

Background

Albendazole is an orally administered anti-parasitic medication with widespread usage in a variety of both programmatic and clinical contexts. Previous work has shown that the drug’s pharmacologically active metabolite, albendazole sulfoxide, is characterised by substantial inter-individual pharmacokinetic variation. This variation might have implications for the efficacy of albendazole treatment, but current understanding of the factors associated with this variation remains incomplete.

Methodology/Principal findings

We carried out a systematic review to identify references containing temporally disaggregated data on the plasma concentration of albendazole and/or (its pharmacologically-active metabolite) albendazole sulfoxide following a single oral dose. These data were then integrated into a mathematical modelling framework to infer albendazole sulfoxide pharmacokinetic parameters and relate them to characteristics of the groups being treated. These characteristics included age, weight, sex, dosage, infection status, and whether patients had received a fatty meal prior to treatment or other drugs alongside albendazole. Our results highlight a number of factors systematically associated with albendazole sulfoxide pharmacokinetic variation including age, existing parasitic infection and receipt of a fatty meal. Age was significantly associated with variation in albendazole sulfoxide systemic availability and peak plasma concentration achieved; as well as the clearance rate (related to the half-life) after adjusting for variation in dosage due to differences in body weight between children and adults. Receipt of a fatty meal prior to treatment was associated with increased albendazole sulfoxide systemic availability (and by extension, peak plasma concentration and total albendazole sulfoxide exposure following the dose). Parasitic infection (particularly echinococcosis) was associated with altered pharmacokinetic parameters, with infected populations displaying distinct characteristics to uninfected ones.

Conclusions/Significance

These results highlight the extensive inter-individual variation that characterises albendazole sulfoxide pharmacokinetics and provide insight into some of the factors associated with this variation.