Review of the 2017 WHO Guideline: Preventive chemotherapy to control soil-transmitted helminth infections in at-risk population groups. An opportunity lost in translation

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.

Efficacy and safety of moxidectin and albendazole compared with ivermectin and albendazole coadministration in adolescents infected with Trichuris trichiura in Tanzania: an open-label, non-inferiority, randomised, controlled, phase 2/3 trial

BACKGROUND

Control efforts against soil-transmitted helminths focus on preventive chemotherapy with albendazole and mebendazole, however these drugs yield unsatisfactory results against Trichuris trichiura infections. We aimed to assess the efficacy and safety of moxidectin and albendazole compared with ivermectin and albendazole against T trichiura in adolescents living on Pemba Island, Tanzania.

METHODS

This open-label, non-inferiority, randomised, controlled, phase 2/3 trial was done in four secondary schools (Kilindi, Kwale, Ndagoni [Chake Chake District], and Kiuyu [Wete District]) on Pemba Island, Tanzania. Adolescents aged 12-19 years who tested positive for T trichiura in at least two of four Kato-Katz slides with a mean infection intensity of 48 eggs per gram (EPG) of stool or higher were considered for inclusion. Participants were randomly assigned (21:21:2:2:8) to five treatment groups (8 mg moxidectin and 400 mg albendazole [group 1], 200 μg/kg ivermectin and 400 mg albendazole [group 2], 400 mg albendazole [group 3], 200 μg/kg ivermectin [group 4], or 8 mg moxidectin [group 5]) using a computer-generated randomisation code, stratified by baseline T trichiura infection intensity. Study site investigators and participants were not masked to study treatment; however, allocation was concealed to participants. The primary outcome was egg reduction rate (ERR) of T trichiura 14-21 days after treatment in the available case population. Moxidectin and albendazole was considered non-inferior to ivermectin and albendazole (control group) when the lower limit of the two-sided 95% CI of the difference was higher than the non-inferiority margin of -2 percentage points. This study is registered with ClinicalTrials.gov, NCT04700423.

FINDINGS

Between March 1 and April 30, 2021, 771 participants were assessed for eligibility. 221 (29%) of 771 participants were ineligible and a further 14 (2%) were excluded. 207 (39%) of 536 participants were randomly assigned to moxidectin and albendazole, 211 (39%) to ivermectin and albendazole, 19 (4%) to albendazole, 19 (4%) to ivermectin, and 80 (15%) to moxidectin. Primary outcome data were available for all 536 participants. The geometric mean ERR of T trichiura after 14-21 days was 96·8% (95% CI 95·8 to 97·6) with moxidectin and albendazole and 99·0% (98·7 to 99·3) with ivermectin and albendazole (difference of -2·2 percentage points [-4·2 to -1·4]). No serious adverse events were reported during the study. The most reported adverse events were headache (160 [34%] of 465), abdominal pain (78 [17%]), itching (44 [9%]), and dizziness (26 [6%]).

INTERPRETATION

Our findings show inferiority of moxidectin and albendazole to ivermectin and albendazole against T trichiura. However, given the high efficacy, moxidectin coadministration might complement treatment progammes, particularly in areas in which ivermectin is not available FUNDING: Bill and Melinda Gates Foundation, reference number OPP1153928.

Prevalence and Associated Risk Factors of Intestinal Parasitic Infections: A Population-Based Study in Phra Lap Sub-District, Mueang Khon Kaen District, Khon Kaen Province, Northeastern Thailand

Intestinal parasitic infections are still a crucial problem among communities in Northeast Thailand. Misuse of antiparasitic drugs and unhealthy food behaviors are known. This study aimed to explore the prevalence, behavioral health factors, and motivation for self-treatment of anti-parasitic drugs in this area. A community-based cross-sectional study was conducted in Phra Lap sub-district, Mu Khon Kaen district, Khon Kaen province, Northeast Thailand, in 2016. A total of 419 participants were recruited to complete a self-administered questionnaire and stool examination. Binary logistic regression was used to assess the association between the risk factor and parasitic infection. Forty-two participants (10%; 95%CI 7.5-13.3) were positive for at least one parasite species. In this community, the most detected intestinal parasite was Opisthorchis viverrini (5.3%), followed by Strongyloides stercoralis (3.1%). A total of 67.5% of the participants had the experience of anti-parasitic drug treatment within previous 1 year, and "Often eat raw food" was the most common reason for the use of anti-parasitic drugs. On multivariate analysis, parasitic infections were significantly associated with male gender (ORadj. 2.42; 95%CI 1.00-5.85), age ≥ 60 years (ORadj. 7.55; 95%CI 1.60-35.76), and often consuming raw food of at least one type (ORadj. 2.37; 95%CI 1.03-5.44). Given these findings, correction of the dietary habit of eating raw fish/meat, which is the most important measure, and limitation of the use of anthelmintic treatment for individuals with stools positive for ova as well as emphasis on sanitary toilets will be implemented for the prevention and control of parasitic infection in endemic communities.

Longitudinal monitoring of prevalence and intensity of soil-transmitted helminth infections as part of community-wide mass drug administration within the Geshiyaro project in the Bolosso Sore district, Wolaita, Ethiopia

Mass drug administration (MDA), targeted at school-aged children (SAC) is recommended by the World Health Organization for the control of morbidity induced by soil-transmitted helminth (STH) infection in endemic countries. However, MDA does not prevent reinfection between treatment rounds, and research suggests that only treating SAC will not be sufficient to interrupt transmission of STH. In countries with endemic infection, such as Ethiopia, the coverage, community-groups targeted, and rates of reinfection will determine how effective MDA is in suppressing transmission in the long-term. In this paper, individually-linked longitudinal data from three epidemiological STH surveys conducted between November 2018 and November 2020 in the Wolaita region of Ethiopia are analysed to determine how STH prevalence and intensity changes according to individual level treatment data collected over two rounds of MDA. This study demonstrates that while community-wide MDA successfully reduces overall infection intensity across the villages treated, the observed levels of non-compliance to treatment by individuals acts to maintain levels of parasite abundance whereby transmission interruption is not possible at to, despite reasonable levels of MDA coverage in the communities studied (ranging from 65% to 84% of the village populations). This quantifies with substantial data the often-postulated difference between coverage (accepting treatment) and compliance (swallowing of treatment), the latter impacting the former to a previously unquantified level. The paper highlights the need to focus treatment to partially treated, or never treated groups of individuals within existing community wide MDA control activities to interrupt the transmission of STH, and to reduce the basic reproductive number, R0, of the parasites to less than unity in value.

Prevalence and associated factors of soil transmitted helminthiasis among school-age children in wetland and non-wetland areas of Blue Nile Basins, northwest Ethiopia: A community-based comparative study

Introduction:

Different interventions have been done to reduce the burden of soil-transmitted helminths (STH). The available evidences in Ethiopia in either school or community-based school-aged children (SAC) have limitation in wetland areas. This study assessed the prevalence and associated factors of STH infection among SAC in wetland and non-wetland areas of Blue Nile Basins, Amhara Region, Northwest Ethiopia.

Method:

A community-based comparative study was conducted from October to November, 2019. Multistage stratified random sampling technique used to select 716 SAC. Data were collected using structured questionnaire and observational checklist. Stool samples were collected from children using tight-fitting plastic cups following the standard procedures. Data were coded and entered into Epi data version 4.6 and exported to SPSS version 20 software. Bivariate and multivariable logistic regression analysis was employed to identify factors associated with STH.

Results:

The overall prevalence of STH was 30.30% (95% CI: 26.90, 33.90) and did not show significant variation between wetland (33.60% (95% CI: 28.80, 39.60%)) and non-wetland (27.0% (95% CI: (21.90, 31.60)) areas. Presence of human feces near the house and certain habits such as nail trimming and playing with mud/soil was not different between wetland and non-wetlands. Nonetheless, the presence of human feces near the house of respondents was found to be significantly associated with STH infection (p value < 0.001). Moreover, other factors significantly associated with STH infection were lack of nail trimming (p value < 0.001) and playing with mud/soil (p value < 0.01).

Conclusions:

The prevalence of STH was high and did not show significant variation between the two areas. Emphasis needs to be given for hygiene and lifestyle-related factors.

Magnitude of Intestinal Parasite Infection and Associated Factors Among Pregnant Women Attending Antenatal Care Service in Shewarobit Town Health Facilities, North Shoa Zone, Amhara Region, Ethiopia

Introduction

Intestinal parasites are the most common infectious gastrointestinal parasites in developing countries including Ethiopia. Globally, it remains a public health problem by affecting 3.2 billion people, of which 10% were pregnant women. In Sub-Saharan Africa, pregnant women are the risky group next to children for this infection. This study aimed to assess the magnitude and associated factors of intestinal parasite infection among pregnant women.

Methods

Facility-based cross-sectional study was conducted among 365 pregnant women attending antenatal care service in Shewarobit town health facilities, North Shoa Zone, Amhara Region, Ethiopia. Data were collected using an interview questionnaire and laboratory microscopic stool examination from February 1, 2020, to March 30, 2020. Descriptive statistics and multivariable analyses were used to characterize the data and to identify the associated factors with the outcome variable at a p-value <0.05, respectively.

Results

A total of 347 (95.1%) pregnant women participated in this study. The magnitude of intestinal parasite infection was 27.7% during the study period. Among the parasites, G. lamblia and S. mansoni were the most prevalent identified parasites. Pregnant mother, who did not have handwashing practice after using the toilet [AOR: 3.89, 95% CI (1.86–8.13)], had a habit of walking on barefoot [AOR: 5.65, 95% CI (1.72, 18.56)], had uncooked food meal habit [AOR: 5.12, 95% CI (1.24, 21.14)], use of water in unimproved water source [AOR: 3.20, 95% CI (1.11–9.24)], lack of health education [AOR: 4.08, 95% CI (2.01–8.27)], and not dewormed [AOR: 3.09, 95% CI (2.01–7.94)] were predictors for parasitic infection.

Conclusion

High prevalence of intestinal parasite infection is observed in pregnant women. Personal hygiene practice, health education, and water quality were factors identified as contributors to intestinal parasite infection in pregnant women. Public health measures on water and environmental sanitation, health education for intestinal parasite infection and personal hygiene practices, and early deworming are vital to reduce the intestinal parasites’ infection and assure safe pregnancy.

Failure of Repeated MDA with Albendazole for Trichuriasis Control in Schoolchildren of the Yangon Region, Myanmar

Soil-transmitted helminth (STH) infections are still a considerable challenge in Myanmar. We undertook a control program for STH infections (especially Trichuris trichiura) among schoolchildren in Myanmar using mass drug administration (MDA) and health education. Around 1,700 schoolchildren from 15 primary schools in 3 suburban districts (Shwe Pyi Thar, Twantay, and Kyauktan) of the Yangon Region were subjected in this study during 2017-2019. All of the schoolchildren in each school were orally administered albendazole (400 mg in a single dose) 2, 3, and 4 times a year in 2017, 2018, and 2019, respectively. The results revealed that the egg positive rate of any intestinal helminths (including STH) was reduced from 37.6% (649/1,724) in 2017 to 22.8% (352/1,542) in 2019. The egg positive rate of Ascaris lumbricoides was decreased remarkably from 23.3% (402/1,724) in 2017 to 3.6% (56/1,542) in 2019. However, that of T. trichiura was only slightly reduced from 26.9% (464/1,724) in 2017 to 20.2% (312/1,542) in 2019. The intensity of infection with A. lumbricoides and T. trichiura was both more or less reduced, and the proportion of light infection cases with A. lumbricoides and T. trichiura increased from 35.6% in 2017 to 64.3% in 2019 and from 70.3% in 2017 to 81.7% in 2019, respectively. The results indicated that repeated MDAs (2-4 times a year for 3 years) using albendazole on schoolchildren in Myanmar failed to control T. trichiura infection. For a successful control of trichuriasis in Myanmar, new MDA strategies, using a modified albendazole regimen (multiple daily doses for 2 or 3 days) or an alternative anthelmintic drug, such as oxantel pamoate, is strongly recommended.

Comparative study of the intestinal parasitism profiles between communities across the 5 municipalities of the Barranquilla metropolitan area, Colombia

Objectives

The aim of this study was to compare the rate of parasitism and intestinal parasitism profiles of children who live in relatively proximal communities across the 5 municipalities of the Barranquilla metropolitan area, Colombia.

Methods

In total, 986 fecal samples from children aged 1 to 10 were analyzed using a direct method (physiological saline and lugol) and the zinc sulfate flotation technique. A comparative analysis of the parasitism profiles between sampling locations (7 schools and 3 health centers providing growth and development services) was conducted using principal component analysis (PCA). The presence of Taenia solium antibodies was evaluated by the enzyme-linked immunosorbent assay method in 269 serum samples from the same group of children.

Results

The overall prevalence of intestinal parasitism was 57.6% (range, 42.1%–77.6%) across the sampling areas. The prevalence of helminthiasis was between 4.1% and 23.7%, and that of intestinal protozoa was between 38.2% and 73.5%. PCA showed that the parasite profiles of each sampling location shared no common characteristics. A total of 3.0% of the serum samples were positive for T. solium antibodies.

Conclusion

The intestinal parasitism profiles between relatively proximal sampling locations with similar geographic conditions were vastly different, indicating the need to study each small ecological niche on a localized scale to develop more cost-effective interventions for controlling intestinal parasitism.

Geographically Targeted Interventions versus Mass Drug Administration to Control Taenia solium Cysticercosis, Peru

Optimal control strategies for Taenia solium taeniasis and cysticercosis have not been determined. We conducted a 2-year cluster randomized trial in Peru by assigning 23 villages to 1 of 3 geographically targeted intervention approaches. For ring screening (RS), participants living near pigs with cysticercosis were screened for taeniasis; identified cases were treated with niclosamide. In ring treatment (RT), participants living near pigs with cysticercosis received presumptive treatment with niclosamide. In mass treatment (MT), participants received niclosamide treatment every 6 months regardless of location. In each approach, half the villages received targeted or mass oxfendazole for pigs (6 total study arms). We noted significant reductions in seroincidence among pigs in all approaches (67.1% decrease in RS, 69.3% in RT, 64.7% in MT; p<0.001), despite a smaller proportion of population treated by targeted approaches (RS 1.4%, RT 19.3%, MT 88.5%). Our findings suggest multiple approaches can achieve rapid control of T. solium transmission.

Prevalence and Correlation Analysis of Soil-Transmitted Helminths Infections and Treatment Coverage for Preschool and School Aged Children in Kenya: Secondary Analysis of the National School Based Deworming Program Data

Background: Soil-transmitted helminths (STH) are among the most common parasitic infections globally, disproportionately affecting children. Treatment of STH in Kenya is often targeted at preschool (PSAC) and school aged (SAC) children delivered through annual mass drug administration (MDA) in primary schools. Understanding group-specific prevalence and dynamics between treatment and coverage is critical for continued treatment success. This study aims to provide detailed information on group-specific infection prevalence and relative reductions (RR), and their relationships with treatment coverage over time. Additionally, it aims to quantify the correlation between the observed school level infection prevalence and treatment coverage. Methods: Secondary analysis of existing data collected between 2012 and 2018 by the monitoring and evaluation (M&E) program of the National School-Based Deworming (NSBD) program was used. The M&E program conducted surveys utilizing cross-sectional study design, at four survey time points, in a nationally-representative sample of schoolchildren across counties in Kenya. In each participating school, the program randomly sampled 108 children per school, of both groups. Infection prevalence was estimated using binomial regression, RR in prevalence using multivariable mixed effects model, statistical correlations using structural equation modeling, and change-point-analysis using the binary segmentation algorithm. Results: Overall, STH prevalence for PSAC was 33.7, 20.2, 19.0, and 17.9% during Year 1 (Y1), Year 3 (Y3), Year 5 (Y5), and Year 6 (Y6) surveys, respectively with an overall RR of 46.9% (p = 0.001) from Y1 to Y6. Similarly, overall STH prevalence for SAC was 33.6, 18.4, 14.7, and 12.5% during Y1, Y3, Y5, and Y6 surveys, respectively with an overall RR of 62.6% (p < 0.001). An overall (all time points) significant but very weak negative correlation was found between treatment coverage and undifferentiated STH prevalence (r = -0.144, p = 0.002) among PSAC but not in SAC. Further, we observed inter-county heterogeneity variation in infection prevalence, RR, as well as correlations. Conclusion: The analysis showed that after six rounds of MDA, prevalence of STH has significantly declined among both groups of children, however not to a point where it is not a public health problem (below 1%). The analysis, additionally established an overall significant but weak negative correlation between treatment coverage and prevalence, indicating that the current treatment coverage might not be sufficient to drive the overall STH prevalence to below 1%. These findings will allow STH control programs in Kenya to make decisions that will accelerate the attainment of STH elimination as a public health problem.

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

Background

Infections with hookworms affect about half a billion people worldwide. Recommended therapy includes 400 mg of albendazole, which is moderately efficacious. Higher doses have been rarely assessed.

Methods

A randomized, controlled dose-finding trial was conducted in Côte d’Ivoire with the aim of recruiting 120 preschool-aged children (PSAC), 200 school-aged children (SAC), and 200 adults. Eligible PSAC were randomized 1:1:1 to 200 mg, 400 mg, or 600 mg of albendazole; the other age groups were randomized 1:1:1:1:1 to placebo or 200 mg, 400 mg, 600 mg, or 800 mg. The primary outcome was cure rates (CRs) assessed 14–21 days post-treatment by quadruplicate Kato-Katz thick smears. Hyperbolic E_max models were used to determine dose-response.

Results

38 PSAC, 133 SAC, and 196 adults were enrolled. In adults, predicted CRs increased with ascending doses of albendazole, with a CR of 74.9% (95% confidence interval [CI], 55.6%–87.7%) in the 800-mg arm. Observed CRs increased with ascending doses of albendazole reaching a maximum of 94.1% (95% CI, 80.3%–99.3%). In SAC, the predicted dose-response curve increased marginally, with CRs ranging from 64.0% in the 200-mg arm to 76.0% in the 800-mg arm. Sample size in PSAC was considered too small to derive meaningful conclusions. 10.7% and 5.1% of participants reported any adverse event at 3 hours and 24 hours post-treatment, respectively.

Conclusions

A single 800-mg albendazole dose provides higher efficacy against hookworm and is well tolerated in adults and should be considered for community-based strategies targeting adults. For PSAC and SAC, current recommendations suffice.

Clinical Trials Registration

NCT03527745.

Impact of Key Assumptions About the Population Biology of Soil-Transmitted Helminths on the Sustainable Control of Morbidity

The design and evaluation of control programs for soil-transmitted helminths (STHs) is based on surveillance data recording measurements of egg counts in the stool of infected individuals, which underpin estimates of the prevalence and average intensity of infection. There is considerable uncertainty around these measurements and their interpretation. The uncertainty is composed of several sources of measurement error and the limit of detection of fecal smear tests on the one hand, and key assumptions on STH biology on the other hand, including assumptions on the aggregation of worms within hosts and on the impact of density-dependent influences on worm reproduction. Using 2 independently developed models of STH transmission we show how different aspects of STH biology and human behavior impact on STH surveillance and control programs and how accounting for uncertainty can help to develop optimal and sustainable control strategies to meet the World Health Organization (WHO) morbidity target for STHs.

Intestinal parasitic infections and associated factors among pregnant women in Ethiopia: a systematic review and meta-analysis

Background

Intestinal parasitic infections (IPIs) are public health problems widely distributed in the world and cause significant morbidity and mortality; many of which occur among women of reproductive age. IPIs caused by helminthes and protozoan parasites are common among pregnant women. Data on the national pooled prevalence of intestinal parasites and associated factors during pregnancy is not documented well in Ethiopia. This review aims at summarizing evidences on the burden of IPIs and associated factors among pregnant women in Ethiopia.

Methods

Published and unpublished studies were thoroughly searched at MEDLINE/PubMed, EMBASE, Google Scholar, CINAHL, Cochrane library and Science Direct. In addition, repositories of Addis Ababa, Gondar and Jimma Universities were searched. Eligible studies were selected following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline. The pooled prevalence of intestinal parasites and summary odds ratios (ORs) were determined with 95 % confidence intervals (CI). Sub-groups analyses were done based on study region, types of parasites, methods of stool examination and study setting. The statistical analyses were performed using STATA version 14.0 software.

Results

Among 168 retrieved studies, 31 studies with a total population of 12,118 pregnant women were included. The estimated pooled prevalence of IPIs among pregnant women in Ethiopia was 27.32 % (95 % CI: 20.61, 33.87 %). In the subgroup analysis, Oromia and Amhara regions had the highest prevalence with a 29.78 % (95 % CI: 15.97, 43.60) and 29.63 % (95 % CI: 15.37, 43.89); respectively. In addition, studies conducted in the community showed higher prevalence than institution based studies (49.93 % Vs 24.84 %; respectively). The most prevalent type of intestinal parasite identified were Hookworm followed by Ascaris lumbricoides with a pooled prevalence of 11.2 and 10.34 %, respectively. In our analysis; residence, being bare footed, lack of hand washing habit and eating uncooked/raw vegetables were significantly associated with IPIs among pregnant women in Ethiopia.

Conclusions

Prevalence of IPIs during pregnancy is relatively high in Ethiopia. Poor hygienic practices were identified as risk factors. Based on our finding, targeted preventive measures shall be considered so as to prevent morbidity and mortality due to IPIs.

Long-term outcomes of ivermectin-albendazole versus albendazole alone against soil-transmitted helminths: Results from randomized controlled trials in Lao PDR and Pemba Island, Tanzania

Background

Preventive chemotherapy is the cornerstone of soil-transmitted helminth (STH) control. Long-term outcomes and adequate treatment frequency of the recently recommended albendazole-ivermectin have not been studied to date.

Methodology/principal findings

Double-blind randomized controlled trials were conducted in Lao PDR, Pemba Island, Tanzania and Côte d’Ivoire between 2018 and 2020 to evaluate the efficacy and safety of ivermectin-albendazole versus albendazole-placebo in Trichuris trichiura-infected individuals aged 6 to 60. In the framework of this study, in Lao PDR 466 and 413 participants and on Pemba Island, 558 and 515 participants were followed-up six and 12 months post-treatment, respectively. From each participant at least one stool sample was processed for Kato-Katz diagnosis and cure rates (CRs), egg reduction rates (ERRs) and apparent reinfection rates were calculated. If found helminth-positive at six months, participants were re-treated according to their allocated treatment.

Long-term outcomes against T. trichiura based on CRs and ERRs of ivermectin-albendazole compared to albendazole were significantly higher at six months in Lao PDR (CR, 65.8 vs 13.4%, difference; 52.4; 95% CI 45.0–60.0; ERRs, 99.0 vs 79.6, difference 19.4; 95% CI 14.4–24.4) and Pemba Island (CR, 17.8 vs 1.4%, difference; 16.4; 95% CI 11.6–21.0; ERRs, 84.9 vs 21.2, difference 63.8; 95% CI 50.6–76.9) and also at 12 months in Lao PDR (CR, 74.0 vs 23.4%, difference; 50.6; 95% CI 42.6–61.0; ERRs, 99.6 vs 91.3, difference 8.3; 95% CI 5.7–10.8) and Pemba Island (CR, 19.5 vs 3.4%, difference; 16.1; 95% CI 10.7–21.5; ERRs, 92.9 vs 53.6, difference 39.3; 95% CI 31.2–47.4) respectively.

Apparent reinfection rates with T. trichiura were considerably higher on Pemba Island (100.0%, 95% CI, 29.2–100.0) than in Lao PDR (10.0%, 95% CI, 0.2–44.5) at 12 months post-treatment for participants treated with albendazole alone.

Conclusions/significance

The long-term outcomes against T. trichiura of ivermectin-albendazole are superior to albendazole in terms of CRs and ERRs and in reducing infection intensities. Our results will help to guide decisions on how to best use ivermectin-albendazole in the context of large-scale PC programs tailored to the local context to sustainably control STH infections.

Trial registration

ClinicalTrials.gov registered with clinicaltrials.gov, reference: NCT03527732, date assigned: 17 May 2018.

Around 1.5 billion people are infected with the gastrointestinal dwelling nematodes, the so-called soil-transmitted helminths (STHs). Especially chronic high-intensity infections with these parasites can cause substantial morbidity in endemic regions. Preventive chemotherapy, which is the regular administration of a single dose of an anthelmintic drug to at-risk populations, aims to reduce morbidity by lowering the prevalence and intensity of STH infections. Due to the suboptimal efficacy of these recommended single dose monotherapies, particularly against Trichuris trichiura, the use of drug combinations with dissimilar modes of action may enhance treatment efficacy. In double-blind randomized controlled trials in Lao PDR and on Pemba Island, Tanzania, we examined the long-term outcomes of ivermectin-albendazole versus albendazole alone, against T. trichiura. We assessed the infection status, apparent reinfections, new infections and the change of infection intensity for the three major STH species six and 12 months post-treatment. The long-term outcomes (in terms of cure and egg-reduction rates) of the ivermectin-albendazole combination therapy against T. trichiura were significantly higher than that of albendazole alone at all-time points and in both countries. Bi-annual treatment intervals using the ivermectin-albendazole combination might be necessary to sustainably decrease transmission of STH infections.

Preclinical and Clinical Characteristics of the Trichuricidal Drug Oxantel Pamoate and Clinical Development Plans: A Review

Soil-transmitted helminths (Ascaris lumbricoides, hookworm and Trichuris trichiura) infect about one-fifth of the world's population. The currently available drugs are all highly efficacious against A. lumbricoides. However, they are only moderately efficacious against hookworm and poorly efficacious against T. trichiura. Oxantel, a tetrahydropyrimidine derivative discovered in the 1970s, has recently been brought back to our attention given its high efficacy against T. trichiura infections (estimated 76% cure rate and 85% egg reduction rate at a 20 mg/kg dose). This review summarizes the current knowledge on oxantel pamoate and its use against T. trichiura infections in humans. Oxantel pamoate acts locally in the human gastrointestinal tract and binds to the parasite's nicotinic acetylcholine receptor (nAChR), leading to a spastic paralysis of the worm and subsequent expulsion. The drug is metabolically stable, shows low permeability and low systemic bioavailability after oral use. Oxantel pamoate was found to be safe in humans, with only a few mild adverse events reported. Several clinical trials have investigated the efficacy of this drug against T. trichiura and suggest that oxantel pamoate is more efficacious against T. trichiura than the currently recommended drugs, which makes it a strong asset to the depleted drug armamentarium and could help delay or even prevent the development of resistance to existing drugs. We highlight existing data to support the use of oxantel pamoate against T. trichiura infections.

A One Health Approach to Defining Animal and Human Helminth Exposure Risks in a Tribal Village in Southern India

The high burden of soil-transmitted helminth infections has been studied in India; however, little data exist on zoonotic helminths, and on animal-associated exposure to soil-transmitted helminths. Our study took place in the Jawadhu Hills, which is a tribal region in Tamil Nadu, India. Using a One Health approach, we included animal and environmental samples and human risk factors to answer questions about the associations among infected household soil, domestic animals, and human risk factors. Helminth eggs were identified by microscopy in animal and soil samples, and a survey about risk factors was administered to the head of the household. Contact with animals was reported in 71% of households. High levels of helminth infections were found across domestic animal species, especially in goats, chickens, and dogs. Helminth eggs were recorded in 44% of household soil (n = 43/97) and separately in 88% of soil near a water source (n = 28/32). Animal contact was associated with 4.05 higher odds of having helminth eggs in the household soil (P = 0.01), and also having a water source at the household was associated with a 0.33 lower odds of having helminth eggs in the household soil (P = 0.04). Soil moisture was a mediator of this association with a significant indirect effect (P < 0.001). The proportion mediated was 0.50. While our work does not examine transmission, these results support consideration of animal-associated exposure to STH and potentially zoonotic helminths in future interventions to reduce helminth burden. Our study provides support for further investigation of the effects of animals and animal fecal matter on human health.

Effect of mass deworming with antihelminthics for soil-transmitted helminths during pregnancy

BACKGROUND

Helminthiasis is an infestation of the human body with parasitic worms. It is estimated to affect 44 million pregnancies, globally, each year. Intestinal helminthiasis (hookworm infestation) is associated with blood loss and decreased supply of nutrients for erythropoiesis, resulting in iron-deficiency anaemia. Over 50% of the pregnant women in low- and middle-income countries (LMIC) suffer from iron-deficiency anaemia. Though iron-deficiency anaemia is multifactorial, hookworm infestation is a major contributory cause in women of reproductive age in endemic areas. Antihelminthics are highly efficacious, but evidence of their beneficial effect and safety when given during pregnancy has not been established. This is an update of a Cochrane Review last published in 2015.

OBJECTIVES

To determine the effects of mass deworming with antihelminthics for soil-transmitted helminths (STH) during the second or third trimester of pregnancy on maternal and pregnancy outcomes.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) (8 March 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all prospective randomised controlled trials evaluating the effect of administration of antihelminthics versus placebo or no treatment during the second or third trimester of pregnancy; both individual-randomised and cluster-randomised trials were eligible. We excluded quasi-randomised trials and studies that were only available as abstracts with insufficient information.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data, checked accuracy and assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included a total of six trials (24 reports) that randomised 7873 pregnant women. All of the included trials were conducted in antenatal clinics within hospitals in LMICs (Uganda, Nigeria, Peru, India, Sierra Leone and Tanzania). Among primary outcomes, five trials reported maternal anaemia, one trial reported preterm birth and three trials reported perinatal mortality. Among secondary outcomes, included trials reported maternal worm prevalence, low birthweight (LBW) and birthweight. None of the included studies reported maternal anthropometric measures or infant survival at six months. Overall, we judged the included trials to be generally at low risk of bias for most domains, while the certainty of evidence ranged from low to moderate. Analysis suggests that administration of a single dose of antihelminthics in the second trimester of pregnancy may reduce maternal anaemia by 15% (average risk ratio (RR) 0.85, 95% confidence interval (CI) 0.72 to 1.00; I²= 86%; 5 trials, 5745 participants; low-certainty evidence). We are uncertain of the effect of antihelminthics during pregnancy on preterm birth (RR 0.84, 95% CI 0.38 to 1.86; 1 trial, 1042 participants; low-certainty evidence) or perinatal mortality (RR 1.01, 95% CI 0.67 to 1.52; 3 trials, 3356 participants; low-certainty evidence). We are uncertain of the effect of antihelminthics during pregnancy on hookworm (average RR 0.31, 95% CI 0.05 to 1.93; Tau² = 1.76, I² = 99%; 2 trials, 2488 participants; low-certainty evidence). Among other secondary outcomes, findings suggest that administration of antihelminthics during pregnancy may reduce the prevalence of trichuris (average RR 0.68, 95% CI 0.48 to 0.98; I²=75%; 2 trials, 2488 participants; low-certainty evidence) and ascaris (RR 0.24, 95% CI 0.19 to 0.29; I²= 0%; 2 trials, 2488 participants; moderate-certainty evidence). Antihelminthics during pregnancy probably make little or no difference to LBW (RR 0.89, 95% CI 0.69 to 1.16; 3 trials, 2960 participants; moderate-certainty evidence) and birthweight (mean difference 0.00 kg, 95% CI -0.03 kg to 0.04 kg; 3 trials, 2960 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence suggests that administration of a single dose of antihelminthics in the second trimester of pregnancy may reduce maternal anaemia and worm prevalence when used in settings with high prevalence of maternal helminthiasis. Further data is needed to establish the benefit of antihelminthic treatment on other maternal and pregnancy outcomes. Future research should focus on evaluating the effect of these antihelminthics among various subgroups in order to assess whether the effect varies. Future studies could also assess the effectiveness of co-interventions and health education along with antihelminthics for maternal and pregnancy outcomes.

Epidemiology of soil-transmitted helminths following sustained implementation of routine preventive chemotherapy: Demographics and baseline results of a cluster randomised trial in southern Malawi

Malawi has successfully leveraged multiple delivery platforms to scale-up and sustain the implementation of preventive chemotherapy (PCT) for the control of morbidity caused by soil-transmitted helminths (STH). Sentinel monitoring demonstrates this strategy has been successful in reducing STH infection in school-age children, although our understanding of the contemporary epidemiological profile of STH across the broader community remains limited. As part of a multi-site trial evaluating the feasibility of interrupting STH transmission across three countries, this study aimed to describe the baseline demographics and the prevalence, intensity and associated risk factors of STH infection in Mangochi district, southern Malawi. Between October-December 2017, a community census was conducted across the catchment area of seven primary healthcare facilities, enumerating 131,074 individuals across 124 villages. A cross-sectional parasitological survey was then conducted between March-May 2018 in the censused area as a baseline for a cluster randomised trial. An age-stratified random sample of 6,102 individuals were assessed for helminthiasis by Kato-Katz and completed a detailed risk-factor questionnaire. The age-cluster weighted prevalence of any STH infection was 7.8% (95% C.I. 7.0%-8.6%) comprised predominantly of hookworm species and of entirely low-intensity infections. The presence and intensity of infection was significantly higher in men and in adults. Infection was negatively associated with risk factors that included increasing levels of relative household wealth, higher education levels of any adult household member, current school attendance, or recent deworming. In this setting of relatively high coverage of sanitation facilities, there was no association between hookworm and reported access to sanitation, handwashing facilities, or water facilities. These results describe a setting that has reduced the prevalence of STH to a very low level, and confirms many previously recognised risk-factors for infection. Expanding the delivery of anthelmintics to groups where STH infection persist could enable Malawi to move past the objective of elimination of morbidity, and towards the elimination of STH. Trial registration: NCT03014167.

Routine deworming during antenatal care decreases risk of neonatal mortality and low birthweight: A retrospective cohort of survey data

Background

Soil transmitted helminths (STH) are a common infection among pregnant women in areas with poor access to sanitation. Deworming medications are cheap and safe; however, the health benefit of deworming during pregnancy is not clear.

Methods / Principal findings

We created a retrospective cohort of more than 800,000 births from 95 Demographic and Health Survey datasets to estimate the impact of deworming medicine during routine antenatal care (ANC) on neonatal mortality and low birthweight. We first matched births on the probability of receiving deworming during ANC. We then modeled the birth outcomes with the matched group as a random intercept to estimate the effect of deworming during antenatal care after accounting for various risk factors. We also tested for effect modification of soil transmitted helminth prevalence on the impact of deworming during ANC. Receipt of deworming medication during ANC was associated with a 14% reduction in the risk of neonatal mortality (95% confidence interval = 10–17%, n = 797,772 births), with no difference between high and low transmission countries. In low transmission countries, we found an 11% reduction in the odds of low birth weight (95% confidence interval = 8–13%) for women receiving deworming medicine, and in high transmission countries, we found a 2% reduction in the odds of low birthweight (95% confidence interval = 0–5%).

Conclusions / Significance

These results suggest a substantial health benefit for deworming during ANC that may be even greater in countries with low STH transmission.

Soil-transmitted helminths cause a significant burden of disease throughout the world, particularly in communities with limited access to sanitation facilities and clean drinking water. Deworming medicines effectively clear these parasites, are inexpensive, and are well tolerated. However the effectiveness of deworming medicines, particularly for pregnant women, has not been clearly demonstrated. In this paper we analyze more than 800,000 births to measure the effect that deworming medicine during pregnancy has on birth outcomes. When women receive deworming medicine during pregnancy we saw two specific benefits for the baby: first the risk of neonatal mortality (a baby’s death within first 4 weeks of life) decreases by an estimated 14%, and second, the odds of low birthweight were 11% lower in countries with lower transmission of soil-transmitted helminths. In countries with higher transmission of soil-transmitted helminths we saw no effect of deworming medicine on the odds of low birthweight. Given the results, resources leading to widescale distribution of deworming during pregnancy would have a positive effect on child survival and health.

Deworming women of reproductive age during adolescence and pregnancy: what is the impact on morbidity from soil-transmitted helminths infection?

Background

Soil-transmitted helminths (STHs) are a major cause of poor health in low- and middle-income countries. In particular, hookworm is known to cause anaemia in children and women of reproductive age (WRA). One goal of the World Health Organization’s (WHO) 2030 roadmap for neglected tropical diseases is to reduce STH-related morbidity in WRA. As a minimal intervention, the WHO recommends deworming adolescent girls annually during human papilloma virus vaccination programmes and WRA during pregnancy and lactation. These routine interventions are low cost and can be implemented even by the most basic health services in endemic countries. In this study we use a cohort model to investigate the potential impact on STH-related morbidity in WRA.

Results

Annual deworming treatment of adolescent girls reduces the prevalence of moderate- and heavy-intensity infections in this age group by up to 60% in moderate transmission settings and by 12–27% in high transmission settings. Treatment of WRA during pregnancy and lactation on its own has a small (< 20%) but significant effect on morbidity although it does not lead to the achievement of the morbidity target (< 2% moderate- to high-intensity infections) in this age group. However, depending on the age-intensity profile of infection, which may vary geographically, and assumptions on the density-dependence of egg production by fertilised female worms, continued school-based treatment may be able to reduce the force of infection acting on WRA, both through an indirect effect on the overall population-based force of infection and via reducing the burden of infection as children age and move into the WRA age classes. As a result, morbidity in WRA may be eliminated.

Conclusion

While deworming during pregnancy and lactation does not lead to the achievement of the morbidity target in WRA and its efficacy may vary by setting, it is still expected to be beneficial for maternity and child health. Monitoring of any WRA-based intervention is recommended to evaluate its effectiveness.

Modeling the Interruption of the Transmission of Soil-Transmitted Helminths Infections in Kenya: Modeling Deworming, Water, and Sanitation Impacts

Kenya, just like other countries with endemic soil-transmitted helminths (STH), has conducted regular mass drug administration (MDA) program for the last 5 years among school aged children as a way to reduce STH infections burden in the country. However, the point of interruption of transmission of these infections still remains unclear. In this study, we developed and analyzed an age structured mathematical model to predict the elimination period (i.e., time taken to interrupt STH transmission) of these infections in Kenya. The study utilized a deterministic age structured model of the STH population dynamics under a regular treatment program. The model was applied to three main age groups: pre-school age children (2-4 years), school age children (5-14 years), and adult populations (≥15 years) and compared the impact of two interventions on worm burden and elimination period. The model-simulated results were compared with the 5 year field data from the Kenyan deworming program for all the three types of STH (Ascaris lumbricoides, Trichuris trichiura, and hookworm). The model demonstrated that the reduction of worm burden and elimination period depended heavily on four parameter groups; drug efficacy, number of treatment rounds, MDA and water, sanitation and hygiene (WASH) coverage. The analysis showed that for STH infections to be eliminated using MDA alone in a short time period, 3-monthly MDA plan is desired. However, complementation of MDA with WASH at an optimal (95%) coverage level was most effective. These results are important to the Kenyan STH control program as it will guide the recently launched Breaking Transmission Strategy.

Impact of Annual Albendazole versus Four-Monthly Test-and-Treat Approach of Intestinal Parasites on Children Growth-A Longitudinal Four-Arm Randomized Parallel Trial during Two Years of a Community Follow-Up in Bengo, Angola

Malnutrition and intestinal parasites continue to have serious impacts on growth and cognitive development of children in Angola. A longitudinal four-arm randomized parallel trial was conducted to investigate if deworming with a single annual dose of albendazole (annual-ALB) or a four-monthly test-and-treat (4TT) intestinal parasites approach at individual or household levels improve nutritional outcomes of pre-school children in Bengo province. Children with intestinal parasites (n = 121) were randomly assigned (1:1:1:1) to arm A1: annual-ALB*individual level; A2: annual-ALB*household level; A3: 4TT*individual; and A4: 4TT*household level. At baseline, 4, 8, 12, 16, 20, and 24 months of follow-up, growth was assessed by height, weight, height-for-age, weight-for-height, weight-for-age, and mid-upper arm circumference. Intention-to-treat analysis was done using non-parametric approach, mixed effect models, and generalized estimating equations (GEE). Initially, 57% and 26% of the children were infected by Giardia lamblia and Ascaris lumbricoides, respectively. This study did not show that a 4TT intestinal parasites approach results on better growth outcomes of children (height, weight, HAZ, WAZ, WHZ and MUACZ) when compared with annual ALB, with exception of height and WHZ using GEE model at 5% level. Positive temporal effects on most nutrition outcomes were observed. Implementing a longitudinal study in a poor setting is challenging and larger sample sizes and 'pure and clean' data are difficult to obtain. Nevertheless, learned lessons from this intensive study may contribute to future scientific research and to tailor multidisciplinary approaches to minimize malnutrition and infections in resource-poor countries.

Drugs that target early stages of Onchocerca volvulus: A revisited means to facilitate the elimination goals for onchocerciasis

Several issues have been identified with the current programs for the elimination of onchocerciasis that target only transmission by using mass drug administration (MDA) of the drug ivermectin. Alternative and/or complementary treatment regimens as part of a more comprehensive strategy to eliminate onchocerciasis are needed. We posit that the addition of “prophylactic” drugs or therapeutic drugs that can be utilized in a prophylactic strategy to the toolbox of present microfilaricidal drugs and/or future macrofilaricidal treatment regimens will not only improve the chances of meeting the elimination goals but may hasten the time to elimination and also will support achieving a sustained elimination of onchocerciasis. These “prophylactic” drugs will target the infective third- (L3) and fourth-stage (L4) larvae of Onchocerca volvulus and consequently prevent the establishment of new infections not only in uninfected individuals but also in already infected individuals and thus reduce the overall adult worm burden and transmission. Importantly, an effective prophylactic treatment regimen can utilize drugs that are already part of the onchocerciasis elimination program (ivermectin), those being considered for MDA (moxidectin), and/or the potential macrofilaricidal drugs (oxfendazole and emodepside) currently under clinical development. Prophylaxis of onchocerciasis is not a new concept. We present new data showing that these drugs can inhibit L3 molting and/or inhibit motility of L4 at IC₅₀ and IC₉₀ that are covered by the concentration of these drugs in plasma based on the corresponding pharmacological profiles obtained in human clinical trials when these drugs were tested using various doses for the therapeutic treatments of various helminth infections.

Hookworm infection in infants: a case report and review of literature

BACKGROUND

Hookworm infections (Necator americanus, Ancylostoma duodenale) are common in rural areas of tropical and subtropical countries. Human acquisition results from direct percutaneous invasion of infective larvae from contaminated soil. Overall, almost 472 million people in developing rural countries are infected. According to simulation models, hookworm disease has a global financial impact of over US$100 billion a year. Hookworm infection in newborn or infancy is rare, and most of the cases reported in literature are from endemic countries. Here, we describe the case of an infant with an Ancylostoma duodenale infection and review the literature currently available on this topic.

CASE PRESENTATION

An Italian 2-month-old infant presented with vomit and weight loss. Her blood exams showed anemia and eosinophilia and stool analysis resulted positive for hookworms' eggs, identified as Ancylostoma duodenale with real time-PCR. Parasite research on parents' stools resulted negative, and since the mother travelled to Vietnam and Thailand during pregnancy, we assumed a transplacental transmission of the infection. The patient was treated successfully with oral Mebendazole and discharged in good conditions.

DISCUSSION

Hookworm helminthiasis is a major cause of morbidity in children in the tropics and subtropics, but rare in developed countries. Despite most of the patients is usually asymptomatic, children are highly exposed to negative sequelae such as malnutrition, retarded growth and impaired cognitive development. In infants and newborns, the mechanism of infection remains unclear. Although infrequent, vertical transmission of larvae can occur through breastfeeding and transplacentally. Hookworm infection should be taken into account in children with abdominal symptoms and unexplained persistent eosinophilia. The treatment of infants infected by hookworm has potential benefit, but further studies are needed to define the best clinical management of these cases.

Assessment of fecal calprotectin and fecal occult blood as point-of-care markers for soil-transmitted helminth attributable intestinal morbidity in a case-control substudy conducted in Côte d'Ivoire, Lao PDR and Pemba Island, Tanzania

BACKGROUND

Infections with soil-transmitted helminths (STHs) may result in chronic inflammatory disorders affecting the human host. The objective of this study was to evaluate Fecal Calprotectin (FC) and Fecal Occult Blood (FOB) in individuals infected and non-infected with STHs to identify potential intestinal morbidity markers.

METHODS

Stool from participants diagnosed positive for Trichuris trichiura and concomitant STH infections from three countries was used to perform FC and FOB point-of-care assays. Simultaneously, identified STH negative participants underwent FC and FOB testing as controls. Potential associations between test results and determinants were analyzed using multivariable logistic regression.

FINDINGS

In total, 1034 T. trichiura infected cases (mostly light infections) and 157 STH negative controls were tested for FC and FOB. Among all participants tested, 18·5% had ≥ 50 µg/g FC concentration, while 14 (1·2%) were positive for FOB. No statistically significant association was found between T. trichiura infection or Ascaris lumbricoides co-infection and FC concentration, while an inverse association (odds ratio (OR): 0·45, 95% credible intervals (CrI): 0·26, 0·75) was found between hookworm co-infection and FC concentration. In Lao PDR, the proportion of participants in the ≥ 50 µg/g FC category was significantly higher in the oldest age category compared to the 5-11 years group (OR: 3·31, 95% CrI: 1·62, 7·24). Too few participants were found positive for FOB to derive any conclusions.

INTERPRETATION

Studies are needed to better understand the relationship between intestinal morbidity and STH infections. Suitable, standardized, low-cost markers of STH attributable morbidity to better monitor the impact of STH control interventions are necessary.

FUNDING

BMGF (OPP1153928).

Baseline patterns of infection in regions of Benin, Malawi and India seeking to interrupt transmission of soil transmitted helminths (STH) in the DeWorm3 trial

Global efforts to control morbidity associated with soil-transmitted helminth infections (STH) have focused largely on the targeted treatment of high-risk groups, including children and pregnant women. However, it is not clear when such programs can be discontinued and there are concerns about the sustainability of current STH control programs. The DeWorm3 project is a large multi-country community cluster randomized trial in Benin, India and Malawi designed to determine the feasibility of interrupting the transmission of STH using community-wide delivery of mass drug administration (MDA) with anthelmintics over multiple rounds. Here, we present baseline data and estimate key epidemiological parameters important in determining the likelihood of transmission interruption in the DeWorm3 trial. A baseline census was conducted in October-December 2017 in India, November-December 2017 in Malawi and in January-February 2018 in Benin. The baseline census enumerated all members of each household and collected demographic data and information on occupation, assets, and access to water, sanitation and hygiene (WASH). Each study site was divided into 40 clusters of at least 1,650 individuals per cluster. Clusters were randomized to receive twice yearly community-wide MDA with albendazole (GSK) targeting eligible individuals of all ages (20 clusters), or to receive the standard-of-care deworming program targeting children provided in each country. In each site, a randomly selected group of 150 individuals per cluster (6,000 total per site) was selected from the baseline census using stratified random sampling, and each individual provided a single stool sample for analysis of STH infection using the Kato-Katz technique. Study site, household and individual characteristics were summarized as appropriate. We estimated key epidemiological parameters including the force of infection and the degree of parasite aggregation within the population. The DeWorm3 sites range in population from 94,969 to 140,932. The population age distribution varied significantly by site, with the highest proportion of infants and young children in Malawi and the highest proportion of adults in India. The baseline age- and cluster-weighted prevalence, as measured by Kato-Katz, varied across sites and by species, Baseline hookworm prevalence in India was 21.4% (95% CI: 20.4–22.4%), while prevalence of Ascaris and Trichuris by Kato-Katz was low (0.1% and 0.3% overall). In Malawi, the overall age- and cluster-weighted STH prevalence was 7.7% (95% CI: 7.1–8.4%) predominantly driven by hookworm infections (7.4%) while Ascaris (0.1%) and Trichuris (0.3%) infections were rare. In Benin, the overall age- and cluster-weighted prevalence was significantly lower (5.6%, 95% CI: 5.1–6.2%) and Ascaris (2.0%, 95% CI: 1.6–2.3%) was more common than in other sites. Ascaris infections were more likely to be moderate- or heavy-intensity (43.7%, unweighted) compared to hookworm (5.0%). The force of infection for hookworm was highest in adults in India and Malawi but appeared relatively stable across age groups in Benin. These data demonstrate the significant variability between the sites in terms of demography, socio-economic status and environmental characteristics. In addition, the baseline prevalence and intensity data from DeWorm3 suggest that each site has unique epidemiologic characteristics that will be critical in determining correlates of achieving STH transmission interruption in the DeWorm3 trial.

Trial registration: The trial was registered at ClinicalTrials.gov (NCT03014167).

Intestinal parasitic worms, soil-transmitted helminths, are among the most common infectious organisms of humans. In many low-resource settings, these infections result in considerable morbidity, including reductions in childhood growth and development, increased risk of anemia and reductions in future educational achievement and income earning potential. The current global strategy for controlling these infections is through routine deworming of school and pre-school aged children as well as pregnant women. Since many adults and non-school going children are infected with these parasites, the current strategy does not prevent the rapid reinfection of individuals despite repeated treatment. The DeWorm3 trial is a large multi-country trial being conducted in Benin, India and Malawi to test the feasibility of using mass drug administration of deworming medications to all individuals in a community to interrupt these infections in some geographic areas. Here we present baseline data from these communities and estimate the transmission potential of these infections at each of the sites.

Patterns of individual non-treatment during multiple rounds of mass drug administration for control of soil-transmitted helminths in the TUMIKIA trial, Kenya: a secondary longitudinal analysis

BACKGROUND

Few studies have been done of patterns of treatment during mass drug administration (MDA) to control neglected tropical diseases. We used routinely collected individual-level treatment records that had been collated for the Tuangamize Minyoo Kenya Imarisha Afya (Swahili for Eradicate Worms in Kenya for Better Health [TUMIKIA]) trial, done in coastal Kenya from 2015 to 2017. In this analysis we estimate the extent of and factors associated with the same individuals not being treated over multiple rounds of MDA, which we term systematic non-treatment.

METHODS

We linked the baseline population of the TUMIKIA trial randomly assigned to receive biannual community-wide MDA for soil-transmitted helminthiasis to longitudinal records on receipt of treatment in any of the four treatment rounds of the study. We fitted logistic regression models to estimate the association of non-treatment in a given round with non-treatment in the previous round, controlling for identified predictors of non-treatment. We also used multinomial logistic regression to identify factors associated with part or no treatment versus complete treatment.

FINDINGS

36 327 participants were included in our analysis: 16 236 children aged 2-14 years and 20 091 adults aged 15 years or older. The odds of having no treatment recorded was higher if a participant was not treated during the previous round of MDA (adjusted odds ratio [OR] 3·60, 95% CI 3·08-4·20 for children and 5·58, 5·01-6·21 for adults). For children, school attendance and rural residence reduced the odds of receiving part or no treatment, whereas odds were increased by least poor socioeconomic status and living in an urban or periurban household. Women had higher odds than men of receiving part or no treatment. However, when those with pregnancy or childbirth in the previous 2 weeks were excluded, women became more likely to receive complete treatment. Adults aged 20-25 years were the age group with the highest odds of receiving part (OR 1·41, 95% CI 1·22-1·63) or no treatment (OR 1·81, 95% CI 1·53-2·14).

INTERPRETATION

Non-treatment was associated with specific sociodemographic groups and characteristics and did not occcur at random. This finding has important implications for MDA programme effectiveness, the relevance of which will intensify as disease prevalence decreases and infections become increasingly clustered.

FUNDING

Bill & Melinda Gates Foundation, Joint Global Health Trials Scheme of the Medical Research Council, UK Department for International Development, Wellcome Trust, Children's Investment Fund Foundation, and London Centre for Neglected Tropical Diseases.

Loop-Mediated Isothermal Amplification as Point-of-Care Diagnosis for Neglected Parasitic Infections

The World Health Organisation (WHO) has placed twenty diseases into a group known as neglected tropical diseases (NTDs), twelve of them being parasitic diseases: Chagas’ disease, cysticercosis/taeniasis, echinococcosis, food-borne trematodiasis, human African trypanosomiasis (sleeping sickness), leishmaniasis, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis, soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis), guinea-worm and scabies. Such diseases affect millions of people in developing countries where one of the main problems concerning the control of these diseases is diagnosis-based due to the most affected areas usually being far from laboratories having suitable infrastructure and/or being equipped with sophisticated equipment. Advances have been made during the last two decades regarding standardising and introducing techniques enabling diagnoses to be made in remote places, i.e., the loop-mediated isothermal amplification (LAMP) technique. This technique’s advantages include being able to perform it using simple equipment, diagnosis made directly in the field, low cost of each test and the technique’s high specificity. Using this technique could thus contribute toward neglected parasite infection (NPI) control and eradication programmes. This review describes the advances made to date regarding LAMP tests, as it has been found that even though several studies have been conducted concerning most NPI, information is scarce for others.

Efficacy, safety and acceptability of a new chewable formulation versus the solid tablet of mebendazole against hookworm infections in children: An open-label, randomized controlled trial

BACKGROUND

Soil-transmitted helminths (STHs) infect almost 1·5 billion people worldwide. The control of STH infections is based on preventive chemotherapy using either albendazole or mebendazole. Before being widely used, a sufficient body of evidence on efficacy, safety and acceptability is warranted for the new chewable child-friendly formulation of mebendazole that was recently developed.

METHODS

We conducted a randomised controlled superiority trial in four primary schools and kindergartens on Pemba Island, Tanzania. We considered eligible children aged 3 to 12 years with a hookworm infection intensity of at least 50 eggs per gram (EPG) of stool and no chronic diseases. Participants were allocated to treatment arms (ratio 1:1) using a computer generated random sequence. Our primary outcome was geometric mean based egg reduction rate (ERR) against hookworm assessed 14-21 days post-treatment. This trial complete and is registered with ClinicalTrials.gov, number NCT03995680 (June 24, 2019).

FINDINGS

397 children were eligible and randomised into the solid (198) or chewable (199) tablet arms, of whom 393 were analysed. We found no significant difference between both formulations in terms of ERR (solid 70·8% versus chewable 68·5%, difference in ERR_{geometric mean} 2·3%-points, 95% CI -7·8 to 12·6, p = 0.65) and CR (11·2 versus 12·7%, 95% CI -4·9 to 7·9, p = 0.65) against hookworm infections. Adverse events were mild in both treatment arms.

INTERPRETATIONS

Though we could not demonstrate superiority in terms of efficacy of the new formulation, the difference between arms was small and therefore, the chewable formulation could be safely used as an alternative to swallowable tablets, in particular in young children who may have swallowing difficulties. This might help increase compliance and, consequently, enhance the effect of preventive chemotherapy.

Soil-Transmitted Helminth Vaccines: Are We Getting Closer?

Parasitic helminths infect over one-fourth of the human population resulting in significant morbidity, and in some cases, death in endemic countries. Despite mass drug administration (MDA) to school-aged children and other control measures, helminth infections are spreading into new areas. Thus, there is a strong rationale for developing anthelminthic vaccines as cost-effective, long-term immunological control strategies, which, unlike MDA, are not haunted by the threat of emerging drug-resistant helminths nor limited by reinfection risk. Advances in vaccinology, immunology, and immunomics include the development of new tools that improve the safety, immunogenicity, and efficacy of vaccines; and some of these tools have been used in the development of helminth vaccines. The development of anthelminthic vaccines is fraught with difficulty. Multiple lifecycle stages exist each presenting stage-specific antigens. Further, helminth parasites are notorious for their ability to dampen down and regulate host immunity. One of the first significant challenges in developing any vaccine is identifying suitable candidate protective antigens. This review explores our current knowledge in lead antigen identification and reports on recent pre-clinical and clinical trials in the context of the soil-transmitted helminths Trichuris, the hookworms and Ascaris. Ultimately, a multivalent anthelminthic vaccine could become an essential tool for achieving the medium-to long-term goal of controlling, or even eliminating helminth infections.

Using RIGHT (Reporting Items for Practice Guidelines in Healthcare) to evaluate the reporting quality of WHO guidelines

BACKGROUND

Without adequate reporting of research, valuable time and resources are wasted. In the same vein, adequate reporting of practice guidelines to optimise patient care is equally important. Our study examines the quality of reporting of published WHO guidelines, over time, using the RIGHT (Reporting Items for Practice Guidelines in HealThcare) reporting checklist.

METHODS

We examined English-language guidelines approved by the WHO Guidelines Review Committee from inception of the committee in 2007 until 31 December 2017. Pairs of independent, trained reviewers assessed the reporting quality of these guidelines. Descriptive data were summarised with frequencies and percentages.

RESULTS

We included 182 eligible guidelines. Overall, 25 out of the 34 RIGHT items were reported in 75% or more of the WHO guidelines. The reporting rates improved over time. Further, 90% of the guidelines reported document type in the title. The identification of evidence, the rationale for recommendations and the review process were reported in more than 80% of guidelines. The certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system was assessed in 81% of the guidelines assessed. While 82% of guidelines reported funding sources, only 25% mentioned the role of funders.

CONCLUSIONS

WHO guidelines provide adequate reporting of many of the RIGHT items and reporting has improved over time. WHO guidelines compare favourably to guidelines produced by other organisations. However, reporting can be further improved in a number of areas.

Prevalence of Intestinal Parasitic Infection and Its Associated Factors Among School Children in Two Primary Schools in Harbu Town, North East Ethiopia: Cross-Sectional Study

BACKGROUND

Intestinal parasitic infections (IPIs) are major health problems in many developing countries. School children between the ages of 5 and 15 years suffer the highest infection rate and parasitic burden that are attributed to poor sanitation and hygiene. In Ethiopia, the prevalence of IPIs among school children is high (ranging from 66.7% to 83.8%).

METHODS

School-based cross-sectional study was conducted in two primary schools at Harbu Town, Northeast Ethiopia from February to May, 2018. Systematic random sampling technique was employed to select study participants from the two school compounds. The sample size was determined by a single population proportion statistical formula and the minimum numbers of study participants defined were 400 school children. Socio-demographic and risk factor-related information were collected using structured questionnaire. Data about detection and identification of intestinal parasites were obtained from laboratory examination of stool specimen by using wet mount and formol-ether concentration techniques. Stool specimen from each study participant was collected using clean, properly labeled and leak-proof stool cup. The data were processed and analyzed using SPSS version 20 software.

RESULTS

Out of a total of 400 study participants, 86 (21.5%) were found with one or more IPIs. Six different types of intestinal parasites were identified, Entamoeba histolytica was the most 33 (8.3%) detected parasite followed by Hymenolopis nana 19 (4.8%) and Schistosoma mansoni 19 (4.8%). The least identified parasite was Giardia lamblia, detected only from four study participants. Male study participants showed 2.42 times risk (AOR = 2.42, 95% CI = 1.25-4.7, P = 0.009) of acquiring parasitic infection than female. Presence of water body near to home and having contact with water bodies showed 7.64 (AOR= 7.64, 95% CI= 3.3-17.8, P= 0.000) and 4.6 (AOR=4.6, 95% CI: 2.04-10.57, P= 0.000) times risk of infection with parasitic infection among school children, respectively.

CONCLUSION

IPIs were highly prevalent health problem among the two primary school children in Harbu Town. Sex, availability of water bodies near to house and contact with water bodies were having significant association with the prevalence of IPIs.

First international external quality assessment scheme of nucleic acid amplification tests for the detection of Schistosoma and soil-transmitted helminths, including Strongyloides: A pilot study

BACKGROUND

Nucleic acid amplification tests (NAATs) are increasingly being used as diagnostic tools for soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and A. ceylanicum), Strongyloides stercoralis and Schistosoma in human stool. Currently, there is a large diversity of NAATs being applied, but an external quality assessment scheme (EQAS) for these diagnostics is lacking. An EQAS involves a blinded process where test results reported by a laboratory are compared to those reported by reference or expert laboratories, allowing for an objective assessment of the diagnostic performance of a laboratory. In the current study, we piloted an international EQAS for these helminths (i) to investigate the feasibility of designing and delivering an EQAS; (ii) to assess the diagnostic performance of laboratories; and (iii) to gain insights into the different NAAT protocols used.

METHODS AND PRINCIPAL FINDINGS

A panel of twelve stool samples and eight DNA samples was validated by six expert laboratories for the presence of six helminths (Ascaris, Trichuris, N. americanus, Ancylostoma, Strongyloides and Schistosoma). Subsequently this panel was sent to 15 globally dispersed laboratories. We found a high degree of diversity among the different DNA extraction and NAAT protocols. Although most laboratories performed well, we could clearly identify the laboratories that were poorly performing.

CONCLUSIONS/SIGNIFICANCE

We showed the technical feasibility of an international EQAS for the NAAT of STHs, Strongyloides and Schistosoma. In addition, we documented that there are clear benefits for participating laboratories, as they can confirm and/or improve the diagnostic performance of their NAATs. Further research should aim to identify factors that explain poor performance of NAATs.

Missed opportunity of deworming a Maasai boy from nomadic family leading to life threatening intestinal obstruction

Mass deworming against soil-transmitted helminthiasis, including Ascaris lumbricoides (AL), is one of the largest public health interventions in low- and middle-income countries. The prevalence of A. lumbricoides in Tanzania is 6.8%. We present a 3-year-old male of a known Tanzanian nomadic tribe (Masaai tribe) with history of missed deworming, who was brought to the emergency department with a 3-day history of constipation, nonprojectile, bilious vomiting, generalized abdominal distension and pain.

He was diagnosed with intestinal obstruction by the use of a plain abdominal X-ray, which revealed marked gaseous distension of the stomach and bowels without significant air-fluid levels. He was initially treated with intravenous ceftriaxone 50 mg/kg, metronidazole 15 mg/kg and acetaminophen 15 mg/kg. An explorative laparotomy was then performed. Intraoperative findings demonstrated a dense collection of A. lumbricoides worms in the gangrenous proximal jejunum and duodenum. Thorough abdominal lavage was carried out and abdomen was closed.

Community Health Impacts of the Trident Copper Mine Project in Northwestern Zambia: Results from Repeated Cross-Sectional Surveys

The application of a health impact assessment (HIA) for a large-scale copper mining project in rural Zambia triggered the long-term monitoring and evaluation of determinants of health and health outcomes in communities living in proximity to the mine. Three consecutive cross-sectional surveys were conducted at intervals of four years; thus, at baseline (2011), four (2015) and eight (2019) years into the project's development. Using the same field and laboratory procedures, the surveys allowed for determining changes in health indicators at the household level, in young children (<5 years), school attendees (9-14 years) and women (15-49 years). Results were compared between communities considered impacted by the project and communities outside the project area (comparison communities). The prevalence of Plasmodium falciparum infection increased in both the impacted and comparison communities between 2011 and 2019 but remained consistently lower in the impacted communities. Stunting in children < 5 years and the prevalence of intestinal parasite infections in children aged 9-14 years mostly decreased. In women of reproductive age, selected health indicators (i.e., anaemia, syphilis, underweight and place of delivery) either remained stable or improved. Impacted communities generally showed better health outcomes than comparison communities, suggesting that the health interventions implemented by the project as a consequence of the HIA have mitigated potential negative effects and enhanced positive effects. Caution is indicated to avoid promotion of health inequalities within and beyond the project area.

Soil-transmitted helminthiasis in four districts in Bangladesh: household cluster surveys of prevalence and intervention status

BACKGROUND

In 2016, after 8 years of twice-annual nationwide preventive chemotherapy (PC) administration to school-age children (SAC), the Bangladesh Ministry of Health & Family Welfare (MOHFW) sought improved impact and intervention monitoring data to assess progress toward the newly adopted goal of eliminating soil-transmitted helminthiasis (STH) as a public health problem.

METHODS

We surveyed four Bangladeshi districts between August and October 2017. We conducted a multi-stage, cluster-sample, household survey which produced equal-probability samples for preschool-age children (PSAC; 1-4 years), SAC (5-14 years), and adults (≥ 15 years). Standardized questionnaires were administered, using Android-based smart phones running an Open Data Kit application. Stool samples were collected and testing for STH prevalence and infection intensity used the Kato-Katz technique.

RESULTS

In all, 4318 stool samples were collected from 7164 participants. Estimates of STH prevalence by risk group in three of the four surveyed districts ranged from 3.4 to 5.0%, all with upper, 1-sided 95% confidence limits < 10%. However, STH prevalence estimates in Sirajganj District ranged from 23.4 to 29.1%. Infections in that district were spatially focal; four of the 30 survey clusters had > 50% prevalence in at least one risk group. Among all tested specimens, Ascaris lumbricoides was the most common STH parasite [8.2% (n = 352)], followed by Trichuris trichiura [0.9% (n = 37)], and hookworm [0.6% (n = 27)]. In each district, PC coverage among SAC was above the 75% program target but did not exceed 45% among PSAC in any district. Improved sanitation at home, school, or work was over 90% in all districts.

CONCLUSIONS

In the three low-prevalence districts, the MOHFW is considering decreasing the frequency of mass drug administration, per World Health Organization (WHO) guidelines. Also, the MOHFW will focus programmatic resources and supervisory efforts on Sirajganj District. Despite considering WHO guidance, the MOHFW will not expand PC administration to women of reproductive age partly due to the low prevalence of hookworm and T. trichiura, the STH parasites that contribute most to morbidity in that risk group. Data collected from surveys such as ours would help effectively guide future STH control efforts in Bangladesh and elsewhere.

Zoonotic Ancylostomiasis: An Update of a Continually Neglected Zoonosis

Hookworm infections are classified as the most impactful of the human soil-transmitted helminth (STH) infections, causing a disease burden of ∼4 million disability-adjusted life years, with a global prevalence of 406-480 million infections. Until a decade ago, epidemiological surveys largely assumed Necator americanus and Ancylostoma duodenale as the relevant human hookworm species implicated as contributing to iron-deficiency anemia. This assumption was based on the indistinguishable morphology of the Ancylostoma spp. eggs in stool and the absence of awareness of a third zoonotic hookworm species, Ancylostoma ceylanicum. The expanded use of molecular diagnostic assays for differentiating hookworm species infections during STH surveys has now implicated A. ceylanicum, a predominant hookworm of dogs in Asia, as the second most common hookworm species infecting humans in Southeast Asia and the Pacific. Despite this, with the exception of sporadic case reports, there is a paucity of data available on the impact of this emerging zoonosis on human health at a population level. This situation also challenges the current paradigm, necessitating a One Health approach to hookworm control in populations in which this zoonosis is endemic. Here, we have summarized the available research studies and case reports on human A. ceylanicum infections in Southeast Asia and the Pacific after 2013 using a systematic review approach. We summarized eight research articles and five clinical case studies, highlighting the importance of future in-depth investigation of zoonotic A. ceylanicum infections using sensitive and cost-effective diagnostic tools.

Soil transmitted helminth infections in Ghana: a ten year review

For more than a decade, intervention programs have been instituted in Ghana to combat soil transmitted helminth (STHs) infections. Knowledge of the trend of the infection in the country is needed for evaluation and modification of existing control programs to achieve national targets. The objective of this review is to examine the pattern of soil transmitted infections in Ghana between 2009-2018. We searched and reviewed published literature on soil transmitted helminths in Ghana in PubMed, Medline, Google Scholar and Institutional Repositories of Kwame Nkrumah University of Science and Technology, University of Ghana, University of Cape Coast, and University for Development Studies-Tamale. We observed paucity of research work on STHs in Ghana over the period of this review. Twenty-nine studies consisting of 24 published works in peer reviewed journals and five graduate theses were included in the study. Hookworm was the most prevalent of STHs recorded followed by roundworm, threadworm, and whipworm. Pinworm was very rarely reported. These infections were reported from different regions and ecological zones of the country and among children, pregnant women, farmers, food vendors, children in orphanage home and psychiatric institution. Although there is some downward trend over the period, soil transmitted helminths are still prevalent in Ghana. This is an indication of some hope of eventual control and elimination of these diseases in the country if control measures are optimised. Further research particularly population studies into soil transmitted helminths in Ghana is needed.

A holistic approach is needed to control the perpetual burden of soil-transmitted helminth infections among indigenous schoolchildren in Malaysia

A cross-sectional survey was conducted among 1,142 Orang Ali schoolchildren in six states of Peninsular Malaysia to investigate the current prevalence and risk factors of STH infections. Faecal samples were examined using direct smear, formalin-ether sedimentation, Kato-Katz, and Harada-Mori methods. A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, personal hygiene, and health status of the participants. Overall, 70.1% (95% CI = 67.4, 72.7) of the participants were infected with at least one of the STH species. The prevalence of Ascaris lumbricoides, Trichuris trichiura, and hookworm infections was 63.1%, 61.8% and 11.5%, respectively. Moderate-to-heavy STH infections accounted for 61.3% of the total infections. Univariate and logistic regression analyses revealed different sets of risk factors, with age (> 10 years) being the significant risk factor of all three STH species. Moreover, other species-specific risk factors were identified including being a member of the Senoi tribe, family size (≥ 7 members), school size (150-250 pupils), maternal unemployment, unimproved source of drinking water, lacking improved toilet in the house, inadequate WASH facilities at school, not washing hands before eating, and not washing fruits before eating; presence of domestic animals, and not wearing shoes when outside. The high prevalence of STH infections found in the study population exceeds the WHO policy intervention threshold (20% prevalence). Thus, an innovative holistic approach should be adopted to control STH infections among these children as part of the efforts to improve the quality of life of the entire Orang Asli population. .

Assessing expanded community wide treatment for schistosomiasis: Baseline infection status and self-reported risk factors in three communities from the Greater Accra region, Ghana

BACKGROUND

This paper reports on the baseline prevalence and associated risk factor findings of a pilot, longitudinal study exploring community-wide treatment of schistosomiasis and soil-transmitted helminthiasis, using albendazole plus praziquantel in the Greater Accra region of Ghana.

METHOD

From three communities, at least, 658 individuals were enrolled into the study via random household selection. Prevalence and intensity of schistosomiasis and STH infection were determined from stool and urine samples with a questionnaire being administered in order to explore other morbidities and risk factors. Factor analysis of household demographic variables was undertaken to generate a socioeconomic score; this was then further categorised into tertiles. Proportional-odds cumulative logit generalised estimating equation (GEE) models were used to investigate categorical ordinal intensity of infection associations with morbidity. Separately, logistic GEE models were used to investigate risk factor associations with infection prevalence.

RESULTS

Both Schistosoma haematobium and S. mansoni were prevalent in the three communities, with the prevalence of S. haematobium ranging from 3.3% (24/679; 95% CI = 1.9-4.7) to 19% (114/632; 95% CI = 15.8-22.2) and S. mansoni ranging from 30% (202/679; 95% CI = 26.5-33.5) to 78.3% (409/536; 95% CI = 74.7-81.9). The total prevalence of STH across all three sites was negligible at 1.3% (24/1847; 95% CI = 0.8-1.9) comprising mainly hookworm (10/1847). Multivariable statistical models indicated males to be 2.3 (95% CI = 1.7-3.3) times more likely to have a high intensity S. mansoni infection and 1.5 (95% CI = 1.1-2) times more likely to have a high intensity of S. haematobium infection compared to females. There was no significant difference in the likelihood of infection with S. mansoni between adults and school age children (SAC), however S. haematobium infections were found to be 2.5 (95% CI = 1.8-3.5) times more likely to occur in school age children than in adults. Multivariable statistical models (adjusted for age and sex) indicated an association between schistosomiasis and a number of self-reported morbidity indicators (notably diarrhoea and blood in stool and urine). Low socio-economic status was also associated with SCH infection (OR: 2; 95% CI = 1.3-3.2).

CONCLUSION

The communities targeted by this study showed a range of Schistosoma prevalence's of infection, from hypo-endemic through to meso-endemic and hyper-endemic. The prevalence of SCH across the different age groups in the study locations highlights the large number of individuals currently being left out of the standard morbidity control method of annual treatment of the SAC.

The Strongyloides stercoralis-hookworms association as a path to the estimation of the global burden of strongyloidiasis: A systematic review

TRIAL REGISTRATION

PROSPERO (registration code CRD42019131127).

Quantifying the handprint-Footprint balance into a single score: The example of pharmaceuticals

Life Cycle Assessment typically focuses on the footprint of products and services, expressed on three Areas of Protection (AoP): Human Health, Ecosystems and Resources. While the handprint is often expressed qualitatively, quantified handprints have recently been compared directly to the footprint concerning one AoP: Human Health. We propose to take this one step further by simultaneously comparing the quantified handprint and footprint on all AoPs through normalization and weighting of the results towards a single score. We discuss two example cases of a pharmaceutical treatment: mebendazole to treat soil-transmitted helminthiases and paliperidone palmitate to treat schizophrenia. Each time, treatment is compared to 'no treatment'. The footprint of health care is compared to the handprint of improved patient health. The handprint and footprint were normalized separately. To include sensitivity in the normalization step we applied four sets of external normalization factors for both handprint (Global Burden of Disease) and footprint (ReCiPe and PROSUITE). At the weighting step we applied 26 sets of panel weighting factors from three sources. We propose the Relative Sustainability Benefit Rate (RSBR) as a new metric to quantify the relative difference in combined handprint and footprint single score between two alternatives. When only considering the footprint, the first case study is associated with an increased single score burden of treatment compared to 'no treatment', while in the second case study treatment reduces the single score burden by 41.1% compared to 'no treatment'. Also including the handprint provided new insights for the first case study, now showing a decrease of 56.4% in single score burden for treatment compared to 'no treatment'. For the second case study the reduction of single score burden was confirmed as the handprint burden was also decreased because of treatment by 9.9%, reinforcing the findings.

Risk map development for soil-transmitted helminth infections in Argentina

BACKGROUND

Soil-transmitted helminths (STHs) comprise a group of helminth parasites that are included in the list of Neglected Tropical Diseases and require a passage through the soil to become infective. Several studies have detected that infection with STHs are associated with certain socioeconomic, environmental and soil characteristics. In Argentina, the presence of these parasites has been detected through a few point studies conducted in localities from 11 of the 23 provinces that comprise the country.

METHODS/PRINCIPAL FINDINGS

The most important characteristics previously associated with the presence of STHs were identified and ranked through the use of an expert survey and the Analytical Hierarchy Process (AHP) in order to construct a risk map of STHs specific for Argentina. Prevalence data from previous studies was used to validate the generated risk map. The map shows that half of Argentina, from the Central provinces to the North, contains localities with the characteristics necessary for the development of these parasites.

CONCLUSIONS/SIGNIFICANCE

The predicted map should serve as a useful tool for guiding the identification of survey areas for the generation of baseline data, detecting hotspots of infection, planning and prioritizing areas for control interventions, and eventually performing post-implementation surveillance activities.

What does soil-transmitted helminth elimination look like? Results from a targeted molecular detection survey in Japan

BACKGROUND

Japan is one of the few countries believed to have eliminated soil-transmitted helminths (STHs). In 1949, the national prevalence of Ascaris lumbricoides was 62.9%, which decreased to 0.6% in 1973 due to improvements in infrastructure, socioeconomic status, and the implementation of national STH control measures. The Parasitosis Prevention Law ended in 1994 and population-level screening ceased in Japan; therefore, current transmission status of STH in Japan is not well characterized. Sporadic cases of STH infections continue to be reported, raising the possibility of a larger-scale recrudescence of STH infections. Given that traditional microscopic detection methods are not sensitive to low-intensity STH infections, we conducted targeted prevalence surveys using sensitive PCR-based assays to evaluate the current STH-transmission status and to describe epidemiological characteristics of areas of Japan believed to have achieved historical elimination of STHs.

METHODS

Stool samples were collected from 682 preschool- and school-aged children from six localities of Japan with previously high prevalence of STH. Caregivers of participants completed a questionnaire to ascertain access to water, sanitation and hygiene (WASH), and potential exposures to environmental contamination. For fecal testing, multi-parallel real-time PCR assays were used to detect infections of Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale and Trichuris trichiura.

RESULTS

Among the 682 children, no positive samples were identified, and participants reported high standards of WASH.

CONCLUSIONS

To our knowledge, this is the first STH-surveillance study in Japan to use sensitive molecular techniques for STH detection. The results suggest that recrudescence of STH infections has not occurred, and that declines in prevalence have been sustained in the sampled areas. These findings suggest that reductions in prevalence below the elimination thresholds, suggestive of transmission interruption, are possible. Additionally, this study provides circumstantial evidence that multi-parallel real-time PCR methods are applicable for evaluating elimination status in areas where STH prevalence is extremely low.

Ruling out early trimester pregnancy when implementing community-based deworming programs

BACKGROUND

Large-scale deworming programs have, to date, mostly targeted preschool- and school-age children. As community-based deworming programs become more common, deworming will be offered to women of reproductive age. The World Health Organization recommends preventive chemotherapy be administered to pregnant women only after the first trimester. It is therefore important for deworming programs to be able to identify women in early pregnancy. Our objective was to validate a short questionnaire which could be used by deworming program managers to identify and screen out women in early pregnancy.

METHODOLOGY/PRINCIPAL FINDINGS

In May and June 2018, interviewers administered a questionnaire, followed by a pregnancy test, to 1,203 adult women living in the Peruvian Amazon. Regression analyses were performed to identify questions with high predictive properties (using the pregnancy test as the gold standard). Test parameters were computed at different decision tree nodes (where nodes represented questions). With 106 women confirmed to be pregnant, the positive predictive value of asking the single question 'Are you pregnant?' was 100%, at a 'cost' of a false negative rate of 1.9% (i.e. 21 women were incorrectly identified as not pregnant when they were truly pregnant). Additional questions reduced the false negative rate, but increased the false positive rate. Rates were dependent on both the combination and the order of questions.

CONCLUSIONS/SIGNIFICANCE

To identify women in early pregnancy when deworming programs are community-based, both the number and order of questions are important. The local context and cultural acceptability of different questions should inform this decision. When numbers are manageable and resources are available, pregnancy tests can be considered at different decision tree nodes to confirm pregnancy status. Trade-offs in terms of efficiency and misclassification rates will need to be considered to optimize deworming coverage in women of reproductive age.

Domains of transmission and association of community, school, and household sanitation with soil-transmitted helminth infections among children in coastal Kenya

INTRODUCTION

Few studies have simultaneously examined the role of sanitation conditions at the home, school, and community on soil-transmitted helminth (STH) infection. We examined the contribution of each domain that children inhabit (home, village, and school) to STH infection and estimated the association of STH infection with sanitation in each domain.

METHODS

Using data from 4,104 children from Kwale County, Kenya, who reported attending school, we used logistic regression models with cross-classified random effects to calculate measures of general contextual effects and estimate associations of village sanitation coverage (percentage of households with reported access to sanitation), school sanitation coverage (number of usable toilets per enrolled pupil), and sanitation access at home with STH infection.

FINDINGS

We found reported use of a sanitation facility by households was associated with reduced prevalence of hookworm infection but not with reduced prevalence of T. trichiura infection. School sanitation coverage > 3 toilets per 100 pupils was associated with lower prevalence of hookworm infection. School sanitation was not associated with T. trichiura infection. Village sanitation coverage > 81% was associated with reduced prevalence of T. trichiura infection, but no protective association was detected for hookworm infection. General contextual effects represented by residual heterogeneity between village and school domains had comparable impact upon likelihood of hookworm and T. trichiura infection as sanitation coverage in either of these domains.

CONCLUSION

Findings support the importance of providing good sanitation facilities to support mass drug administration in reducing the burden of STH infection in children.

Human population movement can impede the elimination of soil-transmitted helminth transmission in regions with heterogeneity in mass drug administration coverage and transmission potential between villages: a metapopulation analysis

BACKGROUND

Soil-transmitted helminth (STH) infections affect predominantly socio-economically disadvantaged populations in sub-Saharan Africa, East Asia and the Americas. Previous mathematical modelling studies have evaluated optimal intervention strategies to break STH transmission in clusters of villages. These studies assumed that villages are closed independent units with no movement of people in or out of communities. Here we examine how human population movement, for example, of seasonal migrant labourers, affect the outcome of mass drug administration (MDA) programmes.

RESULTS

We used a stochastic individual-based metapopulation model to analyse the impact of human population movement at varying rates on STH elimination efforts. Specifically, we looked at seasonal clumped movement events of infected individuals into a village. We showed that even if on average 75% of the entire resident population within a village are treated, an annual rate of 2-3% of the population arriving from an untreated source village can reduce the probability of STH elimination to less than 50% in high-prevalence settings. If a village is infection-free, an annual movement rate of 2-3% from an infected source village imposes a risk of re-introduction of STH of 75% or higher, unless the prevalence in the source village is less than 20%. Even a single arrival of 2-3% of the population can impose a risk of re-introducing STH of 50% or greater depending on the prevalence in the source village. The risk of re-introduction also depends on both the age group of moving individuals and STH species, since the pattern of cross-sectional age-prevalence and age-intensity profiles of infection in the human host are species-specific.

CONCLUSIONS

Planning for STH elimination programmes should account for human mobility patterns in defined regions. We recommend that individuals arriving from areas with ongoing STH transmission should receive preventive chemotherapy for STHs. This can most easily be implemented if migration is seasonal and overlaps with treatment rounds, e.g. seasonal migrant labour. Moreover, transmission hotspots in or near treatment clusters should be eliminated, for example, by implementing appropriate water, sanitation and hygiene (WASH) measures and targeting treatment to individuals living in hotspots.

Soil-Transmitted Helminthiasis in Children from a Rural Community Taking Part in a Periodic Deworming Program in the Peruvian Amazon

Children in the Peruvian Amazon Basin are at risk of soil-transmitted helminths (STH) infections. This study aimed to determine the prevalence of STH infection in children from a rural Amazonian community of Peru and to elucidate epidemiological risk factors associated with its perpetuation while on a school-based deworming program with mebendazole. Stool samples of children aged 2-14 years and their mothers were analyzed through direct smear analysis, Kato-Katz, spontaneous sedimentation in tube, Baermann's method, and agar plate culture. A questionnaire was administered to collect epidemiological information of interest. Among 124 children, 25.8% had one or more STH. Individual prevalence rates were as follows: Ascaris lumbricoides, 16.1%; Strongyloides stercoralis, 10.5%; hookworm, 1.6%; and Trichuris trichiura, (1.6%). The prevalence of common STH (A. lumbricoides, T. trichiura, and hookworm) was higher among children aged 2-5 years than older children (31.6% versus 12.8%; P = 0.01). In terms of sanitation deficits, walking barefoot was significantly associated with STH infection (OR = 3.28; CI 95% = 1.11-12.07). Furthermore, STH-infected children more frequently had a mother who was concomitantly infected by STH than the non-STH-infected counterpart (36.4% versus 14.1%, P = 0.02). In conclusion, STH infection is highly prevalent in children from this Amazonian community despite routine deworming. Institutional health policies may include hygiene and sanitation improvements and screening/deworming of mothers to limit the dissemination of STH. Further studies are needed to address the social and epidemiological mechanics perpetuating these infections.

Reassessment of the prevalence of soil-transmitted helminth infections in Sri Lanka to enable a more focused control programme: a cross-sectional national school survey with spatial modelling

BACKGROUND

In Sri Lanka, deworming programmes for soil-transmitted helminth infections became an integral part of school health in the 1960s, whereas routine antenatal deworming with mebendazole started in the 1980s. A 2003 national soil-transmitted helminth survey done among schoolchildren found an overall prevalence of 6·9%. In our study, we aimed to reassess the national prevalence of soil-transmitted helminth infections to enable implementation of a more focused control programme that targets smaller administrative areas at risk of continued transmission.

METHODS

We did a cross-sectional, school-based, national survey using multistage stratified cluster sampling, covering all nine provinces as well as populations at high risk of soil-transmitted helminth infections living in urban slums and in plantation-sector communities. Our study population was children aged 5-7 years attending state schools. Faecal samples were collected and analysed with duplicate modified Kato-Katz smears. We modelled the risk of soil-transmitted helminth infection using generalised linear mixed-effects models, and we developed prevalence maps to enable informed decision making at the smallest health administrative level in the country.

FINDINGS

Between Jan 23 and May 9, 2017, we recruited 5946 children from 130 schools; 4276 (71·9%) children provided a faecal sample for examination. National prevalence of soil-transmitted helminth infection was 0·97% (95% CI 0·63-1·48) among primary schoolchildren. Prevalence in the high-risk communities surveyed was higher than national prevalence: 2·73% (0·75-6·87) in urban slum communities and 9·02% (4·29-18·0) in plantation sector communities. Our prevalence maps showed that the lowest-level health administrative regions could be categorised into low risk (prevalence <1%), high risk (prevalence >10%), or intermediate risk (1-10%) areas.

INTERPRETATION

Our survey findings indicate that the national prevalence of soil-transmitted helminth infection has continued to decline in Sri Lanka. On the basis of WHO guidelines, we recommend discontinuation of routine deworming in low-risk areas, continuation of annual deworming in high-risk areas, and deworming once every 2 years in intermediate-risk areas, for at least 4 years.

FUNDING

Task Force for Global Health and WHO.

Community-level epidemiology of soil-transmitted helminths in the context of school-based deworming: Baseline results of a cluster randomised trial on the coast of Kenya

TRIAL REGISTRATION

ClinicalTrials.gov NCT02397772.