Soil-transmitted Helminth Burden Research Articles

Effectiveness of one and two doses of ivermectin mass drug administration in reducing the prevalence and intensity of soil-transmitted helminth (STH) infections in Western Province, Solomon Islands: a cluster-randomised, before-after analysis

Ivermectin mass drug administration (MDA) is effective for controlling onchocerciasis and scabies, with evidence supporting its role in some species of soil-transmitted helminth (STH) infections. In the context of RISE, a cluster-randomised trial for scabies, this study evaluated the effectiveness of ivermectin MDA in reducing STH burden in the Western Province of Solomon Islands. Twenty villages were randomised 1:1 to receive ivermectin MDA as one dose (IVM-1) or two doses (IVM-2) for scabies. The effectiveness of one and two doses in reducing STH prevalence and intensity was evaluated before (May 2019) and 21 months after (February 2021) MDA in May 2019. All residents aged 12 months or older in the study villages were eligible to participate and provide stool specimens. Species-specific STH infection and intensity were assessed using quantitative PCR. We compared prevalence and intensity of infection between baseline and 21 months in each intervention arm individually using cluster-level analysis (adjusted for clustering) and individual-level analysis (adjusted for sex, age, and clustering). The primary outcomes were the prevalence risk difference (RD) from the cluster-level analysis, and the change in adjusted odds of infection from the individual-level analysis. Secondary outcomes included change in incident rates of mean eggs per gram (epg) of stool from baseline to 21 months, relative risk difference in prevalence and relative change in odds of infection between arms at 21 months. Sex data (male/female) were self-reported. Overall, STH infection was assessed in 830 participants from 18 villages at baseline and 1172 from 20 villages at follow-up. Females represented 58% (n=478) of the sample at baseline and 59% (n=690) at follow-up. We observed a reduction in Strongyloides spp. prevalence following two doses of ivermectin MDA in the cluster-level analysis from 7.0% (32/458 participants) to 1.2% (8/674 participants), corresponding to a RD of-0.07 (95% CI-0.14 to-0.01, p=0.036), and in the individual-level analysis (OR 0.11, 95% CI 0.04-0.33, p<0.001). T.trichiura prevalence decreased following one dose from 19.4% (74/372 participants) to 11.7% (56/505 participants) (OR 0.44, 95% CI 0.26-0.73, p=0.0040), while egg count reduced in both arms (IVM-1: IRR 0.28, 95% CI 0.11-0.70, p=0.0070; IVM-2: IRR 0.18, 95% CI 0.08-0.40, p<0.001), in the individual-level analysis. We did not detect a significant difference in effect measures between the one- and two-dose arms for any species after 21 months. Our study highlights the long-term benefits of ivermectin MDA in reducing the burden of Strongyloides spp. and T.trichiura. STH control programs should leverage the geographical overlap of NTDs, existing drug distribution channels, and broad-spectrum agents. The National Health and Medical Research Council of Australia.

Using quantitative PCR to identify opportunities to strengthen soil-transmitted helminth control in Solomon Islands: A cross-sectional epidemiological survey

BackgroundThe Kato-Katz microscopy technique is the global standard for assessment of soil-transmitted helminth (STH) burden. However, major limitations include its poor sensitivity, requirement for rapid sample processing, and inability to differentiate hookworm species nor detect Strongyloides spp. infections. We assessed the prevalence and intensity of STH species in Solomon Islands by conducting a province-wide survey using quantitative PCR (qPCR) for diagnosis, which can provide much better characterisation of STH burden than microscopy.Methodology/Principal findingsWe conducted a cross-sectional survey in 18 villages in Western Province to detect infections with six STH species and quantify intensity with three. We used linear mixed model regression to identify potential water, sanitation, and hygiene (WASH) and environmental risk factors for infection. We collected stool specimens from 830 village residents. Overall STH prevalence was 63.3% (range 27.5 to 91.5% across villages), led by Necator americanus (54.5% [range 17.5–89.4%]), followed by Ancylostoma ceylanicum (15.5% [range 2.8–45.8%]), Trichuris trichiura (9.1% [range 0–79.2%]), and Strongyloides spp. (3.2% [range 0–29.2%]). Most infections were of light intensity for N. americanus (85.7%) and T. trichiura (90.7%). Owning a household latrine was associated with a lower risk of N. americanus infection (AOR 0.41, 95% CI 0.24–0.68) while greater precipitation was linked to more common T. trichiura infection (AOR 1.14, 95% CI 1.04–1.25).Conclusion/SignificanceIn this first large-scale population survey of STH in the Pacific using qPCR, we found evidence that ivermectin should be incorporated into STH control programmes because of the presence of T. trichiura and Strongyloides spp., both of which are poorly responsive to albendazole. Furthermore, One Health strategies are needed for improved A. ceylanicum and Strongyloides spp. control, WASH access and use should be improved to complement deworming programmes, and control efforts should ideally be expanded to entire communities.Trial registrationClinicalTrials.gov Australian and New Zealand Clinical Trials Registry ACTRN12618001086257.

Impact of ivermectin mass drug administration on burden of soil-transmitted helminths in onchocerciasis control and elimination programs, Yeki district, southwest Ethiopia.

Community-directed treatment with ivermectin (CDTi) is the primary strategy employed to control and eliminate human onchocerciasis in Ethiopia. After long-term mass distribution for onchocerciasis, ivermectin is expected to have additional benefits beyond the envisioned targets by reducing the burden of other co-endemic parasitic infections as to STHs. To date, studies focused on the collateral impact of CDTi on STH in Ethiopia are scanty. Two community-based cross-sectional surveys (baseline in 1997 and post-CDTi in 2017) were conducted to evaluate the impact of long-term CDTi employed to control and eliminate onchocerciasis on the burden of STH infections in Yeki district of southwest Ethiopia. Stool samples were collected and examined using Ritchie`s concentration and Kato-Katz techniques in the baseline and current study, respectively. Overall, 188(38.3%, 95% Confidence interval (CI) 34.1–42.7%) individuals were positive at least for any of the STH species from 491 study participants in the post-CDTi. The prevalence of A. lumbricoides, hookworms, and T. trichiura was 11.2% (95% CI 8.7–14.3%), 16.3% (95% CI 13.3–19.8%), and 29.9% (95% CI 26.1–34.1%), respectively. Individuals aged 5–9 years had a significantly higher prevalence of A. lumbricoides (Adjusted odds ratio (AOR) 6.5, 95% CI 1.7–25.4), T. trichuria (AOR 8, 95% CI 2.6–25.1), and any STH infection (AOR 5, 95% CI 1.7–14.7) than those of ≥ 51 years. Also, significantly higher prevalences of T. trichuria infection were observed in individuals aged 10–14 years (AOR 4.1, 95% CI 1.7–9.9), 15–20 years (AOR 3.1, 95% CI 1.2–8.1), 21–30 years (AOR 2.4, 95% CI 1.1–5.5), and 31–40 years (AOR 3.2, 95% CI 1.3–7.5) compared with those of ≥ 51 years. The prevalence of A. lumbricoides was significantly higher in males (AOR 0.5, 95% CI 0.3–0.9). Of the 491 study participants, only data from 400 individuals who had not been involved in a mass drug administration (MDA) with other STH anthelmintics were considered in the comparative analysis. Before CDTi, the prevalence of A. lumbricoides, T. trichiura, hookworm, and any STH infection was 47.1% (95% CI 41.6–52.7%), 3.3% (95% CI 1.8–5.9%), 37.9% (95% CI 32.7–43.5%), and 58.8% (95% CI 53.2–64.1%), respectively. Long-term CDTi considerably reduced the prevalences of A. lumbricoides and hookworm by 76.2% and 56.9%, respectively (p < 0.001). Nonetheless, CDTi did not affect the prevalence of T. trichiura infection and, in contrast, it was significantly higher in the current study (P < 0.001). Overall post-CDTi prevalence of any STH infection was considerably lower than reported in the baseline (p < 0.001). It is evidenced that long-term CDTi for onchocerciasis control and elimination had additional benefits by reducing the prevalence of STH infections specifically of A. lumbricoides and hookworm, but had no impact on infections with T. trichuria. Our finding of additional health benefits of large-scale ivermectin administration taking it will aid to increase positive engagement and sustain participation of communities during MDA campaigns, and strengthen governmental and non-governmental organizations (NGOs) support for the undergoing national onchocerciasis elimination program.

Trend of Soil-Transmitted Helminths in Ethiopian Children: A Systematic Review and Meta-Analysis (2000-2018).

Background Ethiopia is one of the tropical countries with a heavy burden of soil-transmitted helminths. As a result, the nation has been implementing mass drug administration, water, sanitation, and hygiene and health extension programs to control those parasites. Hence, updated data about the prevalence and trend of parasites over time has a pivotal role to assess the success of existing control programs. Methods Studies conducted between 2000 and 2018 were searched from PubMed, Google Scholar, and local journals for systematic reviews and meta-analysis following the PRISMA guideline and checklists. Eligible studies were selected based on preset inclusion and exclusion criteria. The quality of the included studies was assessed using the Newcastle-Ottawa Scale in meta-analysis. Heterogeneity between studies was assessed using the Cochran Q test and I2 test statistics based on the random effect model. Comprehensive meta-analysis (CMA 2.0) was used to calculate the pooled prevalence, and metaregression was run to assess the trend of parasite prevalence over time. Results Thirty-eight studies recruiting 16,266 participants were included in the review. The pooled prevalence of intestinal parasites was 52.0% (95% CI: 44.4-59.5). Amhara region was with the highest prevalence (60.3%; 95% CI: 50.1-69.6). Among soil-transmitted helminths, Ascaris lumbricoides (11.2%; 95% CI: 8.4-14.8) was with the highest pooled prevalence followed by hookworms (10.4%; 95% CI: 7.9-13.7) and Trichuris trichiura (3.6%; 95% CI: 2.4-5.4). Metaregression analysis revealed that all soil-transmitted helminths did not show a significantly decreasing trend over time (p > 0.05). Conclusion Despite various control efforts having been made, soil-transmitted helminths are of high distribution, and their prevalence is not significantly decreasing in Ethiopia. Hence, other control approaches like community-led sanitation should be integrated with mass drug administration to achieve the national goal of soil-transmitted helminth elimination by 2025.

Diagnostic Techniques for Soil-Transmitted Helminths - Recent Advances.

Soil-transmitted helminth (STH) infections (hookworms, Trichuris, Ascaris) and Strongyloides spp. are associated with a substantial global burden and high morbidity. Sensitive and specific methods for diagnosis of these infections are essential for mapping the burden in communities, accurate assessment of infection levels, to guide interventions and monitoring the success of STH control programs. Despite considerable progress to control STH over several decades, we are still far from identifying a fully adequate diagnostic test. Conventional microscopy-based methods such as direct Kato–Katz smear or mounts after stool centrifugation/flotation-based concentration techniques have been the mainstay of diagnosis, especially in resource-poor countries where these infections abound. However, recently, these are being adapted to closed, easy to perform, digital formats, thereby improving the sensitivity as well as applicability in a remote, resource-limited setting. The use of image analysis systems to identify and quantify helminth eggs, with potential adaptation to smartphones, is also promising. Antibody detection tests have a limited role mostly in the case of Strongyloides hyperinfection. Coproantigen detection tests have been developed and used in veterinary practice for detection of STH, but these have not been evaluated for use in humans. More sensitive molecular diagnostics, including assays developed with new bioinformatic tools and techniques such as polymerase chain reaction (PCR), quantitative PCR (qPCR) and loop-mediated amplification assay, can help in the clear and precise assessment of STH burden during elimination phase and are of immense value for diagnosis in areas with low endemicity and in travelers to endemic regions. Moreover, the molecular techniques will help detect new species that may emerge. Sample preservation and efficient DNA extraction are critical and significantly affect the efficiency of molecular diagnostic tests. In addition to the diagnosis of clinical or asymptomatic infection in humans, detection of STH eggs in environmental samples is imperative to boost STH control efforts. Overall the diagnostic performance, cost-effectiveness, ease of performance, rapidity and in-field applicability of any test should be considered when choosing from the various diagnostic assays in areas with different endemicity, in addition to striving towards the development of novel technologies and optimization of existing methods.

Post-intervention epidemiology of STH in Bangladesh: Data to sustain the gains.

In 2008, Bangladesh initiated Preventive Chemotherapy (PCT) for school-age children (SAC) through bi-annual school-based mass drug administration (MDA) to control Soil-Transmitted Helminth (STH) infections. In 2016, the Ministry of Health and Family Welfare's Program on Lymphatic Filariasis Elimination and STH (ELFSTH) initiated district-level community impact assessments with Children Without Worms (CWW) using standardized, population-based sampling to measure the post-intervention STH burden across all ages (≥ 1 yr) for the three STH species. The Integrated Community-based Survey for Program Monitoring (ICSPM) was developed by CWW and was used to survey 12 districts in Bangladesh from 2017-2020. We excluded the first two district data as piloting caused some sampling errors and combined the individual demographic and parasite-specific characteristics from the subsequent 10 districts, linking them with the laboratory data for collective analysis. Our analysis identified district-specific epidemiologic findings, important for program decisions. Of the 17,874 enrolled individuals, our results are based on 10,824 (61.0%) stool samples. Overall, the prevalence of any STH species was substantially reduced to 14% from 79.8% in 2005. The impact was similar across all ages. STH prevalence was 14% in 10 districts collectively, but remained high in four districts, despite their high reported PCT coverage in previous years. Among all, Bhola district was unique because it was the only district with high T.trichuris prevalence. Bangladesh successfully lowered STH prevalence across all ages despite targeting SAC only. Data from the survey indicate a significant number of adults and pre-school age children (PSAC) were self-deworming with purchased pills. This may account for the flat impact curve across all ages. Overall prevalence varied across surveyed districts, with persistent high transmission in the northeastern districts and a district in the central flood zone, indicating possible service and ecological factors. Discrepancies in the impact between districts highlight the need for district-level data to evaluate program implementation after consistent high PCT coverage.

The impact of Worms and Ladders, an innovative health educational board game on Soil-Transmitted Helminthiasis control in Abeokuta, Southwest Nigeria.

In most endemic sub-Saharan African countries, repeated infections with soil-transmitted helminth (STH) occur as early as six weeks after the end of mass drug administration (MDA) with albendazole. In this study, we designed a new health educational board game Worms and Ladders and evaluated its potential to complement MDA with albendazole and reduce reinfection rates through the promotion of good hygiene practices among school-aged children. The evaluation employed a randomized control trial (RCT) design. Baseline knowledge, attitude and practices (KAP) relating to STH were obtained using a questionnaire from 372 pupils across six schools in Abeokuta, Nigeria. Schools were randomly assigned into intervention and control group, with the former and latter receiving Worms and Ladders and the common Snake and Ladder board game respectively. Fresh stool samples were also collected at baseline for STH diagnosis before administering 400mg single dose albendazole. Follow-up assessments of STH burden and KAP were conducted three and six months' post-intervention. Data generated from the study were analyzed using SPSS 20.0 software, with confidence interval set at 95%. Prevalence of STH dropped from 25.0% to 10.4% in the intervention group and 49.4% to 33.3% in the control group at three months' post-intervention. The prevalence further dropped to 5.6% in the intervention group at six months' post-intervention. However, it increased to 37.2% in the control group at six months' post-intervention. There was a significant difference (p<0.05) in prevalence after intervention among the groups. KAP on transmission, control and prevention of STH significantly improved (p<0.05) from 5.2% to 97.9% in the intervention group compared to 6.2% to 7.1% in the control group. The Worms and Ladders board game shows the potential to teach and promote good hygiene behavior among SAC. These findings posit the newly developed game as a reliable tool to complement mass drug administration campaigns for STH control.

Prevalence of soil-transmitted helminthes and its association with water, sanitation, hygiene among schoolchildren and barriers for schools level prevention in technology villages of Hawassa University: Mixed design.

BackgroundSoil-transmitted helminths (STH) remain one of the most common causes of morbidity among children in Ethiopia. Assessment of the magnitude of STH and its association with water, sanitation, and hygiene (WASH) and identify barriers for school-level prevention assist public health planners to prioritize promotion strategies and is a basic step for intervention. However, there is a lack of evidence on the prevalence of STH and its association with WASH and barriers for school-level prevention among schoolchildren.ObjectiveTo assess the prevalence of STH and its association with WASH and identify barriers for school level prevention in technology village of Hawassa University; 2019.MethodsAn institution-based analytical cross-sectional study was conducted on a sample of 1080 schoolchildren from September 5 to October 15, 2019. A two-stage cluster and purposive sampling technique were used to draw the study participants. A pretested, structured questionnaire, observation checklist, and in-depth interview were used to collect the data. Two grams of stool samples were collected from each study participant and examined using direct wet mount and Kato-Katz technique. Data were entered into Epi Info version 7 and analyzed using SPSS version 25. Both bi-variable and multivariable logistic regression analyses were done. Qualitative data were analyzed using thematic content analysis method by Atlas-Ti software and presented in narratives.ResultsThe overall prevalence of STHs was 23.1% (95% CI = 21.4, 27.6). The identified predictors of STHs were large family size (AOR = 2.03; 95% CI = 1.53–3.99), absence of separate toilet room for male and female (AOR = 3.33; 95% CI = 1.91–5.79), toilet not easy to clean (AOR = 2.17; 95% CI = 1.44–3.33), inadequate knowledge about STHs (AOR = 2.08; 95% CI = 1.07–3.44) and children who had travelled greater than 100 meters to access toilet (AOR = 3.45; 95% CI = 2.24–8.92). These results were supported by the individual, institutional, socio-economic and cultural qualitative results.ConclusionThe STHs was moderate public health concerns. Reinforcing the existing fragile water, sanitation and hygiene programs and regular deworming of schoolchildren may support to reduce the burden of STHs. Also, increasing modern family planning methods utilization to decrease family size is recommended.

Helminthiasis among School-Age Children and Hygiene Conditions of Selected Schools in Lafia, Nasarawa State, Nigeria.

The burden of soil-transmitted helminths (STHs) infections in Nigeria is enormous with serious public health significance. This study, therefore, assessed helminthiasis among school-age children and the hygiene conditions of schools in Lafia, Nasarawa State, Nigeria between December 2015 and April 2016 from four randomly selected primary schools. Stool samples were collected from 200 primary school pupils including 80 males (40%) and 120 females (60%) between five and 16 years, using clean sample bottles and a standard parasitology examination technique at the central laboratory at the Federal University, Lafia. An overall prevalence of 33.5% (67/200) helminths infections was recorded. A checklist of Ascaris lumbricoides, hookworm, Trichuris trichiura, and Strongyloides stercoralis was generated from the pooled data of the four studied schools in which A. lumbricoides occurred highest with 13% (26/200) while S. stercoralis was the least prevalent at 2.50% (5/200). Among the schools sampled, St. James Pilot Science Primary School’s children were the most infected at 44% (22/50). Multiple infections were observed in three of the four schools sampled. There was no significant difference (p > 0.05) in prevalence rates of different STHs infections in relation to age group and gender across schools. Our findings showed that the hygiene conditions in the studied schools were poor without water, hand washing materials, refuse bins, as well as poor sanitary conditions. This study also identified ova and larvae of STHs parasites in the analyzed soil samples from the studied schools. Most school-age children had knowledge about contamination but few among them washed their hands with water and soap. The obtained result indicated a negative association between the prevalence of STHs and the proportion of pupils that cleaned up with water after defection. We, therefore, advise that hygiene conditions in schools be improved and that the government should prioritize enrolling all primary schools in Nasarawa state for the school health program so as to reduce the burden of STHs among school-age children in the state.

Mapping Soil-Transmitted Helminth Parasite Infection in Rwanda: Estimating Endemicity and Identifying At-Risk Populations.

Soil-transmitted helminth (STH) infections are globally distributed intestinal parasite infections caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms (Ancylostoma duodenale and Necator americanus). STH infection constitutes a major public health threat, with heavy burdens observed in many of the world’s tropical and subtropical regions. Mass drug administration and sanitation improvements can drastically reduce STH prevalence and associated morbidity. However, identifying targeted areas in need of treatment is hampered by a lack of knowledge on geographical and population-level risk factors. In this study, we applied Bayesian geostatistical modelling to data from a national school-based STH infection survey in Rwanda to (1) identify ecological and population-level risk factors and (2) provide comprehensive precision maps of infection burdens. Our results indicated that STH infections were heterogeneously distributed across the country and showed signatures of spatial clustering, though the magnitude of clustering varied among parasites. The highest rates of endemic clustering were attributed to A. lumbricoides infection. Concordant infection patterns among the three parasite groups highlighted populations currently most at-risk of morbidity. Population-dense areas in the Western and North-Western regions of Rwanda represent areas that have continued to exhibit high STH burden across two surveys and are likely in need of targeted interventions. Our maps support the need for an updated evaluation of STH endemicity in western Rwanda to evaluate progress in MDA efforts and identify communities that need further local interventions to further reduce morbidity caused by STH infections.

Epidemiology of soil-transmitted helminths and Schistosoma mansoni: a base-line survey among school children, Ejaji, Ethiopia

School children are among the high risk groups for soil-transmitted helminths (STHs) and Schistosoma mansoni (S. mansoni) infections in developing countries. The aim of this study was to determine the prevalence and associated factors of STHs and S. mansoni among primary school children. A cross-sectional study was conducted from February 15 to March 30, 2016, involving a total of 340 primary school children (age range 6 to 19 years). Socio-demographic and related data were collected using interviewer-administered questionnaire. Stool samples were collected from each study participant and examined using direct wet mount and modified Kato-Katz thick smear technique. Intensity of the STHs and S. mansoni were determined by estimating the eggs per gram (EPG) of stool. Factors associated with STH and S. mansoni infections were analyzed using multivariable logistic regression model. Prevalence of the STHs and S. mansoni were 38.2% and 12.94%, respectively. The main predictors of STH infections among the children studied were being in the age group of 16-19 years, untrimmed finger nail and household latrine unavailability. Moreover, male children, children with habit of swimming and bathing in the river had significantly higher odds of S. mansoni infection. Most of the children infected with the parasites had light infection. The burden of STHs and S. mansoni was high among the school children. Deworming intervention should be strengthened, along with awareness creation on proper disposal of human excreta and personal hygiene. Regular monitoring of the burden of the parasites and mass drug administration is required.

Inclusion of edaphic predictors for enhancement of models to determine distribution of soil-transmitted helminths: the case of Zimbabwe

BackgroundReliable mapping of soil-transmitted helminth (STH) parasites requires rigorous statistical and machine learning algorithms capable of integrating the combined influence of several determinants to predict distributions. This study tested whether combining edaphic predictors with relevant environmental predictors improves model performance when predicting the distribution of STH, Ascaris lumbricoides and hookworms at a national scale in Zimbabwe.MethodsGeo-referenced parasitological data obtained from a 2010/2011 national survey indicating a confirmed presence or absence of STH among school children aged 10–15 years was used to calibrate ten species distribution models (SDMs). The performance of SDMs calibrated with a set of environmental and edaphic variables was compared to that of SDMs calibrated with environmental variables only. Model performance was evaluated using the true skill statistic and receiver operating characteristic curve.ResultsResults show a significant improvement in model performance for both A. lumbricoides and hookworms for all ten SDMs after edaphic variables were combined with environmental variables in the modelling of the geographical distribution of the two STHs at national scale. Using the top three performing models, a consensus prediction was developed to generate the first continuous maps of the potential distribution of the two STHs in Zimbabwe.ConclusionsThe findings from this study demonstrate significant model improvement if relevant edaphic variables are included in model calibration resulting in more accurate mapping of STH. The results also provide spatially-explicit information to aid targeted control of STHs in Zimbabwe and other countries with STH burden.

Impact of single annual treatment and four-monthly treatment for hookworm and Ascaris lumbricoides, and factors associated with residual infection among Kenyan school children

BackgroundSchool-based deworming is widely implemented in various countries to reduce the burden of soil-transmitted helminths (STHs), however, the frequency of drug administration varies in different settings. In this study, we compared the impact of a single annual treatment and 4-monthly treatment over a follow-up among Kenyan school children, and investigated the factors associated with residual infection.MethodsWe performed a secondary analysis of data from a randomized trial investigating whether deworming for STHs alters risk of acquiring malaria. Children received either a single treatment or 4-monthly albendazole treatments were followed longitudinally from February 2014 to October 2014. The relative impact of treatment and factors associated with residual infections were investigated using mixed-effects regression models. Predisposition to infection was assessed based on Spearman’s rank and Kendall’s Tau correlation coefficients.ResultsIn the 4-monthly treatment group, the proportion of children infected with hookworm decreased from 59.9 to 5.7%, while Ascaris lumbricoides infections dropped from 55.7 to 6.2%. In the single treatment group, hookworm infections decreased over the same time period from 58.7 to 18.3% (12.6% absolute difference in reduction, 95% CI: 8.9–16.3%), and A. lumbricoides from 56.7 to 23.3% (17.1% absolute difference in reduction, 95% CI: 13.1–21.1%). There was strong evidence for predisposition to both STH types. Residual hookworm infection among children on 4-monthly treatment were associated with male sex and baseline nutritional status, whereas A. lumbricoides infection was associated with individual and school-level infection at baseline, latrine cleanliness at schools.ConclusionsThis study found that 4-monthly treatment w more effective than single annual treatment. Repeated treatments led to dramatic reductions in the intensities of STHs, but did not completely clear infections among school children in Kenya, a presumed reflection of reinfection in a setting where there is ongoing transmission.

Soil-Transmitted Helminth Infections Are Associated With an Increase in Human Papillomavirus Prevalence and a T-Helper Type 2 Cytokine Signature in Cervical Fluids.

An ecological correlation between invasive cervical cancer incidence and burden of soil-transmitted helminths (STH) is hypothesized to explain the excess in detectable human papillomavirus (HPV) infection in Latin America, via a global T-helper type 2 (Th2)-biased mucosal immune response secondary to STH infection. The association between current STH infection and HPV prevalence was compared in regions of Peru where STH is or is not endemic. Adjusted prevalence ratios (PRs) with robust variance were estimated as an effect measure of STH infection on HPV prevalence in each study site. Soluble immune marker profiles in STH-infected and STH-uninfected women were compared using Spearman rank correlation with the Sidak correction. Among women in the helminth-endemic region of the Peruvian Amazon, those with STH infection women had a 60% higher prevalence of HPV, compared with those without STH infection (PR, 1.6; 95% confidence interval, 1.0-2.7). Non-STH parasitic/protozoal infections in the non-STH-endemic population of Peru were not associated with HPV prevalence. In Iquitos, A Th2 immune profile was observed in cervical fluid from helminth-infected women but not helminth-uninfected women. A proportion of the increased HPV prevalence at older ages observed in Latin America may be due to a population-level difference in the efficiency of immunological control of HPV across the lifespan due to endemic STH infection.

Malaria, schistosomiasis and soil transmitted helminth burden and their correlation with anemia in children attending primary schools in Kinshasa, Democratic Republic of Congo.

BackgroundAnaemia reduces cognitive potential in school children, retards their growth and predisposes them to other diseases. As there is a paucity of data on the current burden of P. falciparum, S. mansoni and soil transmitted helminths (STH) infections and their correlation with schoolchildren’s anemia in the Democratic Republic of Congo (DRC), we collect these data.MethodsThis study reports baseline data collected from a randomized controlled trial investigating the impact of IPT with SP and SP-PQ on anemia and malaria morbidity in Congolese schoolchildren (Trial registration: NCT01722539; PACTR201211000449323). S. mansoni and STH infections were assessed using kato-katz technique. Malaria infection and hemoglobin concentration were assessed using Blood smear and Hemocontrol device, respectively.ResultsA total of 616 primary schoolchildren from 4 to 13 years old were enrolled in the study. The prevalence of Plasmodium spp. infection was 18.5% (95%CI:15.6–21.9). Amongst those infected, 24 (21%), 40 (35.1%), 40 (35.1%), 10 (8.8%), had light, moderate, heavy, very high malaria parasite density, respectively. Above 9 years of age (p = 0.02), male and history of fever (p = 0.04) were both associated with malaria infection. The overall prevalence of S. mansoni infection was 6.4% (95%CI:4.4–9.1). Girls were associated with S. mansoni infection (p = 0.04). T. trichiura was the most prevalent STH infection (26.3%), followed by A. lumbricoides (20.1%). Co-infection with malaria-S. mansoni and malaria-STH was, respectively, 1.5% (CI95%:0.7–3.3) and 6.4% (CI95% 4.4–9.1). The prevalence of anemia was found to be 41.6% (95%CI:37.7–45.6) and anemia was strongly related with Plasmodium ssp infection (aOR:4.1; CI95%:2.6–6.5;p<0.001) and S. mansoni infection (aOR:3.3;CI95%:1.4–7.8;p<0.01).ConclusionMalaria and S. mansoni infection were strongly associated with high prevalence of anemia in schoolchildren. Therefore, specific school-based interventions, such as intermittent preventive treatment or prophylaxis, LLITN distribution, anthelminthic mass treatment and micronutrient supplementation are needed to improve school children’s health.

The effectiveness of 4 monthly albendazole treatment in the reduction of soil-transmitted helminth infections in women of reproductive age in Viet Nam

Soil-transmitted helminth (STH) infections are endemic in northern Viet Nam where the climate and agricultural practices, such as the use of human excreta as fertiliser and the use of wastewater for irrigation, favour transmission. An intervention was conducted in Yen Bai Province, north-west Viet Nam, to measure the effectiveness of single dose albendazole (400 mg) administered every 4 months for reducing the prevalence of STH infections in women of reproductive age. Stool samples were collected from women before the intervention and 3 and 12 months post-intervention. Information on a range of demographic and socio-economic variables was also collected to measure the major risk factors for high STH burden in this area. The prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura infection in the baseline sample of 366 women were 76.2%, 19.2% and 29.1%, respectively. In the women who were surveyed at baseline and again at 3 and 12 months after the intervention ( n = 118) cure rates were 71.3% for hookworm, 87.0% for A. lumbricoides and 81.4% for T. trichiura by the end of the 12 month study period (i.e. after three doses of albendazole). The main risk factor for hookworm infection was if women worked outside (odds ratio (OR) = 3.2 (95% Confidence Interval (CI) 1.6–6.2), P = 0.001) and the major risk factor for A. lumbricoides and T. trichiura infection was a lack of education. Low educational attainment was also the strongest risk factor for co-infection with all three species of STH (OR = 7.5 (95% CI 3.4–16.4), P < 0.001). The high rates of hookworm infection in this area of Viet Nam and the high cure rates for all three species of STH with 4 monthly albendazole treatment suggest that this programme should be expanded to all endemic areas in Viet Nam. The study also highlights the important contribution of education to women’s health.