Important Nematodes in Children

Intestinal nematode infections caused by soil-transmitted helminths (STH), such as the roundworm Ascaris lumbricoides, the whipworm Trichuris trichiura, and the hookworms Ancylostoma duodenale, and Necator americanus, infect more than 1 billion people throughout the world. School-aged children tend to harbor the greatest numbers of intestinal worms, and as a result, experience more adverse health consequences, such as poor growth, anemia, and cognitive decline. Clinicians should maintain a high degree of suspicion in endemic areas when patients present with surgical abdomens, particularly children. Current antihelminthic drugs are moderately effective, but reinfection is possible. Global efforts are needed to eradicate STH infections.

Mobile microscopy and telemedicine platform assisted by deep learning for the quantification of Trichuris trichiura infection

Soil-transmitted helminths (STH) are the most prevalent pathogens among the group of neglected tropical diseases (NTDs). The Kato-Katz technique is the diagnosis method recommended by the World Health Organization (WHO) although it often presents a decreased sensitivity in low transmission settings and it is labour intensive. Visual reading of Kato-Katz preparations requires the samples to be analyzed in a short period of time since its preparation. Digitizing the samples could provide a solution which allows to store the samples in a digital database and perform remote analysis. Artificial intelligence (AI) methods based on digitized samples can support diagnosis by performing an objective and automatic quantification of disease infection. In this work, we propose an end-to-end pipeline for microscopy image digitization and automatic analysis of digitized images of STH. Our solution includes (a) a digitization system based on a mobile app that digitizes microscope samples using a 3D printed microscope adapter, (b) a telemedicine platform for remote analysis and labelling, and (c) novel deep learning algorithms for automatic assessment and quantification of parasitological infections by STH. The deep learning algorithm has been trained and tested on 51 slides of stool samples containing 949 Trichuris spp. eggs from 6 different subjects. The algorithm evaluation was performed using a cross-validation strategy, obtaining a mean precision of 98.44% and a mean recall of 80.94%. The results also proved the potential of generalization capability of the method at identifying different types of helminth eggs. Additionally, the AI-assisted quantification of STH based on digitized samples has been compared to the one performed using conventional microscopy, showing a good agreement between measurements. In conclusion, this work has presented a comprehensive pipeline using smartphone-assisted microscopy. It is integrated with a telemedicine platform for automatic image analysis and quantification of STH infection using AI models.

Factors associated with soil-transmitted helminths infection in Benin: Findings from the DeWorm3 study

Background

Despite several years of school-based MDA implementation, STH infections remain an important public health problem in Benin, with a country-wide prevalence of 20% in 2015. The DeWorm3 study is designed to assess the feasibility of using community-based MDA with albendazole to interrupt the transmission of STH, through a series of cluster-randomized trials in Benin, India and Malawi. We used the pre-treatment baseline survey data to describe and analyze the factors associated with STH infection in Comé, the study site of the DeWorm3 project in Benin. These data will improve understanding of the challenges that need to be addressed in order to eliminate STH as a public health problem in Benin.

Methods

Between March and April 2018, the prevalence of STH (hookworm spp., Ascaris and Trichuris trichiura) was assessed by Kato-Katz in stool samples collected from 6,153 residents in the community of Comé, Benin using a stratified random sampling procedure. A standardized survey questionnaire was used to collect information from individual households concerning factors potentially associated with the presence and intensity of STH infections in pre-school (PSAC, aged 1–4), school-aged children (SAC, aged 5–14) and adults (aged 15 and above). Multilevel mixed-effects models were used to assess associations between these factors and STH infection.

Results

The overall prevalence of STH infection was 5.3%; 3.2% hookworm spp., 2.1% Ascaris lumbricoides and 0.1% Trichuris. Hookworm spp. were more prevalent in adults than in SAC (4.4% versus 2.0%, respectively; p = 0.0001) and PSAC (4.4% versus 1.0%, respectively; p<0.0001), whilst Ascaris lumbricoides was more prevalent in SAC than in adults (3.0% versus 1.7%, respectively; p = 0.004). Being PSAC (adjusted Odds Ratio (aOR) = 0.2, p< 0.001; adjusted Infection Intensity Ratio (aIIR) = 0.1, p<0.001) or SAC (aOR = 0.5, p = 0.008; aIIR = 0.3, p = 0.01), being a female (aOR = 0.6, p = 0.004; aIIR = 0.3, p = 0.001), and having received deworming treatment the previous year (aOR = 0.4, p< 0.002; aIIR = 0.2, p<0.001) were associated with a lower prevalence and intensity of hookworm infection. Lower income (lowest quintile: aOR = 5.0, p<0.001, 2^nd quintile aOR = 3.6, p = 0.001 and 3^rd quintile aOR = 2.5, p = 0.02), being a farmer (aOR = 1.8, p = 0.02), medium population density (aOR = 2.6, p = 0.01), and open defecation (aOR = 0.5, p = 0.04) were associated with a higher prevalence of hookworm infection. Lower education—no education, primary or secondary school- (aIIR = 40.1, p = 0.01; aIIR = 30.9, p = 0.02; aIIR = 19.3, p = 0.04, respectively), farming (aIIR = 3.9, p = 0.002), natural flooring (aIIR = 0.2, p = 0.06), peri-urban settings (aIIR = 6.2, 95%CI 1.82–20.90, p = 0.003), and unimproved water source more than 30 minutes from the household (aIIR = 13.5, p = 0.02) were associated with a higher intensity of hookworm infection. Improved and unshared toilet was associated with lower intensity of hookworm infections (aIIR = 0.2, p = 0.01). SAC had a higher odds of Ascaris lumbricoides infection than adults (aOR = 2.0, p = 0.01) and females had a lower odds of infection (aOR = 0.5, p = 0.02).

Conclusion

Hookworm spp. are the most prevalent STH in Comé, with a persistent reservoir in adults that is not addressed by current control measures based on school MDA. Expanding MDA to target adults and PSAC is necessary to substantially impact population prevalence, particularly for hookworm.

Trial registration

ClinicalTrials.gov NCT03014167.

Despite several years of deworming campaigns targeting school-aged children, soil-transmitted helminths (STH) remains a public health problem in most developing countries, including Benin. The burden is mostly on children and pregnant women, but also on the whole society. Soil-transmitted helminths are responsible for malnutrition, anemia, low birth weight, cognitive impairment, decrease of school performance, and subsequently economic loss. The current strategy of the Benin National Neglected Tropical Diseases (NTD) Program is to achieve STH control through mass drug administration campaigns targeting school-aged children (SAC). The baseline data of Deworm3 study, implemented in Comé, southern Benin, as part of a multicountry (Benin, Malawi and India) STH elimination trial, shows that previous school deworming campaigns decreased STH prevalence; however there is a persistent reservoir of STH infection in adults and pre-school aged children that should be targeted for a better impact. In order to eliminate STH as a public health problem, Benin National NTD Program would need to increase its target population, from the SAC to the whole community. The future results of Deworm3 trial would demonstrate whether the STH elimination goal STH using community wide mass drug administration would be achievable.

Comparison of the egg recovery rates and limit of detection for soil-transmitted helminths using the Kato-Katz thick smear, faecal flotation and quantitative real-time PCR in human stool

Background

Monitoring the success of soil-transmitted helminth (STH) control programs relies on accurate diagnosis and quantitative assessment of infection prevalence and intensity. As preventative chemotherapeutic program coverage for STH expands, the necessity of gaining insights into the relative or comparative sensitivities, in terms of limits of detection (LOD) and egg-recovery-rates (ERR) for microscopy and quantitative polymerase chain reaction qPCR-based diagnostic techniques becomes imperative to inform suitability for their intended use for large scale STH monitoring and treatment efficacy studies.

Methodology/Principal findings

The diagnostic performance in terms of ERR and LOD of the Kato-Katz (KK) thick smear technique, sodium nitrate (NaNO₃) faecal floatation (FF) and qPCR for the accurate detection and enumeration of STH eggs were calculated and expressed in eggs per gram (EPG), by experimentally seeding parasite-free human faeces with Ascaris spp., Trichuris spp. and Necator americanus eggs representing low, medium and high intensity infections. The efficiency of NaNO₃ flotation was also calculated over a range of specific gravities (SpGr) for the optimum recovery of STH eggs. FF of SpGr 1.30 recovered 62.7%, 11% and 8.7% more Trichuris spp., Necator americanus and Ascaris spp. eggs respectively, than the recommended SpGr of 1.20. All diagnostic methods demonstrated strong direct correlation to the intensity of seeded EPG. KK and FF (SpGr 1.30) resulted in significant lower ERRs compared to qPCR (p <0.05). qPCR demonstrated significantly (p <0.05) greater sensitivity with an ability to detect as little as 5 EPG for all three STH, compared to 50 EPG by KK and FF (SpGr 1.30).

Conclusions/Significance

This study compares the diagnostic parameters in terms of LOD and ERRs of STHs for the KK, FF and qPCR. These results indicate that the diagnostic performance of qPCR assays should be considered by control programs in the phase that aims to seek confirmation of transmission break and cessation of preventive chemotherapy in low-transmission settings, in line with the control targets of the WHO neglected tropical diseases 2030 Roadmap.

STH infections predominately affect resource-poor communities and negatively impact on child and maternal health. Diagnostics play a critical role in guiding and informing existing STH control programs and the implementation and evaluation of intervention strategies. The KK technique is most commonly used as per WHO guidelines and is the basis for determining quantitative thresholds for low, moderate and heavy infections. More recently, FF and laboratory-based quantitative PCR techniques have provided alternative options of diagnosing STH infections. A number of studies correlating the relative sensitivity, diagnostic agreement, and egg enumeration of these techniques by comparing field-generated diagnostic data have attempted to correlate quantitative outputs to those defined by the WHO, with little resolution. Moreover, as large-scale deworming programs levels scale up, the necessity to apply techniques that can precisely detect light infections is of outmost importance to establish preventive chemotherapy end-points using more accurate means. In this study we compared the LOD and ERR of seeded non-infected human faecal samples with Ascaris, Trichuris and Necator spp. eggs using KK, FF and qPCR. When compared to copro-microscopy methods, qPCR showed the highest sensitivity for the detection of light-intensity infections and was more accurate in enumerating the original number of eggs per gram of seeded faeces. In addition to this, the results indicated that the diagnostic performance of both KK and FF (using solution at a SpGr of 1.30) were equally efficient and should be considered with their diagnostic limitations in mind, when aiming to monitor STH infections in low-transmission settings.

Epidemiology of soil transmitted helminths and risk analysis of hookworm infections in the community: Results from the DeWorm3 Trial in southern India

Since 2015, India has coordinated the largest school-based deworming program globally, targeting soil-transmitted helminths (STH) in ~250 million children aged 1 to 19 years twice yearly. Despite substantial progress in reduction of morbidity associated with STH, reinfection rates in endemic communities remain high. We conducted a community based parasitological survey in Tamil Nadu as part of the DeWorm3 Project—a cluster-randomised trial evaluating the feasibility of interrupting STH transmission at three geographically distinct sites in Africa and Asia—allowing the estimation of STH prevalence and analysis of associated factors. In India, following a comprehensive census, enumerating 140,932 individuals in 36,536 households along with geospatial mapping of households, an age-stratified sample of individuals was recruited into a longitudinal monitoring cohort (December 2017-February 2018) to be followed for five years. At enrolment, a total of 6089 consenting individuals across 40 study clusters provided a single adequate stool sample for analysis using the Kato-Katz method, as well as answering a questionnaire covering individual and household level factors. The unweighted STH prevalence was 17.0% (95% confidence interval [95%CI]: 16.0–17.9%), increasing to 21.4% when weighted by age and cluster size. Hookworm was the predominant species, with a weighted infection prevalence of 21.0%, the majority of which (92.9%) were light intensity infections. Factors associated with hookworm infection were modelled using mixed-effects multilevel logistic regression for presence of infection and mixed-effects negative binomial regression for intensity. The prevalence of both Ascaris lumbricoides and Trichuris trichiura infections were rare (<1%) and risk factors were therefore not assessed. Increasing age (multivariable odds ratio [mOR] 21.4, 95%CI: 12.3–37.2, p<0.001 for adult age-groups versus pre-school children) and higher vegetation were associated with an increased odds of hookworm infection, whereas recent deworming (mOR 0.3, 95%CI: 0.2–0.5, p<0.001) and belonging to households with higher socioeconomic status (mOR 0.3, 95%CI: 0.2–0.5, p<0.001) and higher education level of the household head (mOR 0.4, 95%CI: 0.3–0.6, p<0.001) were associated with lower odds of hookworm infection in the multilevel model. The same factors were associated with intensity of infection, with the use of improved sanitation facilities also correlated to lower infection intensities (multivariable infection intensity ratio [mIIR] 0.6, 95%CI: 0.4–0.9, p<0.016). Our findings suggest that a community-based approach is required to address the high hookworm burden in adults in this setting. Socioeconomic, education and sanitation improvements alongside mass drug administration would likely accelerate the drive to elimination in these communities.

Trial Registration:NCT03014167.

Approximately 1 in 5 people in India are infected with soil transmitted helminths (STH), leading to anaemia and malnutrition. To tackle this large burden of infection, the government of India launched one of the world’s largest school-based deworming programs in 2015 aiming to deworm all pre-school and school-aged children between 1 to 19 years of age twice yearly on the National Deworming Days. Deworming programs, including those in India, are focused on pre-school aged children, school aged children and women of reproductive age group. However, prevailing environmental and socioeconomic conditions, including poor sanitation, can contribute to high rates of reinfection from untreated adults and children. The DeWorm3 Project is a cluster-randomised trial evaluating the feasibility of interrupting STH transmission with community wide deworming of all individuals aged one to 99 years of age or older. As part of the study, we conducted a parasitological survey in the Deworm3 trial site in rural Tamil Nadu. Here we present the factors associated with STH infection and burden in these communities.

Epidemiology of soil-transmitted helminth infections in Semarang, Central Java, Indonesia

Soil-transmitted helminth (STH) infections are endemic in Indonesia. However, prevalence data for many parts of the country are incomplete. The aim of this study was to determine human STH prevalence and knowledge and practices relating to STH risk behaviour, to provide a current view of the status of STH infection in rural communities in Central Java. A cross-sectional survey of 16 villages was conducted in Semarang, Central Java in 2015. Demographic and household data together with information about knowledge and practices relating to STH and hygiene were elicited through face-to-face interviews. Stool samples were collected and examined using the flotation method. Children (aged 2–12 years) also had their haemoglobin (Hb) levels, height and weight data collected, and BMI estimated. Data were analysed using univariate logistic regression analysis. A total of 6,466 individuals with a mean age of 33.5 years (range: 2–93) from 2,195 households were interviewed. The overall prevalence of STH was 33.8% with Ascaris lumbricoides (roundworm) the predominant nematode identified (prevalence = 26.0%). Hookworm and Trichuris trichiura (whipworm) were found in 7.9% and 1.8% of participants, respectively. Females were at increased odds of infection with A. lumbricoides (adjusted OR 1.14, 95% CI [1.02–1.29], p = 0.02). Adults in age groups 51–60 and over 60 years had the highest odds of being infected with hookworm (adjusted OR 3.01, 95% CI [1.84–4.91], p<0.001 and adjusted OR 3.79, 95% CI [2.30–6.26], p<0.001, respectively) compared to 6–12 year olds. Farmers also had higher odds of being infected with hookworm (adjusted OR 2.36, 95% CI [1.17–4.76], p = 0.02) compared to other occupation categories. Poverty (OR 2.14, 95% CI [1.77–2.58], p<0.001), overcrowding (OR 1.35, 95% CI [1.27–1.44], p<0.001), goat ownership (OR 1.61, 95% CI [1.10–2.41], p = 0.02) and the presence of dry floor space in the home (OR 0.73, 95% CI [0.58–0.91], p = 0.01) were all household factors significantly associated with an increased odds of infection. Infection with STH was not significantly associated with the gastrointestinal illness (p>0.05), BMI or Hb levels; however, one third of all 2–12 year olds surveyed were found to be anaemic (i.e. Hb concentrations below 110g/l or 115g/l for children under 5 and 5 years or older, respectively), with a greater proportion of school-age children at risk. Knowledge and behaviour related to hygiene and gastrointestinal diseases varied widely and were generally not associated with STH infection. The study revealed that STH infection remains endemic in Central Java despite ongoing deworming programs. Current control efforts would benefit from being re-evaluated to determine a more effective way forward.

Among the major NTDs, STH are one of the most common disabling chronic infections. Currently available drug treatments, whilst considered safe and generally well tolerated, do not confer protection against new infections. In Indonesia, prevalences of STH of up to 90% have been reported but these estimates are based on data from the 1980s and 90s. More up-to-date STH prevalence estimates are urgently needed to help guide future control efforts.

A cross-sectional survey was conducted in rural villages in Semarang, Central Java to determine human STH prevalence and associated risk factors. One-third of all cohort participants were positive for STH with prevalences of 26%, 7.9% and 1.8% identified for Ascaris lumbricoides, hookworm and Trichuris trichiura at 7.9% and 1.8%, respectively. Risk of A. lumbricoides infection was higher for females, whilst farmers and adults over 50 had an increased risk of hookworm infection. Poverty, overcrowding in the home and goat ownership were also associated with an increased risk at the household level.

Soil-transmitted helminthiases remains a significant health problem in Central Java, Indonesia, exacerbated by limited knowledge about STH, poor sanitation and hygiene and poverty prevalent in the region. Control efforts would benefit from an integrated approach emphasising WASH, health education and chemotherapy. Further studies investigating environmental contamination with STH in and around homes in endemic areas could provide further insight into links between household factors and STH identified in our study.

Community-based survey on helminth infections in Kwilu province, the Democratic Republic of the Congo, and implications for local control strategies

To adequately plan mass drug administration campaigns, the Democratic Republic of the Congo (DRC) needs further support for the mapping and monitoring of schistosomiasis (SCH) and soil-transmitted helminths (STH). We conducted a community-based survey in the health districts of Mosango and Yasa Bonga of the Kwilu province, DRC. A stratified two-stage cluster random sampling method was used to include participants into three different strata: Preschool-aged children (PSAC), school-aged children (SAC), and adults who were further subdivided into women of reproductive age (WRA) and other adults. In total, surveyors visited 30 villages, and 1 206 individuals participated in the study. Stool samples were collected to perform duplicate Kato-Katz smears for the detection of SCH and STH infection. Hookworm was the most prevalent infection in both districts, 34.1% (95%CI: 32.0–38.4), followed by A. lumbricoides (2.7%; 95%CI: 1.3–2.9) and T. trichiura (1.9%; 95%CI: 1.1–2.7). We did not find any SCH infection. The prevalence of each STH infection was similar across all risk groups, and the majority of the infected individuals was carrying light intensity infection. Compared to SAC, other adults were equally infected with hookworm. The prevalence of STH infection in SAC guides the MDA implementation because schoolchildren are most at risk and easily accessible program targets if school attendance is high. The current treatment strategy targets PSAC, SAC and WRA. However, this study shows that adults in general could also benefit from deworming. Therefore, community-wide preventive chemotherapy would be the most appropriate choice to control the hookworm burden rapidly.

Helminths are a group of intestinal worms that cause abdominal discomfort, diarrhea, and anemia due to blood loss in the stool. Regular mass drug administration (MDA) is one strategy to fight these worm infections. The appropriate MDA treatment scheme is chosen based on a population survey estimating the burden of infection. This survey is usually done in schoolchildren because they suffer the most from these infections and they are easy to reach through school infrastructures. However, one particular worm, the hookworm, is also highly present and clinically relevant in adults. We conducted a community-based survey in two districts of the Kwilu Province of the DRC. We found that hookworm was the predominant infection in the area and that adults were as often infected as the schoolchildren. Therefore, to effectively reduce hookworm infection, we advise extending treatment schemes to the entire community.

Performance of the Kato-Katz method and real time polymerase chain reaction for the diagnosis of soil-transmitted helminthiasis in the framework of a randomised controlled trial: treatment efficacy and day-to-day variation

BACKGROUND

Accurate, scalable and sensitive diagnostic tools are crucial in determining prevalence of soil-transmitted helminths (STH), assessing infection intensities and monitoring treatment efficacy. However, assessments on treatment efficacy comparing traditional microscopic to newly emerging molecular approaches such as quantitative Polymerase Chain Reaction (qPCR) are scarce and hampered partly by lack of an established diagnostic gold standard.

METHODS

We compared the performance of the copromicroscopic Kato-Katz method to qPCR in the framework of a randomized controlled trial on Pemba Island, Tanzania, evaluating treatment efficacy based on cure rates of albendazole monotherapy versus ivermectin-albendazole against Trichuris trichiura and concomitant STH infections. Day-to-day variability of both diagnostic methods was assessed to elucidate reproducibility of test results by analysing two stool samples before and two stool samples after treatment of 160 T. trichiura Kato-Katz positive participants, partially co-infected with Ascaris lumbricoides and hookworm, per treatment arm (n = 320). As negative controls, two faecal samples of 180 Kato-Katz helminth negative participants were analysed.

RESULTS

Fair to moderate correlation between microscopic egg count and DNA copy number for the different STH species was observed at baseline and follow-up. Results indicated higher sensitivity of qPCR for all three STH species across all time points; however, we found lower test result reproducibility compared to Kato-Katz. When assessed with two samples from consecutive days by qPCR, cure rates were significantly lower for T. trichiura (23.2 vs 46.8%), A. lumbricoides (75.3 vs 100%) and hookworm (52.4 vs 78.3%) in the ivermectin-albendazole treatment arm, when compared to Kato-Katz.

CONCLUSIONS

qPCR diagnosis showed lower reproducibility of test results compared to Kato-Katz, hence multiple samples per participant should be analysed to achieve a reliable diagnosis of STH infection. Our study confirms that cure rates are overestimated using Kato-Katz alone. Our findings emphasize that standardized and accurate molecular diagnostic tools are urgently needed for future monitoring within STH control and/or elimination programmes.

Prevalence and risk factors of geohelminthiasis among the rural village children in Kota Marudu, Sabah, Malaysia

Geohelminthiasis is a worldwide problem, especially in low-income countries. Children from rural areas and those living in poverty, lacking basic health amenities and having poor environmental sanitation are likely to be affected. Adverse effects such as anemia, protein malnutrition, colitis are common which can affect both the children's physical and mental growing development. A cross-sectional study on geohelminthiasis was conducted among children from 238 households in 13 villages in Kota Marudu of northern Sabah, East Malaysia. The study involved interviewing villagers using questionnaires to collect demographic and socio-economic data, getting faecal samples from the children, collecting soil samples and identifying parasite eggs with microscopy and molecular methods. A total of 407 children (6 months-17 years old) enrolled in the study. Geohelminthiasis was detected in the faecal samples of children from 54% (7/13) of the villages with mean prevalence of infection per village of 9.0% (0%-34.9%). On a household basis, 18% (43/238) of the households sampled had infected children, with mean prevalence rate per household of 11% (0%-43%). The prevalence was for Ascaris lumbricoides: 9.6% (39/407), Trichuris trichiura: 2.7% (11/407) and hookworms (Necator americanus and Ancylostoma sp.): 2.7% (11/407). The overall mean infection rate of the children examined was 14.3%. Significantly higher prevalence was recorded for the children of mothers who did not have any formal education (p = 0.003); household income of less than USD119 (RM500) (p<0.001); children from homes without proper sanitation facilities (p<0.001); children who usually go about barefoot (p<0.001) and not washing feet before entering the house (p = 0.017). Soil samples were found to have geohelminth eggs or larvae which could be due to unhygienic sanitation practices. This study shows the geohelminthiasis is prevalent in the villages, and the risk factors are lack of maternal education, low income, poor sanitation facilities and irregular deworming practice. Expanding deworming coverage in the study region may help reduce the worm infections in these communities, so that the mental and physical development of the children would not be affected by geohelminthiasis. The data on the prevalence of geohelminthiasis in this study would contribute to better public health monitoring and operation to reduce the infection in rural areas.

A first nation-wide assessment of soil-transmitted helminthiasis in Fijian primary schools, and factors associated with the infection, using a lymphatic filariasis transmission assessment survey as surveillance platform

BACKGROUND

Soil-transmitted helminthiasis (STH) is endemic in Fiji but its prevalence is not known and likely to have changed after a decade of mass drug administration (MDA) for lymphatic filariasis (LF). By linking with LF transmission assessment surveys (LF-TAS), we undertook the first nation-wide assessment of STH in Fijian primary schools, as well as an analysis of factors associated with STH infections.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional assessment for STH was conducted in all four Divisions of Fiji from 2014 to 2015. In the Western, Central, and Northern Divisions, schools were sub-sampled after LF-TAS, while, in the Eastern Division, schools were selected via simple random sampling. For the diagnosis of STH, stool samples were examined by coproscopy with a single Kato-Katz thick smear (KK) and the formol-ether-acetate concentration technique, except for the samples from the Eastern Division where only KK was used. Mean prevalence of any STH among class 1-2 students at the national level was 10.5% (95% CI: 6.9-15.5). Across the three Divisions via LF-TAS, the prevalence levels for ascariasis were 8.7% (95% CI: 4.3-16.6), hookworm 3.9% (95% CI: 2.3-6.6) and trichuriasis 0%. In the Eastern Division, ascariasis prevalence was 13.3% (95% CI: 6.4-25.6), and hookworm 0.7% (95% CI: 0.2-2.5), with one case of trichuriasis. Among class 3-8 students, ascariasis prevalence was lower. Lower risk of any STH was associated with wearing shoes (adjusted OR 0.54, 95% CI: 0.32-0.90) and having piped water from the Fiji Water Authority at home (adjusted OR 0.48, 95% CI: 0.25-0.92).

CONCLUSIONS

After a decade of community-based LF-MDA, STH in school-age children in Fiji is now close to 10%, but localities of endemicity remain. Preventive chemotherapy should be maintained in areas with elevated STH prevalence alongside targeted delivery of integrated WASH interventions. LF-TAS has provided an opportunity to develop future public health surveillance platforms.

Market integration and soil-transmitted helminth infection among the Shuar of Amazonian Ecuador

BACKGROUND

Soil-transmitted helminth (STH) infections have many negative health outcomes (e.g., diarrhea, nutritional deficiencies) that can also exacerbate poverty. These infections are generally highest among low-income populations, many of which are also undergoing market integration (MI; increased participation in a market-based economy). Yet the direct impact of MI-related social and environmental changes on STH infection patterns is poorly understood, making it unclear which lifestyle factors should be targeted to better control disease spread. This cross-sectional study examines if household infrastructure associated with greater MI is associated with lower STH burdens among Indigenous Ecuadorian Shuar.

METHODS

Kato-Katz fecal smears were used to determine STH infection status and intensity (n = 620 participants; 308 females, 312 males, aged 6 months-86 years); Ascaris lumbricoides (ascarid) and Trichuris trichiura (whipworm) were the primary infection types detected. Structured interviews assessing lifestyle patterns (e.g., measures of household infrastructure) measured participant MI. Multilevel regression analyses and zero-inflated negative binomial regression models tested associations between MI measures and STH infection status or intensity, controlling for individual and community characteristics.

RESULTS

Participants residing in more market-integrated households exhibited lower infection rates and intensities than those in less market integrated households. Parasite infection status and T. trichiura infection intensity were lower among participants living in houses with wood floors than those with dirt floors, while individuals using well or piped water from a spring exhibited lower A. lumbricoides infection intensities compared to those using river or stream water. Unexpectedly, latrine type was not significantly related to STH infection status or intensity. These results suggest that sources of exposure differ between the two helminth species.

CONCLUSIONS

This study documents associations between household measures and STH infection among an Indigenous population undergoing rapid MI. These findings can help healthcare programs better target interventions and reduce STH exposure among at-risk populations.

Metagenomics and microscope revealed T. trichiura and other intestinal parasites in a cesspit of an Italian nineteenth century aristocratic palace

This study evidenced the presence of parasites in a cesspit of an aristocratic palace of nineteenth century in Sardinia (Italy) by the use of classical paleoparasitological techniques coupled with next-generation sequencing. Parasite eggs identified by microscopy included helminth genera pathogenic for humans and animals: the whipworm Trichuris sp., the roundworm Ascaris sp., the flatworm Dicrocoelium sp. and the fish tapeworm Diphyllobothrium sp. In addition, 18S rRNA metabarcoding and metagenomic sequencing analysis allowed the first description in Sardinia of aDNA of the human specific T. trichiura species and Ascaris genus. Their presence is important for understanding the health conditions, hygiene habits, agricultural practices and the diet of the local inhabitants in the period under study.

The impact of four years of semiannual treatments with albendazole alone on lymphatic filariasis and soil-transmitted helminth infections: A community-based study in the Democratic Republic of the Congo

Background

The World Health Organization now recommends semiannual mass drug administration (MDA) of albendazole with integrated vector management as an option for eliminating lymphatic filariasis (LF) in areas of loiasis-endemic countries where it may not be safe to use diethylcarbamazine or ivermectin in MDA programs. However, the published evidence base to support this policy is thin, and uptake by national programs has been slow.

Methodology/Principal findings

We conducted a community trial to assess the impact of semiannual MDA on lymphatic filariasis and soil-transmitted helminth infections (STH) in two villages in the Bandundu province of the Democratic Republic of the Congo with moderately high prevalences for LF and hookworm infections. MDA with albendazole was provided every six months from June 2014 to December 2017 with treatment coverages of the eligible population (all ≥ 2 year of age) that ranged between 56% and 88%. No adverse effects were reported during the trial. Evaluation at 48 months, (i.e. 6 months after the 8^th round of MDA), showed that W. bancrofti microfilaremia (Mf) prevalence in the study communities had decreased between 2014 to 2018 from 12% to 0.9% (p<0.001). The prevalence of W. bancrofti antigenemia was also significantly reduced from 31.6% to 8.5% (p<0.001). MDA with albendazole also reduced hookworm, Ascaris lumbricoides and Trichuris trichiura infection prevalences in the community from 58.6% to 21.2% (p<0.001), from 14.0% to 1.6% and 4.1% to 2.9%, respectively. Hookworm and Ascaris infection intensities were reduced by 93% (p = 0.02) and 57% (p = 0.03), respectively. In contrast, Trichuris infection intensity was not significantly reduced by MDA (p = 0.61) over this time period.

Conclusion/Significance

These results provide strong evidence that semiannual MDA with albendazole alone is a safe and effective strategy for LF elimination in Central Africa. Community MDA also had a major impact on STH infections.

In low-income rural settings of Africa, populations are commonly affected by multiple parasitic diseases. Some of these diseases have been targeted for elimination through dedicated national or international programs. In 2012, the World Health Organization (WHO) defined a specific strategy to eliminate lymphatic filariasis, the disease responsible for elephantiasis, in central Africa. This strategy consists in treating the whole population living in endemic areas every six months with a single donated drug—albendazole. Together with the use of the night bed nets distributed as part of malaria programs, it was expected that this strategy could interrupt the transmission and eliminate lymphatic filariasis locally within period of 4 to 7 years. Here, we evaluated this strategy in two endemic communities near Bandundu in the Democratic Republic of the Congo. We also assessed the impact of the semiannual community treatments on three species of gastrointestinal parasitic worms. Our results suggest that semiannual MDA with albendazole is effective for LF elimination in Central Africa, but they also indicate that drug-based only intervention is not enough to eliminate gastrointestinal worm infections in areas with high transmission.

Comparison of multi-parallel qPCR and double-slide Kato-Katz for detection of soil-transmitted helminth infection among children in rural Bangladesh

There is growing interest in local elimination of soil-transmitted helminth (STH) infection in endemic settings. In such settings, highly sensitive diagnostics are needed to detect STH infection. We compared double-slide Kato-Katz, the most commonly used copromicroscopic detection method, to multi-parallel quantitative polymerase chain reaction (qPCR) in 2,799 stool samples from children aged 2–12 years in a setting in rural Bangladesh with predominantly low STH infection intensity. We estimated the sensitivity and specificity of each diagnostic using Bayesian latent class analysis. Compared to double-slide Kato-Katz, STH prevalence using qPCR was almost 3-fold higher for hookworm species and nearly 2-fold higher for Trichuris trichiura. Ascaris lumbricoides prevalence was lower using qPCR, and 26% of samples classified as A. lumbricoides positive by Kato-Katz were negative by qPCR. Amplicon sequencing of the 18S rDNA from 10 samples confirmed that A. lumbricoides was absent in samples classified as positive by Kato-Katz and negative by qPCR. The sensitivity of Kato-Katz was 49% for A. lumbricoides, 32% for hookworm, and 52% for T. trichiura; the sensitivity of qPCR was 79% for A. lumbricoides, 93% for hookworm, and 90% for T. trichiura. Specificity was ≥ 97% for both tests for all STH except for Kato-Katz for A. lumbricoides (specificity = 68%). There were moderate negative, monotonic correlations between qPCR cycle quantification values and eggs per gram quantified by Kato-Katz. While it is widely assumed that double-slide Kato-Katz has few false positives, our results indicate otherwise and highlight inherent limitations of the Kato-Katz technique. qPCR had higher sensitivity than Kato-Katz in this low intensity infection setting.

Soil-transmitted helminth infections (STH) (e.g., Ascaris, hookworm, Trichuris) contribute to a large burden of disease among children in low- and middle-income countries. There is increasing interest in implementing large-scale deworming programs to eliminate STH in certain settings. Efforts to monitor whether local elimination has occurred require sensitive diagnostic tests that will not miss positive cases. Kato-Katz, a microscopy-based diagnostic test, has commonly been used to identify STH eggs in stool, but in settings where infection intensity is low, this method frequently misses positive samples because it requires visual identification of small numbers of eggs, and hookworm eggs may degrade prior to visualization. Quantitative polymerase chain reaction (qPCR) is a molecular diagnostic method for detecting STH. It may detect more low intensity infections than Kato-Katz because it identifies STH DNA in stool; DNA can be detected in very small quantities and is less likely to degrade than STH ova. Thus, qPCR is likely to be more accurate than Kato-Katz. This study compared the performance of double-slide Kato-Katz and qPCR using 2,799 stool samples from children aged 2–12 years in a setting in rural Bangladesh with predominantly low STH infection intensity. qPCR was more sensitive than Kato-Katz for hookworm and Trichuris infections. 26% of samples were classified as Ascaris positive by Kato-Katz and negative by qPCR. DNA sequencing of 10 samples confirmed that Ascaris was absent in samples classified as positive by Kato-Katz and negative by qPCR. We conclude that Kato-Katz likely produced false positive results for Ascaris and that qPCR had a higher sensitivity than double-slide Kato-Katz in this low infection intensity setting.

Hand hygiene intervention to optimize helminth infection control: Design and baseline results of Mikono Safi-An ongoing school-based cluster-randomised controlled trial in NW Tanzania

INTRODUCTION

Soil transmitted helminths (STH) can affect over 50% of children in some parts of Tanzania. Control measures involve annual deworming campaigns in schools, but re-infection is rapid. This paper presents the design and baseline survey results of an ongoing school-based cluster-randomised controlled trial in Kagera region, NW Tanzania. The trial aims to determine whether the effect of routine deworming on the prevalence of Ascaris lumbricoides and Trichuris trichiura infections among school aged children can be sustained when combined with a behaviour change intervention promoting handwashing with water and soap.

METHODS

As part of the trial, a total of 16 schools were randomised to receive the intervention (N = 8) or as controls (N = 8). Randomisation was stratified per district and restricted to ensure pre-trial STH prevalence was balanced between study arms. The combination intervention to be tested comprises class-room based teacher-led health education, improvement of handwash stations, coloured nudges to facilitate handwashing and parental engagement sessions. The impact evaluation involves two cross-sectional surveys conducted at baseline and endline. The objectives of the baseline survey were: (i) to confirm whether the deworming campaign was successful, and identify and treat students still infected about 2 weeks after deworming, (ii) to document any baseline differences in STH prevalence between trial arms, and (iii) to assess handwashing behaviours, and access to water and sanitation at school and home. We randomly sampled 35 students per class in Grades 1-6 (an average of 200 children per school), stratified to ensure equal representation between genders. Assenting students were interviewed using a structured questionnaire and asked to provide a stool specimen.

RESULTS

Results of the baseline survey conducted about 2 weeks after deworming shows balanced demographic and STH prevalence data across trial arms. We observed a low prevalence of ascariasis (< 5%) as expected; however, the prevalence of trichuriasis was still about 35% in both arms.

CONCLUSION

The randomisation procedure was successful in achieving a balanced distribution of demographic characteristics and helminth infections between trial arms. The intervention is being rolled out. The current deworming treatment regimen may need to be revised with regards to the treatment of trichuriasis.

Differential Change in the Prevalence of the Ascaris, Trichuris and Clonorchis infection Among Past East Asian Populations

As we learn more about parasites in ancient civilizations, data becomes available that can be used to see how infection may change over time. The aim of this study is to assess how common certain intestinal parasites were in China and Korea in the past 2000 years, and make comparisons with prevalence data from the 20th century. This allows us to go on to investigate how and why changes in parasite prevalence may have occurred at different times. Here we show that Chinese liver fluke (Clonorchis sinensis) dropped markedly in prevalence in both Korea and China earlier than did roundworm (Ascaris lumbricoides) and whipworm (Trichuris trichiura). We use historical evidence to determine why this was the case, exploring the role of developing sanitation infrastructure, changing use of human feces as crop fertilizer, development of chemical fertilizers, snail control programs, changing dietary preferences, and governmental public health campaigns during the 20th century.

Comparison of four DNA extraction and three preservation protocols for the molecular detection and quantification of soil-transmitted helminths in stool

Background

A DNA extraction and preservation protocol that yields sufficient and qualitative DNA is pivotal for the success of any nucleic acid amplification test (NAAT), but it still poses a challenge for soil-transmitted helminths (STHs), including Ascaris lumbricoides, Trichuris trichiura and the two hookworms (Necator americanus and Ancylostoma duodenale). In the present study, we assessed the impact of different DNA extraction and preservativation protocols on STH-specific DNA amplification from stool.

Methodology and principal findings

In a first experiment, DNA was extracted from 37 stool samples with variable egg counts for T. trichiura and N. americanus applying two commercial kits, both with and without a prior bead beating step. The DNA concentration of T. trichiura and N. americanus was estimated by means of qPCR. The results showed clear differences in DNA concentration across both DNA extraction kits, which varied across both STHs. They also indicated that adding a bead beating step substantially improved DNA recovery, particularly when the FECs were high. In a second experiment, 20 stool samples with variable egg counts for A. lumbricoides, T. trichiura and N. americanus were preserved in either 96% ethanol, 5% potassium dichromate or RNAlater and were stored at 4°C for 65, 245 and 425 days. DNA was extracted using the DNeasy Blood & Tissue kit with a bead beating step. Stool samples preserved in ethanol proved to yield higher DNA concentrations as FEC increased, although stool samples appeared to be stable over time in all preservatives.

Conclusions

The choice of DNA extraction kit significantly affects the outcome of NAATs. Given the clear benefit of bead beating and our validation of ethanol for (long-term) preservation, we recommend that these aspects of the protocol should be adopted by any stool sampling and DNA extraction protocol for downstream NAAT-based detection and quantification of STHs.

DNA-based tools are increasingly being used for the diagnosis of intestinal worm infections in both clinical and research laboratories. However, recovering DNA from intestinal worm eggs in stool remains a challenge since this DNA is protected by a very rigid egg shell. Furthermore, stool contains inhibitors that can affect test results and these should be removed during DNA extraction. Prior to DNA extraction, samples are often preserved, but the impact of the type of preservatives and the duration of preservation remains poorly studied. In the present study, we assessed the impact of four DNA extraction and three preservation protocols on the downstream performance of a DNA-based diagnostic tool for intestinal worms. We found significant differences in DNA recovery across the DNA and preservation protocols, but DNA from worm eggs in stool proved to be stable over time in all preservatives.

Effect of endoparasites occurrence in sows from intensive production system

The goal of this study was to assess the effect of farm size (FS) and farrowing order (FO) on the occurrence of endoparasites eggs in commercial sows housed in maternity and gestation areas during the period from May to July 2014. Forty-three piglet production units were classified by FS: small (100 to 250 sows), medium (251 to 510 sows), large (511 to 1,000 sows) and very large (more than 1,000 sows). Sows were classified by FO: up to two, three to five or more than five parturitions. Faecal samples were processed using the simple flotation technique in a hypersaturated salt solution (30-35% NaCl). The results revealed that the overall prevalence of gastrointestinal endoparasites obtained in this study was 12.47%, in that 4.64% were positive for Ascaris suum, 0.56% for Trichuris suis and 8.27% for coccidia oocysts. The prevalence of endoparasites obtained for small and medium size farm, and for large and very large farm was 34.58% and 15.52%, respectively. In conclusion, the study shows that more than half of the farms were positive for A. suum and coccidia oocysts, but mainly for younger females. In general, sows with up to two parturitions and small farms showed a higher endoparasites percentage.

Elimination of morbidity due to soil-transmitted helminthiases among Afghan schoolchildren

Large sectors of the Afghan population have limited access to safe water and sanitation, which increases the risk of transmission of water- and food- borne diseases, including Soil-Transmitted Helminth (STH) infections. STHs interfere with the human host's health status, and their burden of disease is highest among children of school age. Based on the results of a nationwide survey conducted in 2003, which showed an STH prevalence of 47.2%, and with the aim of reducing morbidity among school children, Afghanistan has been conducting nationwide deworming for preschool-age and school-age children since 2004. In 2017, 14 years after the first baseline assessment, a follow-up survey was carried out among schoolchildren aged 8-10 years to provide an update on STH epidemiology and facilitate evidence-informed planning of future deworming campaigns. Stool samples were collected from 2263 pupils aged 8-10 years in five provinces representing the different ecological zones of the country - Kabul, Balkh, Herat, Nangarhar and Kandahar. Microscopic examination was carried out by the Kato-Katz thick smear technique, to assess the presence and the number of parasites and/or their eggs. The survey revealed that 26.6% of the sample was infected with at least one of the STH, a marked decrease from the level registered in 2003. The most prevalent infection was the one with A. lumbricoides (25.7%), followed by T. trichiura (1.0%) and hookworms (0.1%). All positive children were noted to have light-intensity infections, compared to the previous survey where 9.7% of the sample had moderate-to-heavy intensity infections. Only 0.2% of the children had co-infection with two or more parasites. Meanwhile, 6.8% of the students were found infected with the dwarf tapeworm, Hymenolepis nana. The absence of infections of moderate-to-heavy intensity after several yearly rounds of deworming and overall improvements in provision of safe water and sanitation, indicates successful control of morbidity due to STH and, overall, their elimination as a public-health problem from Afghanistan. Nevertheless, current levels of prevalence of infection still show persistence of active transmission of STHs, thus justifying the continued implementation of mass deworming interventions among children. The permanent elimination of STH transmission, however, will be possible only when the country reaches a sanitation level sufficient to impede fecal contamination of the environment with human excreta.

Kankanet: An artificial neural network-based object detection smartphone application and mobile microscope as a point-of-care diagnostic aid for soil-transmitted helminthiases

Background

Endemic areas for soil-transmitted helminthiases often lack the tools and trained personnel necessary for point-of-care diagnosis. This study pilots the use of smartphone microscopy and an artificial neural network-based (ANN) object detection application named Kankanet to address those two needs.

Methodology/Principal findings

A smartphone was equipped with a USB Video Class (UVC) microscope attachment and Kankanet, which was trained to recognize eggs of Ascaris lumbricoides, Trichuris trichiura, and hookworm using a dataset of 2,078 images. It was evaluated for interpretive accuracy based on 185 new images. Fecal samples were processed using Kato-Katz (KK), spontaneous sedimentation technique in tube (SSTT), and Merthiolate-Iodine-Formaldehyde (MIF) techniques. UVC imaging and ANN interpretation of these slides was compared to parasitologist interpretation of standard microscopy.Relative to a gold standard defined as any positive result from parasitologist reading of KK, SSTT, and MIF preparations through standard microscopy, parasitologists reading UVC imaging of SSTT achieved a comparable sensitivity (82.9%) and specificity (97.1%) in A. lumbricoides to standard KK interpretation (97.0% sensitivity, 96.0% specificity). The UVC could not accurately image T. trichiura or hookworm. Though Kankanet interpretation was not quite as sensitive as parasitologist interpretation, it still achieved high sensitivity for A. lumbricoides and hookworm (69.6% and 71.4%, respectively). Kankanet showed high sensitivity for T. trichiura in microscope images (100.0%), but low in UVC images (50.0%).

Conclusions/Significance

The UVC achieved comparable sensitivity to standard microscopy with only A. lumbricoides. With further improvement of image resolution and magnification, UVC shows promise as a point-of-care imaging tool. In addition to smartphone microscopy, ANN-based object detection can be developed as a diagnostic aid. Though trained with a limited dataset, Kankanet accurately interprets both standard microscope and low-quality UVC images. Kankanet may achieve sensitivity comparable to parasitologists with continued expansion of the image database and improvement of machine learning technology.

For rainforest-enshrouded rural villages of Madagascar, soil-transmitted helminthiases are more the rule than the exception. However, the microscopy equipment and lab technicians needed for diagnosis are a distance of several days’ hike away. We piloted a solution for these communities by leveraging resources the villages already had: a traveling team of local health care workers, and their personal Android smartphones. We demonstrated that an inexpensive, commercially available microscope attachment for smartphones could rival the sensitivity and specificity of a regular microscope using standard field fecal sample processing techniques. We also developed an artificial neural network-based object detection Android application, called Kankanet, based on open-source programming libraries. Kankanet was used to detect eggs of the three most common soil-transmitted helminths: Ascaris lumbricoides, Trichuris trichiura, and hookworm. We found Kankanet to be moderately sensitive and highly specific for both standard microscope images and low-quality smartphone microscope images. This proof-of-concept study demonstrates the diagnostic capabilities of artificial neural network-based object detection systems. Since the programming frameworks used were all open-source and user-friendly even for computer science laymen, artificial neural network-based object detection shows strong potential for development of low-cost, high-impact diagnostic aids essential to health care and field research in resource-limited communities.

Genetic Analysis of Small-Subunit Ribosomal RNA, Internal Transcribed Spacer 2, and ATP Synthase Subunit 8 of Trichuris trichiura Ancient DNA Retrieved from the 15th to 18th Century Joseon Dynasty Mummies' Coprolites from Korea

Although parasitic infection by Trichuris trichiura is a very common intestinal helminthic disease worldwide, there is still insufficient information on the genetic characteristics of ancient T. trichiura in different spatiotemporal perspectives. Utilizing coprolite specimens obtained from 15th-18th century mummies dating to the Joseon Dynasty, we analyzed small-subunit ribosomal RNA, internal transcribed spacer 2, and ATP synthase subunit 8 of T. trichiura ancient DNA (aDNA). In BLAST and phylogenetic analyses, the T. trichiura aDNA sequences of this study belong to a separate cluster that is evidently distinct from the other genus Trichuris spp. reported in GenBank. This report characterizes T. trichiura aDNA of pre-20th century East Asia, and in so doing, it also proves the potential of aDNA analysis for differential diagnosis of T. trichiura in cases where ancient parasite eggs are morphologically indeterminate for species identification.

Intestinal parasitic infections and associated factors in children of three rural schools in Colombia. A cross-sectional study

Rural children are one of the populations that are most vulnerable to gastrointestinal parasite infections. Such diseases decrease the quality of life and result in growth and cognitive delays in the long term. This cross-sectional study was conducted to determine the frequency of intestinal parasite infections among rural schoolchildren in the municipality of Apulo, Colombia. A total of 97 stool samples from children aged between 5 and 15 years were collected and examined via direct light microscopy. Microscopic examination was repeated with sediments obtained using a fecal parasite concentrator, and the Kato–Katz test was performed. Frequency of intestinal parasite infection was 100%. Endolimax nana (77.35%), Blastocystis sp. (71.1%), Giardia intestinalis (39.1%), Entamoeba coli (25.7%), and the Entamoeba histolytica/dispar/moshkovskii complex (9.2%) were the most prevalent protozoa. Trichuris trichiura was the most prevalent helminth (12.3%), followed by Enterobius vermicularis (6.15%) and Ascaris lumbricoides (5.1%). Among the analyzed associated factors, consumption of untreated water increased the risk of acquiring pathogenic intestinal parasites. Finally, because G. intestinalis was the most prevalent pathogenic protozoan, molecular analysis was conducted to establish genetic assemblages and subassemblages of Giardia through sequence-based genotyping of the glutamate dehydrogenase, triose phosphate isomerase, and beta-giardin genes. A total of 14 G. intestinalis-positive samples were genotyped, which revealed the presence of subassemblages AI (n = 1), AII (n = 7), BIII (n = 2), BIV (n = 2), and BIII/BIV (n = 1) as well as a mixed subassemblage AII + BIII (n = 1). Our results indicate that gastrointestinal parasite infections in the tested population were mainly caused by suboptimal water quality. Moreover, molecular typing of G. intestinalis suggested contamination of water by animal- and human-derived cysts.

Diagnostic performance of mini parasep® solvent-free foecal parasite concentrator for the diagnosis of intestinal parasitic infections

Introduction

Various stool concentration techniques have been used to increase the microscopic detection of parasites. We assessed the enclosed, single-vial, Mini Parasep® technique in comparison to the currently used coprodiagnosis procedures.

Materials and Methods

A total of 150 stool samples were collected. Samples concentrated by formol-ether method (FEM) and Mini Parasep® SF foecal concentrator and unconcentrated samples were subjected to wet mount, iodine mount microscopy and smear examination by modified acid-fast staining.

Results

Direct wet mount detected 72 positive samples (48.6%), whereas 77 (51.3%) and 80 (53.3%) samples were detected by FEM and Mini Parasep® SF methods, respectively. The sensitivity of detection of parasites was 98.7%, 95% and 90.1% with Mini Parasep®, FEM and direct microscopy, respectively. A clearer background with less foecal debris and a better yield of Hymenolepis nana, Trichuris trichiura, Entamoeba coli and Giardia lamblia were noted with Mini Parasep®.

Conclusion

Mini Parasep® SF technique is simple, rapid and less cumbersome than conventional diagnostics, making it suitable for routine use. In addition, it offers higher sensitivity and better background clearance than both direct stool examination and FEM.

Parasitological contamination with eggs Ascaris spp., Trichuris spp. and Toxocara spp. of dehydrated municipal sewage sludge in Poland

The objective of the present study was to evaluate the contamination of sewage sludge produced by municipal waste treatment plants in Poland by viable eggs of intestinal parasites of the genera Ascaris, Toxocara and Trichuris (ATT). Ninety-two municipal, mechanical-biological sewage treatment plants located within Poland were selected. These plants belonged to types of agglomerations: group 0 (large), group 1 (medium), group 2 (smaller) and group 3 (small). Samples were collected at the final stage of sewage treatment after the addition of flocculent to sludge, followed by dehydration. The samples were examined by a method adjusted to examine sewage sludge dehydrated using polyelectrolytes. The viability of the isolated eggs was evaluated based on incubation in a moist chamber. Live eggs of intestinal nematodes were found in 99% of samples. Most samples were contaminated by the eggs of Ascaris spp. (95%) and Toxocara spp. (96%). However, Trichuris spp. eggs were detected in 60% of samples. The mean number of eggs in 1 kg of dry mass (eggs/kg d.m.) was 5600 for Ascaris, 3700 for Toxocara and 1100 for Trichuris. The highest number of ATT eggs was detected in samples from sewage treatment plants located in south-eastern and central Poland. The highest number of ATT eggs was found in sewage sludge produced in large sewage treatment plants (agglomeration Groups 0 and 1), with mean values of 15,000 and 8900 eggs/kg d.m. The present study is the first parasitological investigation conducted on a large number of samples (92 samples) taken from various types of municipal sewage treatment plants located throughout Poland (16 regions) after the common introduction of polyelectrolytes during sewage sludge dehydration. The results of this study indicate that sludge produced in municipal sewage treatment plants is highly contaminated with parasite eggs.

Capillaria Ova and Diagnosis of Trichuris trichiura Infection in Humans by Kato-Katz Smear, Liberia

We examined human stool samples from Liberia for soil-transmitted helminth ova by Kato-Katz smear and by quantitative PCR. Twenty-five samples were positive for Trichuris trichiura by smear but negative by quantitative PCR. Reexamination of samples showed that they contained Capillaria eggs that resemble T. trichiura in Kato-Katz smears.

Soil-transmitted helminth infections in school children of three districts of Malakand region, Khyber Pakhtunkhwa, Pakistan

Information on prevalence of soil-transmitted helminth (STH) infections among school children is scarce in Pakistan. This study was aimed to investigate the prevalence of soil-transmitted helminth in school children of three districts in, Khyber Pakhtunkhwa, Pakistan. A total of 300 stool samples were examined from August 2015 to August 2016 using direct smear (Normal saline and Lugol's Iodine solution) and the concentration methods. One hundred and eighty seven (62.3%) pupils were found infected with soil-transmitted helminths. One hundred and forty five (77.5%) were infected with single parasite and forty two (22.4%) with multiple infections. Ascaris lumbricoides 125 (66.4%), Trichuris trichura 50 (26.5%) and Ancylostoma duedenale 13 (6.91%) were detected. The children above 8 years in age were more parasitized than below 8 years (p=0.7832; P>0.05). Males were found more parasitized than females (p=0.9315; P>0.05). Children in lower Dir district were found more infected followed by Swat and upper Dir (P< 0.0001; p<0.05). No significant relationship was found among the examined and that of infected children for ages and sex in all the districts. Malakand division is an area with poor hygiene located in temperate zone near the border of Afghanistan and China. The prevalence of reported nematode parasites here compared with the same studies is unexpectedly high. These types of studies should continue time to time to know the hazardous nature of such parasitic infections for the betterment of the human health.

A new Trichuris species (Nematoda: Trichuridae) from capybaras: Morphological-molecular characterization and phylogenetic relationships

A new species of Trichuris (Nematoda: Trichuridae) is described from the capybara, Hydrochoeris hydrochaeris (Rodentia: Caviidae), from two localities of Corrientes Province, based on morphological characteristics and ITS1 and ITS2 of nuclear rDNA region sequences. This species present morphological differences with 28 species of the genus described from North and South American rodents. Also, the new species is molecularly characterized and differentiated from those species from Muridae, Cricetidae and Myocastoridae rodents recorded from North and South America, Europe and Africa. Trichuris cutillasae n. sp. constitutes the ninth record from rodents of Argentina, and the second record for Caviidae. The phylogenetic analysis showed that the specimens of new species are in the same clade, and separated from specimens of T. myocastoris (ITS1and ITS2), T. navonae, T. bainae, Trichuris sp. and T. pardinasi (ITS2). Similarly, analysis of concatenated sequences ITS1 and ITS2 added further evidence that T. cutillasae n. sp. is a different species from those previously analyzed.

Long-Tailed Macaques (Macaca fascicularis) in Urban Landscapes: Gastrointestinal Parasitism and Barriers for Healthy Coexistence in Northeast Thailand

Gastrointestinal parasites have diverse life cycles that can involve people, animals, and the environment (e.g., water and soil), demonstrating the utility of One Health frameworks in characterizing infection risk. Kosumpee Forest Park (Thailand) is home to a dense population of long-tailed macaques (Macaca fascicularis) that frequently interact with tourists and local residents. Our study investigated the presence of zoonotic parasites, and barriers to healthy coexistence by conducting stool analysis on macaques (N = 102) and people (N = 115), and by examining risk factors for infection with a household questionnaire (N = 95). Overall, 44% of macaques and 12% of people were infected with one or more gastrointestinal helminths, including Strongyloides spp., Ascaris spp., and Trichuris sp. An adults-only generalized linear mixed model identified three factors significantly associated with human infection: household size, occupational exposure, and contact with macaque feces at home. Participants identified both advantages and disadvantages to living in close contact with macaques, suggesting that interventions to improve human and animal health in Kosumpee Forest Park would be welcome.

Quantitative Polymerase Chain Reaction for Diagnosis of Soil-Transmitted Helminth Infections: A Comparison with a Flotation-Based Technique and an Investigation of Variability in DNA Detection

Appropriate diagnostic techniques are crucial to global soil-transmitted helminth (STH) control efforts. The recommended Kato-Katz method has low sensitivity in low-transmission settings. Quantitative polymerase chain reaction (qPCR) is a highly sensitive alternative diagnostic option. However, little is known about the variability in qPCR results, and there are few published comparisons between qPCR and other microscopy-based techniques such as sodium nitrate flotation (SNF). Using 865 stool samples collected from 571 individuals, we compared SNF and qPCR in terms of diagnostic sensitivity and infection intensity measurements. In addition, we conducted repeated examinations on a single Necator americanus-positive stool sample over a 6-month period. Results showed good diagnostic agreement between SNF and qPCR for Ascaris spp. (κ = 0.69, P < 0.001), and moderate agreement for hookworm (κ = 0.55, P < 0.001) and Trichuris spp. (κ = 0.50, P < 0.001). Quantitative polymerase chain reaction demonstrated higher sensitivity than SNF for Ascaris spp. (94.1% versus 68.1%) and hookworm (75.7% versus 66.9%) but not for Trichuris spp. (53.1% versus 81.3%), which had very low prevalence. Sodium nitrate flotation and qPCR infection intensity measurements were strongly correlated for Ascaris spp. (ρ = 0.82, P < 0.001) and moderately correlated for hookworm (ρ = 0.58, P < 0.001). Repeated examinations using qPCR showed that N. americanus cycle threshold values decreased significantly at 1 month and remained stable thereafter. Results confirm the high diagnostic sensitivity of qPCR for Ascaris spp. and hookworm, particularly for light-intensity infections, which is ideal for settings approaching transmission elimination. Results support the potential for qPCR to be used as a quantitative assay for STH. Further research is needed in settings where Trichuris trichiura is endemic.

Contamination of selected recreational areas in Lublin Province, Eastern Poland, by eggs of Toxocara spp., Ancylostoma spp. and Trichuris spp

INTRODUCTION

While using recreational areas, people take with them accompanying animals (dogs, cats). These animals are the main source and reservoir of dangerous zoonoses, including parasitoses caused by genera of nematodes, also called roundworms, Toxocara spp., Trichuris spp. and Ancylostoma spp. Attention should also be paid to the possibility of contamination of recreational areas with the eggs of intestinal parasites by wild animals (e.g. red fox).

MATERIAL AND METHODS

Sand was collected on beaches and leisure terrains located in recreational areas in Zwierzyniec, Rudka reservoir on the river Wieprz, 'Echo' reservoir, accessible to tourists to the Roztocze National Park, and the 'Florianiecki' reservoir, chich is inaccessible to tourists due to its location in the depths of the National Park. Material for the research was also collected from the 'Zemborzycki reservoir in Lublin, A total of 300 sand samples were collected. The samples, approximately 500 g each, were collected into plastic bags from the superficial layer of sand, at a depth up to 3 cm. For egg detection, flotation with the Wasylikowa metod and the modified Quinn method were used. In the Quinn metod, the flotation solution is NaCl saturated solution, in the Wasylikowa method, 5% solution of NaOH is used.

RESULTS

The most contaminated grounds were areas by the water 'Zemborzycki' reservoir in Lublin. The eggs of intestinal parasites were isolated from 13 out of 24 samples examined. In sand collected from the beach by the 'Echo', 'Florianiecki' and 'Rudka' water resevoirs in Zwierzyniec, no eggs of intestinal parasites were detected.

CONCLUSIONS

Such a dissemination of results may indicate a connection between the degree of occurrence of geohelmint eggs and the intensity of human movement, together with accompanying animals, in places that can be used for recreation.

Prevalence and Risk Factors of Ascaris lumbricoides, Trichuris trichiura and Cryptosporidium Infections in Elementary School Children in Southwestern China: A School-Based Cross-Sectional Study

Background: Intestinal parasitic infections pose great public health challenges in school children in developing countries. The aim of this study was to assess the prevalence of A. lumbricoides, T. trichiura and Cryptosporidium among elementary school children in rural southwestern China. Methods: A school-based cross-sectional study involving 321 elementary school children was conducted in 2014 in the southwest of China. They were invited to provide a stool sample and interviewed about the sanitary situation and hygiene behavior. Stool specimens were examined for A. lumbricoides and T. trichiura using the Kato-Katz fecal thick-smear technique. The presence of Cryptosporidium was determined using a modified acid-fast staining method. Results: The prevalence of infection was 10.0% (95% CI: 6.9–13.8%) for A. lumbricoides, 25.2% (95% CI: 20.6–30.4%) for T. trichiura and 2.4% for (95% CI: 1.1–4.9%) Cryptosporidium. The prevalence of co-infection was 3.7% (95% CI: 1.9–6.4%) for A. lumbricoides/T. trichiura, 0.3% (95% CI: 0–1.7%) for A. lumbricoides/Cryptosporidium and 0.9% (95% CI: 0.2–2.7%) for T. trichiura/Cryptosporidium. Children from households using well or river water were associated with a greater odds of A. lumbricoides infection (aOR = 2.61, 95% CI: 1.12–6.05). Having a household lavatory was associated with a lower odds of T. trichiura infection (aOR = 0.50, 95% CI: 0.30–0.84). Children who had three meals at the school canteen on week days were at a lower risk of Cryptosporidium infection. The use of spring water as a water source was associated with lower odds of any intestinal infection (aOR = 0.56, 95% CI: 0.35–0.91). Conclusions: Our study calls for an intervention program of school-based deworming combined with health education, hygiene promotion and provision of safe water and improved sanitation.

MaxEnt modeling of soil-transmitted helminth infection distributions in Thailand

Infections due to soil-transmitted helminths (STHs), i.e. Ascaris lumbricoides, Trichuris trichiura, hookworms, and Strongyloides stercoralis, are widely distributed in tropical and subtropical areas in which approximately 1.5 billion people are infected. A clear understanding of the epidemiology and distribution of diseases is an important aid for control and prevention. The aim of our study was to identify the effects of environmental and climatic factors on distribution patterns of STHs and to develop a risk map for STH infections under current environmental and climate regimes in Thailand. Geographical information systems (GIS), remote sensing, and Maximum Entropy (MaxEnt) algorithm software were used to determine the significant factors and to create predictive risk maps for STH infections in Thailand. The disease data from Thailand covered the years from 1969 to 2014, while environmental and climatic data were compiled from the Worldclim database, MODIS satellite imagery, Soilgrids and ISCGM. The models predicted that STHs occur mainly in southern Thailand. Mean annual precipitation was the factor most affecting the current distribution of A. lumbricoides, T. trichiura, and S. stercoralis. Land cover class was the main predictor for distribution of S. stercoralis and important for hookworms. Altitude was the dominant factor affecting the distribution of hookworms, and mean temperature of the wettest quarter was significantly associated with A. lumbricoides distribution. A predicted distribution map of STHs to identify environmental risk factors in Thailand is presented. This work provides a model for use in STH monitoring and health planning not only in Thailand but also in other countries with similar disease conditions.

Parasitic infections and resource economy of Danish Iron Age settlement through ancient DNA sequencing

In this study, we screen archaeological soil samples by microscopy and analyse the samples by next generation sequencing to obtain results with parasites at species level and untargeted findings of plant and animal DNA. Three separate sediment layers of an ancient man-made pond in Hoby, Denmark, ranging from 100 BC to 200 AD, were analysed by microscopy for presence of intestinal worm eggs and DNA analysis were performed to identify intestinal worms and dietary components. Ancient DNA of parasites, domestic animals and edible plants revealed a change in use of the pond over time reflecting the household practice in the adjacent Iron Age settlement. The most abundant parasite found belonged to the Ascaris genus, which was not possible to type at species level. For all sediment layers the presence of eggs of the human whipworm Trichuris trichiura and the beef tapeworm Taenia saginata suggests continuous disposal of human faeces in the pond. Moreover, the continuous findings of T. saginata further imply beef consumption and may suggest that cattle were living in the immediate surrounding of the site throughout the period. Findings of additional host-specific parasites suggest fluctuating presence of other domestic animals over time: Trichuris suis (pig), Parascaris univalens (horse), Taenia hydatigena (dog and sheep). Likewise, alternating occurrence of aDNA of edible plants may suggest changes in agricultural practices. Moreover, the composition of aDNA of parasites, plants and vertebrates suggests a significant change in the use of the ancient pond over a period of three centuries.

Diagnostic comparison between FECPAKG2 and the Kato-Katz method for analyzing soil-transmitted helminth eggs in stool

BACKGROUND

Over one billion people are infected with soil-transmitted helminths (STH), i.e. Ascaris lumbricoides, hookworm and Trichuris trichiura. For estimating drug efficacy and monitoring anthelminthic drug resistance, accurate diagnostic methods are critical. FECPAKG2 is a new remote-diagnostic tool used in veterinary medicine, which produces an image of the stool sample that can be stored on an internet cloud. We compared for the first time FECPAKG2 with the recommended Kato-Katz method.

METHODOLOGY/PRINCIPAL FINDINGS

Two stool samples were collected from adolescent participants (age 15-18 years) at baseline and 14 to 21 days after treatment in the framework of a randomized clinical trial on Pemba Island, Tanzania. Stool samples were analyzed with different diagnostic efforts: i) one or ii) two Kato-Katz thick smears from the first sample, iii) two Kato-Katz thick smears from two samples and iv) FECPAKG2 from the first sample. Parameters were calculated based on a hierarchical Bayesian egg count model. Complete data for all diagnostic efforts were available from 615 participants at baseline and 231 hookworm-positive participants at follow-up. At baseline FECPAKG2 revealed a sensitivity of 75.6% (72.0-77.7) for detecting A. lumbricoides, 71.5% (67.4-95.3) for hookworm and 65.8% (64.9-66.2) for T. trichiura, which was significantly lower (all p<0.05) than any of the Kato-Katz methods and highly dependent on infection intensity. Despite that the egg counts based on FECPAKG2 were relatively lower compared to Kato-Katz by a ratio of 0.38 (0.32-0.43) for A. lumbricoides, 0.36 (0.33-0.40) for hookworm and 0.08 (0.07-0.09) for T. trichiura, the egg reduction rates (ERR) were correctly estimated with FECPAKG2.

CONCLUSIONS/SIGNIFICANCE

The sensitivity to identify any STH infection was considerably lower for FECPAKG2 compared to Kato-Katz. Following rigorous development, FECPAKG2 might be an interesting tool with unique features for epidemiological and clinical studies.

Results of the first mapping of soil-transmitted helminths in Benin: Evidence of countrywide hookworm predominance

Background

National mapping of soil-transmitted helminth infections (STH) was conducted for the first time in all of the 77 districts of Benin (West Africa) from 2013 to 2015. This mapping aimed to provide basic epidemiological data essential for the implementation of the national strategy against the neglected tropical diseases (NTDs) in the context of achieving the WHO target of controlling these infections by 2020.

Methods

In each district, 5 schools were purposively selected in 5 villages and 50 school-children (25 girls and 25 boys) from ages 8 to 14 years were randomly enrolled in each school. In total, 19,250 stool samples of school children (9,625 girls and 9,625 boys) from 385 schools were examined by Kato-Katz technique.

Results

The three major species of STH (hookworm, Ascaris lumbricoides and Trichuris trichiura) were observed with intra- and inter-specific variations in the prevalence and the intensity of these parasites. Hookworm infection was present in all of the surveyed districts with an average prevalence of 17.14% (95% CI 16.6%-17.6%). Among the infected schoolchildren, at national level, 90.82%, 6.73% and 2.45% of infections were of light, moderate and heavy parasite intensities respectively. A. lumbricoides infection, with a national average prevalence of 5.35% (95% CI 5.00%-5.60%),was the second most prevalent STH, and 84.37%, 14.27% and 1.36% of the infections were of light, moderate and heavy parasite intensities, respectively. T. trichiura had a national average prevalence of 1.15% (95% CI 0.90%-1.20%) and 80.45%, 13.18% and 6.36% infections were of light, moderate and heavy parasite intensities, respectively. The national cumulative prevalence of the three STH infections was 22.74% (95% CI 22.15%-23.33%), with58.44% (45/77) of the districts requiring mass treatment according to WHO recommendations. In all of the surveyed districts, multiple infections by STH species were common, and boys seemed more at risk of hookworm and Ascaris infections.

Conclusions

This first national mapping provided an overview of the epidemiological pattern of STH infections and was essential for the implementation of a control strategy with an effective preventive chemotherapy treatment (PCT). Results show that while preventive chemotherapy is not indicated for children in 32/77 districts, 43 require annual deworming and two require twice yearly deworming. If no environmental change occurs, and no mass treatment is delivered, prevalence is likely to remain stable for many years owing to poor hygiene and sanitation.

Benin, like other low or moderate-income countries in the African continent, is endemic for several neglected tropical diseases, including soil-transmitted helminthiases. The National Program for Neglected Tropical Diseases of the Ministry of Health has conducted the national STH mapping using the Kato-Katz method to assess the baseline epidemiological status in all 77 districts of Benin, in order to guide implementation of a preventive chemotherapy program using albendazole. The results of the survey showed that infection with at least one of the three targeted species (hookworm, roundworm or whipworm) affected 20% or more of school aged children in 45 out of 77 districts, and which therefore require PCT. Hookworm infection was the most prevalent followed by ascariasis and trichuriasis. Boys were significantly more likely than girls to be infected with hookworm or ascariasis.

Ancient Soil-Transmitted Parasite Eggs Detected from the Sixth Century Three Kingdom Period Silla Tomb

The parasitic infection patterns of the Joseon period have begun to be revealed in a series of paleoparasitological studies. However, parasitism prevailing during or before the Three Kingdom period is still relatively unexplored. In the present study, we therefore conducted parasitological examinations of soil and organic-material sediments precipitated upon human hipbone and sacrum discovered inside an ancient Mokgwakmyo tomb dating to the Silla Dynasty (57 BCE-660 CE). Within the samples, we discovered ancient Ascaris lumbricoides (eggs per gram [EPG], 46.6-48.3) and Trichuris trichiura (EPG, 32.8-62.1) eggs, the species commonly detected among Korean populations until just prior to the 1970s. These findings show that soil-transmitted parasitic infection among the Silla nobility might not have been uncommon. This is the first-ever report on the presence of ancient parasite eggs in the samples obtained from a Three Kingdom period tomb; and it also presents the earliest positive results for any of the ancient South Korean tombs paleoparasitologically examined to date.

Intestinal parasitic infections: Current prevalence and risk factors among schoolchildren in capital area of the Republic of Marshall Islands

Intestinal parasitic infections (IPIs) among schoolchildren in Republic of Marshall Islands (RMI) largely remains unknown, thus investigation on IPIs status to establish the baseline data is urgently needed. This cross-sectional study intended to investigate the current IPIs status and associated risk factors among schoolchildren at capital of RMI. Single stool sample from 400 schoolchildren (207 boys and 193 girls) aged 9.73±2.50 yrs old was examined by employing merthiolate-iodine-formaldehyde concentration method. Demographic characteristics, uncomfortable symptoms and risk factors were obtained by questionnaires investigation. The overall prevalence of IPIs in schoolchildren was 22.8% (91/400), of them 24.2% harbored at least 2 different parasites. Notably, the majority was infected by waterborne protozoan parasites (82.4%, 75/91). Nine different intestinal parasites have been identified, of which six were pathogenic including Hook worm, Trichuris trichiura, Enterobius vermicularis, Entamoeba histolytica/dispar, Giardia intestinalis and Blastocystis hominis. Schoolchildren who ever complained dizziness or headache showed a significant higher prevalence of pathogenic IPIs than those who did not (p<0.05). Schoolchildren who lived in urban area than rural area had higher chance to acquire pathogenic IPIs (p=0.03). However, none of risk factors were identified to be associated with pathogenic IPIs.

Turning poop into profit: Cost-effectiveness and soil transmitted helminth infection risk associated with human excreta reuse in Vietnam

Human excreta is a low cost source of nutrients vital to plant growth, but also a source of pathogens transmissible to people and animals. We investigated the cost-savings and infection risk of soil transmitted helminths (STHs) in four scenarios where farmers used either inorganic fertilizer or fresh/composted human excreta supplemented by inorganic fertilizer to meet the nutrient requirements of rice paddies in the Red River Delta, Vietnam. Our study included two main components: 1) a risk estimate of STH infection for farmers who handle fresh excreta, determined by systematic review and meta-analysis; and 2) a cost estimate of fertilizing rice paddies, determined by nutrient assessment of excreta, a retailer survey of inorganic fertilizer costs, and a literature review to identify region-specific inputs. Our findings suggest that farmers who reuse fresh excreta are 1.24 (95% CI: 1.13–1.37, p-value<0.001) times more likely to be infected with any STH than those who do not handle excreta or who compost appropriately, and that risk varies by STH type (Ascaris lumbricoides RR = 1.17, 95% CI = 0.87–1.58, p-value = 0.29; Hookworm RR = 1.02, 95% CI = 0.50–2.06, p-value = 0.96; Trichuris trichiura RR = 1.38, 95% CI = 0.79–2.42, p-value = 0.26). Average cost-savings were highest for farmers using fresh excreta (847,000 VND) followed by those who composted for 6 months as recommended by the WHO (312,000 VND) and those who composted for a shorter time (5 months) with lime supplementation (37,000 VND/yr); however, this study did not assess healthcare costs of treating acute or chronic STH infections in the target group. Our study provides evidence that farmers in the Red River Delta are able to use a renewable and locally available resource to their economic advantage, while minimizing the risk of STH infection.

Each year, hundreds of millions of people worldwide are infected with intestinal worms spread by contaminated soil, also known as soil transmitted helminths (STHs). These worms are most common in tropical climates in areas lacking good hygiene and sanitation, and negatively impact child development, quality of life, and economic wellbeing. Reuse of human excreta for fertilizer is a common practice in many low to middle income countries because farmers require a low cost source of nutrients to grow food crops eaten by people and animals. Excreta can contain microbes, such as STHs, that cause disease in people; however, composting is a known method of killing STHs. Therefore, our goal was to determine if Vietnamese rice farmers involved in this practice are at higher risk of STH infection, and to calculate the amount of money saved by farmers composting for different lengths of time, and supplementing with various commercial fertilizers. We suggest that farmers compost excreta for six months to reduce disease exposure and optimize household savings. Optimizing practices to improve food production and protect farmer health is critical for poverty alleviation in low to middle income countries.

Status of soil-transmitted helminth infections in schoolchildren in Laguna Province, the Philippines: Determined by parasitological and molecular diagnostic techniques

BACKGROUND

Soil-transmitted helminths (STH) are the most common parasitic infections in impoverished communities, particularly among children. Current STH control is through school-based mass drug administration (MDA), which in the Philippines is done twice annually. As expected, MDA has decreased the intensity and prevalence of STH over time. As a result, the common Kato Katz (KK) thick smear method of detecting STH is less effective because it lacks sensitivity in low intensity infections, making it difficult to measure the impact of deworming programs.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional study was carried out over a four-week period from October 27, 2014 until November 20, 2014 in Laguna province, the Philippines. Stool samples were collected from 263 schoolchildren, to determine the prevalence of STH and compare diagnostic accuracy of multiplex quantitative polymerase chain reaction (qPCR) with the KK. A large discrepancy in the prevalence between the two techniques was noted for the detection of at least one type of STH infection (33.8% by KK vs. 78.3% by qPCR), Ascaris lumbricoides (20.5% by KK vs. 60.8% by qPCR) and Trichuris trichiura (23.6% by KK vs. 38.8% by qPCR). Considering the combined results of both methods, the prevalence of at least one type of helminth infection, A. lumbricoides, and T. trichiura were 83.3%, 67.7%, and 53.6%, respectively. Sensitivity of the qPCR for detecting at least one type of STH infection, A. lumbricoides, and T. trichiura were 94.1%, 89.9%, and 72.3% respectively; whereas KK sensitivity was 40.6%, 30.3%, and 44.0%, respectively. The qPCR method also detected infections with Ancylostoma spp. (4.6%), Necator americanus (2.3%), and Strongyloides stercoralis (0.8%) that were missed by KK.

CONCLUSION/SIGNIFICANCE

qPCR may provide new and important diagnostic information to improve assessment of the effectiveness and impact of integrated control strategies particularly in areas where large-scale STH control has led to low prevalence and/or intensity of infection.

Diagnostic strategies to reveal covert infections with intestinal helminths in dogs

Intestinal helminths are common in dogs in the United States, particularly non-treated dogs in animal shelters, but surveys by fecal flotation may underestimate their prevalence. To determine the prevalence of intestinal helminths and evaluate the ability of fecal flotation and detection of nematode antigen to identify those infections, contents of the entire gastrointestinal tract of 97 adult (>1year) dogs previously identified for humane euthanasia at two animal control shelters in northeastern Oklahoma, USA, were screened. All helminths recovered were washed in saline and fixed prior to enumeration and identification to genus and species. Fecal samples from each dog were examined by passive sodium nitrate (SG 1.33) and centrifugal sugar solution (SG 1.25) flotation. Fecal antigen detection assays were used to confirm the presence of nematode antigen in frozen fecal samples from 92 dogs. Necropsy examination revealed Ancylostoma caninum in 45/97 (46.4%), Toxocara canis in 11/97 (11.3%), Trichuris vulpis in 38/97 (39.2%), Dipylidium caninum in 48/97 (49.5%), and Taenia sp. in 7/97 (7.2%) dogs. Passive fecal flotation identified 38/45 (84.4%) A. caninum, 6/11 (54.5%) T. canis, 26/38 (68.4%) T. vulpis, 2/48 (4.2%) D. caninum, and 1/7 (14.3%) Taenia sp. infections, while centrifugal flotation combined with antigen detection assays identified A. caninum in 97.7% (43/44), T. canis in 77.8% (7/9), and T. vulpis in 83.3% (30/36) of infected dogs based on necropsy recovery of nematodes. Taken together, these data indicate that detection of nematode antigen is a useful adjunct to microscopic examination of fecal samples for parasite eggs, and that this approach can improve diagnostic sensitivity for intestinal nematode infections in dogs.

Clinical correlates of trichuriasis diagnosed at colonoscopy

Diagnosis of Trichuris trichiura infestations is usually based on identification of barrel-shaped ova in stool, but is frequently missed on stool microscopy. We describe the clinical profile of patients in whom Trichuris infection was incidentally diagnosed at colonoscopy. In a cross-sectional study, patients with colonoscopic diagnosis of trichuriasis were enrolled from the endoscopy unit in a tertiary care center. Blood and stool samples were collected from all those who were willing to participate and provide samples. Sixty-two patients participated, with mean (SD) age of 50.5 (13.6) years and male to female ratio of 40:22. Abdominal pain (61.2%) and/or altered bowel habits (32.2%) were the most common indication for colonoscopy. Most (66.6%) of the Trichuris were located in the cecum and ascending colon. Majority of the patients had live worms, either motile or adhering to the colonic mucosa. The number of worms was single or a few (<15) in 74.2% of patients. Out of 62 patients, 16 (25.8%) had relatively heavy load of parasites. Most patients had normal colonoscopic findings (80.6%). Periappendicular and/or cecal ulcerations/erosions were the most common (16.1%) abnormalities noted. Stool examination showed parasite ova only in four (6.4%) patients. In conclusion, colonoscopy was better than stool microscopy for the diagnosis of trichuriasis in our study.

A cross-sectional survey of soil-transmitted helminthiases in two Myanmar villages receiving mass drug administration: epidemiology of infection with a focus on adults

BACKGROUND

Soil-transmitted helminths (STH) are still highly prevalent in southeast Asia. The country of Myanmar has had ongoing mass drug administration (MDA) programmes since 2003 in an attempt to control STH and reduce STH-related morbidities. Whilst the MDA programmes have reported high nationwide coverage, there have been no epidemiological surveys that included measurements from adults. This paper details three cross-sectional surveys that took place over the course of a year in two villages endemic for STH and receiving MDA in lower Myanmar.

RESULTS

At baseline, 27.81% of participants were infected with at least one type of STH. The most prevalent STH was Trichuris trichiura (18.12%) followed by hookworm (8.71%) and Ascaris lumbricoides (5.34%). Most infections were of low intensity, measured by eggs per gram of faeces (EPG). Gender stratification revealed that A. lumbricoides prevalence was significantly higher in females, whereas hookworm prevalence was significantly higher in males. The distribution of EPG in the study sample was highly overdispersed, suggesting that most people release few eggs whereas a few people release many eggs. Adults harbour a major proportion of the overall STH burden; 65.15% of STH infections were harboured by adults.

CONCLUSIONS

STH infection remains at medium prevalence in the study villages despite past and recent MDA. Recorded prevalence of STH in school-aged children has not substantially decreased since the last monitoring and evaluation activities in Myanmar in 2013. Analyses suggest that adults are a major contributor to the total STH prevalence and EPG burden, probably perpetuating transmission.

Detecting and enumerating soil-transmitted helminth eggs in soil: New method development and results from field testing in Kenya and Bangladesh

Globally, about 1.5 billion people are infected with at least one species of soil-transmitted helminth (STH). Soil is a critical environmental reservoir of STH, yet there is no standard method for detecting STH eggs in soil. We developed a field method for enumerating STH eggs in soil and tested the method in Bangladesh and Kenya. The US Environmental Protection Agency (EPA) method for enumerating Ascaris eggs in biosolids was modified through a series of recovery efficiency experiments; we seeded soil samples with a known number of Ascaris suum eggs and assessed the effect of protocol modifications on egg recovery. We found the use of 1% 7X as a surfactant compared to 0.1% Tween 80 significantly improved recovery efficiency (two-sided t-test, t = 5.03, p = 0.007) while other protocol modifications—including different agitation and flotation methods—did not have a significant impact. Soil texture affected the egg recovery efficiency; sandy samples resulted in higher recovery compared to loamy samples processed using the same method (two-sided t-test, t = 2.56, p = 0.083). We documented a recovery efficiency of 73% for the final improved method using loamy soil in the lab. To field test the improved method, we processed soil samples from 100 households in Bangladesh and 100 households in Kenya from June to November 2015. The prevalence of any STH (Ascaris, Trichuris or hookworm) egg in soil was 78% in Bangladesh and 37% in Kenya. The median concentration of STH eggs in soil in positive samples was 0.59 eggs/g dry soil in Bangladesh and 0.15 eggs/g dry soil in Kenya. The prevalence of STH eggs in soil was significantly higher in Bangladesh than Kenya (chi-square, χ² = 34.39, p < 0.001) as was the concentration (Mann-Whitney, z = 7.10, p < 0.001). This new method allows for detecting STH eggs in soil in low-resource settings and could be used for standardizing soil STH detection globally.

Intestinal worm infections are common in populations living in tropical, low-income countries. People primarily become infected when they consume intestinal worm eggs from contaminated water, hands, and food. Intestinal worm eggs are transmitted from infected people and spread through the environment, particularly via soil. There is no standard laboratory method for counting intestinal worm eggs in soil, which is a major barrier to comprehensive research on the transmission of infection. We tested different laboratory protocol steps to extract soil-transmitted helminth eggs, which is one type of intestinal worm, from soil and propose a new, fast, and efficient field method. We tested the method in Kenya and Bangladesh and found that soil contamination with helminth eggs was prevalent in both study areas. We propose that environmental contamination be included in discussions about intestinal worm transmission, control, and elimination, especially in areas with low infection prevalence. The method we propose will help researchers assess soil contamination, which can be used to examine the effectiveness of intestinal worm transmission control measures.

Quantifying the risk of zoonotic geohelminth infections for rural household inhabitants in Central Poland

The objective of this study was to evaluate the risk of soil transmitted zoonotic helminth infections for families with young children, inhabitants of villages in the Mazowieckie Province of Central Poland. Epidemiological survey was conducted at 33 randomly selected households with 2-3 children present. Examination of soil samples from yards surrounding the houses for the presence of geohelminth eggs was conducted, the households were inspected, and family members interviewed using a designed questionnaire. Among 55 localities examined, i.e. 33 backyards, 10 vegetable gardens and 12 sandpits, contamination was found in 2 backyards (6.1%) and 1 sandpit (8.3%) at 3 households (9.1%). Of the total 550 examined soil samples, 4 (0.7%) were found to contain Trichuris and Toxocara eggs, with an average density of 1.5 and 2.0 eggs per sample. The study showed a low level of soil contamination, which was the result of inhabitants care about the sanitation of their domiciles. However, the results of the questionnaire survey demonstrated the need to warn rural residents about the risk factors for zoonotic helmints infections. In particular, parents should be advised how to minimize the threat of parasitic diseases for children in the rural environment. The presented study showed that promotional campaigns implemented in recent years on the prevention of parasitic zoonoses have had little effect to increase the awareness of the rural community. The present results confirmed that Toxocara is the most common zoonotic agent among geohelminths in the rural environment.

Geophagy as risk behaviour for gastrointestinal nematode infections among pregnant women attending antenatal clinics in a humid tropical zone of Nigeria

BACKGROUND

Geophagy is wide spread among pregnant women in Ebonyi State, Nigeria.

OBJECTIVE

The aim of this study was to assess intestinal nematode infections among geophagous pregnant women in Southern Ebonyi State, Nigeria.

METHODS

Pregnant women were aged 17-45 years at gestational ages of ≥ 14 to 24 weeks on hospital enrolment were sampled. Data on geophagy was collected using structured questionnaire. Gastrointestinal nematode status of the participants was determined by stool analyses. Soil types ingested were examined for intestinal nematode ova / larvae.

RESULTS

The prevalence of geophagy (46.4%) was associated with socio-demographic characteristics. Ascaris lumbricoides and hookworm were associated with geophagy while Trichuris trichiura and Strongyloides stercoralis had no association. Prevalence of A. lumbricoides, T. trichiura and S. stercoralis differed significantly (p<0.05) between geophagous and non-geophagous women. The soil types consumed had eggs / larvae of A. lumbricoides and T. trichiura. Geophagy is a risk behaviour directly associated with A. lumbricoides, hookworm, T. trichiura, and to a lesser extent S. stercoralis infection among pregnant women.

CONCLUSION

Sensitization and mass education of pregnant women on the dangers of geophagy is needed. Furthermore, deworming of pregnant women should be integrated into the healthcare delivery system of the State.

Association of community sanitation usage with soil-transmitted helminth infections among school-aged children in Amhara Region, Ethiopia

BACKGROUND

Globally, in 2010, approximately 1.5 billion people were infected with at least one species of soil-transmitted helminth (STH), Ascaris lumbricoides, Trichuris trichiura, hookworm (Ancylostoma duodenale and Necator americanus). Infection occurs through ingestion or contact (hookworm) with eggs or larvae in the environment from fecal contamination. To control these infections, the World Health Organization recommends periodic mass treatment of at-risk populations with deworming drugs. Prevention of these infections typically relies on improved excreta containment and disposal. Most evidence of the relationship between sanitation and STH has focused on household-level access or usage, rather than community-level sanitation usage. We examined the association between the proportion of households in a community with latrines in use and prevalence of STH infections among school-aged children.

METHODS

Data on STH prevalence and household latrine usage were obtained during four population-based, cross-sectional surveys conducted between 2011 and 2014 in Amhara, Ethiopia. Multilevel regression was used to estimate the association between the proportion of households in the community with latrines in use and presence of STH infection, indicated by > 0 eggs in stool samples from children 6-15 years old.

RESULTS

Prevalence of STH infection was estimated as 22% (95% CI: 20-24%), 14% (95% CI: 13-16%), and 4% (95% CI: 4-5%) for hookworm, A. lumbricoides, and T. trichiura, respectively. Adjusting for individual, household, and community characteristics, hookworm prevalence was not associated with community sanitation usage. Trichuris trichuria prevalence was higher in communities with sanitation usage ≥ 60% versus sanitation usage < 20%. Association of community sanitation usage with A. lumbricoides prevalence depended on household sanitation. Community sanitation usage was not associated with A. lumbricoides prevalence among households with latrines in use. Among households without latrines in use, A. lumbricoides prevalence was higher comparing communities with sanitation usage ≥ 60% versus < 20%. Households with a latrine in use had lower prevalence of A. lumbricoides compared to households without latrines in use only in communities where sanitation usage was ≥ 80%.

CONCLUSIONS

We found no evidence of a protective association between community sanitation usage and STH infection. The relationship between STH infection and community sanitation usage may be complex and requires further study.

Human intestinal parasitism in three areas of Indonesia: a survey

Stools from 1387 people were examined quantitatively for eggs of nematode parasites. The people were residents of Padangganting, near Sawahlunto, Sumatra (227 people), Sukamaju and Cibungur rubber plantations near Sukabumi, Java (831 people) and the villages of Mahima and Rabo near Reo, Manggarai, Flores (329 people). Ascaris lumbricoides, Trichuris trichiura and Necator americanus were common; Ancylostoma was not observed. Prevalence of parasitism was highest in Java and lowest in Flores. Egg counts were low, suggesting low worm burdens; intensity of infection with Ascaris and Trichuris was highest in Java, while hookworm was highest in Sumatra. Ascaris infections decreased and hookworm infections increased in prevalence and intensity with age; Trichuris was unaffected. A sex-related difference was observed only in Sumatra, where more females than males were infected with Ascaris. Village-to-village variation in prevalence of nematode infestation was observed in Flores and on the Sukamaju plantation; the topography of other areas did not allow for village comparisons. Ad hoc anthelmintic treatment of the residents of Cibungur plantation was reflected in reduced parasitism by Ascaris and Trichuris, but not hookworm, compared with neighbouring Sukamaju. Comparison of the patterns of disease in the three areas, in terms of the occurrence of single, double or triple infections, revealed marked differences. In Java most people with parasitism had triple infections. In Sumatra the most common expression of parasitism was single infection with hookworm. In Flores single infection with Ascaris prevailed. It is suggested that the clinical effects of intestinal parasitism might depend on the pattern of infection. Samples collected in Flores were also examined for protozoa which were found in about half the population; Entamoeba coli and E. histolytica were most common.

A First Case of Human Trichuriasis from a Roman Lead Coffin in France

A paleoparasitological study was carried out on 2 lead coffins recovered from the Roman site of Jaunay-Clan (near Poitiers, France). For the first time, this particular type of burial gave positive parasitological results, and eggs of the whipworm Trichuris trichiura were identified in 1 individual. In the present case, thanatomorphose associated with funerary practices may explain the scarcity of the recovered eggs. However, human whipworm has now been observed in 9 individuals dated to the Roman period. The very high frequency of Trichuris sp. eggs in Roman archaeological sites (up to 80%) suggests that fecal peril, hygiene, and waste management were problematic during this period. Finally, due to the fact that very few analyses have been conducted on human bodies dated to the Roman period, more analyses must be performed in the future to provide further information about diseases in the Roman world.

Economic Analysis of the Impact of Overseas and Domestic Treatment and Screening Options for Intestinal Helminth Infection among US-Bound Refugees from Asia

BACKGROUND

Many U.S.-bound refugees travel from countries where intestinal parasites (hookworm, Trichuris trichuria, Ascaris lumbricoides, and Strongyloides stercoralis) are endemic. These infections are rare in the United States and may be underdiagnosed or misdiagnosed, leading to potentially serious consequences. This evaluation examined the costs and benefits of combinations of overseas presumptive treatment of parasitic diseases vs. domestic screening/treating vs. no program.

METHODS

An economic decision tree model terminating in Markov processes was developed to estimate the cost and health impacts of four interventions on an annual cohort of 27,700 U.S.-bound Asian refugees: 1) "No Program," 2) U.S. "Domestic Screening and Treatment," 3) "Overseas Albendazole and Ivermectin" presumptive treatment, and 4) "Overseas Albendazole and Domestic Screening for Strongyloides". Markov transition state models were used to estimate long-term effects of parasitic infections. Health outcome measures (four parasites) included outpatient cases, hospitalizations, deaths, life years, and quality-adjusted life years (QALYs).

RESULTS

The "No Program" option is the least expensive ($165,923 per cohort) and least effective option (145 outpatient cases, 4.0 hospitalizations, and 0.67 deaths discounted over a 60-year period for a one-year cohort). The "Overseas Albendazole and Ivermectin" option ($418,824) is less expensive than "Domestic Screening and Treatment" ($3,832,572) or "Overseas Albendazole and Domestic Screening for Strongyloides" ($2,182,483). According to the model outcomes, the most effective treatment option is "Overseas Albendazole and Ivermectin," which reduces outpatient cases, deaths and hospitalization by around 80% at an estimated net cost of $458,718 per death averted, or $2,219/$24,036 per QALY/life year gained relative to "No Program".

DISCUSSION

Overseas presumptive treatment for U.S.-bound refugees is a cost-effective intervention that is less expensive and at least as effective as domestic screening and treatment programs. The addition of ivermectin to albendazole reduces the prevalence of chronic strongyloidiasis and the probability of rare, but potentially fatal, disseminated strongyloidiasis.