Autochthonous Ascariasis, Mississippi, USA

We describe a case of a 2-year-old child who expelled a single adult female Ascaris lumbricoides worm. The patient is from a rural county in Mississippi, USA, with no reported travel outside of the United States. The caregivers in the home practice good sanitation. Exposure to domestic pigs is the likely source of infection.

Impact of Ascaris lumbricoides infection on the development of chronic pulmonary aspergillosis in patients with COPD

The aetiopathogenesis of chronic obstructive pulmonary disease (COPD) remains unclear. The aim of our study was to determine the possible influence of Ascaris lumbricoides on the development of chronic pulmonary aspergillosis (CPA) in patients with COPD. The prevalence of A. lumbricoides in patients with COPD with CPA (19.05%) was significantly higher than that in those without (9.20%) and controls (4.9%) (p < 0.05). Trends in levels of Interleukin-1β and of tumour necrosis factor α suggest ascariasis increases susceptibility to Aspergillus sp. in patients with COPD and can be considered an additional risk factor for CPA.

Extra-intestinal complications of Ascaris lumbricoides infections in India: A systematic review and meta-analysis

The aberrant migration of Ascaris lumbricoides may cause extra-intestinal ascariasis (EIA) involving hepato-biliary-pancreatic (HBP) or other extra-gastro-intestinal (EGI) organs. We performed a systematic review and meta-analysis to study the risk factors and clinical presentations of EIA, and differences in HBP and EGI ascariasis. Medline, Web of Science and Embase were searched for cases of EIA in the English language from India. From 1204 articles, 86 studies (105 cases) were included. The majority of the cases involved the HBP system (78%). Among HBP ascariasis, the most commonly involved site was the bile duct (53.6%). Females had 11.3 times higher odds (95% CI 2.852 to 44.856; p=0.001) of HBP ascariasis, while the pediatric population had lower odds (OR=0.323). Previous gallbladder disease was significantly associated with HBP ascariasis in adults (p=0.046), while a significantly higher number of cases of EGI ascariasis were observed among pediatric patients (p=0.003). Ocular symptoms occurred exclusively in the pediatric population (p=0.017). Overall, death was reported in 3.8% of patients (n=4). This review emphasizes the importance of the complications of EIA. It encourages future research into issues such as the reasons of higher gall bladder ascariasis in females and the implications of Ascaris-related complications following biliary tract interventions. It also suggests considering Ascaris as a differential diagnosis for airway obstuction in intubated critically ill patients.

A molecular and morphological study of Ascaris suum in a human-pig contact scenario in northeastern Brazil

The aim of the present study was to assess morphologic and genetic data on ascariasis in swine (Sus scrofa domesticus) and humans in low-resource rural and periurban communities in the state of Piauí, Brazil. Our cross-sectional survey included 100 fecal samples obtained from swine and 682 samples from humans. Fifteen pigs were necropsied. Human and porcine fecal samples were examined to identify Ascaris eggs. Parasites obtained in the swine necropsies were studied using scanning electron microscopy (SEM), and the mitochondrial gene encoding the cytochrome oxidase 1 (cox1) enzyme was partially amplified and sequenced for molecular taxonomy and phylogenetic analyses. The overall prevalence of Ascaris eggs in the swine fecal samples was 16/100 (16%). No Ascaris eggs were identified in the human fecal samples. SEM of six worms recovered from pigs demonstrated morphological characteristics of A. suum. Cox1 sequences were compatible with A. suum reference sequences. Original and reference (GenBank) nucleotide sequences were organized into clusters that did not segregate the parasites by host species or and region. The largest haplogroups were dominated by haplotypes H01, H02 and H31. In the communities studied, there was no epidemiological evidence of the zoonotic transmission of ascariasis at the human-swine interface.

Prevalence of soil-transmitted helminth infections in HIV patients: a systematic review and meta-analysis

Soil-transmitted Helminth (STH) infections have been found associated with people living with human immunodeficiency virus (HIV) but little is known about the overall burden of STH coinfection in HIV patients. We aimed to assess the burden of STH infections among HIV patients. Relevant databases were systematically searched for studies reporting the prevalence of soil-transmitted helminthic pathogens in HIV patients. Pooled estimates of each helminthic infection were calculated. The odds ratio was also determined as a measure of the association between STH infection and the HIV status of the patients. Sixty-one studies were finally included in the meta-analysis, consisting of 16,203 human subjects from all over the world. The prevalence of Ascaris lumbricoides infection in HIV patients was found to be 8% (95% CI 0.06, 0.09), the prevalence of Trichuris trichiura infection in HIV patients was found to be 5% (95% CI 0.04, 0.06), the prevalence of hookworm infection in HIV patients was found to be 5% (95% CI 0.04, 0.06), and prevalence of Strongyloides stercoralis infection in HIV patients was found to be 5% (95% CI 0.04, 0.05). Countries from Sub-Saharan Africa, Latin America & Caribbean and Asia were identified with the highest burden of STH-HIV coinfection. Our analysis indicated that people living with HIV have a higher chance of developing Strongyloides stercoralis infections and decreased odds of developing hookworm infections. Our findings suggest a moderate level of prevalence of STH infections among people living with HIV. The endemicity of STH infections and HIV status both are partially responsible for the burden of STH-HIV coinfections.

Seroprevalence of Ascaris suum compared to milk spot prevalence at slaughter in Italian fattening pigs

Ascaris suum is one of the most important parasites of pigs. Apart from liver condemnation due to lesions caused by migrating larvae ("milk spots"), A. suum infections can compromise weight gain, feed conversion efficacy, as well as meat quality. The true prevalence of infection depends on the diagnostic test used and is often underestimated. We compared liver inspection at slaughter with serology, based on the recognition of a purified A. suum haemoglobin or complete homogenate of the 3rd stage larvae isolated from lungs, in nine pig farms in northern Italy. Liver lesions were found on all farms with prevalence ranging from 3.8% to 98.3%. All farms were also positive for circulating antibodies against As-Hb and As-Lung-L3, with prevalence among pigs on each farm ranging from 36.4-100% and 54.5-100%, respectively. Seroprevalence was consistently higher when compared to the prevalence of milk spots at slaughter. The higher sensitivity of the ELISA tests combined with their ease of use makes them an interesting tool to evaluate A. suum infection levels.

Schistosoma mansoni and soil-transmitted helminths among schoolchildren in An-Nadirah District, Ibb Governorate, Yemen after a decade of preventive chemotherapy

The Ministry of Public Health in Yemen continues the implementation of school and community–based preventive chemotherapy with praziquantel and albendazole for the control and elimination of schistosomiasis and soil-transmitted helminths (STH). The latest remapping to update the distribution of schistosomiasis and STH was conducted seven years ago. This study aimed to estimate the prevalence, intensity and associated risk factors of Schistosoma mansoni and STH among schoolchildren in An-Nadirah District, Ibb Governorate, Yemen. A cross-sectional study was carried out among schoolchildren aged 6–15 years in four selected schools. Biological, demographic, socioeconomic and environmental data were collected using a pre-tested questionnaire. S. mansoni and STH eggs were detected and counted by the microscopic examination of Kato-Katz fecal smears. Out of 417 schoolchildren, 17.0% were infected with at least one intestinal helminth. Prevalence of S. mansoni and STH were 6.5% and 9.1%, respectively. The most prevalent parasite among STH was Ascaris lumbricoides (8.4%). Unemployed fathers (Adjusted Odds Ratio (AOR) = 3.2; 95% Confidence interval (CI): 1.23, 8.52; P = 0.018), eating exposed food (AOR: 2.9; 95%CI = 1.24, 6.89; P = 0.014), not washing hands before eating and after defecation (AOR: 4.8; 95%CI = 1.77, 12.81; P = 0.002), and schools located close to water stream (AOR: 22.1; 95%CI = 5.12, 95.46; P <0.001) were independent risk factors of ascariasis. Swimming in ponds/stream (AOR: 3.9; 95%CI = 1.63, 9.55; P = 0.002), and schools close to the stream (AOR: 24.7; 95%CI = 3.05, 200.07; P = 0.003) were independent risk factors of intestinal schistosomiasis. The present study does not indicate a reduction in the prevalence of intestinal schistosomiasis in this rural area since the latest remapping conducted in 2014, although ascariasis was reduced by half. The prevalence of the two parasites was highly focal in areas close to the valley, suggesting a significant role of the stream in sustaining and accelerating the parasitic infection. Children practicing swimming and having poor hygienic practices were at high exposure to S. mansoni and A. lumbricoides, respectively. Water, Sanitation and Hygiene intervention, school–based health education, and snail control, in addition to mass drug administration, will help in the interruption of transmission of schistosomiasis and STH.

Genetic diversity and identity of Ascaris worms from human and pig hosts in Thailand

Ascaris roundworms are of public health and socio-economic importance worldwide. They are conventionally attributed to two taxa - A. lumbricoides infecting principally human and A. suum infecting principally pig. Phylogenomic analysis has revealed that Ascaris worms from both human and pig are represented in Clades A and B. A recent study indicates that the Ascaris worms from human and pig in Thailand belong to Clade A. We examined adult Ascaris worms from human and pig in Thailand by means of the partial sequences of three mitochondrial genes (cox1, cox2 and nad1) and concatenation of these genes. Phylogenomic analysis indicates that two isolates (H1,H2) of A. lumbricoides from human belonged to Clade B; one isolate (H3) belonged to Clade A (based on cox1, cox2 and concatenated sequences) or as an outlier to Clades A and B (based on nad1 sequences). All the eight isolates of A. suum from pig clustered in Clade A. The partial nad1 and the concatenated sequences revealed two lineages of A. suum isolates which were distinct from the two A. lumbricoides isolates of Clade B. It is evident that greater genetic diversity, and a more robust phylogeny, could be uncovered by the application of multiple genes. In sum, the present study reveals the presence in Thailand of A. lumbricoides from human in Clades A and B which necessitates appropriate treatment and control measures; Clades A and B have been reported to contain haplotypes of Ascaris worms from both human and pig in other parts of the world. A country wide study is needed to elucidate the identity, distribution, prevalence, cross transmission, genetic diversity and phylogeny of the Ascaris worms in Thailand.

National mapping of schistosomiasis, soil-transmitted helminthiasis and anaemia in Yemen: Towards better national control and elimination

BACKGROUND

Schistosomiasis (SCH) and soil-transmitted helminthiasis (STH) are known to be endemic in Yemen. However, the distribution of both diseases had not previously been assessed by a well-structured national mapping study covering all governorates. The main aim of this study was, therefore, to map the prevalence of SCH and STH in Yemen in order to better inform implementation of effective national control and elimination interventions. The assessment of the distribution of anaemia was also included as a well-known consequence of infection with both SCH and STH. Secondarily, the study aimed to provide a broad indication of the impact of large-scale treatment on the distribution of infection.

METHODOLOGY AND PRINCIPAL FINDINGS

To achive these aims, 80,432 children (10-14 years old) from 2,664 schools in 332 of Yemen's 333 districts were included, in 2014, into this national cross-sectional survey. Countrywide, 63.3% (210/332) and 75.6% (251/332) of districts were found to be endemic for SCH and STH respectively. More districts were affected by intestinal than urogenital SCH (54.2% and 31.6% respectively). SCH infection was mostly mild and moderate, with no districts reporting high infection. One quarter (24.4%) of Yemeni districts had high or moderate levels of Ascaris lumbricoides infection. Infection with Trichuris trichiura was the second most common STH (44.9% of districts infected) after A. lumbricoides (68.1%). Hookworm was the least prevalent STH (9.0%). Anaemia was prevalent in 96.4% of districts; it represented a severe public health problem (prevalence ≥ 40%) in 26.5% of districts, and a mild to moderate problem in two thirds of the districts (33.7% and 36.1% respectively).

CONCLUSION

This study provided the first comprehensive mapping of SCH, STH, and anaemia across the country. This formed the basis for evaluating and continuing the national control and elimination programme for these neglected tropical diseases in Yemen.

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.

Longitudinal assessment of the exposure to Ascaris lumbricoides through copromicroscopy and serology in school children from Jimma Town, Ethiopia

Background

We previously demonstrated that serology holds promise as an alternative diagnostic tool to copromicroscopy to monitor and evaluate deworming programs targeting soil-transmitted helminths (STHs). Here we explored the dynamics of anti-Ascaris antibodies (Ab) and evaluated the Ab-isotype of choice to assess the longitudinal exposure to Ascaris in Ethiopian school children.

Methodology

Between October 2018 and February 2020, stool and blood samples were collected every four months from school children (4 to 6 years of age). Stool samples were analyzed by duplicate Kato-Katz to assess the presence and intensity of any STH infection. Plasma Ab-responses against the total extract of Ascaris suum lung third stage larvae were measured through in-house Ab-ELISA’s for seven different Ab-isotypes.

Principal findings

At baseline, 42.4% of the 66 children were excreting eggs of any STH, Trichuris (37.9%) being the most prevalent. The cumulative prevalence (proportion of children tested that positive at least once over the entire study period) was 56.1% for Trichuris and 31.8% for Ascaris. For Ascaris, re-infections were frequently observed, whereas for Trichuris, children often remained excreting eggs following drug administration. When measuring anti-Ascaris Ab-levels, the cumulative seroprevalence was generally higher (IgG4: 60.6%; IgG1: 50.0%; IgE: 36.4%). The individual anti-Ascaris IgG4 levels at baseline were positively associated with the fecal egg counts averaged over the study period, the rate of egg-appearance and the number of positive test results. There was no apparent cross-reactivity between the anti-Ascaris IgG4 Ab-ELISA and Trichuris.

Conclusions/Significance

We demonstrate that the children are exposed to STH before the age of four and that the exposure to Ascaris is underestimated when measured with copromicroscopy. Compared to other Ab-isotypes, IgG4 is the Ab-isotype of choice to measure Ascaris exposure in STH endemic settings. Finally, the results also highlight that measuring anti-Ascaris IgG4 levels holds promise as a tool to identify individuals at higher risk for continued exposure to this STH.

World-wide large-scale deworming programs are being implemented to control the morbidity attributable to intestinal worms. Our group has recently shown that diagnostic tools that detect anti-parasite antibodies hold promise as an alternative to the current diagnostic standard (detecting worm eggs in stool using microscopy) to monitor and evaluate the progress of these programs towards the set targets. In the present study, we further explored the potential of antibody-based assays by monitoring the exposure of Ethiopian school children during a 17-month period to worm infections. Our results indicated that children in this area are exposed to intestinal worms from an early age onwards and that, based on serological results, more children are exposed to worm infections than measured by the current diagnostic standard. In addition, we demonstrated that test results of the antibody assay at the start of the study were positively associated with mean egg counts averaged over the study period, the rate of egg-appearance and the number of positive stool tests, highlighting that such assay holds promise as a tool to identify individuals at higher high risk for continued exposure to worms, and ultimately improve control programs.

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

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

Retrospective analysis and time series forecasting with automated machine learning of ascariasis, enterobiasis and cystic echinococcosis in Romania

The epidemiology of neglected tropical diseases (NTD) is persistently underprioritized, despite NTD being widespread among the poorest populations and in the least developed countries on earth. This situation necessitates thorough and efficient public health intervention. Romania is at the brink of becoming a developed country. However, this South-Eastern European country appears to be a region that is susceptible to an underestimated burden of parasitic diseases despite recent public health reforms. Moreover, there is an evident lack of new epidemiologic data on NTD after Romania's accession to the European Union (EU) in 2007. Using the national ICD-10 dataset for hospitalized patients in Romania, we generated time series datasets for 2008-2018. The objective was to gain deep understanding of the epidemiological distribution of three selected and highly endemic parasitic diseases, namely, ascariasis, enterobiasis and cystic echinococcosis (CE), during this period and forecast their courses for the ensuing two years. Through descriptive and inferential analysis, we observed a decline in case numbers for all three NTD. Several distributional particularities at regional level emerged. Furthermore, we performed predictions using a novel automated time series (AutoTS) machine learning tool and could interestingly show a stable course for these parasitic NTD. Such predictions can help public health officials and medical organizations to implement targeted disease prevention and control. To our knowledge, this is the first study involving a retrospective analysis of ascariasis, enterobiasis and CE on a nationwide scale in Romania. It is also the first to use AutoTS technology for parasitic NTD.

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.

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.

SHOULD ASCARIASIS BE CONSIDERED AS A REPRODUCTOLOGY PROBLEM?

OBJECTIVE

The aim: To study the epidemiological situation of ascariasis among women with pathology of the reproductive system on the basis of a literature database (PubMed, Medline, Google Scholar, PLoS, Hindawi) and to present our experience with ascariasis and pathology of reproductive system.

PATIENTS AND METHODS

Materials and methods: We investigated parasitic invasions in 174 women reproductive losses and 186 patients with primary infertility.

RESULTS

Results: The results performed in women with infertility and reproductive losses have proved the role of parasitic infection in the emergence of disorders of hormonal homeostasis, endothelial-lymphocytic dysfunction, severe vaginal and intestinal dysbiosis and, as a consequence, reproduction of conditionally pathogenic flora, etiopathogenetic risk factors for the development of various forms of women's reproductive health pathology.

CONCLUSION

Conclusions: More global attention to the diagnosis and treatment of parasitic infections in the examination of women with infertility and reproductive losses is warranted. The influence of ascariasis as a source of autoinfection of the gastrointestinal tract, allowed us to consider the presence of this invasion a risk factor for the development of chronic inflammatory process of the lower genital tract.

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.

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.

Effects of nutritional supplements on the re-infection rate of soil-transmitted helminths in school-age children: A systematic review and meta-analysis

Background

The effect of nutritional supplements on the re-infection rate of species-specific soil-transmitted helminth infections in school-aged children remains complex and available evidence on the subject matter has not been synthesized.

Methods

The review included randomised controlled trials (RCTs) and cluster RCTs investigating food supplements on school-aged children between the age of 4–17 years. A search for RCTs was conducted on eight databases from inception to 12^th June 2019. Cochrane Risk of Bias tool was used to assess the risk of bias in all included studies. Meta-analysis and narrative synthesis were conducted to describe and analyze the results of the review. Outcomes were summarized using the mean difference or standardized mean difference where appropriate.

Results

The search produced 1,816 records. Six studies met the inclusion criteria (five individually RCTs and one cluster RCT). Four studies reported data on all three STH species, while one study only reported data on Ascaris lumbricoides infections and the last study reported data on only hookworm infections. Overall, the risk of bias in four individual studies was low across most domains. Nutritional supplementation failed to statistically reduce the re-infection rates of the three STH species. The effect of nutritional supplements on measures of physical wellbeing in school-aged children could not be determined.

Conclusions

The findings from this systematic review suggest that nutritional supplements for treatment of STH in children should not be encouraged unless better evidence emerges. Conclusion of earlier reviews on general populations may not necessarily apply to children since children possibly have a higher re-infection rate.

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.

Epidemiology of Schistosomiasis and Soil-Transmitted Helminth Coinfections among Schoolchildren Living in Lambaréné, Gabon

Schistosomiasis is a parasitic infection highly prevalent in Central Africa where it is co-endemic with many other parasitic infections, including soil-transmitted helminths (STHs). For its optimal control, there is a need of descriptive epidemiological data for each endemic region. The objective of the present study was to determine the epidemiological situation around schistosomiasis in Lambaréné, Gabon. A cross-sectional study was conducted among schoolchildren. One urine sample per day was collected on three consecutive days for the diagnosis of schistosomiasis using a urine filtration technique. One stool sample was collected for the detection of Schistosoma spp. and STH spp. eggs using the Kato-Katz technique, and for larvae, using the coproculture technique. A total of 614 schoolchildren were included in the analysis. The overall prevalence of schistosomiasis and STH infections was 26% (159/614) and 15% (70/473), respectively. Human-freshwater contact was the main risk factor for schistosomiasis in the area (relative risk (RR) = 2.96 [2.20-4.00], P < 0.001). Hematuria (RR = 5.53 [4.30-7.10], P < 0.001) and proteinuria (RR = 2.12 [1.63-2.75], P < 0.001) as well as infection with Trichuris trichiura (RR = 1.86 [1.33-2.61], P = 0.002) and Ascaris lumbricoides (RR = 1.96 [1.19-3.21], P = 0.039) were associated with an increased risk of schistosomiasis. Trichuris trichiura was the highest prevalent STH species in the area. Our study reports a moderate prevalence for schistosomiasis with human-water contact as the main risk factor, whereas the prevalence of STH infections appears to be low. Our results stress the need for the implementation of WHO recommendations for schistosomiasis control.

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.

Distribution of ascariasis, trichuriasis and hookworm infections in Ogun State, Southwestern Nigeria

BACKGROUND

Ascariasis, Trichuriasis and Hookworm infections poses a considerable public health burden in Sub-Saharan Africa, and a sound understanding of their spatial distribution facilitates to better target control interventions. This study, therefore, assessed the prevalence of the trio, and mapped their spatial distribution in the 20 administrative regions of Ogun State, Nigeria.

METHODS

Parasitological surveys were carried out in 1,499 households across 33 spatially selected communities. Fresh stool samples were collected from 1,027 consenting participants and processed using ether concentration method. The locations of the communities were georeferenced using a GPS device while demographic data were obtained using a standardized form. Data were analysed using SPSS software and visualizations and plotting maps were made in ArcGIS software.

RESULTS

Findings showed that 19 of the 20 regions were endemic for one or more kind of the three infections, with an aggregated prevalence of 17.2%. Ascariasis was the most frequently observed parasitic infection in 28 communities with a prevalence of 13.6%, followed by hookworm infections with a prevalence of 4.6% while Trichuriasis was the least encountered with a prevalence of 1.7%. The spatial distribution of infections ranges between 5.3-49.2% across the regions. The highest and lowest distribution of overall helminth infections was recorded in Egbado South and Egbado North respectively. Nine regions had infection status between 20.0%-49.2%, while 10 regions had infection status between 5.3%-15.8%.

CONCLUSION

This study provides epidemiological data on the prevalence and spatial distribution of ascariasis, trichuriasis and hookworm infections which will add to the baseline data and guide the public health officers in providing appropriate control strategies in the endemic communities.

Interactions between helminths and tuberculosis infections: Implications for tuberculosis diagnosis and vaccination in Africa

Africa is the second most populous continent and has perennial health challenges. Of the estimated 181 million school aged children in sub-Saharan Africa (SSA), nearly half suffer from ascariasis, trichuriasis, or a combination of these infections. Coupled with these is the problem of tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) infection, which is a leading cause of death in the region. Compared to the effect of the human immunodeficiency virus on the development of TB, the effect of chronic helminth infections is a neglected area of research, yet helminth infections are as ubiquitous as they are varied and may potentially have profound effects upon host immunity, particularly as it relates to TB infection, diagnosis, and vaccination. Protection against active TB is known to require a clearly delineated T-helper type 1 (Th1) response, while helminths induce a strong opposing Th2 and immune-regulatory host response. This Review highlights the potential challenges of helminth-TB co-infection in Africa and the need for further research.

Evaluation of copromicroscopy and serology to measure the exposure to Ascaris infections across age groups and to assess the impact of 3 years of biannual mass drug administration in Jimma Town, Ethiopia

BACKGROUND

The scientific community has recently summarized the desired characteristics for diagnostic tools across the different phases of a soil-transmitted helminth (STH) mass drug administration (MDA) program. Although serology meets some of the desired criteria, there is a scarcity of data on baseline serological profiles in human populations, both prior to and during MDA programs.

METHODS

In this study, we compared the copromicroscopic and the serological infection profiles in 600 school-aged children (SAC) and 600 adults at the advent of the MDA program in Jimma Town, Ethiopia. The serological profiles were examined by two ELISAs that measure IgG4 responses to the Ascaris suum haemoglobin antigen (AsHb) and a somatic extract of lung stage larvae (AsLungL3). Three years into the MDA program, we sampled another group of 600 SAC from the same schools to assess the reduction in prevalence and intensity of Ascaris infections measured by copromicroscopy and serology.

PRINCIPAL FINDINGS

Prior to the start of MDA, copromicroscopy revealed an Ascaris prevalence of 31.0% and a mean fecal egg count of 2,919 eggs per gram (EPG) in SAC. Following three years of biannual treatment, the prevalence reduced to 13.2% (57.8% reduction) and the mean fecal egg count to 1,513 EPG (48.1% reduction). This reduction was also reflected in the serological results. The seroprevalence reduced with 40.9% and 27.4% and the mean optical density ratio reduced with 44.2% and 38.2% as measured by the AsHb or AsLungL3 ELISA respectively. We also showed that, despite a decreasing coproprevalence, seroprevalence to Ascaris increased with age.

CONCLUSIONS

This study is the first to provide IgG4 response profiles of an endemic population to two different A. suum antigens. The results suggest that exposure to the infectious stages of Ascaris reaches beyond SAC alone. Furthermore, it highlights the possible use of serological assays to monitor changes in STH exposure during MDA programs.

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.

Ascaris lumbricoides infection: Still a threat for iron deficiency anaemia in 2-year-old Bangladeshi slum-dwelling children

INTRODUCTION

Although parasitic infections lead to extracorporeal iron loss resulting in iron deficiency anaemia (IDA), data associating IDA with parasitic infections in the first two years of life are limited. We sought to evaluate the prevalence and severity of anaemia and IDA during this period and to investigate the association between intestinal parasitic infections and IDA.

METHODOLOGY

Data was collected under MAL-ED study protocol in Bauniabadh slum of Dhaka, Bangladesh. The presence of parasites in stool was detected using wet preparation microscopy at 7, 15, and 24 months. Anaemia was defined as serum haemoglobin < 11 g/dL and IDA was defined by serum haemoglobin < 11 g/dL, serum ferritin < 12 g/L and soluble transferrin receptor > 8.3 mg/L. Logistic regression was done to quantify the relation between stool parasite and IDA separately on samples collected at 7, 15 and 24 months.

RESULTS

265 children were enrolled after birth and samples were collected at 7, 15 and 24 months. Anaemia was detected at 7, 15 and 24 months in 117 (48.8%), 106 (44.2%) and 67 (27.9%) cases whereas IDA was found in 15 (6.3%), 47 (19.6%) and 39 (16.3%) cases, respectively. Iron deficiency anaemia at 24 months was significantly associated with Ascaris lumbricoides infection (OR 3.76; 95 % CI, 1.08-13.11).

CONCLUSIONS

The prevalence of anaemia and IDA in slum dwelling children of Dhaka is high and Ascaris lumbricoides infection was found to have a strong association with IDA at 24 months of age.

Concurrent decreases in the prevalence of wheezing and Ascaris infection among 5-year-old children in rural Bangladesh and their regulatory T cell immunity after the implementation of a national deworming program

INTRODUCTION

Epidemiological research on the prevalence of asthma and helminthic infections in various countries has led to the hypothesis that helminthic infections protect against asthma by suppressing the host's immune response. This study was conducted to elucidate whether decreased Ascaris infection following a national deworming program was associated with increased recurrent wheezing among rural Bangladeshi children and to test their anti-inflammatory immunity.

METHODS

This nested case-control study was conducted from December 2015 to October 2016 in the rural service area of the International Centre for Diarrhoeal Disease Research, Bangladesh. Of the 1800 5-year old children randomly selected for the study, informed consent was obtained from the guardians of 1658 children. Data were collected using a semistructured questionnaire adopted from the International Study of Asthma and Allergies in Childhood and blood samples for the analysis of regulatory T (Treg) cell immune responses and the balance between Th1 and Th2 immunity in Ascaris infections.

RESULTS

A total of 145 children were found to have wheezing, yielding a prevalence rate of 8.7%, which was significantly lower than the rate found in 2001 (16.2%, P < .001); Ascaris infection also decreased from 2001 to 2016. The 127 wheezing children who agreed to participate further were compared to 114 randomly selected never-wheezing children. Wheezing had a significant positive association with antibiotic use, history of pneumonia, parents' history of asthma, and Ascaris infection; children with Ascaris infection were twice as likely to have wheezing (adjusted odds ratio = 2.31, P = .053). Flow cytometry found no significant differences in the rates of Th1, Th2, and CD4 + CD25 + CD127low cells by the wheezing group.

CONCLUSIONS

Ascaris infection had a positive rather than a negative association with wheezing and the rates of wheezing and Ascaris infections both decreased from 2001 to 2016. These findings undermines the hypothesis that such infections provide protection against asthma.

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.

Effects, equity, and cost of school-based and community-wide treatment strategies for soil-transmitted helminths in Kenya: a cluster-randomised controlled trial

BACKGROUND

School-based deworming programmes can reduce morbidity attributable to soil-transmitted helminths in children but do not interrupt transmission in the wider community. We assessed the effects of alternative mass treatment strategies on community soil-transmitted helminth infection.

METHODS

In this cluster-randomised controlled trial, 120 community units (clusters) serving 150 000 households in Kenya were randomly assigned (1:1:1) to receive albendazole through annual school-based treatment targeting 2-14 year olds or annual or biannual community-wide treatment targeting all ages. The primary outcome was community hookworm prevalence, assessed at 12 and 24 months through repeat cross-sectional surveys. Secondary outcomes were Ascaris lumbricoides and Trichuris trichiura prevalence, infection intensity of each soil-transmitted helminth species, and treatment coverage and costs. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02397772.

FINDINGS

After 24 months, prevalence of hookworm changed from 18·6% (95% CI 13·9-23·2) to 13·8% (10·5-17·0) in the annual school-based treatment group, 17·9% (13·7-22·1) to 8·0% (6·0-10·1) in the annual community-wide treatment group, and 20·6% (15·8-25·5) to 6·2% (4·9-7·5) in the biannual community-wide treatment group. Relative to annual school-based treatment, the risk ratio for annual community-wide treatment was 0·59 (95% CI 0·42-0·83; p<0·001) and for biannual community-wide treatment was 0·46 (0·33-0·63; p<0·001). More modest reductions in risk were observed after 12 months. Risk ratios were similar across demographic and socioeconomic subgroups after 24 months. No adverse events related to albendazole were reported.

INTERPRETATION

Community-wide treatment was more effective in reducing hookworm prevalence and intensity than school-based treatment, with little additional benefit of treating every 6 months, and was shown to be remarkably equitable in coverage and effects.

FUNDING

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

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.

Soil-transmitted helminth reinfection four and six months after mass drug administration: results from the delta region of Myanmar

BACKGROUND

Mass drug administration (MDA), targeted at school-aged children (SAC) is the method recommended by the World Health Organization for the control of morbidity induced by soil-transmitted helminth (STH) infection in endemic countries. However, MDA does not prevent reinfection between treatment rounds and research suggests that only treating SAC will not be sufficient to bring prevalence to low levels and possibly interrupt transmission of STH. In countries with endemic infection, such as Myanmar, the coverage, who is targeted, and rates of reinfection will determine how effective MDA is in suppressing transmission in the long-term.

METHODS/PRINCIPAL FINDINGS

In this paper, data from an epidemiological study on STH, comprising three surveys conducted between June 2015 and June 2016 in the delta region of Myanmar, are analysed to determine how STH prevalence and intensity in the study community changes over the course of a year, including reinfection after two MDA rounds in which the whole study sample (all age groups, n = 523) were treated with albendazole. Prevalence in the first survey (August 2015) was 27.92% for any STH, 5.54% for Ascaris lumbricoides, 17.02% for Trichuris trichiura and 9.75% for hookworm. Over the year (survey one to survey three), prevalence of any STH decreased by 8.99% (P < 0.001) and mean EPG significantly decreased for T. trichiura (P < 0.01) and hookworm (P < 0.001). Risk ratios (RRs) for a four-month reinfection period (August to December) were statistically significant and were below one, indicating that STH prevalence had not bounced back to the prevalence levels recorded immediately prior to the last round of treatment (any STH RR = 0.67, 95% CI 0.56-0.81; A. lumbricoides RR = 0.31, 95% CI 0.16-0.59; T. trichiura RR = 0.70, 95% CI 0.55-0.88; hookworm RR = 0.69, 95% CI 0.50-0.95). The only statistically significant RR for the six-month reinfection period (December to June) was for A. lumbricoides infection in SAC (RR = 2.67, 95% CI 1.37-5.21). All six-month RRs were significantly higher than four-month RRs (P < 0.05). Evidence of predisposition to infection (low and high), as measured by the Kendall Tau-b statistic, was found for all species overall and within most age groups stratifications, except for hookworm infection in preschool-aged children.

CONCLUSIONS/SIGNIFICANCE

This study demonstrates that, for certain demographic groups, a six-month gap between MDA in these communities is enough time for STH infection to return to STH prevalence levels recorded immediately before the previous MDA round, and that on average the same individuals are being consistently infected between MDA rounds.

Off-target effects of tribendimidine, tribendimidine plus ivermectin, tribendimidine plus oxantel-pamoate, and albendazole plus oxantel-pamoate on the human gut microbiota

Soil-transmitted helminths infect 1.5 billion people worldwide. Treatment with anthelminthics is the key intervention but interactions between anthelminthic agents and the gut microbiota have not yet been studied. In this study, the effects of four anthelminthic drugs and combinations (tribendimidine, tribendimidine plus ivermectin, tribendimidine plus oxantel-pamoate, and albendazole plus oxantel-pamoate) on the gut microbiota were assessed. From each hookworm infected adolescent, one stool sample was collected prior to treatment, 24 h post-treatment and 3 weeks post-treatment, and a total of 144 stool samples were analyzed. The gut bacterial composition was analyzed using 16S rRNA gene sequencing. Tribendimidine given alone or together with oxantel-pamoate, and the combination of albendazole and oxantel pamoate were not associated with any major changes in the taxonomic composition of the gut microbiota in this population, at both the short-term post-treatment (24 h) and long-term post-treatment (3 weeks) periods. A high abundance of the bacterial phylum Bacteroidetes was observed following administration of tribendimidine plus ivermectin 24 h after treatment, due predominantly to difference in abundance of the families Prevotellaceae and Candidatus homeothermaceae. This effect is transient and disappears three weeks after treatment. Higher abundance of Bacteroidetes predicts an increase in metabolic pathways involved in the synthesis of B vitamins. This study highlights a strong relationship between tribendimidine and ivermectin administration and the gut microbiota and additional studies assessing the functional aspects as well as potential health-associated outcomes of these interactions are required.

The public health benefit and burden of mass drug administration programs in Vietnamese schoolchildren: Impact of mebendazole

BACKGROUND

Mass anthelmintic drug administration is recommended in developing countries to address infection by soil-transmitted helminthiases (STH). We quantified the public health benefit of treatment with mebendazole in eight million Vietnamese children aged 5-14 years from 2006 to 2011. This was compared to the environmental impact of the pharmaceutical supply chain of mebendazole, as the resource use and emissions associated with pharmaceutical production can be associated with a public health burden, e.g. through emissions of fine particulate matter.

METHODOLOGY

Through Markov modelling the disability due to STH was quantified for hookworm, Ascaris lumbricoides and Trichuris trichiura. For each worm type, four levels of intensity of infection were included: none, light, medium and heavy. The treatment effect on patients was quantified in Disability-Adjusted Life Years (DALYs). The public health burden induced by the pharmaceutical supply chain of mebendazole was quantified in DALYs through Life Cycle Assessment.

PRINCIPAL FINDINGS

Compared to 'no treatment', the modelled results of five-year treatment averted 116,587 DALYs (68% reduction) for the three worms combined and largely driven by A. lumbricoides. The main change in DALYs occurred in the first year of treatment, after which the results stabilized. The public health burden associated with the pharmaceutical supply chain was 6 DALYs.

CONCLUSIONS

The public health benefit of the Mass Drug Administration (MDA) averted substantially more DALYs than those induced by the pharmaceutical supply chain. These results were verified in a sensitivity analysis. The starting prevalence for each worm was the most sensitive model parameter. This methodology is useful for policymakers interested in a holistic approach towards the public health performance of MDA programs, enveloping both the treatment benefit received by the patient and the public health burden associated with the resource consumption and environmental emissions of the pharmaceutical production and supply chain.

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.

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.

Current prevalence of intestinal parasitic infections and their impact on hematological and nutritional status among Karen hill tribe children in Omkoi District, Chiang Mai Province, Thailand

Intestinal parasitic infection represents a substantial problem for children living in rural or limited resources areas and significantly relates to anemia and nutritional status. This study aimed to determine the current prevalence of intestinal parasitic infections among school-age children of Karen hill tribe population in Omkoi District, Chiang Mai Province, Thailand and assess the impact of intestinal parasitic infection on hematological and nutritional status in those children. A total of 375 Karen hill tribe children, 6-14 years of age, in Omkoi District were randomly selected to participate in this study. Stool samples were collected and examined for intestinal parasitic infection through formalin-ether concentration method. Blood samples were collected for hematological and iron analysis. The overall prevalence of intestinal parasitic infection was 47.7% (179/375), with single infections (29.3%) and polyparatism (18.4%). The most common pathogenic parasite was Trichuris trichiura (16.0%), followed by Ascaris lumbricoides (13%) and Giardia lamblia (3.5%). In addition, non-pathogenic amoeba, Entamoeba coli was observed with a high prevalence rate (31.2%). Anemia and eosinophilia prevalence were 6.40% (24/375) and 74.7% (280/375), respectively. Eosinophilia was significantly more prevalent in children with intestinal parasitic infection compared to uninfected children. Among 249 children, 13.7% were iron deficiency, 9.6% were thalassemia and hemoglobinophathy and 8% were G-6-PD deficiency. A high prevalence infection rate was significantly associated with eosinophilia, but independently related to anemia and iron deficiency. Intestinal parasitic infections are endemic in school-age children of Karen hill tribe population in Omkoi District. These data highlight the need for an integrated approach to control transmission of intestinal parasites and improve the health and sanitation status of Karen hill tribe children in Thailand.

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.

Current epidemiological evidence for predisposition to high or low intensity human helminth infection: a systematic review

BACKGROUND

The human helminth infections include ascariasis, trichuriasis, hookworm infections, schistosomiasis, lymphatic filariasis (LF) and onchocerciasis. It is estimated that almost 2 billion people worldwide are infected with helminths. Whilst the WHO treatment guidelines for helminth infections are mostly aimed at controlling morbidity, there has been a recent shift with some countries moving towards goals of disease elimination through mass drug administration, especially for LF and onchocerciasis. However, as prevalence is driven lower, treating entire populations may no longer be the most efficient or cost-effective strategy. Instead, it may be beneficial to identify individuals or demographic groups who are persistently infected, often termed as being "predisposed" to infection, and target treatment at them.

METHODS

The authors searched Embase, MEDLINE, Global Health, and Web of Science for all English language, human-based papers investigating predisposition to helminth infections published up to October 31st, 2017. The varying definitions used to describe predisposition, and the statistical tests used to determine its presence, are summarised. Evidence for predisposition is presented, stratified by helminth species, and risk factors for predisposition to infection are identified and discussed.

RESULTS

In total, 43 papers were identified, summarising results from 34 different studies in 23 countries. Consistent evidence of predisposition to infection with certain species of human helminth was identified. Children were regularly found to experience greater predisposition to Ascaris lumbricoides, Schistosoma mansoni and S. haematobium than adults. Females were found to be more predisposed to A. lumbricoides infection than were males. Household clustering of infection was identified for A. lumbricoides, T. trichiura and S. japonicum. Ascaris lumbricoides and T. trichiura also showed evidence of familial predisposition. Whilst strong evidence for predisposition to hookworm infection was identified, findings with regards to which groups were affected were considerably more varied than for other helminth species.

CONCLUSION

This review has found consistent evidence of predisposition to heavy (and light) infection for certain human helminth species. However, further research is needed to identify reasons for the reported differences between demographic groups. Molecular epidemiological methods associated with whole genome sequencing to determine 'who infects whom' may shed more light on the factors generating predisposition.

Prevalence and intensity of Ascaris lumbricoides infections in relation to undernutrition among children in a tea plantation community, Sri Lanka: a cross-sectional study

BACKGROUND

Ascaris lumbricoides infections are one of the commonnest intestinal nematode infections in the world, with a profound negative effect on nutritional status among underprivileged populations. In Sri Lanka, Ascaris infections and low nutritional status still persist in the plantation sector. However, research regarding the association between Ascaris infections and nutritional status is scarce. The main purpose of this study was to determine the association between Ascaris infections and physical growth among children in a plantation sector in Sri Lanka.

METHODS

A cross sectional study was conducted among 489 children aged between 1 and 12 years ina plantation sector, Sri Lanka, from January to April 2013. Anthropometric measurements were collected to assess height-for-age (HAZ), weight-for-age (WAZ) and weight-for-height (WHZ) to determine stunting, underweight and wasting respectively. Data on socio-demographic and antihelminthic treatment were ascertained using an interviewer administrated structured questionnaire. Stool samples were subjected to wet mount preparation followed byformaldehyde-ether sedimentation technique to diagnose Ascaris infection and a Kato Katz technique was performed to determine the eggs intensity. AnthroPlus, EpiInfo and SPSS software was used to analyze data.

RESULTS

Of the study sample, 38.4% showed Ascaris lumbricoides infections. Light intensity infections (51%) were common in the infected children, followed by moderate (30%) and heavy (19%) infections. Prevalence of Ascaris infections was significantly associated with de-worming more than six months prior to the study. Prevalence of undernutrition among children was 61.7%. Forty-five per cent were underweight, while 24.1% and 21.5% of children were stunted and wasted respectively. However, no significant association was found between Ascaris infections status and undernutrition. Meanwhile, heavy intensity infections were associated with decreased values of WHZ (p = 0.020).

CONCLUSIONS

Ascaris infections and undernutrition are still highly prevalent and a major public health problem in the plantation sector in Sri Lanka. Health and nutrition intervention programs should be implemented to increase the nutritional status of children.

Seasonally timed treatment programs for Ascaris lumbricoides to increase impact-An investigation using mathematical models

There is clear empirical evidence that environmental conditions can influence Ascaris spp. free-living stage development and host reinfection, but the impact of these differences on human infections, and interventions to control them, is variable. A new model framework reflecting four key stages of the A. lumbricoides life cycle, incorporating the effects of rainfall and temperature, is used to describe the level of infection in the human population alongside the environmental egg dynamics. Using data from South Korea and Nigeria, we conclude that settings with extreme fluctuations in rainfall or temperature could exhibit strong seasonal transmission patterns that may be partially masked by the longevity of A. lumbricoides infections in hosts; we go on to demonstrate how seasonally timed mass drug administration (MDA) could impact the outcomes of control strategies. For the South Korean setting the results predict a comparative decrease of 74.5% in mean worm days (the number of days the average individual spend infected with worms across a 12 month period) between the best and worst MDA timings after four years of annual treatment. The model found no significant seasonal effect on MDA in the Nigerian setting due to a narrower annual temperature range and no rainfall dependence. Our results suggest that seasonal variation in egg survival and maturation could be exploited to maximise the impact of MDA in certain settings.

The optimal timing of post-treatment sampling for the assessment of anthelminthic drug efficacy against Ascaris infections in humans

The egg reduction rate (ERR) is the current standard mean to assess the efficacy of drugs against human soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura and hookworm). Although the timing of post-treatment sampling is pivotal for a readily interpretation of drug efficacy, there is lack empirical data that allows recommending the optimal time point for a follow-up egg counting. In the present study, we re-analyzed both the kinetics of worm expulsion and egg output for Ascaris lumbricoides following a single oral dose of albendazole in a series of studies previously conducted in Kenyan communities. The results indicate that it takes up to 10 days post-treatment before the expulsion of both adult male and female Ascaris worms is completed, approximately 20% of the worms being expelled between day 7 and 10 post-treatment. The sequential analysis of the egg out put, indicated a poor ERR (89.4%) at day 7 post-treatment, but a 100% ERR at day 14 and 21 post-treatment. Based on our findings we recommend to wait at least 14 days after an albendazole treatment before conducting the follow-up egg count. Any sampling before this time point may result in biased ERR estimates, due the release of residual eggs from moribund or degenerating worms.

Host-Parasite Interactions in Individuals with Type 1 and 2 Diabetes Result in Higher Frequency of Ascaris lumbricoides and Giardia lamblia in Type 2 Diabetic Individuals

Host-parasite interactions in diabetic patients might influence diabetes complications and intestinal parasitosis. The aim was to investigate the occurrence of enteroparasites in individuals with diabetes types 1 and 2. A descriptive study was designed to estimate frequencies of parasites and to compare them in individuals with diabetes types 1 and 2 from two Health Centers and one hospital in the Federal District of Brazil. Patients were allocated to the study by convenience. Three fecal samples of 156 diabetic individuals (120 type 1 and 36 type 2) were analyzed using two parasitological methods. Enteroparasites or commensals frequency in diabetics was 64%. Diabetics infected with up to six species of intestinal parasites or commensals were found. Frequencies of Ascaris lumbricoides and Giardia lamblia were higher in individuals with type 2 diabetes. The lower frequency of A. lumbricoides found in type 1 diabetes may be related to a strong Th2 response to parasites. Autoimmune response developed in type 1 diabetic individuals characterized by the production of Th1 cytokines could explain low frequency of G. lamblia. High frequency of parasites found in type 2 diabetes emphasizes the importance of periodic parasitological examinations in these individuals.

Geographical distribution of soil transmitted helminths and the effects of community type in South Asia and South East Asia - A systematic review

BACKGROUND

Soil-transmitted helminth (STH) infections are among the most prevalent neglected tropical diseases (NTD) worldwide. Since the publication of the WHO road map to combat NTD in 2012, there has been a renewed commitment to control STH. In this study, we analysed the geographical distribution and effect of community type on prevalence of hookworm, Trichuris and Ascaris in south Asia and south east Asia.

METHODOLOGY

We conducted a systematic review of open-access literature published in PubMed Central and the Global Atlas of Helminth Infection. A total of 4182 articles were available and after applying selection criteria, 174 studies from the region were retained for analysis.

PRINCIPAL FINDINGS

Ascaris was the commonest STH identified with an overall prevalence of 18% (95% CI, 14-23%) followed by Trichuris (14%, 9-19%) and hookworm (12%, 9-15%). Hookworm prevalence was highest in Laos, Vietnam and Cambodia. We found a geographical overlap in countries with high prevalence rates for Trichuris and Ascaris (Malaysia, Philippines, Myanmar, Vietnam and Bangladesh). When the effect of community type was examined, prevalence rates of hookworm was comparable in rural (19%, 14-24%) and tribal communities (14%, 10-19%). Tribal communities, however, showed higher prevalence of Trichuris (38%, 18-63%) and Ascaris (32%, 23-43%) than rural communities (13%, 9-20% and 14%, 9-20% respectively). Considerable between and within country heterogeneity in the distribution of STH (I2 >90%) was also noted. When available data from school aged children (SAC) were analysed, prevalence of Ascaris (25% 16-31%) and Trichuris (22%, 14-34%) were higher than among the general population while that of hookworm (10%, 7-16%) was comparable.

CONCLUSIONS/SIGNIFICANCE

Our analysis showed significant variation in prevalence rates between and within countries in the region. Highlighting the importance of community type in prevalence and species mix, we showed that tribal and rural communities had higher hookworm infections than urban communities and for ascariasis and trichuriasis, tribal populations had higher levels of infection than rural populations. We also found a higher prevalence of ascariasis and trichuriasis in SAC compared to the general population but comparable levels of hookworm infections. These key findings need to be taken into account in planning future MDA and other interventions.

Shrinking risk profiles after deworming of children in Port Elizabeth, South Africa, with special reference to Ascaris lumbricoides and Trichuris trichiura

Risk maps facilitate discussion among different stakeholders and provide a tool for spatial targeting of health interventions. We present maps documenting shrinking risk profiles after deworming with respect to soil-transmitted helminthiasis among schoolchildren from disadvantaged neighbourhoods in Port Elizabeth, South Africa. Children were examined for soil-transmitted helminth infections using duplicate Kato-Katz thick smears in March 2015, October 2015 and May 2016, and subsequently treated with albendazole after each survey. The mean infection intensities for Ascaris lumbricoides were 9,554 eggs per gram of stool (EPG) in March 2015, 4,317 EPG in October 2015 and 1,684 EPG in March 2016. The corresponding figures for Trichuris trichiura were 664 EPG, 331 EPG and 87 EPG. Repeated deworming shrank the risk of soil-transmitted helminthiasis, but should be complemented by other public health measures.

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.