The epidemiology of soil-transmitted helminths in Bihar State, India

Amphiregulin in infectious diseases: Role, mechanism, and potential therapeutic targets

Amphiregulin (AREG) serves as a ligand for the epidermal growth factor receptor (EGFR) and is involved in vital biological functions, including inflammatory responses, tissue regeneration, and immune system function. Upon interaction with the EGFR, AREG initiates a series of signaling cascades necessary for several physiological activities, such as metabolism, cell cycle regulation, and cellular proliferation. Recent findings have provided evidence for the substantial role of AREG in maintaining the equilibrium of homeostasis in damaged tissues and preserving epithelial cell structure in the context of viral infections affecting the lungs. The development of resistance to influenza virus infection depends on the presence of type 1 cytokine responses. Following the eradication of the pathogen, the lungs are subsequently colonized by several cell types that are linked with type 2 immune responses. These cells contribute to the process of repairing and resolving the tissue injury and inflammation caused by infections. Following influenza infection, the activation of AREG promotes the regeneration of bronchial epithelial cells, enhancing the tissue's structural integrity and increasing the survival rate of infected mice. In the same manner, mice afflicted with influenza experience rapid mortality due to a subsequent bacterial infection in the pulmonary region when both bacterial and viral infections manifest concurrently inside the same host. The involvement of AREG in bacterial infections has been demonstrated. The gene AREG experiences increased transcriptional activity inside host cells in response to bacterial infections caused by pathogens such as Escherichia coli and Neisseria gonorrhea. In addition, AREG has been extensively studied as a mitogenic stimulus in epithelial cell layers. Consequently, it is regarded as a prospective contender that might potentially contribute to the observed epithelial cell reactions in helminth infection. Consistent with this finding, mice that lack the AREG gene exhibit a delay in the eradication of the intestinal parasite Trichuris muris. The observed delay is associated with a reduction in the proliferation rate of colonic epithelial cells compared to the infected animals in the control group. The aforementioned findings indicate that AREG plays a pivotal role in facilitating the activation of defensive mechanisms inside the epithelial cells of the intestinal tissue. The precise cellular sources of AREG in this specific context have not yet been determined. However, it is evident that the increased proliferation of the epithelial cell layer in infected mice is reliant on CD4+ T cells. The significance of this finding lies in its demonstration of the crucial role played by the interaction between immunological and epithelial cells in regulating the AREG-EGFR pathway. Additional research is necessary to delve into the cellular origins and signaling mechanisms that govern the synthesis of AREG and its tissue-protective properties, independent of infection.

Access to basic sanitation facilities reduces the prevalence of anaemia among women of reproductive age in sub-saharan Africa

BACKGROUND

The prevalence (≈ 30%) of anaemia among women of reproductive age in Sub-Saharan Africa (SSA) is a significant concern. Additionally, less than half of households in the region have access to basic sanitation facilities, raising questions about the potential role of poor sanitation in increasing anaemia prevalence. To address this, we examined the relationship between access to basic sanitation facilities and the prevalence of anaemia among women of reproductive age in SSA.

METHODS

The study analysed cross-sectional household-level Demographic and Health Survey data from selected SSA countries. A total of 100,861 pregnant and non-pregnant women aged 15 to 49 from 27 countries were analysed. Access to basic sanitation and haemoglobin (Hb) levels were classified using WHO and UNICEF standards. To examine the link between access to basic sanitation facilities and the prevalence of anaemia, a multilevel regression analysis was conducted, which adjusted for country fixed-effects to ensure that the findings were not biassed by variations in country-level factors.

RESULTS

Nearly 37% (95% CI: 36.4, 37.9) of households had access to basic sanitation facilities, and 41% (95% CI: 40.8, 42.1) of women had Hb levels that indicated anaemia. Women with access to basic sanitation had a lower risk of anaemia than those without access (AOR = 0.95; 95% CI: 0.93, 0.98, p < 0.01). Factors, including maternal age, education, marital status, breastfeeding, health insurance enrollment, and wealth group, were also associated with anaemia prevalence.

CONCLUSIONS

Anaemia is a severe public health problem among women of reproductive age across all 27 SSA countries analysed, with nearly four in ten being affected. Access to basic sanitation facilities was associated with a reduced anaemia risk. However, only slightly over a third of households had access to such facilities. Further research is required to examine the underlying mechanisms and inform effective interventions.

Why Are We Still a Worm World in the 2020s? An Overview of Risk Factors and Endemicity for Soil-Transmitted Helminthiasis

PURPOSE

Soil-transmitted helminthiasis (STH) is one of the most common chronic infections in developing countries associated with poor socioeconomic and sanitary conditions. The main objective of this overview was to evaluate the influence of environmental factors, risk factors related to the host, and control strategies on the prevalence of STH in different regions of the world.

METHODS

LILACS, PubMed, Web of Knowledge, Embase, the Cochrane Library, and Clinical Trials (gray literature) databases were used to obtain the systematic reviews published until December 2020. The methodological quality of systematic reviews was assessed using the standard criteria recommended by AMSTAR.

RESULTS

The initial results of the bibliographic search identified 1448 articles, of which 66 studies were read in full and 16 met the inclusion criteria. All the reviews included in this overview associated variations in the global prevalence of STH with at least one of the factors related to the environment, host, and/or control strategies. Climate, temperature, soil moisture, precipitation, mass drug administration, lack of access to water, sanitation and hygiene (WASH), and non-use of footwear were considered the main factors associated with the prevalence of STH. Socioeconomic factors, low educational level, and wearing shoes were universal factors related to prevalence, regardless of the location studied.

CONCLUSION

The combination of environmental factors, with factors associated with hosts that predispose infection and reinfection of helminths, as well as the adoption of control strategies based on the treatment of target populations instead of the entire population, influenced the prevalence of STH in all the continents evaluated.

Present status with impacts and roles of miRNA on Soil Transmitted Helminthiosis control: A review

Soil-Transmitted Helminthiasis (STH) is one of the most widespread Neglected Tropical Diseases (NTDs), and almost 1.5 billion of the global population is affected, mostly in the indigent, countryside sectors of tropics/subtropics. STH, commonly caused by various nematodes, adversely affects the hosts' growth, cognatic development, and immunity. Albendazole is most commonly used against STH (Soil-Transmitted Helminths) but resistance has already been reported in different countries. To date, no effective vaccine is present against STH. miRNAs are a unique class of small non-coding RNA, regulating various biological activities indulging host immune responses in host-pathogen interaction of STH. Dysregulation of miRNAs are being considered as one of the most important aspect of host-parasite interactions. Thus, it is the prime importance to identify and characterize parasite-specific as well as host-derived miRNAs to understand the STH infection at the molecular level. Systematic bibliometric analysis reveals a huge knowledge gap in understanding the disease by using both host and parasitic miRNAs as a potential biomarker. In this study, we addressed the present status of the STH prevalence, and therapy under the light of miRNAs. This would further help in designing new inhibitors and therapeutic strategies to control STH.

Prevalence of intestinal parasites in animal hosts and potential implications to animal and human health in Edo, Nigeria

BACKGROUND

Intestinal parasites in livestock cause huge economic setbacks. Moreover, these parasites can threaten human health when also present in companion animals.

OBJECTIVES

The study examined the prevalence and burden of intestinal parasites among roaming/migrating animals (goats, sheep, cattle, and dogs) to provide insights into the risk of potential human parasitic infections.

METHODS

A total of 1,741 fecal samples from goats (n = 920), sheep (n = 335), cattle (n = 230) and dogs (n = 256) were obtained randomly across 18 local government areas in Edo State, Nigeria. The parasite samples were recovered and identified under a microscope. Molecular tools were used to identify Toxocara spp.

RESULTS

Eighteen different parasites were isolated. Among the different groups of parasites observed, nematodes occurred the most, followed by protozoans. Among nematodes, Haemonchus was most prevalent in goats (28.04%) and sheep (29.85%), while Strongyloides (10.86%) and Bunostomum (8.69%) were relatively high in cattle. Strongyloides (3.9%), hookworm (3.9%), and Toxocara (3.12%) were the predominant parasites in dogs. For protozoan parasites, Eimeria was most common in all 4 animal hosts. Several goats (2.39%) and sheep (2.38%) tested positive for Fasciola spp. Molecular analysis confirmed Toxocara canis in dogs for the first time in Nigeria.

CONCLUSIONS

The major parasites recovered from these roaming/migrating animals have zoonotic potentials that can threaten human health.

Strategies to Decrease the Prevalence of Soil-Transmitted Helminths in Central India

Background Intestinal parasites are a major public health problem in tropical countries. Over 1.5 billion people are infected with soil-transmitted helminths (STH), of which 225 million are in India. Parasitic infections are associated with poor sanitation, lack of safe potable water, and improper hygiene.

Materials and Methods The study was undertaken to ascertain the impact of control strategies, namely open-defecation free drive and mass drug administration of single dose albendazole. Stool samples received at AIIMS Bhopal Microbiology laboratory, across all age groups, were studied for protozoan trophozoites/cysts and helminthic ova.

Results Out of 4,620 stool samples, 389 (8.41%) were positive either for protozoal or helminthic infections. Protozoan infections were more common than helminthic infections with Giardia duodenalis infection being the most common, 201 (51.67%), followed by Entamoeba histolytica, 174 (44.73%). The helminthic infections constituted 14 (3.5%) of the positive stool samples with Hookworm ova in 6 (1.5%) cases.

Conclusion This study proves that strategies, namely “Swachh Bharat Abhiyan” and “National Deworming Day” started in 2014 and 2015 led to significant reduction of intestinal parasite infections in Central India, with a higher reduction of STH compared with protozoan parasite infection being ascribed to the activity spectrum of albendazole.

Potential drivers of leprosy infection: A case–control study of parasitic coinfection and water, sanitation, and hygiene in North Gondar, Ethiopia

Background

Despite extensive control measures and a declining number of human reservoirs, the incidence of leprosy in excess of 200,000 new cases each year suggests that alternative pathways of transmission may play a role in continued endemicity. Parasitic coinfection and limited water, sanitation, and hygiene (WASH) have been suggested to predispose individuals to Mycobacterium leprae infection and were further explored in this study.

Methods

Leprosy cases and uninfected controls were recruited from areas around North Gondar, Ethiopia throughout 2019. Participants completed dietary and WASH surveys in addition to providing stool for helminth microscopic diagnosis and urine for Schistosoma mansoni Point-of-care circulating cathodic antigen (POC-CCA)™ rapid diagnostic testing. A similar methodology was employed for a case–control study of leprosy previously conducted by our research team in North Gondar from May to October of 2018. To more comprehensively evaluate associations between the above exposures and leprosy, data from the present 2019 study and the previous 2018 study were combined in select multivariate logistic regression analyses.

Results

A total of 47 men (59%) and 33 women (41%) participated in this study with an average age of 40 (SD 15.0 years). Most leprosy cases were multibacillary (93%). There was a high prevalence of parasitic coinfection among both cases (71%) and controls (60%). WASH insecurities were also widespread. On multivariate analysis, lack of soap for handwashing [aOR= 2.53, 95% CI (1.17, 5.47)] and the lack of toilet facilities [Adjusted odds ratio (aOR)= 2.32, 95% CI (1.05, 5.12)] were significantly associated with leprosy. Positive directionality was identified for a number of other inputs, including helminth infection [aOR= 3.23, 95% CI (0.85, 12.35)].

Conclusions

Taken together, these findings strengthen previous research conducted in 2018 implicating poor WASH conditions as a driver of leprosy infection. Leprosy remains the leading infectious cause of disability in the world. As such, future research should explore the above susceptibilities in more depth to curtail the global burden of disease.

Prevalence and Risk Factors of Soil-Transmitted Helminthic Infections in the Pediatric Population in India: A Systematic Review and Meta-Analysis

Soil-transmitted helminths (STH) is a major healthcare challenge in the pediatric age group affecting poor and deprived parts of our community. The main species that infect people are roundworm (AL, Ascaris lumbricoides), whipworm (TT, Trichuris trichiura), and hookworms (HW, Ancylostoma duodenale and Necator americanus). We aimed to estimate the pooled prevalence of STH infections in India in the pediatric age group (< 18 years) and assess the risk factors associated with STH in this age group. Three databases were searched (PubMed, Scopus, and Embase) up to February 16, 2021 with deliberate and inclusive search terms for original research articles estimating the prevalence of either of the three STH in India. Data extracted included individual prevalence of the three STH, prevalence of double or triple infections, and associated risk factors.

We identified systematically 1,408 publications, of which 44 were included for the final analysis, including studies from 20 states covering 34,590 children. In our study, the prevalence of AL ranged from 0.8 to 91% with a pooled prevalence of 25%, prevalence of TT ranged from 0.3 to 72% with a pooled prevalence of 13%, and for HW prevalence ranged from 0.2 to 80% with pooled prevalence of 10%. Two most important risk factors with higher odds ratio were open defecation practices or open latrine (odds ratio: 5.2) and washing hands without soap using water only (odds ratio: 2.49). Knowledge of areas with high prevalence of STH and associated risk factors would help in designing effective control strategies in the high-risk groups to prevent infection and aid in a drastic reduction of morbidity in children.

Increased amphiregulin expression by CD4+ T cells from individuals with asymptomatic Leishmania donovani infection

Objectives

There is an urgent need to be able to identify individuals with asymptomatic Leishmania donovani infection, so their risk of progressing to VL and transmitting parasites can be managed. This study examined transcriptional markers expressed by CD4+ T cells that could distinguish asymptomatic individuals from endemic controls and visceral leishmaniasis (VL) patients.

Methods

CD4+ T cells were isolated from individuals with asymptomatic L. donovani infection, endemic controls and VL patients. RNA was extracted and RNAseq employed to identify differentially expressed genes. The expression of one gene and its protein product during asymptomatic infection were evaluated.

Results

Amphiregulin (AREG) was identified as a distinguishing gene product in CD4+ T cells from individuals with asymptomatic L. donovani infection, compared to VL patients and healthy endemic control individuals. AREG levels in plasma and antigen-stimulated whole-blood assay cell culture supernatants were significantly elevated in asymptomatic individuals, compared to endemic controls and VL patients. Regulatory T (Treg) cells were identified as an important source of AREG amongst CD4+ T-cell subsets in asymptomatic individuals.

Conclusion

Increased Treg cell AREG expression was identified in individuals with asymptomatic L. donovani infection, suggesting the presence of an ongoing inflammatory response in these individuals required for controlling infection and that AREG may play an important role in preventing inflammation-induced tissue damage and subsequent disease in asymptomatic individuals.

Epidemiology of Soil-Transmitted Helminth Infections among Primary School Children in the States of Chhattisgarh, Telangana, and Tripura, India, 2015-2016

Soil-transmitted helminth (STH) infections are highly prevalent in many developing countries, affecting the poorest and most deprived communities. We conducted school-based surveys among children studying in first to fifth standard in government schools in the Indian States of Chhattisgarh, Telangana, and Tripura to estimate the prevalence and intensity of STH infections during November 2015 and January 2016. We adopted a two-stage cluster sampling design, with a random selection of districts within each agro-climatic zone in the first stage. In the second stage, government primary schools were selected by probability proportional to size method from the selected districts. We collected information about demographic details, water, sanitation, and hygiene (WASH) characteristics and stool samples from the school children. Stool samples were tested using Kato-Katz method. Stool samples from 3,313 school children (Chhattisgarh: 1,442, Telangana: 1,443, and Tripura: 428) were examined. The overall prevalence of any STH infection was 80.2% (95% confidence interval [CI]: 73.3-85.7) in Chhattisgarh, 60.7% (95% CI: 53.8-67.2) in Telangana, and 59.8% (95% CI: 49.0-69.7) in Tripura. Ascaris lumbricoides was the most prevalent STH infection in all three states. Most of the STH infections were of light intensity. Our study findings indicate that STH infections were highly prevalent among the school children in Chhattisgarh, Telangana, and Tripura, indicating the need for strengthening STH control program in these states. The prevalence estimates from the survey would serve as a baseline for documenting the impact of the National Deworming Day programs in these states.

Trichostrongyloid nematodes in ruminants of northern Iran: prevalence and molecular analysis

BACKGROUND

This study was carried out to investigate the prevalence and analyze the molecular characteristics based on the internal transcribed spacer (ITS) 2 region of the ribosomal RNA (RNA) gene of trichostrongylid nematodes in different ruminants from Guilan province, northern of Iran.

METHODS

The gastrointestinal tracts of 144 ruminants including 72 cattle, 59 sheep, and 13 goats were collected from an abattoir in Guilan province during July to September 2018. After isolation the helminths, male specimens were identified based on morphological parameters. PCR and partial sequencing of the ITS2 fragment were conducted. After phylogenetic analysis, the intraspecific and interspecific differences were calculated.

RESULTS

The prevalence of total infections with the nematodes was 38.9, 74.6 and 84.6% among cattle, sheep and goats, respectively. Eleven species of trichostrongylid nematodes including Haemonchus contortus, Marshallagia marshalli, Trichostrongylus axei, T. colubriformis, T. vitrinus, Ostertagia trifurcata, Teladorsagia circumcincta, Marshallagia occidentalis, O. lyrata, O. ostertagi, and Cooperia punctate were recovered from the ruminants. The most prevalent trichostrongyloid nematodes in cattle, sheep and goats were O. ostertagi (26.4%), M. marshalli (64.4%) and T. circumcincta (69.2%), respectively. Phylogenetic tree was discriminative for Trichostrongylidae family, while phylogenetic analysis of the ITS2 gene represented low variations and no species identification of Haemonchidae and Cooperiidae families.

CONCLUSIONS

This study suggests the high prevalence and species diversity of trichostrongyloid nematodes in different ruminants, indicating the importance of implement antiparasitic strategies in north regions of Iran. As well, this study showed that the ITS2 fragment is not a discriminative marker for Haemonchidae and Cooperiidae families, and investigation of other genetic markers such as mitochondrial genes would be more valuable for better understanding of their phylogenetic relationships.

Access to Water and Sanitation Infrastructures for Primary Schoolchildren in the South-Central Part of Côte d'Ivoire

In rural settings of Côte d'Ivoire, access to water, sanitation, and hygiene (WASH) at schools is often lacking. The purpose of this study was to assess the availability, quality, and use of WASH infrastructure in schools in the south-central part of Côte d'Ivoire, and to determine the hygiene practices of schoolchildren. A cross-sectional study was conducted in 20 primary schools with (n = 10) or without (n = 10) direct access to drinking water. The survey was comprised of a questionnaire directed at schoolchildren aged 8-17 years, an assessment of the WASH infrastructure, and the testing of drinking water samples for Escherichia coli and total coliforms. Overall, 771 schoolchildren were enrolled in the study. One out of four children (24.9%) reported that they used available toilets. Among those children not using toilets, more than half (57.5%) reported that they practised open defecation. Drinking water infrastructure was limited in most schools because of poor storage tanks, the low flow of water, or broken wells. All drinking water samples (n = 18) tested positive for total coliforms and 15 (83.3%) tested positive for E. coli. The lack of WASH infrastructures in primary schools in the south-central part of Côte d'Ivoire, in combination with poor hygiene practices, might govern disease transmission and absenteeism at school, especially among females.

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.

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.

Prevalence and Associated Factors of Soil-Transmitted Helminth Infections among Children Living with and without Open Defecation Practices in Northwest Ethiopia: A Comparative Cross-Sectional Study

Soil-transmitted helminth (STH) infections cause devastating effect in human health. School-age children (SAC) account for the highest prevalence of STH infections in sub-Sahara. Open defecation practicing might be the major contributing factor, and creating an open defecation-free (ODF) declared community is also a big challenge. This study aimed to assess the prevalence of STH infections and associated factors among SAC in ODF declared and open defecation-practicing kebeles. A comparative cross-sectional study was conducted among 806 SAC from January 2019 to April 2019. Questionnaire-based data were collected using a structured questionnaire. Stool samples were collected and processed via the Kato-Katz technique. Prevalence and associated factors were computed with descriptive statistics and regression, respectively. Variables with a P-value < 0.05 were considered as significantly associated. This study revealed that the prevalence of STH infections in open defecation-practicing and ODF declared kebeles were 39.0% and 30.0%, respectively. Wearing open shoes, wearing shoes sometimes, and playing with soil were significantly associated (P < 0.01) with STH infections in ODF declared kebeles. Similarly, wearing shoes sometimes, not using latrine, and playing with soil were also significantly associated (P < 0.01) with STH infections in open defection-practicing kebeles. In conclusion, lower prevalence of STH infections was recorded in ODF declared than in open defection-practicing kebeles. Wearing shoes sometimes, playing with soil, and not using latrine were associated with STH infections. Therefore, creating an ODF environment and community awareness should be strengthened.

Prevalence, seasonal and geographical distribution of parasitic diseases in dogs in Plateau State Nigeria: a 30-year retrospective study (1986-2015)

Parasitic diseases of dogs are now major economic and public health issues in Nigeria due to indiscriminate reproduction of dogs, lack of appropriate policies on pet ownership and diseases control as well as inadequate veterinary care. In order to understand the prevalence, seasonal variation and distribution of parasitic diseases of dogs in this region of Nigeria, the present study conducted a 30-year retrospective analysis in the referral veterinary centre, Vom, and analysed data using the Chi square test and the factor analysis. Of the 26,844 dogs handled between January 1986 and December 2015, 17,663 (65.8%) had different parasitic diseases. Yearly distribution of parasitic diseases varied significantly (p < 0.0001) and ranged between 52.0 and 85.4%. Age, seasonal and disease specific prevalence rates ranged between 2.8 and 80.5%. Prevalence rates in females 78.2% (95% CI 77.6-78.9) and indigenous breed 70.0% (95% CI 69.2-70.7) were significantly higher (p < 0.0001) from those of the males 47.2% (95% CI 46.2-48.1) and exotic breeds of dogs 60.7% (95% CI 59.8-61.6), respectively. Ancylostomosis was the most prevalent (15.9%) disease while Barkin Ladi recorded the highest regional prevalence. It is pertinent to enact appropriate disease control policies and observe control programmes including vector control and improved hygiene to curtail the economic and public health threats associated with these diseases.

Gender-based differences in water, sanitation and hygiene-related diarrheal disease and helminthic infections: a systematic review and meta-analysis

BACKGROUND

Qualitative evidence suggests that inadequate water, sanitation and hygiene (WASH) may affect diarrheal and helminthic infection in women disproportionately. We systematically searched PubMed in June 2014 (updated 2016) and the WHO website, for relevant articles.

METHODS

Articles dealing with the public health relevance of helminthic and diarrheal diseases, and highlighting the role of gender in WASH were included. Where possible, we carried out a meta-analysis.

RESULTS

In studies of individuals 5 years or older, cholera showed lower prevalence in males (OR 0.56; 95% CI 0.34-0.94), while Schistosoma mansoni (1.38; 95% CI 1.14-1.67), Schistosoma japonicum (1.52; 95% CI 1.13-2.05), hookworm (1.43; 95% CI 1.07-1.89) and all forms of infectious diarrhea (1.21; 95% CI 1.06-1.38) showed a higher prevalence in males. When studies included all participants, S. mansoni and S. japonicum showed higher prevalence with males (OR 1.40; 95% CI 1.27-1.55 and 1.84; 95% CI 1.27-2.67, respectively). Prevalence of Trichiuris and hookworm infection showed effect modification with continent.

CONCLUSIONS

Evidence of gender differences in infection may reflect differences in gender norms, suggesting that policy changes at the regional level may help ameliorate gender related disparities in helminthic and diarrheal disease prevalence.

Soil-Transmitted Helminth infections reduction in Bhutan: A report of 29 years of deworming

Soil Transmitted Helminth (STH) infections affect over 1.5 billion people worldwide. Although prevalent in all age groups, school aged children are a high-risk groups for STH infections. In Bhutan, epidemiological data on STH were collected from western Bhutan in 2003, which found a prevalence of 16.5%. However, little evidence is available on the prevalence of infection at national level. Therefore, this study was conducted with the aim to assess the prevalence and intensity of STH infections, and identify significant correlates of STH among students. A school-based survey was conducted in three regions of Bhutan. Two-stage cluster sampling was adopted to select a sample of 1500 students from 24 schools, in equal proportion from three regions of the country. A total of 1456 (97%) students were interviewed and their stool sample examined for the presence of parasites. Mini-FLOTAC technique was used to detect the parasite eggs/ova. The prevalence of any STH infection was 1.4%, with 0.8% Ascaris lumbricoides, 0.5% Trichuris trichiura and 0.2% hookworms. The eastern region had the highest prevalence at 2.3%. Except for one student who had moderate intensity of A. lumbricoides, the rest had light infection. Any STH presence was significantly associated with father's occupation, father's education level, type of house and the flooring of the house in which students reported to live. No significant associations were observed between water, sanitation and hygiene (WASH) variables measured and presence of any STH infection. The prevalence of STH was found to be very low with primarily light intensity in this study. Nonetheless, it was also found that the sanitation situation is not ideal in the country, with several students reporting constant or partial open defecation leading to environmental contamination. Based on this prevalence and in line with the WHO guideline, it is recommended that deworming be reduced to once a year in combination with concerted health education on proper hygiene and sanitation practice.

Soil transmitted helminth infections among school going age children of slums from Bhubaneswar, Odisha

OBJECTIVE

The objective is to determine prevalence and risk factors for soil-transmitted helminth (STH) infection among school-going age children from slums of Bhubaneswar.

DESIGN

Cross-sectional observational study.

SETTING

Microbiology laboratory of a tertiary care hospital, Bhubaneswar, during May 1-October 30, 2015 (6 months) including 360 children of 3-15 years from two populated slums of Bhubaneswar, assuming STH prevalence - 50%, confidence interval 95% and 10% relative precision. Purposively sampling by house to house visit was adopted to collect stool samples along with risk factors through questionnaires from each child after written informed consent of parents/guardians.

MATERIALS AND METHODS

Direct saline mount and egg counting by Kato-Katz (KK) method for STH-positive samples was done.

RESULTS

STH prevalence was 13.3%, more in males (68.8%), and significantly high (62.5%. P < 0.05) in school-going children between 6 and 12 years of age. Predominant STH was Ancylostoma duodenale (56.2%), 15% of parents were illiterate, 80% of houses had toilets, 70% were washing hand with soap and using footwear. STH infection was much less (12.5%) in those practicing handwashing with soap. Fifty percent of children had STH infection even after receiving deworming within the past 6 months. More egg counts - 216 eggs/gram of feces were found in 29 cases by KK method. Entamoeba histolytica (56.5%) was predominant among non-STH infections.

CONCLUSION

STH prevalence of Bhubaneswar slums was minimum (13.3%), school-going children of 6-12 years were more affected and handwashing habit with soap was the key factor to prevent STH infection. The proportion of participants having toilet facility and using footwear regularly had no role in STH prevention.

Health and social impacts of open defecation on women: a systematic review

BACKGROUND

The significance of sanitation to safeguard human health is irrefutable and has important public health dimensions. Access to sanitation has been essential for human dignity, health and well-being. Despite 15 years of conjunctive efforts under the global action plans like Millennium Development Goals (MDGs), 2.3 billion people have no access to improved sanitation facilities (flush latrine or pit latrine) and nearly 892 million of the total world's population is still practicing open defecation.

METHODS

The study provides a systematic review of the published literature related to implications of open defecation that goes beyond the scope of addressing health outcomes by also investigating social outcomes associated with open defecation. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) was used to frame the review, empirical studies focusing upon open defecation in women aged 13-50 in low and middle income countries were included in the review. Research papers included in the review were assessed for quality using appropriate critical appraisal tools. In total 9 articles were included in the review; 5 of these related to health effects and 4 related to social effects of open defecation.

RESULTS

The review identified 4 overarching themes; Health Impacts of open defecation, Increased risk of sexual exploitation, Threat to women's privacy and dignity and Psychosocial stressors linked to open defecation, which clearly present a serious situation of poor sanitation in rural communities of Lower-Middle Income Countries (LMICs). The findings of the review identified that open defecation promotes poor health in women with long-term negative effects on their psychosocial well-being, however it is a poorly researched topic.

CONCLUSION

The health and social needs of women and girls remain largely unmet and often side-lined in circumstances where toilets in homes are not available. Further research is critically required to comprehend the generalizability of effects of open defecation on girls and women.

PROSPERO REGISTRATION

CRD42019119946 . Registered 9 January 2019 .

Analysis of Schistosomiasis and soil-transmitted helminths mixed infections among pupils in Enugu State, Nigeria: Implications for control

BACKGROUND

Schistosomiasis and Soil-transmitted helminthiasis cause considerable morbidity and mortality in developing countries, especially among children. To this end it, a cross-sectional survey to determine the pattern of Schistosomiasis and Soil-transmitted helminthiasis co-infection was undertaken among primary school pupils in Oduma Community in Enugu State, Nigeria.

METHODS

Fresh urine and stool samples were collected from pupils. The urine and stool samples were examined using sedimentation and Kat-Katz techniques respectively.

RESULTS

Of the 236 pupils examined, 137 (58.1%) were found positive for at least one helminth infection. Ascaris lumbricoides was the most prevalent soil-transmitted helminth (STH), with a prevalence rate of 40.3%, followed by Trichuris trichiura (15.3%) and hookworm (8.9%). Infection with Schistosoma haematobium was detected in 13.6% of the pupils while Schistosoma mansoni infection prevalence was 7.2%. Age group 4 -7 years recorded the highest prevalence for S. haematobium, A. lumbricoides, T. Trichiura and hookworm infections. Multiple infections were also recorded, with 22.9% having double infections and 2.5% having triple infections. The most common double infection was A. lumbricoides with T. trichiura (8.9%), while the most common triple infection was A. lumbricoides, S. haematobium and hookworm (1.7%).

CONCLUSION

The results from the present study revealed an evident need for the systematic and sustained administration of school-based chemotherapy program targeting the control of STH infection and Schistosomiasis using Albendazole and Praziquantel respectively in the community, instead of a one-off approach that was carried out.

Intervention strategies to reduce the burden of soil-transmitted helminths in India

Soil-transmitted helminth (STH) infections continue to be a major global cause of morbidity, with a large proportion of the burden of STH infections occurring in India. In addition to direct health impacts of these infections, including anaemia and nutritional deficiencies in children, these infections also significantly impact economic development, as a result of delays in early childhood cognitive development and future income earning potential. The current World Health Organization strategy for STH is focused on morbidity control through the application of mass drug administration to all pre-school-aged and school-aged children. In India, the control of STH-related morbidity requires mobilization of significant human and financial resources, placing additional burdens on limited public resources. Infected adults and untreated children in the community act as a reservoir of infection by which treated children get rapidly reinfected. As a result, deworming programmes will need to be sustained indefinitely in the absence of other strategies to reduce reinfection, including water, hygiene and sanitation interventions (WASH). However, WASH interventions require sustained effort by the government or other agencies to build infrastructure and to promote healthy behavioural modifications, and their effectiveness is often limited by deeply entrenched cultural norms and behaviours. Novel strategies must be explored to provide a lasting solution to the problem of STH infections in India other than the indefinite provision of deworming for morbidity control.

Worm Infestation: Diagnosis, Treatment and Prevention

Worm infections continue to be among the most common diseases affecting children from low and middle income countries. Major worm infections of public health importance include Ascariasis, Trichuriasis, Hookworm, and Enterobiasis, which are transmitted through contaminated soil. In India, combined prevalence rates of worm infestation as per pooled data of 127 surveys is over 20%. Although most helminthic infections are mild and are often asymptomatic, but moderate to heavy worm infestations are generally associated with growth faltering, nutritional compromise, anemia and suboptimal academic performance among children from endemic regions. Migration of larval or adult worms also underpins pulmonary and gastrointestinal morbidity in affected children. Some of the distinctive life cycle and clinical features of various worms are discussed in the review. The gold standard diagnostic technique for evaluation of worm infestation includes stool microscopy for direct egg detection and species identification. Most of the community based surveys for detecting soil transmitted helminths (STH) use Kato-Katz technique. The drug armamentarium against worm infestation has evolved tremendously in last three to four decades with the availability of more efficacious and broad spectrum anthelminthics. The key strategies of a multi-component integrated management of worm infestation include individualized treatment, community management (mass drug administration) as well as preventive measures. Finally, barriers to diagnosis, treatment and prevention of worm infestations need to be identified and aggressively managed at individual, family and societal levels so that WHO's 75% coverage target can be achieved to eliminate soil transmitted helminthiasis in children by 2020.

Gastrointestinal helminths in farmers and their ruminant livestock from the Coastal Savannah zone of Ghana

To identify the gastrointestinal helminths of veterinary, zoonotic and public health importance in farmers and their ruminant livestock in Ghana, faecal samples were collected from 95 farmers and their livestock (cattle = 328, sheep = 285 and goats = 217) and examined by microscopy and/or molecular techniques. Overall, 21 farmers tested positive for at least one gastrointestinal helminth, 80.9% of which were single infections and 19.0% co-infections. The parasites identified in the farmers consisted of hookworms (n = 13) (9 were Necator americanus and the other 4 could not be amplified by PCR), Trichostrongylus spp. (n = 9), Schistosoma mansoni (n = 1), Schistosoma haematobium (n = 1) and Diphyllobothrium latum (n = 1). In livestock, strongylid nematodes were dominant (56.6%), followed by Paramphistomum spp. (16.9%), Dicrocoelium spp. (7.1%), Thysaniezia spp. (5.8%), Trichuris spp. (3.3%), Moniezia spp. (3.1%), Fasciola spp. (2.8%), Toxocara spp. (1.1%) and Schistosoma spp. (0.2%). Genotyping of Trichostrongylus spp. in the farmer's stools identified six T. colubriformis similar to T. colubriformis detected in cattle, sheep and goats in the study, two Trichostrongylus spp. with 98.3% and 99.2% genetic similarity to T. probolurus respectively and one Trichostrongylus spp. which showed 96.6% similarity to both T. probolurus and T. rugatus. Trichostrongylus axei was also identified in cattle, sheep and goats. This is the first molecular characterisation of Trichostrongylus spp. in Ghana and the species identified in the present study suggests zoonotic transmission from cattle, sheep and goats. Further studies involving larger numbers of farmers and their household members are essential to understand the transmission dynamics and impact of these parasites on farming communities in Ghana.

Helminths of veterinary and zoonotic importance in Nigerian ruminants: a 46-year meta-analysis (1970-2016) of their prevalence and distribution

BACKGROUND

The livestock industry plays a vital role in the economy of Nigeria. It serves as a major source of income and livelihood for majority of Nigerians who are rural settlers and contributes about 5.2% to the National Gross Domestic Product (GDP). Helminths however, cause economic losses due to reductions in milk production, weight gain, fertility and carcass quality. Zoonotic helminths of livestock origin cause health problems in humans.

METHODS

Using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, the prevalence and distribution of helminths of veterinary and zoonotic importance in Nigerian ruminants were determined in a meta-analysis of data published between 1970 and 2016. Data were stratified based on regions, hosts, study periods, sample sizes and study types while helminths were phylogenetically grouped into cestodes, nematodes and trematodes.

RESULTS

Data from 44 studies reported across 19 Nigerian states revealed an overall pooled prevalence estimate (PPE) of 7.48% (95% CI: 7.38-7.57) for helminths of veterinary and zoonotic importance from a total of 320 208 ruminants. We observed a significant variation (P < 0.001) between the PPEs range of 1.90% (95% CI: 1.78-2.02) and 60.98% (95% CI: 58.37-63.55) reported across different strata. High heterogeneity (99.78, 95% CI: 7.38-7.57) was observed. Strongyloides papillosus was the most prevalent (Prev: 32.02%, 95% CI: 31.01-33.11), while, Fasciola gigantica had the widest geographical distribution.

CONCLUSIONS

Helminths of veterinary and zoonotic importance are prevalent in ruminants and well distributed across Nigeria. Our findings show that helminths of ruminants may also be possible causes of morbidity in humans and economic losses in the livestock industry in Nigeria. High heterogeneity was observed within studies and the different strata. Good agricultural practices on farms, standard veterinary meat inspection and adequate hygiene and sanitation in abattoirs, farms and livestock markets need to be implemented in Nigeria in order to reduce the economic, public health and veterinary threats due to these helminths.

High prevalence of soil-transmitted helminth infections among primary school children, Uttar Pradesh, India, 2015

Background

Soil-transmitted helminth (STH) infections often affect the poorest and most deprived communities. In order to generate reliable data for planning a school based deworming program, we conducted a survey among primary school children studying in government schools in the Indian state of Uttar Pradesh. The objectives of our survey were to estimate the prevalence and intensity of STH infections.

Methods

We conducted a cross-sectional survey among children studying in 130 primary schools from 9 agro-climatic zones, during May – August 2015. Information about socio-demographic details, defecation and hand-hygiene practices, and stool samples were collected from the school children. Stool samples were examined using the Kato-Katz method.

Results

Stool samples from 6421 school children were examined. The overall weighted prevalence of any STH in the State was 75.6% (95% CI: 71.2–79.5). The prevalence was more than 50% in six of the nine agro-climatic zones. A. lumbricoides was the most prevalent STH (prevalence: 69.6%), followed by hookworm (prevalence: 22.6%) and T. trichura (4.6%). The majority of the STH infections were of low intensity. The practice of open defecation and not washing hands with soap after defecation and residence in kutcha house were significant risk factors of STH infection.

Conclusions

STH prevalence among primary school children in Uttar Pradesh was high. Given the WHO guidelines on deworming frequency according to STH prevalence, Govt of Uttar Pradesh needs to implement a school-based deworming program with bi-annual frequency. The findings of our survey would also help monitor the performance of school based deworming programme.

Electronic supplementary material

The online version of this article (10.1186/s40249-017-0354-7) contains supplementary material, which is available to authorized users.

A tale of two neglected tropical infections: using GIS to assess the spatial and temporal overlap of schistosomiasis and leprosy in a region of Minas Gerais, Brazil

BACKGROUND

Despite public health efforts to reduce the global burden of leprosy, gaps remain in the knowledge surrounding transmission of infection. Helminth co-infections have been associated with a shift towards the lepromatous end of the disease spectrum, potentially increasing transmission in co-endemic areas.

OBJECTIVES

Using this biologically plausible association, we conducted a geographic information systems (GIS) study to investigate the spatial associations of schistosomiasis and leprosy in an endemic area of Minas Gerais (MG), Brazil.

METHODS

Data on new cases of Mycobacterium leprae and Schistosoma mansoni infections from 2007-2014 were retrieved from the Brazilian national notifiable diseases information system for seven municipalities in and surrounding Vespasiano, MG. A total of 139 cases of leprosy and 200 cases of schistosomiasis were mapped to a municipality level. For one municipality, cases were mapped to a neighborhood level and a stratified analysis was conducted to identify spatial associations.

FINDINGS

A relative risk of 6.80 [95% confidence interval (CI) 1.46 - 31.64] of leprosy was found in neighborhoods with schistosomiasis. Incidence rates of leprosy increased with corresponding incidence rates of schistosomiasis, and the temporal trends of both infections were similar.

CONCLUSIONS

The associations found in this project support the hypothesis that helminth infections may influence the transmission of leprosy in co-endemic areas.

Geospatial distribution of intestinal parasitic infections in Rio de Janeiro (Brazil) and its association with social determinants

BACKGROUND

Intestinal parasitic infections remain among the most common infectious diseases worldwide. This study aimed to estimate their prevalence and provide a detailed analysis of geographical distribution of intestinal parasites in the metropolitan region of Rio de Janeiro, considering demographic, socio-economic, and epidemiological contextual factors.

METHODS/PRINCIPAL FINDINGS

The cross-section survey was conducted among individuals attending the Evandro Chagas National Institute of Infectious Diseases (FIOCRUZ, RJ) during the period from April 2012 to February 2015. Stool samples were collected and processed by sedimentation, flotation, Kato-Katz, Baermann-Moraes and Graham methods, iron haematoxylin staining and safranin staining. Of the 3245 individuals analysed, 569 (17.5%) were infected with at least one parasite. The most common protozoa were Endolimax nana (28.8%), Entamoeba coli (14.8%), Complex Entamoeba histolytica/Entamoeba dispar (13.5%), Blastocystis hominis (12.7%), and Giardia lamblia (8.1%). Strongyloides stercoralis (4.3%), Schistosoma mansoni (3.3%), Ascaris lumbricoides (1.6%), and hookworms (1.5%) were the most frequent helminths. There was a high frequency of contamination by protozoa (87%), and multiple infections were observed in 141 participants (24.8%). A positive association between age (young children) and gender (male) with intestinal parasites was observed. Geospatial distribution of the detected intestinal parasitic infections was not random or homogeneous, but was influenced by socioeconomic conditions (through the material deprivation index (MDI)). Participants classified in the highest levels of deprivation had higher risk of having intestinal parasites.

CONCLUSIONS/SIGNIFICANCE

This study provides the first epidemiological information on the prevalence and distribution of intestinal parasitic infections in the Rio de Janeiro metropolitan area. Intestinal parasites, especially protozoa, are highly prevalent, indicating that parasitic infections are still a serious public health problem. MDI showed that intestinal parasites were strongly associated with the socioeconomic status of the population, thus making it possible to identify social vulnerable areas.

Prevalence and distribution of soil-transmitted helminth infections in India

Background

Understanding the prevalence of soil-transmitted helminth infections is necessary to plan control strategies and focus on highly endemic regions for preventive chemotherapy and improved sanitation facilities. India is known to be endemic for soil-transmitted helminth infections.

Methods

To understand the prevalence, spatial distribution and identify high-risk zones, a systematic search of published literature was carried out based on PRISMA guidelines from the year 2000 to 2015.

Results

A careful screening of the identified literature yielded 39 studies that reported the prevalence of soil-transmitted helminth infections from 19 different states of India. Ascaris lumbricoides was the most prevalent parasite. Higher than 50% prevalence was reported from six states. Nearly 90% studies reported the prevalence of more than one parasite species in the same sample population.

Conclusion

This is the first study to comprehensively review the literature associated with soil-transmitted helminth infections from India giving a clear idea of its prevalence, distribution and high endemic areas.

Modeling the economic and epidemiologic impact of hookworm vaccine and mass drug administration (MDA) in Brazil, a high transmission setting

BACKGROUND

Although mass drug administration (MDA) has helped reduce morbidity attributed to soil-transmitted helminth infections in children, its limitations for hookworm infection have motivated the development of a human hookworm vaccine to both improve morbidity control and ultimately help block hookworm transmission leading to elimination. However, the potential economic and epidemiologic impact of a preventive vaccine has not been fully evaluated.

METHODS

We developed a dynamic compartment model coupled to a clinical and economics outcomes model representing both the human and hookworm populations in a high transmission region of Brazil. Experiments simulated different implementation scenarios of MDA and vaccination under varying circumstances.

RESULTS

Considering only intervention costs, both annual MDA and vaccination were highly cost-effective (ICERs ≤ $790/DALY averted) compared to no intervention, with vaccination resulting in lower incremental cost-effectiveness ratios (ICERs ≤ $444/DALY averted). From the societal perspective, vaccination was economically dominant (i.e., less costly and more effective) versus annual MDA in all tested scenarios, except when vaccination was less efficacious (20% efficacy, 5 year duration) and MDA coverage was 75%. Increasing the vaccine's duration of protection and efficacy, and including a booster injection in adulthood all increased the benefits of vaccination (i.e., resulted in lower hookworm prevalence, averted more disability-adjusted life years, and saved more costs). Assuming its target product profile, a pediatric hookworm vaccine drastically decreased hookworm prevalence in children to 14.6% after 20 years, compared to 57.2% with no intervention and 54.1% with MDA. The addition of a booster in adulthood further reduced the overall prevalence from 68.0% to 36.0% and nearly eliminated hookworm infection in children.

CONCLUSION

Using a human hookworm vaccine would be cost-effective and in many cases economically dominant, providing both health benefits and cost-savings. It could become a key technology in effecting control and elimination efforts for hookworm globally.

Anemia, diet and therapeutic iron among children living with HIV: a prospective cohort study

BACKGROUND

Children living with HIV have higher-than-normal prevalence of anemia. The beneficial effect of therapeutic iron has been questioned in the setting of high prevalence of infections. This study examines anemia prevalence and effect of standard therapeutic iron on HIV disease progression among children.

METHODS

Perinatally-infected children aged 2-12 years were enrolled at three sites in southern India, and were followed for 1 year with clinical assessments, dietary recall and anthropometry. Laboratory parameters included iron markers (ferritin, soluble transferrin receptor) and other micronutrient levels (vitamin A, B12, folate). Iron was given to anemic children based on WHO guidelines. Statistical analyses including frequency distributions, chi square tests and multivariate logistic regression were performed using Stata v13.0.

RESULTS

Among 240 children enrolled (mean age 7.7 years, 54.6% males), median CD4 was 25%, 19.2% had advanced disease, 45.5% had malnutrition, and 43.3% were on antiretroviral treatment (ART) at baseline. Anemia was prevalent in 47.1% (113/240) children. Iron deficiency was present in 65.5%; vitamin A and vitamin B12 deficiency in 26.6% and 8.0% respectively; and anemia of inflammation in 58.4%. Independent risk factors for anemia were stunting, CD4 < 25%, detectable viral load ≥ 400 copies/ml and vitamin A deficiency. Inadequate dietary iron was prominent; 77.9% obtained less than two-thirds of recommended daily iron. Among clinically anemic children who took iron, overall adherence to iron therapy was good, and only minor self-limiting adverse events were reported. Median hemoglobin rose from 10.4 g/dl to 10.9 mg/dl among those who took iron for 3 months, and peaked at 11.3 mg/dl with iron taken for up to 6 months. Iron was also associated with a greater fall in clinical severity of HIV stage; however when adjusted for use of ART, was not associated with improvement in growth, inflammatory and CD4 parameters.

CONCLUSIONS

Children living with HIV in India have a high prevalence of anemia mediated by iron deficiency, vitamin A deficiency and chronic inflammation. The use of therapeutic iron for durations up to 6 months appears to be safe in this setting, and is associated with beneficial effects on anemia, iron deficiency and HIV disease progression.

Recent advances and perspectives in molecular epidemiology of Taenia solium cysticercosis

Cysticercosis caused by accidental ingestion of eggs of Taenia solium is spreading all over the world through globalization and is one of the most neglected, neglected tropical diseases (NTDs) or neglected zoonotic diseases (NZDs). In the present study, the reason why T. solium cysticercosis has been neglected is discussed at first, and followed with an overview on the most recent advances and perspectives in molecular approaches for epidemiology of T. solium taeniasis/cysticercosis, since although taeniasis does not constitute recognized zoonoses, transmission and complete development are dependent on human definitive hosts. Main topics are discussions on (1) the two, Asian and Afro/American, genotypes of T. solium, (2) comparative analysis of mitochondrial (haploid) and nuclear (diploid) genes, and (3) the presence of hybrids of these two genotypes which indicates out-crossing of two genotypes in hermaphrodite tapeworms in Madagascar. Additional topics are on (4) the usefulness of phylogeographic analyses to discuss where the infection was acquired from, and (5) miscellaneous unsolved topics around these genetic diversity of T. solium.