Update on the mapping of prevalence and intensity of infection for soil-transmitted helminth infections in Latin America and the Caribbean: a call for action

Molecular detection of intestinal parasites in a rural community of Colombia: A one health approach to explore potential environmental-zoonotic transmission

AIMS

Protozoan and helminth parasitic infections pose significant public health challenges, especially in developing countries with rural populations marked by suboptimal hygiene practices and socio-economic constraints. The parasites are the etiological agents of these infections and have a notably elevated global prevalence. Therefore, this study focuses on estimating the frequency and transmission dynamics of several parasitic species, including Blastocystis, Giardia, Cryptosporidium spp., Entamoeba histolytica, Ascaris lumbricoides, Trichuris trichiura, Taenia spp. and hookworms, within a rural community in southwest Colombia with a particular emphasis on the One Health framework, considering environmental and zoonotic transmission potentials.

METHODS AND RESULTS

This study involved the analysis of 125 samples, encompassing human participants (n = 99), their domestic pets (dogs) (n = 24) and water sources (n = 2). Parasite detection was carried out utilizing a combination of microscopy and molecular techniques. Furthermore, the characterization of Blastocystis subtypes (STs) was achieved through Oxford Nanopore sequencing of the rRNA-18S gene. The investigation also entailed the examination of potential associations between intestinal parasitism and various sociodemographic factors. Results revealed a high frequency of parasitic infections when employing molecular methods, with Blastocystis (n = 109/87%), Giardia (n = 20/16%), Ancylostoma duodenale (n = 28/22%), Ancylostoma ceylanicum (n = 7/5.6%), E. histolytica (n = 6/4.8%), Cryptosporidium spp. (n = 12/9.6%) and even Taenia (n = 1/0.8%) detected. Cryptosporidium spp. was also identified in water samples. Coinfections were prevalent, with 57% (n = 70) of samples exhibiting single-parasite infections and 43% (n = 53) showing various degrees of polyparasitism, emphasizing the complexity of transmission dynamics. Blastocystis subtyping, conducted via Oxford Nanopore sequencing, revealed a diversity of subtypes and coexistence patterns, with ST2 being the most prevalent.

CONCLUSIONS

This research underscores the importance of using molecular techniques for frequency estimation, particularly emphasizing the relevance of zoonotic transmission in parasitic infections. It highlights the significance of the One Health approach in comprehending the circulation of parasites among animals, humans and environmental sources, thereby directly impacting public health and epidemiological surveillance.

A 14-year review (2007-2020) of helminthiasis epidemiology in a hospital in Southern Madrid, Spain

PURPOSE

Vast majority of helminth diseases remain neglected tropical diseases (NTDs), causing significant morbidity. The widespread and periodic distribution of antiparasitic drugs, remains the cornerstone for controlling these diseases. In Spain, most helminthiasis cases are imported, and suspicion and diagnosis have become increasingly important. Our primary objective is to present the epidemiological landscape of helminthiasis diagnoses within our facility, while also detailing the demographic characteristics of the affected population.

METHODS

A retrospective study was conducted at the Hospital Universitario Severo Ochoa (HUSO) from January 1, 2007, to December 31, 2020, encompassing all diagnosed cases of helminthiasis during this period. Comprehensive epidemiological, clinical, and microbiological data were gathered for all diagnosed patients. The study population comprised patients receiving treatment at the HUSO, as well as those receiving treatment at the Leganés and Fuenlabrada Primary Care Units. Subsequently, descriptive and comparative statistics were performed, comparing Spanish and foreign patients.

RESULTS

During this period, a total of 952 patients were diagnosed with some form of helminthiasis. Among them, 495 were Spanish, and 457 were foreign. The total number of helminths identified, including patients with multiple infections, was 1,010. Significant differences were observed between Africans and Americans in terms of age distribution, with a higher prevalence among Africans in the 0-15 age range and among Americans in the 31-60 age range. Variations were noted in the distribution of helminths, with S. stercoralis significantly affecting Americans. For Spanish patients, the presence of Trichuris trichiura and S. stercoralis was significantly associated with eosinophilia, whereas among foreign patients, it was associated with Trichuris trichiura, Ascaris lumbricoides among others. Regarding symptoms, skin manifestations were more frequent among Spanish, while digestive were more common among foreigners.

CONCLUSIONS

This study offers crucial epidemiological insights into helminth infections observed over time in a Madrid hospital. Although the prevalence of helminth infections has been decreasing, there is still a need for screening and diagnosing foreign patients.

The burden of intestinal parasitic infections in Antioquia, Colombia: Impact in childhood growth development and nutritional status

Gastrointestinal protist (GP) and soil-transmitted helminth (STH) infections cause significant morbidity among children in poor-resource settings of tropical and sub-tropical countries including Colombia. Few prospective transversal studies investigating how GP and STH infections affect growth development and nutritional status during childhood have been conducted in this country, none of them in the Antioquia Department. This microscopy-based study estimated the prevalence of GP and helminth (including STH) infections in faecal samples from schoolchildren (n = 384) collected during April-May 2019 in three municipalities of the Antioquia Department. Demographic, epidemiological, and household data were elicited through face-to-face interviews. Parasite detection was carried out by direct microscopic examination of both fresh smears and concentrated faecal material. Children (aged 6-15 years) also had their haemoglobin (Hb) levels, height and weight data collected, and BMI estimated. Data were analysed using bivariate and multivariate logistic regression analysis. Overall, 60.7 % (233/384) of schoolchildren were infected by at least one intestinal parasitic species. Among GPs, Blastocystis sp. was the most common species found (47.7 %, 95 % CI: 42.6-52.8), followed by G. duodenalis (15.9 %, 95 % CI: 12.4-19.9). Cryptosporidium spp. and Cyclospora cayetanensis were sporadically identified (0.3 %, 95 % CI: 0.1-1.4 each). Among helminths, the most prevalent species found were Trichuris trichiura (6.0 %, 95 % CI: 3.8-8.9) and Enterobius vermicularis (1.0 %, 95 % CI: 0.3-2.6). Hookworms, Ascaris lumbricoides, and Strongyloides stercoralis were found at prevalence rates <1 %. Underweight, overweigh, or obese schoolchildren had 1.2 times greater chance of being infected with intestinal parasites than their counterparts with a healthy weight (P-value: 0.015). Variables significantly associated with an increased likelihood of being infected by intestinal parasites include living in a household with unfinished flouring, not wearing shoes, being in close proximity to rodents, and having improper waste disposal. Relatively simple interventional measures directed towards the improvement of household conditions, access to sanitary toilets, and promoting shoe wearing can significantly reduce childhood infections by GP and helminths in the Antioquia Department.

Model nematodes as a practical innovation to promote high throughput screening of natural products for anthelmintics discovery in South Asia: Current challenges, proposed practical and conceptual solutions

With the increasing prevalence of anthelmintic resistance in animals recorded globally, and the threat of resistance in human helminths, the need for novel anthelmintic drugs is greater than ever. Most research aimed at discovering novel anthelmintic leads relies on high throughput screening (HTS) of large libraries of synthetic small molecules in industrial and academic settings in developed countries, even though it is the tropical countries that are most plagued by helminth infections. Tropical countries, however, have the advantage of possessing a rich flora that may yield natural products (NP) with promising anthelmintic activity. Focusing on South Asia, which produces one of the world's highest research outputs in NP and NP-based anthelmintic discovery, we find that limited basic research and funding, a lack of awareness of the utility of model organisms, poor industry-academia partnerships and lack of technological innovations greatly limit anthelmintics research in the region. Here we propose that utilizing model organisms including the free-living nematode Caenorhabditis elegans, that can potentially allow rapid target identification of novel anthelmintics, and Oscheius tipulae, a closely related, free-living nematode which is found abundantly in soil in hotter temperatures, could be a much-needed innovation that can enable cost-effective and efficient HTS of NPs for discovering compounds with anthelmintic/antiparasitic potential in South Asia and other tropical regions that historically have devoted limited funding for such research. Additionally, increased collaborations at the national, regional and international level between parasitologists and pharmacologists/ethnobotanists, setting up government-industry-academia partnerships to fund academic research, creating a centralized, regional collection of plant extracts or purified NPs as a dereplication strategy and HTS library, and holding regional C. elegans/O. tipulae-based anthelmintics workshops and conferences to share knowledge and resources regarding model organisms may collectively promote and foster a NP-based anthelmintics landscape in South Asia and beyond.

[Schistosomiasis, soil-transmitted helminthiases and sanitation in Latin America and the Caribbean: a systematic reviewRelación entre la prevalencia de esquistosomiasis y geohelmintiasis y las condiciones sanitarias en América Latina y el Caribe: una revisión sistemática]

Objective

To investigate the relationship between the prevalence of schistosomiasis and soil-transmitted helminthiasis with variables related to access to water, sanitation and solid waste in Latin American and Caribbean (LAC) countries.

Method

A systematic review was performed in the LILACS, PubMed, Web of Science, and SciELO databases. Studies published between 1950 and August 2021, with an ecological design and a focus on population groups (states, municipalities and/or districts), having the prevalence of infection by Schistosoma mansoni, Ancylostoma sp., Necator americanus, Ascaris lumbricoides or Trichuris trichiura as primary variable and access to water, sewage and/or solid waste as explanatory variables were included. Open access articles with full text available in English, Spanish, or Portuguese were considered. The risk of bias and the quality of the studies were assessed according to the Joanna Briggs Institute manual.

Results

Of 2 714 articles, nine were eligible, published between 1994 and 2021 and covering 22 LAC countries and 14 350 municipalities. All articles had moderate methodological quality. Environmental variables indicated an association between water supply and solid waste collection with schistosomiasis; water supply with ascariasis, trichuriasis and hookworm; and sewage with ascariasis and hookworm. Except for one article, which had regional coverage for LAC, all the others were developed in Brazil.

Conclusion

There is a clear need to expand research on the association between household and collective health conditions and parasitic diseases for all endemic countries in LAC to support environmental strategies to control these diseases.

Eliminating morbidity caused by neglected tropical diseases by 2030

The objective of this manuscript is to provide selective examples of the work of the Pan American Health Organization/World Health Organization (PAHO/WHO) Collaborating Centre for Research and Training in Parasite Epidemiology and Control which contribute to the WHO goal of eliminating neglected tropical diseases by 2030. This PAHO/WHO CC specifically aligns its activities with the Sustainable Development Goals and with the goals outlined in the WHO Road Map for Neglected Tropical Diseases 2021-2030. Its role is to contribute to advancing global action on NTDs, primarily through policy development and knowledge translation. Three important projects have recently been completed: 1. Finalizing the Monitoring and Evaluation Framework for the NTD Road Map (published May 2021; this PAHO/WHO CC was a member of the working group); 2. Developing new guidelines for the preventive chemotherapy of Taenia solium taeniasis (published September 2021; this PAHO/WHO CC was co-Chair; and 3. Formulating a policy brief on deworming for adolescent girls and women of reproductive age (published January 2022; this PAHO/WHO CC is co-lead). These projects are the result of the integration of expertise and experience from multiple partners, including from PAHO and WHO (where both organizations provided key leadership), this PAHO/WHO CC, government ministries, civil society organizations and universities, among others. In conclusion, this PAHO/WHO CC contributes timely guidance to country-led evidence-informed public health policy, to cost-effective program implementation and to the identification of priority research topics - all focused, ultimately, on eliminating NTD-attributable morbidity by 2030.

Prevalence and Associated Risk Factors of Soil-Transmitted Helminth Infections among Schoolchildren around Lake Tana, Northwest Ethiopia

Background

Soil-transmitted helminths (STHs) are among the most common neglected tropical diseases widely distributed in tropical countries with poor socioeconomic development. Ascaris lumbricoides, Trichuris trichiura, and hookworm are the three major STHs. This study aimed to determine the prevalence of STHs and associated risk factors among schoolchildren in selected primary schools around Lake Tana, Northwestern Ethiopia.

Methods

A school-based cross-sectional study was conducted from February to May 2021 involving 337 study participants. A systematic random sampling method was utilized to select the study participants from the selected schools. Data related to sociodemographic characteristics of the study participants and risk factors for STH infections were collected using a pretested questionnaire. Stool samples were collected in sterile plastic containers from each participant and processed using Kato-Katz thick fecal smear and Ritchie's concentration techniques. The data were analyzed using the Statistical Package for Social Sciences software tool version 23, and factors with a p < 0.05 were considered as statistically significant.

Results

The overall prevalence of STH infection was 38.3% (95% CI: 33.1-43.7). Hookworm infection was the predominant STH infection, which was detected in 26.1% schoolchildren followed by A. lumbricoides (14.8%) and T. trichiura (1.5%). Most of the study subjects (34.1%) had single infections, whereas only 4.2% study subjects had multiple helminthic infections. Among the risk factors considered in the study, lack of shoe wearing habit (adjusted odds ratio [AOR]=29.5; 95% confidence interval [CI]=6.59-132.55; p < 0.001), lack of knowledge on the prevention and control methods (AOR = 5.41; 95% CI = 2.44-11.98; p < 0.001), engagement in irrigation activities (AOR = 2.14; 95% CI = 1.02-4.57, p = 0.049), lack of toilet (AOR = 3.06; 95% CI = 1.31-7.16; p = 0.01), children grades of 5-8 (AOR = 2.62; 95% CI = 1.26-5.43; p = 0.01), playing on soils (AOR = 5.90; 95% CI = 2.79-12.49; p < 0.001), lack of fingernail trimming habit (AOR = 3.21; 95% CI = 1.57-6.55; p = 0.001), and male gender (AOR = 2.28; 95% CI: 1.19-4.39; p = 0.013) were significant explanatory factors for STH infection among schoolchildren in the study area.

Conclusions

The present study showed that STHs were common among schoolchildren around Lake Tana. Therefore, education on personal and environmental hygiene should be taken into account to reduce the prevalence of STH infection in the study area.

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.

Soil-transmitted helminthes and Schistosoma mansoni infections among primary school children at Ambasame primary school, North-West Ethiopia: a cross-sectional study

BACKGROUND

Schistosomiasis and soil-transmitted helminthiasis (STHs) are the major public health problem in the world especially in school age children. Therefore, this study aimed to determine the burden of soil transmitted helminths and Schistosoma mansoni among Ambesame primary school children, North-West Ethiopia.

METHOD

A cross sectional study was carried out at Ambasame primary school children from March to May, 2019. Study participants were selected using systematic random sampling technique. Socio-demographic characteristics and other factors were collected using structured questionnaire. Moreover, stool samples were examined microscopically using wet mount and formol ether concentration techniques. Data were entered and analyzed using SPSS version 20. Logistic regression analysis was done to investigate the association between dependent and independent variables. P-value less than 0.05 was considered as statistically significant.

RESULT

The overall prevalence of intestinal parasites was 117(31.2%). The prevalence of soil-transmitted helminthes and S.mansoni was 110 (29.3%) using formol ether concentration technique. The most predominant parasite was S. mansoni (10.7%), followed by hookworm (5.6%). Multivariate logistic regression analysis revealed that, helminthic infection was associated with children less than 7 years of age (P-value = 0.019, AOR = 3.29, 95% CI (1.21-8.91)); fathers who are able to read and write (P-value< 0.001, AOR = 5.4, 95% CI (2.37-12.33)); absence of latrine (P-value = 0.016, AOR = 12.96, 95% CI (1.60-104.87)) and untrimmed nail (P-value = 0.043, AOR = 2.09, 95% CI (1.02-4.27)).

CONCLUSION

This study revealed that the prevalence of intestinal helminthes among Ambasame primary school children was relatively high. The lower educational status of father, absence of latrine and untrimmed finger nail showed statistically significant association with intestinal helminthic infection. This indicates the school community, health offices and other stakeholders should plan a strategy to tackle problems associated with sanitary condition. Furthermore, Health policy makers, healthcare workers and health extension workers should enhance their effort of awareness creation for school children, parents, school community about personal hygiene, environmental sanitation, intestinal parasites transmission, prevention and control. Moreover, mass deworming of school children and periodic screening for parasitic infection should be done.

Detangling the Crosstalk Between Ascaris, Trichuris and Gut Microbiota: What´s Next?

Helminth infections remain a global public health issue, particularly in low- and middle-income countries, where roundworms from theTrichuris and Ascaris genera are most prevalent. These geohelminths not only impact human health but most importantly also affect animal well-being, in particular the swine industry. Host-helminth parasite interactions are complex and at the same time essential to understand the biology, dynamics and pathophysiology of these infections. Within these interactions, the immunomodulatory capacity of these helminths in the host has been extensively studied. Moreover, in recent years a growing interest on how helminths interact with the intestinal microbiota of the host has sparked, highlighting how this relationship plays an essential role in the establishment of initial infection, survival and persistence of the parasite, as well as in the development of chronic infections. Identifying the changes generated by these helminths on the composition and structure of the host intestinal microbiota constitutes a field of great scientific interest, since this can provide essential and actionable information for designing effective control and therapeutic strategies. Helminths like Trichuris and Ascaris are a focus of special importance due to their high prevalence, higher reinfection rates, resistance to anthelmintic therapy and unavailability of vaccines. Therefore, characterizing interactions between these helminths and the host intestinal microbiota represents an important approach to better understand the nature of this dynamic interface and explore novel therapeutic alternatives based on management of host microbiota. Given the extraordinary impact this may have from a biological, clinical, and epidemiological public health standpoint, this review aims to provide a comprehensive overview of current knowledge and future perspectives examining the parasite-microbiota interplay and its impact on host immunity.

Occurrence and removal of intestinal parasites in two wastewater treatment plants in the south of Morocco

BACKGROUND

Agadir city plans to reuse treated wastewater on a large scale to irrigate these green spaces. This study aims to evaluate the risk of intestinal parasites, to which human and animal populations are exposed during the reuse of treated wastewaters.

METHODS

Over 21 months, wastewater samples were collected in Bensergao and Mzar wastewater treatment plants, in Agadir city, southern Morocco. The occurrences and removal of intestinal parasites were inspected using the modified Bailenger method.

RESULTS

The biodiversity of helminths is higher than protozoa, while the protozoa cysts are more abundant and more prevalent. Generally, the highest parasitic loads were recorded during the hot season. For raw waters, the average concentration of protozoa cysts was 173.33 ± 70.81 cysts per L for Bensergao plant and 179.33 ± 129.22 cysts per L for Mzar plant. However, the helminths average concentration was 48.70 ± 39.91 eggs/larvae per L for Bensergao plant and 51.10 ± 31.76 eggs/larvae per L for Mzar plant. The purified water of the Mzar plant does not contain parasites, unlike the Bensergao plant where a small numbers of parasites were detected, included 2.33 ± 1.53 cysts per L for protozoa and 0.45 ± 0.58 eggs/larvae per L for helminths.

CONCLUSIONS

Considering parasitological risks, the purified waters of Bensergao plant cannot be used without risks to the public health and environment. In contrast, the purified waters and the purified waters disinfected by ultraviolet radiation from the Mzar plant can be used safely to water the green spaces of Agadir city.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Effectiveness of Deworming with Single-Dose Albendazole for Preschool-Aged Children in the Dominican Republic

Background. The World Health Organization recommends biannual deworming with single-dose albendazole for all children over 1 year in regions where soil-transmitted helminths (STH) are endemic. There are limited data from the Dominican Republic (DR) on the effectiveness of deworming programs. Methods. Between January and June 2019, we enrolled 63 preschool-aged children at a community clinic in the DR. Participants received albendazole at enrollment. Stool samples were collected and examined for parasites at enrollment, 2 to 4 and 12 to 16 weeks post-albendazole. Caregivers were surveyed on home hygiene practices and children’s symptoms. Findings. At enrollment, 1 or more parasites were noted in 89% of samples. Ascaris lumbricoides (68%) was the most common species, followed by Entamoeba histolytica (35%) and Giardia intestinalis (8%). Two-to-four weeks post-albendazole, fewer than half of those with A. lumbricoides infections at baseline had cleared the infection. STH symptoms significantly improved between enrollment and 2 to 4 weeks. By 12 to 16 weeks after treatment, A. lumbricoides infections were as high as baseline. Interpretation. Although limited by size and available technology, our study contributes data on STH in the DR. Single-dose deworming with albendazole did not reduce Ascaris lumbricoides infections in our sample. As STH are the most common neglected tropical diseases and negatively impact children’s health globally, further studies on both effective deworming programs and interventions to prevent STH are needed.

Health screening results of Cubans settling in Texas, USA, 2010-2015: A cross-sectional analysis

BACKGROUND

Protecting the health of refugees and other migrant populations in the United States is key to ensuring successful resettlement. Therefore, to identify and address health concerns early, the US Centers for Disease Control and Prevention (CDC) recommends a domestic medical examination (screening for infectious and noninfectious diseases/conditions) shortly after arrival in the US. However, because refugee/migrant populations often have differing health patterns from one another and the US population, the collection and analysis of health information is key to developing population-specific clinical guidelines to guide the care of resettled individuals. Yet little is known regarding the health status of Cubans resettling in the US. Among the tens of thousands of Cuban migrants who have resettled in the US, some applied as refugees in Cuba, some applied for parole (a term used to indicate temporary US admission status for urgent humanitarian reasons or reasons of public benefit under US immigration law) in Cuba, and others applied for parole status after crossing the border. These groups were eligible for US government benefits to help them resettle, including a domestic medical examination. We reviewed health differences found in these examinations of those who were determined to be refugees or parolees in Cuba and those who were given parole status after arrival.

METHODS AND FINDINGS

We conducted a retrospective cross-sectional analysis of the Texas Department of State Health Services database. Cubans who arrived from 2010 to 2015 and received a domestic medical examination in Texas were included. Those granted refugee/parolee status in Cuba were listed in federal databases for US-bound refugees/parolees; those who were paroled after arrival were not listed. Overall, 2,189 (20%) obtained either refugee or parolee status in Cuba, and 8,709 (80%) received parolee status after arrival. Approximately 62% of those who received parolee status after arrival at the border were male, compared with 49% of those who obtained prior refugee/parolee status in Cuba. Approximately one-half (45%) of those paroled after arrival were 19-34 years old (versus 26% among those who obtained refugee/parolee status in Cuba). Separate models were created for each screening indicator as the outcome, with entry route as the main exposure variable. Crude and adjusted prevalence ratios were estimated using PROC GENMOD procedures in SAS 9.4. Individuals paroled after arrival were less likely to screen positive for parasitic infections (9.6% versus 12.2%; adjusted prevalence ratio: 0.79, 0.71-0.88) and elevated blood lead levels (children ≤16 years old, 5.2% versus 12.3%; adjusted prevalence ratio: 0.42, 0.28-0.63). Limitations include potential disease misclassification, missing clinical information, and cross-sectional nature.

CONCLUSIONS

Within-country variations in health status are often not examined in refugee populations, yet they are critical to understand granular health trends. Results suggests that the health profiles of Cuban Americans in Texas differed by entry route. This information could assist in developing targeted screenings and health interventions.

Biological role of excretory-secretory proteins in endemic parasites of Latin America and the Caribbean

Neglected tropical diseases (NTDs) share certain traits: they are parasitic infections, prevailing in tropical environments and affecting marginalized sectors of the population. Six NTDs - ascariasis, cysticercosis, echinococcosis, hookworm infection, onchocerciasis and trichuriasis - all of them endemic in Latin America and the Caribbean (LAC), are analysed in this work. This review aims to discuss key information on the function of excretory/secretory (E/S) proteins from these parasites in their infectivity, pathogeny and diagnosis. The modulation of the host immune system to favour the permanence and survival of the parasite is also discussed. An updated knowledge on the function of E/S molecules in endemic parasitoses in LAC may lead to new approaches for the clinical management and diagnosis of these diseases. In turn, this could allow us to optimize their treatment and make it more affordable - a relevant goal given the economic constraints that the region is facing.

Soil-Transmitted Helminth Infections and Anemia in Schoolchildren from Corn Island Archipelago (RAAS, Nicaragua)

The prevalence and intensity of soil-transmitted helminth (STH) infections in schoolchildren from Corn Islands (Nicaragua) were examined to detect mono- or poly-STH infected children, measuring different intensity levels, and to elucidate measurably increased odds of being anemic. A total of 341 stool samples provided by 2- to 15-year-old children were examined using a concentration technique and a Kato-Katz slide. Intensity of infection was expressed as eggs per gram (epg) of feces to classify light, moderate, or heavy intensity infection. A finger-prick blood sample was obtained from each student in the field. Soil-transmitted helminth prevalence was 54.3%, with Trichuris trichiura as the most prevalent species (48.9%). The combination T. trichiura/Ascaris lumbricoides (12.6%) was the most common. When T. trichiura or A. lumbricoides appeared as a single infection, light or moderate intensity infections were seen, whereas when multiple species were identified, heavy infections were present. Anemia was detected in those with any kind of STH infection (42.7%), with statistically significant differences (P = 0.004) when compared with uninfected individuals (28.2%). Polyparasite infection with one parasite species at moderate intensity and the other parasite species at light intensity or absent was found to be a significant factor for the odds of being anemic (odds ratio = 2.07). The present study reveals a high level of STH transmission requiring a deworming control program in Corn Islands and pointing to the need of improving the education and sanitary conditions of the population to avoid environmental contamination and reinfection.

Prevalence, intensity and factors associated with soil-transmitted helminths infections among preschool-age children in Hoima district, rural western Uganda

Background

Over 80% of morbidity due to soil-transmitted helminthiasis (STH) occurs in low-income countries. Children under 5 account for 20–30% of the burden in endemic areas. This study assessed the prevalence, intensity and factors associated with STH infections among preschool-age children (PSAC) in Hoima district, Uganda. The PSAC are particularly vulnerable because the chronicity of this condition usually affects their physical and mental growth and development.

Methods

A cross-sectional study was carried out among 562 PSAC (1–5 years old) in 6 counties of Hoima district using Expanded Program on Immunization (EPI) method. Stool samples from children were examined using the formol ether concentration technique for STH egg detection. Egg counts were represented as egg per gram (EPG). A structured questionnaire was used to collect information on factors associated with STH infection. Generalized linear models were used to analyze relationships between STH infection and associated factors.

Results

Overall STH prevalence was 26.5%. Hookworm infection was the most prevalent (18.5%), followed by A.lumbricoides (9.8%) and T.trichiura (0.5%). Prevalence of STH infection was significantly higher in children aged 5 years (Pearson chi-square test, p = 0.009) than in children aged 1 year. The general geometric mean (GM) counts for Hookworm infection was (696.1 EPG; range (530.3–913.8)) with girls having a higher GM (789.8 EPG; range (120–13,200)) than boys. Eating uncooked or unwashed vegetables (adj. Prevalence Ratio (PR) = 1.9, 95% CI: 1.3–2.7) and fruits (adj.PR = 1.8, 95% CI: 1.1–2.8), indiscriminate disposal of young children’s faeces (adj.PR = 1.5, 95% CI: 1.1–2.0); not washing hands after defecation (adj.PR = 2.6, 95% CI: 1.9–3.6); and not deworming children regularly (adj.PR = 1.4, 95% CI: 1.1–1.8) were significantly associated with STH infection.

Conclusion

The prevalence of Soil transmitted helminths infection among preschool-age children in Hoima district significantly increased with age. Poor hygiene, inadequate sanitation and irregular deworming were associated with STH infections among PSAC in the study area. Intense health education on the importance of hygienic practices, improved sanitation and regular deworming of PSAC should be integrated into prevention and control programs.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3289-0) contains supplementary material, which is available to authorized users.

Scaling down of a deworming programme among school-age children after a thirty-year successful intervention in the Bolivian Chaco

OBJECTIVE

Preventive chemotherapy is the WHO-recommended control method for soil-transmitted helminthiases. In the Bolivian Chaco, 6-monthly single-dose mebendazole delivery to school-age children achieved a dramatic decrease in soil-transmitted helminthiases prevalence between 1987 and 2013. Consequently, in September 2016, preventive chemotherapy delivery was interrupted in nine rural communities. In compliance with WHO recommendations, we intensified surveillance to monitor soil-transmitted helminthiases prevalence and detect potential changes that would require interventions.

METHODS

We conducted two cross-sectional parasitology surveys 12 months apart (September 2016-2017) among school-age children living in the communities where preventive chemotherapy delivery had been halted. Study design, methods of sampling and sample analysis technique (direct microscopy, Kato-Katz technique) followed WHO recommendations, aiming to obtain data representative of the Bolivian Chaco ecological zone.

RESULTS

We collected 426 samples in 2016 and 520 in 2017. Soil-transmitted helminthiasis prevalence was unremarkable: 0.7% (95% CI 0-1.5%) in 2016 and 0.8% (0-1.5%) in 2017. Conversely, the prevalence of tapeworms (13% in 2016, 12% in 2017) and intestinal protozoan infections (81% in 2016 and 75% in 2017) continued to be high.

CONCLUSIONS

Our findings support the role of preventive chemotherapy in reducing soil-transmitted helminthiases transmission, as otherwise poor hygienic and health conditions persist in the Bolivian Chaco. A national survey, involving areas from all the ecological zones of Bolivia, is now warranted.

Soil-transmitted helminth infections and nutritional status in Ecuador: findings from a national survey and implications for control strategies

OBJECTIVE

The estimation of prevalence and intensity of soil-transmitted helminth (STH) infections at a country-level is an essential prerequisite for the implementation of a rational control programme. The aim of this present study was to estimate the prevalence and distribution of STH infections and malnutrition in school-age children in rural areas of Ecuador.

DESIGN

Cross-sectional study from October 2011 to May 2012.

SETTING

Eighteen rural schools were randomly selected from the three ecological regions of Ecuador (coastal, highlands and Amazon basin).

PARTICIPANTS

920 children aged 6-16 years.

MAIN OUTCOME MEASURES

Prevalence and intensity of STH infections associated with malnutrition (thinness/wasting or stunting).

RESULTS

The results showed that 257 (27.9%) children were infected with at least one STH parasite. The prevalence of Trichuris trichiura, Ascaris lumbricoides and hookworm was 19.3%, 18.5% and 5.0%, respectively. Malnutrition was present in 14.2% of children and most common was stunting (12.3%). Compared with other regions, schoolchildren in the Amazon region had the highest STH prevalence (58.9%) of which a greater proportion of infections were moderate/heavy intensity (45.6%) and had the highest prevalence of malnutrition (20.4%). A positive association was observed between moderate to heavy infections with A. lumbricoides and malnutrition (adjusted OR 1.85, 95% CI 1.04 to 3.31, p=0.037).

CONCLUSIONS

Our estimate of the prevalence of STH infections of 27.9% at a national level in Ecuador is lower than suggested by previous studies. Our data indicate that schoolchildren living in the Amazon region have a greater risk of STH infection and stunting compared with children from other regions. The implementation of school-based preventive chemotherapy and nutritional supplement programmes within the Amazon region should be prioritised. Long-term control strategies require improvements in water, sanitation and hygiene.

Enteroparasites in Preschool Children on the Pacific Region of Nicaragua

The aim of this study was to determine for the first time the prevalence of enteroparasites in preschool children originating from the seven departments of the Pacific region in Nicaragua. One stool sample of each of 1,217 children, from 6 months to 5 years of age, was collected and personal data were recorded on delivery of the container. Samples fixed in 10% formalin were processed by a formol-acetate concentration and a modified Ziehl-Neelsen technique. The overall prevalence of enteroparasite infections was 68.2% with a total of at least 20 species. Blastocystis hominis (45.5%), Giardia intestinalis (31.7%), Trichuris trichiura (8.2%), and Ascaris lumbricoides (5.2%) were the most prevalent protozoa and helminth species in the total study as well as in all departments. Protozoan prevalence presented a statistically significant difference by gender (male: 69.6%; female: 46.7%; P < 0.001), and males presented a higher T. trichiura infection rate than females (male: 9.9%; female 6.4%; P < 0.035). Protozoan prevalence increased with age with a statistically significant difference (P < 0.001). Helminths were always more prevalent in urban areas (P < 0.0002). Protozoan infections result statistically higher than helminth infections so that water-based transmission could be suspected. Based on the differences with respect to species and parasite prevalence between the seven departments in the Pacific region of Nicaragua, the exploration of local factors associated with the transmission of enteroparasites should also be considered to reduce infection.

Soil-transmitted Helminth Infections in Schoolchildren of Laguna de Perlas (Nicaragua)

Soil-transmitted helminth (STH) prevalence, intensity, polyparasitism and co-infections in 425 children from 3 schools of Laguna de Perlas (Nicaragua) were investigated. Single stool samples were analysed by the formalin-ether method and the Kato-Katz. A total of 402 (94.6%) children were infected. Trichuris trichiura 308 (72.4%), Ascaris lumbricoides 115 (27.1%) and Hookworms 54 (12.7%) were the most prevalent STHs. Polyparasitism (322; 75.8%) with two species was most prevalent (109; 25.6%). T. trichiura with A. lumbricoides (19.3%) and T. trichiura with Hookworm (6.8%) were the most common combinations. Positive associations were observed between T. trichiura and A. lumbricoides and T. trichiura and Hookworm (p = 0.0001). Highest Hookworm intensities appeared when three STH co-infections occurred. Moderate- heavy STH intensities appear in up to 42.1% in trichuriasis, 57.5% in ascariasis and 11.1% in Hookworm infections. Integrated control interventions covering children need to be implemented mainly in a rural environment.

Uncovering the Pathogenic Landscape of Helminth (Opisthorchis viverrini) Infections: A Cross-Sectional Study on Contributions of Physical and Social Environment and Healthcare Interventions

BACKGROUND

Helminth infections have proven recalcitrant to control by chemotherapy in many parts of Southeast Asia and indeed farther afield. This study isolates and examines the influence of different aspects of the physical and social environment, and uneven intervention effort contributing to the pathogenic landscape of human Opisthorchis viverrini infections.

METHODOLOGY

A cross-sectional survey, involving 632 participants, was conducted in four villages in northeast Thailand to examine the impact on prevalence and parasite burden of the reservoir dam environment, socio-economic, demographic, and behavioral factors, and health center intervention efforts. Formalin-ether concentration technique was used for diagnoses, and multivariate models were used for analyses.

PRINCIPAL FINDINGS

The importance attributed to O. viverrini infections varied among health centers in the four study villages. Villages where O. viverrini infections were not prioritized by the health centers as the healthcare focus were at a higher risk of infection (prevalence) with odds ratio (risk factor) of 5.73 (3.32-10.27) and p-value < 0.01. Priority of healthcare focus, however, did not appear to influence behavior, as the consumption of raw fish, the main source of O. viverrini infections in the study area, was 11.4% higher in villages that prioritized O. viverrini infections than those that did not (p-value = 0.01). Landscape variation, notably proximity to reservoir, affects vulnerability of local population to infection. Infection intensity was higher in population located closer to the reservoir with risk ratio of 2.09 (1.12-4.02) and p-value < 0.01. Patterns of infection intensities among humans were found to match fish infection intensity, where higher infection intensities were associated with fish obtained from the reservoir waterbody type (p-value = 0.023).

CONCLUSIONS/SIGNIFICANCE

This study demonstrated the importance of environmental influence and healthcare focus as risk factors of infections in addition to the socio-economic, demographic, and behavioral factors commonly explored in existing studies. The reservoir was identified as a crucial source to target for opisthorchiasis intervention efforts and the need to consider infection intensity in disease control efforts was highlighted. The holistic approach in this study, which underscores the close relationship between the environment, animals, and humans in development of human infections or diseases, is an important contribution to the framework of One Health approach, where consideration of helminth diseases has largely been overlooked.

Effects of poor hygiene on cytokine phenotypes in children in the tropics

We describe immune phenotypes (innate and adaptive cytokines) according to environmental exposure using latent class analysis. A total of 310 schoolchildren living in Ecuador were assayed for spontaneous cytokine production as well as mitogen (SEB)-stimulated cytokines in whole blood cultures. We collected data on environmental exposures by questionnaire and on intestinal parasites by examination of stool samples. Latent class analysis (LCA) was used to group children according to their innate (IL-6, IL-8, IL-10 and TNF-α) and adaptive (IL-5, IL-13, IL-17, IFN-γ and IL-10) cytokine profile. We also conducted multiple-group LCA and LCA with covariates to evaluate the effect of predictors on profile membership. We identified both hyporesponsive and Th2-modified immune phenotypes produced by peripheral blood leukocytes (PBLs) that were associated with intestinal worms and birth order, providing insights into how poor hygiene mediates immunologic effects on immune-mediated diseases.

Seroprevalence of five parasitic pathogens in pregnant women in ten Caribbean countries

To date, published epidemiological studies of parasitic infections in humans in the Caribbean region are very limited. Here, we report the seroprevalence of five parasitic pathogens, including Ascaris lumbricoides, Entamoeba histolytica, Giardia lamblia, Schistosoma mansoni, and Toxocara canis in 435 serum samples collected between 2008 and 2011 from pregnant women in ten Caribbean islands. We tested the serum samples for IgG antibodies against the five parasites by enzyme-linked immunosorbent assay (ELISA). Among them, 66.2 % were serologically positive for at least one parasite. The most prevalent parasite was G. lamblia (40.5 %), followed by A. lumbricoides (37.9 %), T. canis (14.5 %), E. histolytica (6.7 %), and S. mansoni (3.0 %). Evidence of infections of G. lamblia and A. lumbricoides were detected in all ten Caribbean countries. Seroprevalence estimates significantly differed between countries for A. lumbricoides, E. histolytica, and T. canis (p values <0.001). For S. mansoni, significance was observed by Fisher's exact test (p = 0.013) but not by multiple comparisons. The prevalence of G. lamblia was not significantly different between countries (p = 0.089). A significant negative correlation between the gross domestic product (GDP) per capita and overall seroprevalence by country was also observed (Pearson's r = -0.9202, p = 0.0002). The data strongly indicates that neglected parasitic infections remain a significant health burden on people in these countries. Thus, justification has been provided to regional health planners to enhance existing public health surveillance programs on parasitic diseases and to heighten the public's awareness through education and outreach programs on how they can minimize the occurrence of parasitic infections.

Spatial distribution of intestinal parasitic infections in a Kaingáng indigenous village from Southern Brazil

The spatial distribution of enteroparasitosis in an indigenous village from Paraná was evaluated to identify areas of risk for these infections. A cross-sectional study (from November 2010 to June 2011) was performed using Three Faecal Test(®) and Kato & Katz method and a questionnaire on housing and hygiene conditions was administered. Local geostatistical analyses were performed to determine the spatial distribution of intestinal parasitic infections. The overall prevalence of enteroparasites was 67.2 % (457/680), and the most prevalent taxa were Ascaris lumbricoides (48.8 %) and Trichuris trichiura (44.7 %). The prevalence of heavy infection by soil-transmitted helminths was 3.6 % and the families lived in houses with an average of 5.1 residents and < 2 bedrooms per household. The average number of species per individual present spatial heterogeneity with the highest values (≥0.8) in areas with high clustering of residences. The visualization of the spatial distribution of intestinal parasites in this indigenous village is an important contribution to determining health risk areas and planning decisions and services.

Heavy burden of intestinal parasite infections in Kalena Rongo village, a rural area in South West Sumba, eastern part of Indonesia: a cross sectional study

BACKGROUND

Intestinal parasitic infections (IPIs) are one of the major public health problems, especially in the rural area of developing countries with low socio-economic status and poor sanitation. The study was aimed to determine the prevalence of IPIs among the inhabitants of a rural area in South West Sumba, eastern part of Indonesia.

METHODS

A cross-sectional study was done in Kalena Rongo village, South West Sumba in April 2014. Stool samples were collected and examined for IPIs using direct smear method.

RESULTS

Faecal samples were collected from 424 of 473 inhabitants of the village, age 2 months to 80 years. About 95.5 % (405/424) of the participants had any IPIs. The most prevalent parasites found were Ascaris lumbricoides 65.8 % (279/424), Trichuris trichiura 60.4 % (256/424), hookworms 53.5 % (227/424), Blastocystis hominis 34.4 % (146/424), Entamoeba histolytica 17.9 % (76/424), and Giardia lamblia 4.5 % (19/424). The villagers used no latrine and defecated in their backyard. Clean water sources were scarce and far from the village.

CONCLUSIONS

In Kalena Rongo village, the rural area in eastern part of Indonesia, the finding of IPIs was conspicuous and therefore expressed the poor hygiene and absence of proper sanitation in the area. Integrated efforts, such as improving infrastructure to provide clean water source and educating the inhabitants for appropriate hygienic lifestyle are needed.

Prevalence and intensity of soil-transmitted helminthiasis, prevalence of malaria and nutritional status of school going children in honduras

Background

Many small studies have been done in Honduras estimating soil-transmitted helminthiasis (STH) prevalence but a country-wide study was last done in 2005. The country has the highest burden of malaria among all Central American countries. The present study was done to estimate country-wide STH prevalence and intensity, malaria prevalence and nutritional status in school going children.

Methods and Findings

A cross-sectional study was conducted following PAHO/WHO guidelines to select a sample of school going children of 3^rd to 5^th grades, representative of ecological regions in the country. A survey questionnaire was filled; anthropometric measurements, stool sample for STH and blood sample for malaria were taken. Kato-Katz method was used for STH prevalence and intensity and rapid diagnostic tests, microscopy, and polymerase chain reaction (PCR) were used for malaria parasite detection. A total of 2554 students were studied of which 43.5% had one or more STH. Trichuriasis was the most prevalent (34%) followed by ascariasis (22.3%) and hookworm (0.9%). Ecological regions II (59.7%) and VI (55.6%) in the north had the highest STH prevalence rates while IV had the lowest (10.6%). Prevalence of one or more high intensity STH was low (1.6%). Plasmodium vivax was detected by PCR in only 5 students (0.2%), all of which belonged to the same municipality; no P. falciparum infection was detected. The majority of children (83%) had normal body mass index for their respective age but a significant proportion were overweight (10.42%) and obese (4.35%).

Conclusions

Biannual deworming campaigns would be necessary in ecological regions II and VI, where STH prevalence is >50%. High prevalence of obesity in school going children is a worrying trend and portends of future increase in obesity related diseases. Malaria prevalence, both symptomatic and asymptomatic, was low and provides evidence for Honduras to embark on elimination of the disease.

Soil-transmitted helminthiasis (STH) are one of the most important neglected infectious diseases (NID). These not only have the potential to affect the growth and development of children, but can have irreversible consequences that carry into adulthood. However its prevalence has not been estimated since many years in Honduras. Although Honduras is the country with the highest burden of malaria in Central America, efforts to reduce the number of cases due to Plasmodium falciparum have lead the country towards an initiative for elimination. Using common platforms to do mapping of NID allows countries to reduce costs, build local capacities and strengthen monitoring and evaluation systems to track progress towards control and elimination goals. Honduras, one of the poorest countries in Central America, took advantage of an initiative to establish the prevalence of STH in school age children to assess the prevalence of malaria as a step in compiling evidence to support a future process of elimination of the disease. This innovative manner to put together epidemiological information for several NID might be replicated in other countries in the Americas to produce baseline and follow-up data to support decision making for processes to reach the goals established for these diseases.

School hygiene and deworming are key protective factors for reduced transmission of soil-transmitted helminths among schoolchildren in Honduras

BACKGROUND

Among many neglected tropical diseases endemic in Honduras, soil-transmitted helminth (STH) infections are of particular importance. However, knowledge gaps remain in terms of risk factors involved in infection transmission. The aim of this study was to investigate risk factors associated with STH infections in schoolchildren living in rural Honduras.

METHODS

A cross-sectional study was conducted among Honduran rural schoolchildren in 2011. Demographic, socio-economic, and epidemiological data were obtained through a standardized questionnaire and STH infections were determined by the Kato-Katz method. Logistic regression models accounting for school clustering were used to assess putative risk factors for infection.

RESULTS

A total of 320 children completed the study. Prevalences for any STH and for Ascaris lumbricoides, Trichuris trichiura and hookworms were: 72.5%, 30.3%, 66.9% and 15.9%, respectively. A number of risk factors were identified at the individual, household, and school level. Boys were at increased odds of infection with hookworms (OR 2.33, 95% CI = 1.23-4.42). Higher socio-economic status in the family had a protective effect against infections by A. lumbricoides (OR 0.80, 95% CI = 0.65-0.99) and T. trichiura (OR 0.77, 95% CI = 0.63-0.94).Low school hygiene conditions significantly increased the odds for ascariasis (OR 14.85, 95% CI = 7.29-30.24), trichuriasis (OR 7.32, 95% CI = 3.71-14.45), mixed infections (OR 9.02, 95% CI = 4.66-17.46), and ascariasis intensity of infection (OR 3.32, 95% CI = 1.05 -10.52).Children attending schools not providing deworming treatment or that had provided it only once a year were at increased odds of ascariasis (OR 10.40, 95% CI = 4.39-24.65), hookworm (OR 2.92, 95% CI = 1.09-7.85) and mixed infections (OR 10.57, 95% CI = 4.53-24.66).

CONCLUSIONS

Poverty-reduction strategies will ultimately lead to sustainable control of STH infections in Honduras, but as shorter-term measures, uninterrupted bi-annual deworming treatment paired with improvements in school sanitary conditions may result in significant reductions of STH prevalence among Honduran schoolchildren.

Brazil's neglected tropical diseases: an overview and a report card

Today, the nation of Brazil leads the Western Hemisphere in terms of the number of its citizens living with neglected tropical diseases (NTDs). These diseases continue to trap Brazil's "bottom 20 million" in extreme poverty.

Prevalence of gastrointestinal parasites in children from Verón, a rural city of the Dominican Republic

Gastrointestinal infections impose a great and often silent burden of morbidity and mortality on poor populations in developing countries. The Dominican Republic (DR) is a nation on the island of Hispaniola in the Caribbean Sea. Verón is located in La Alta Grácia province in the southeastern corner of the DR. Dominican and Haitian migrant workers come to Verón to work in Punta Cana, a tourist resort area. Few definitive or comprehensive studies of the prevalence of gastrointestinal parasitic infections have been published in the DR. Historically, most of the definitive studies of water-borne or soil-transmitted parasites in the DR were published more than 30 years ago. Presently, there is a high prevalence of gastrointestinal parasitic infections throughout the poorest areas of the DR and Haiti. In this study we report the prevalence of gastrointestinal protozoan and helminth parasites from children recruited from the Clínica Rural de Verón during 2008 through 2011. Each participant was asked to provide a fecal sample which was promptly examined microscopically for protozoan and helminth parasites using the Centers for Disease Control and Prevention (CDC) fecal flotation technique to concentrate and isolate helminth ova and protozoan cysts. Of the 128 fecal samples examined, 127 were positive for one or more parasites. The age of the infected children ranged from 2–15 years; 61 were males and 66 were females. The only uninfected child was a 9 year old female. Percent infection rates were 43.8% for Ascaris lumbricoides, 8.5% for Enterobius vermicularis, 21.1% for Entamoeba histolytica, and 22.7% for Giardia duodenalis. Of the children examined, 7.8% had double infections. Any plan of action to reduce gastrointestinal parasites in children will require a determined effort between international, national, and local health authorities combined with improved education of schools, child care providers, food handlers, and agricultural workers. A special effort must be made to reach out to both documented and undocumented immigrants working or living in the area and to pre-school aged children or those who are not part of the public education system. Lastly, it is important to address the microbial water quality and food preparation, especially during the weaning transition to solid foods and throughout childhood.

Current status of human hookworm infections, ascariasis, trichuriasis, schistosomiasis mekongi and other trematodiases in Lao People's Democratic Republic

Soil-transmitted helminth (STH) infections, and schistosomiasis and other trematodiases often have a high prevalence in developing countries. Here, we present updated information on the prevalence of these parasites in the Lao People's Democratic Republic (Lao PDR) in 2012, arising from the annual national helminthiasis survey. Fecal specimens were collected from 8,610 inhabitants of 12 provinces and one municipality (Bokeo, Houaphan, Luang Namtha, Luang Prabang, Oudomxay, and Phongsaly Provinces from northern Lao PDR; Bolikhamxay and Xieng Khouang Provinces and Vientiane Municipality from the central part of the country; and Attapeu, Champasak, Saravan, and Sekong Provinces from southern Lao PDR). The overall prevalence of three major STHs, Ascaris lumbricoides, Trichuris trichiura, and hookworms (Necator americanus and Ancylostoma duodenale) were 11.6%, 8.5%, and 25.0%, respectively. Prevalence of Schistosoma mekongi infection was 0.1%, and of miscellaneous trematodiases (including opisthorchiasis) was 14.0%. Clearly, the nationwide parasite control project is still necessary to reduce morbidity caused by helminthic diseases.

A scoping review and prevalence analysis of soil-transmitted helminth infections in Honduras

BACKGROUND

Honduras is endemic for soil-transmitted helminth (STH) infections, but critical information gaps still remain on the prevalence and intensity of these infections as well as on their spatial distribution at subnational levels.

OBJECTIVES

Firstly, to review the research activity on STH infections in Honduras and secondly, to carry out a national prevalence analysis and map the geographical distribution of these infections in children.

METHODS

A systematic search was conducted of the published and grey literature to identify scientific work on the impact and prevalence of STH infections done between May 1930 and June 30, 2012. International databases and Honduran journals were searched. Grey literature was gleaned from local libraries and key informants. Select studies conducted between 2001 and 2012 were used to produce prevalence maps and to investigate association between STH prevalence and socio-economic and environmental factors.

RESULTS

Of 257 identified studies, 211 (21.4% peer-reviewed) were retained for analysis and categorized as clinical research (10.9%), treatment efficacy studies (8.1%) or epidemiological studies (81%). Prevalence analysis and geographical mapping included 36 epidemiological studies from Honduras's 18 departments and 23% of its municipalities. Overall STH prevalence was >50% in 40.6% of municipalities. Prevalences above 20% for each trichuriasis, ascariasis, and hookworm infection were found in 68%, 47.8%, and 7.2% of studied municipalities, respectively. Municipalities with lower human development index, less access to of potable water, and with higher annual precipitation showed higher STH prevalences.

CONCLUSIONS

This is the first study to provide a comprehensive historic review of STH research activity and prevalence in Honduras, revealing important knowledge gaps related to infection risk factors, disease burden, and anti-parasitic drug efficacy, among others. Our decade-long prevalence analysis reveals geographical differences in STH prevalence and these findings suggest that differential intervention strategies might be necessary in Honduras for the control of these infections.