Prevalence of soil transmitted helminths in school-aged children, Colombia, 2012-2013

Systematic review and meta-analysis of soil-transmitted helminth infections in South America (2000-2024)

Soil-transmitted helminths (STHs) are parasitic nematodes commonly found in tropical and subtropical regions, where poor sanitation makes them a significant public health concern. This study provides a comprehensive review and meta-analysis of human STH infections across 13 South American countries from 2000 to 2023. It covers these infections' prevalence, distribution, and diagnosis, highlighting the environmental factors influencing transmission pathways. The review identified 134 studies on human STH infections, revealing Brazil as the most researched country. The meta-analysis found prevalence rates of Ascaris lumbricoides, Trichuris trichiura, hookworms, and Strongyloides stercoralis below 20 %, with notable heterogeneity across studies. Most studies used conventional microscopy for diagnosis, pointing out the need for implementing advanced diagnostic tools. Environmental and climatic factors, including temperature annual range, vegetation density, soil types, and properties were significant predictors of STH prevalence. The study calls for more research performing advanced diagnostic methods and broader geographical coverage to address existing data gaps. Furthermore, it emphasizes the need for holistic public health policies integrating biomedical and environmental approaches to ensure effective disease management.

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.

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.

Anaemia among school children of different socioeconomical status in a city of Southern Brazil

Background: Iron deficiency is one of the leading causes of anaemia, with those most affected being children and women of childbearing age, in Brazil there is a scarcity of studies involving the local prevalence of anaemia. Aim: To evaluate anaemia and associated factors in schoolchildren in Santa Cruz do Sul through the analysis of biochemical and haematological markers and parasitological examination of faeces. Subjects and methods: School children from 10 to 12 years of age were evaluated through complete blood count, serum ferritin, C-reactive protein and stool parasitological examination, as well as socio-demographic characteristics and prophylaxis with ferrous sulphate in childhood. Results: It was found that 13.0% of the population was anaemic, girls were very slightly overrepresented among the anaemic children. Only 5.3% had altered haematocrit levels; 26.6% had low Mean Corpuscular Volume levels; 18.4% had low ferritin levels; 2.4% had increased C-reactive protein levels, and 21.7% had altered eosinophils. As for the socioeconomic level, classes A2 and D presented lower haemoglobin levels, as well as class D presenting lower ferritin levels, although without statistical significance. Only 6.0% of the population presented iron-deficiency anaemia and 46.0% of the schoolchildren had used ferrous sulphate supplementation in childhood. Conclusion: The prevalence of anaemia in the studied municipality is low, probably due to the high municipal human development index. Epidemiological studies are essential to characterise the population in a systematic form, to prevent future problems.

Crushed Capsicum chacoense Hunz Fruits: A Food Native Resource of Paraguay with Antioxidant and Anthelmintic Activity

The nutritional composition and toxicity of native plants with food potential like Capsicum chacoense are important for the safe use of populations and could be used as a source for searching for new drug candidates. Infections produced by parasites such as helminths are a public health concern for many countries. The drugs used for treating these diseases are few, and the emergence of resistance is a risk. In this work, the nutritional composition, acute toxicity, antioxidant activity, and anthelmintic activity of crushed C. chacoense fruits were evaluated. The composition was analyzed by standard procedures. Antioxidant activity was evaluated using the ABTS radical and the total phenolic compound (TPC) tests. The toxicity was evaluated on Swiss albino mice by the single-DL50-dose procedure. The anthelmintic activity was tested against Eisenia foetida. The samples presented high levels of dietary fiber (47.05-49.19 g/100 g), proteins (14.43-15.60 g/100 g), and potassium (1708-1733 mg/100 g). In the samples, the absence of acute lethal effects in doses lower than 2000 mg/kg was observed. A rich composition of TPC (517.26-543.32 mg GAE/100 g sample), total carotenoids (125.72-239.57 mg/kg), β-carotene (3.29-5.60 mg/kg), and good TAC was observed (154-158 mM TEAC/g SMTC). The methanolic extracts at the doses tested (2.5 to 40 mg/mL) showed good anthelmintic activity. The presence of alkaloids was demonstrated in the methanolic extract, consistent with the levels of capsaicin (131.85 and 98.80 mg/100 g) and dihydrocapsaicin (80.75 and 63.68 mg/100 g), with significant statistical differences between samples (p < 0.05). These results show that through the chemical composition of this underutilized native resource and good fruit processing procedures, the C. chacoense fruits have a great nutraceutical potential of interest for the food and pharmaceutical industries.