Prevalence and associated risk factors of intestinal parasites among schoolchildren in Ecuador, with emphasis on the molecular diversity of Giardia duodenalis, Blastocystis sp. and Enterocytozoon bieneusi

Occurrence and genotyping of Enterocytozoon bieneusi in flying squirrels (Trogopterus xanthipes) from China

Enterocytozoon bieneusi is an obligate intracellular microsporidian parasite with a worldwide distribution. As a zoonotic pathogen, E. bieneusi can infect a wide range of wildlife hosts through the fecal-oral route. Although the feces of flying squirrels (Trogopterus xanthipes) are considered a traditional Chinese medicine (as "faeces trogopterori"), no literature is available on E. bieneusi infection in flying squirrels to date. In this study, a total of 340 fresh flying squirrel fecal specimens from two captive populations were collected in Pingdingshan city, China, to detect the prevalence of E. bieneusi and assess their zoonotic potential. By nested PCR amplification of the ITS gene, six specimens tested positive, with positive samples from each farm, with an overall low infection rate of 1.8%. The ITS sequences revealed three genotypes, including known genotype D and two novel genotypes, HNFS01 and HNFS02. Genotype HNFS01 was the most prevalent (4/6, 66.7%). Phylogenetic analysis showed that all genotypes clustered into zoonotic Group 1, with the novel genotypes clustering into different subgroups. To our knowledge, this is the first report of E. bieneusi infection in flying squirrels, suggesting that flying squirrels could act as a potential reservoir and zoonotic threat for E. bieneusi transmission to humans in China.

Gastrointestinal parasitic infections: Prevalence and risk factors in West Ismailia, Arab Republic of Egypt

BACKGROUND

This study aimed to determine the prevalence of gastrointestinal parasites (GIP) in the rural community of West Ismailia and its associated risk factors. Human infection by GIP is natural and expected. There are few records concerning parasitic infection in the rural areas of the Ismailia Governorate.

METHODS

From 520 individuals, sociodemographic and risk factors information were retrieved. Fecal samples were collected, concentrated, and tested for GIP infection using a microscopic examination.

RESULTS

The West Ismailia study population had a 40.4% prevalence of GIP infection, including single and concomitant parasite infections. The most common cause of GIP infection was protists (38%). Entamoeba sp., Blastocystis sp., and G. duodenalis were the most common parasites. Poly-parasitism was prevalent within the West Ismailia region. Age, abdominal symptoms, perianal itching, ownership of numerous animal species, exposure to turbid water, previous parasitic infection (PPI), and non-treatment reception of PPI were all considered significant factors associated with GIP infection. Specific individuals from the same family have been observed to have identical GIP.

CONCLUSION

GIP infection remains underestimated in rural areas. Periodic screening and treatment for GIP infection in children and public education on GIP hazards and prevention, focusing on personal hygiene, are recommended. Family members of affected individuals should be screened and treated for GIP.

Spatial patterns of intestinal parasite infections among children and adolescents in some indigenous communities in Argentina

Argentina has a heterogeneous prevalence of infections by intestinal parasites (IPs), with the north in the endemic area, especially for soil-transmitted helminths (STHs). We analyzed the spatial patterns of these infections in the city of Tartagal, Salta province, by an observational, correlational, and cross-sectional study in children and adolescents aged 1 to 15 years from native communities. One fecal sample per individual was collected to detect IPs using various diagnostic techniques: Telemann sedimentation, Baermann culture, and Kato-Katz. Moran's global and local indices were applied together with SaTScan to assess the spatial distribution, with a focus on cluster detection. The extreme gradient boosting (XGBoost) machine-learning model was used to predict the presence of IPs and their transmission pathways. Based on the analysis of 572 fecal samples, a prevalence of 78.3% was found. The most frequent parasite was Giardia lamblia (30.9%). High- and low-risk clusters were observed for most species, distributed in an east-west direction and polarized in two large foci, one near the city of Tartagal and the other in the km 6 community. Spatial XGBoost models were obtained based on distances with a minimum median accuracy of 0.69. Different spatial patterns reflecting the mechanisms of transmission were noted. The distribution of the majority of the parasites studied was aligned in a westerly direction close to the city, but the STH presence was higher in the km 6 community, toward the east. The purely spatial analysis provides a different and complementary overview for the detection of vulnerable hotspots and strategic intervention. Machine-learning models based on spatial variables explain a large percentage of the variability of the IPs.

Molecular detection and characterization of Blastocystis in herbivore livestock species in Portugal

Blastocystis is a ubiquitous intestinal protist in humans and animals worldwide. The traditional livestock free-roaming raising system in rural communities increases the risk of infection with contact with a wider range of pathogens transmitted via the faecal-oral route associated with that wildlife-livestock-human interface. However, no studies have been conducted to determine the occurrence and subtype distribution of Blastocystis in livestock in Portugal. Here, we collected 180 faecal samples from herbivore livestock (cattle, goats, horses, and sheep) in different regions of the country to investigate Blastocystis prevalence and subtype diversity using PCR and next-generation amplicon sequencing. Blastocystis was present in 40.6% (73/180; 95% CI: 33.31-48.11) of the samples (goats, 81.0%; sheep, 60.9%; cattle, 32.2%). None of the horse samples were Blastocystis-positive. Eighteen subtypes were detected (ST1-ST3, ST5-ST7, ST10, ST13, ST14, ST21, ST23-ST26, ST30, ST42-ST44). Mixed infections were detected in 97.3% of the Blastocystis-positive samples. Potentially zoonotic subtypes were identified in 75.0%, 96.4%, and 100% of the Blastocystis-positive specimens collected from cattle, sheep, and goats, respectively. These results demonstrate that cattle, sheep, and goats harbour a high diversity of Blastocystis subtypes in the study regions. Importantly, our data provide novel molecular evidence strongly suggesting that some Blastocystis STs/ST subgroups may have differential host specificity.

Molecular prevalence and subtype distribution of Blastocystis spp. among children who have diarrheia or are asymptomatic in Wenzhou, Zhejiang Province, China

Blastocystis sp., a significant zoonotic parasite with a global distribution, was the focus of this study, which aimed to investigate its prevalence and genetic diversity among diarrheic and asymptomatic children in Wenzhou, China. We collected 1,032 fecal samples from Yuying Children's Hospital, Wenzhou, China, comprising 684 from children with diarrhea and 348 from asymptomatic children. Genomic DNA extracted from these samples was used to detect Blastocystis spp. by PCR, targeting the small subunit ribosomal RNA gene. Subsequently, a phylogenetic tree was constructed, applying the maximum likelihood method. Blastocystis spp. were detected in 67 (6.5%) of the fecal samples. The prevalence rate of Blastocystis spp. in diarrheic children (8.8%; 60/684) was significantly higher than that in asymptomatic children (2.0%; 7/348) (χ 2 = 17.3, p < 0.001). Sequence analysis of the SSU rRNA gene identified five known Blastocystis spp. subtypes, ST1 (n = 12), ST2 (n = 5), ST3 (n = 35), ST4 (n = 12), and ST7 (n = 3). ST1 and ST3 were present in both diarrheic and asymptomatic children, while ST2, ST4, and ST7 were exclusive to diarrheic children. Intra-subtype genetic polymorphisms were identified, comprising four variations in ST1 (ST1-1 to ST1-4), five in ST3 (ST3-1 to ST3-5), two in ST4 (ST4-1 and ST4-2), and two in ST7 (ST7-1 and ST7-2). Notably, ST1-2 to ST1-4, ST3-3 to ST3-5, and ST7-1 and ST7-2 represent newly identified variations. The composition and genetic characteristics of subtypes among children in this region suggest various sources of infection, including human-to-human and animal-to-human transmission.

Cortinarius and Tomentella Fungi Become Dominant Taxa in Taiga Soil after Fire Disturbance

Fungi have important ecological functions in the soil of forests, where they decompose organic matter, provide plants with nutrients, increase plant water uptake, and improve plant resistance to adversity, disease, and disturbance. A forest fire presents a serious disturbance of the local ecosystem and can be considered an important component affecting the function of ecosystem biomes; however, the response of soil fungi to fire disturbance is largely unknown. To investigate the effects of fire disturbance on the community composition and diversity of soil fungi in a taiga forest, we collected soil from plots that had undergone a light, moderate, and heavy fire 10 years previously, with the inclusion of a fire-free control. The present soil fungi were characterized using Illumina MiSeq technology, and the sequences were analyzed to identify differences in the community composition and diversity in response to the changed soil physicochemical properties. The results showed that the Chao1 index, which characterizes the alpha diversity of the fungi, did not change significantly. In contrast, the Shannon index increased significantly (p < 0.05) and the Simpson index decreased significantly (p < 0.05) following a light or heavy fire disturbance compared to the control. The relative abundance of Basidiomycota was significantly higher in the soil of the fire sites than that in the control (p < 0.01), and the relative abundance of Ascomycota was significantly lower (p < 0.01). The results of principal coordinates analyses (PCoAs) showed that fire disturbance highly significantly affected the beta diversity of soil fungi (p < 0.001), while the results of canonical correlation analysis (CCA) indicated that the available nitrogen (AN), moisture content (MC), pH, available potassium (AK), and total nitrogen (TN) contents of the soil significantly affected the compositional structure and diversity of the soil fungal communities. The results of functional prediction showed that the majority of the detected soil fungi were symbiotrophs, followed by saprotrophs and saprotroph-symbiotrophs, with ectomycorrhiza being the dominant functional taxon. Fire disturbance significantly reduced the relative abundance of ectomycorrhiza (p < 0.05). This study illustrates that fire disturbance alters the structural composition, diversity, dominance, and relative abundance of the guilds of soil fungal communities in taiga forest, and strongly affected the beta diversity of soil fungi, with AN, MC, pH, AK, and TN being the most important factors affecting their community structure. The results may provide a useful reference for the restoration and rehabilitation of taiga forests after fire disturbance.

Epidemiology of giardiasis and assemblages A and B and effects on diarrhea and growth trajectories during the first 8 years of life: Analysis of a birth cohort in a rural district in tropical Ecuador

BACKGROUND

There are limited longitudinal data on the acquisition of Giardia lamblia infections in childhood using molecular assays to detect and type assemblages, and measure effects of infections on diarrhea risk and childhood growth.

METHODS

We analysed stool samples from a surveillance sample within a birth cohort in a rural district in tropical Ecuador. The cohort was followed to 8 years of age for the presence of G. lamblia in stools by quantitative PCR and A and B assemblages by Taqman assay or Sanger sequencing. We explored risk factors associated with infection using generalized estimating equations applied to longitudinal binary outcomes, and longitudinal panel data analysis to estimate effects of infection on diarrhea and growth trajectories.

RESULTS

2,812 stool samples collected between 1 month and 8 years of age from 498 children were analyzed and showed high rates of infection: 79.7% were infected at least once with peak prevalence (53.9%) at 5 years. Assemblage B was accounted for 56.8% of genotyped infections. Risk factors for infection included male sex (P = 0.001), daycare attendance (P<0.001), having a household latrine (P = 0.04), childhood (P<0.001) and maternal soil-transmitted helminth (P = 0.029) infections, and exposures to donkeys (age interaction P = 0.034). G. lamblia was associated with increased risk of diarrhea (per episode, RR 1.03, 95% CI 1.01-1.06, P = 0.011) during the first 3 years of life and a transient impairment of weight (age interaction P = 0.017) and height-for-age (age interaction P = 0.025) trajectories between 1 and 4 years of age. There was no increased risk of either assemblage being associated with outcomes.

CONCLUSION

Our data show a relatively high edemicity of G. lamblia transmission during childhood in coastal Ecuador, and evidence that infection is associated with a transiently increased risk of diarrhea during the first 3 years of life and impairment of weight and height between 1 and 4 years.