Prevalence and associated risk factors for Giardia and Cryptosporidium infections among children of northwest Mexico: a cross-sectional study

Remediation of multifarious metal ions and molecular docking assessment for pathogenic microbe disinfection in aqueous solution by waste-derived Ca-MOF

The present study demonstrates an eco-friendly and cost-effective synthesis of calcium terephthalate metal-organic frameworks (Ca-MOF). The Ca-MOF were composed of metal ions (Ca2+) and organic ligands (terephthalic acid; TPA); the former was obtained from egg shells, and the latter was obtained from processing waste plastic bottles. Detailed characterization using standard techniques confirmed the synthesis of Ca-MOF with an average particle size of 461.9 ± 15 nm. The synthesized Ca-MOF was screened for its ability to remove multiple metal ions from an aqueous solution. Based on the maximum sorption capacity, Pb2+, Cd2+, and Cu2+ ions were selected for individual parametric batch studies. The obtained results were interpreted using standard isotherms and kinetic models. The maximum sorption capacity (qm) obtained from the Langmuir model was found to be 644.07 ± 47, 391.4 ± 26, and 260.5 ± 14 mg g-1 for Pb2+, Cd2+, and Cu2+, respectively. Moreover, Ca-MOF also showed an excellent ability to remove all three metal ions simultaneously from a mixed solution. The metal nodes and bonded TPA from Ca-MOF were dissociated by the acid dissolution method, which protonated and isolated TPA for reuse. Further, the crystal structure of Ca-MOF was prepared and docked with protein targets of selected pathogenic water-borne microbes, which showed its disinfection potential. Overall, multiple metal sorption capability, regeneration studies, and broad-spectrum antimicrobial activity confirmed the versatility of synthesized Ca-MOF for industrial wastewater treatment.

Assessment of prevalence of Giardia lamblia infection and its associated factors among government elementary school children from Sidama zone, SNNPR, Ethiopia

Giardiasis is a protozoan disease caused by the parasite Giardia lamblia. Around 200 million people are infected worldwide annually while, 500,000 deaths were reported each year. The infection rates were between 2–5% in the developed nations and 20–30% in the developing countries. The parasite is associated with poverty, poor sanitation, lack of clean and safe drinking water supply, and poor personal hygiene. The aim of our study was to assess the prevalence rate and associated risk factors of G. lamblia infection among the elementary school children at Loka Abaya town, Ethiopia. A cross-sectional study was conducted from December 2018 to July 2019. A total number of 422 students were selected by using simple random sampling. Structured and semi-structured questionnaire was used to identify known risk factors such as environmental, socio-demographic, and behavioural. Stool specimens were collected from the study subjects and examined using direct smear method, microscopically. A bivariate and multivariate logistic regression analysis was done. P value less than 0.05 at 95% of the confidence interval was considered statistically significant. The overall prevalence rates of G. lamblia infection were 27.1%. Rural school from Aregeda [AOR: 9.997, P = 0.005], age group of 6–9 years [AOR: 2.305, P = 0.019], consuming tap water [AOR: 0.011, P = 0.006], hand washing habit after defecation with water only [AOR = 0.313, P = 0.040], use of soap and water [AOR: 0.046, P = 0.000] were the factors which are found to be associated with the parasite infection when compared to urban school. As such, the prevalence of G. lamblia infection was found to be high in the studied area among school children. Thus, scaling-up of access to safe water, toilets, education, and health facilities are required to possibly eradicate this predicament.

Prevalence of Giardiasis and Entamoeba Species in Two of the Six Governorates of Kuwait

Intestinal parasitic infections are a global concern owing to elevated rates of morbidity and mortality in many parts of the world. Increased rates of intestinal parasitic infections are observed in developing and low-income countries. In Kuwait, many expatriates and foreigners hail from endemic countries, thus increasing the rate and risk factor of infection. This retrospective study is aimed at assessing the prevalence of Giardia lamblia and Entamoeba sp. in stool samples handled by two of Kuwait's general hospitals during the period from January 2018 to July 2019: Mubarak Al Kabeer (serving Hawalli governorate population) and Aladan hospitals (serving Mubarak Al Kabeer governorate population) serving 27% of total Kuwait population with Kuwaitis making up only 32%. A total of 9,653 samples were tested for consistency and the availability of any parasitic particles using visual, direct wet mount, and concentration method. Statistical analysis was implemented using SPSS statistical program, at p < 0.05. Of all the 9,653 tested stool samples, 74 were positive for G. lamblia or Entamoeba sp. This represented a mere 1% rate of infection and showed no significant correlation to the prevalence of intestinal parasite infections in Kuwait. On the other hand, comparing the rate of infection in different seasons revealed an increased rate of infection during spring compared to other seasons (p = 0.03). Findings revealed low rates of intestinal parasitic infection within the two governorates of Kuwait representing no statistical significance to the distribution of the investigated parasites in Kuwait. This may be attributed to improved living conditions and healthcare. Elevated infection rates in spring in relation to other seasons raised the importance of increasing public awareness during camping season for maintaining proper personal hygiene and waste management to contain and decrease the rate on infection.

Association between allergic sensitization and intestinal parasite infection in schoolchildren in Gqeberha, South Africa

Background

Inconsistent data exist regarding the influence of parasitic infection on the prevalence of allergic sensitization and disorders.

Objective

To investigate the impact of geohelminth and protozoan infections on sensitization patterns and allergic symptoms of children living in low‐income communities in Gqeberha, South Africa.

Methods

In a cross‐sectional study, 587 schoolchildren aged 8–12 years were recruited in June 2016 and screened for reactivity to common allergens by skin prick tests (SPTs) and for parasitic infections by stool examination. Additionally, questionnaires were completed to record allergic symptoms the children may have experienced.

Results

Positive SPTs were found in 237/587 children (40.4%), and about one‐third of whom were polysensitized. Sensitizations were most frequently detected against the house dust mites (HDM) Dermatophagoides spp. (31.9%) and Blomia tropicalis (21.0%). Infections with geohelminths (Ascaris lumbricoides, Trichuris trichiura) were found in 26.8% and protozoan infections (Giardia intestinalis, Cryptosporidia spp.) in 13.9% of study participants. Mixed logistic regression analyses revealed negative associations between parasite infection and sensitization to Blomia tropicalis (OR: 0.54, 95% CI 0.33–0.89) and to Dermatophagoides spp. (OR 0.65, 95% CI 0.43–0.96), and between protozoan infection and allergic sensitization to any aeroallergen, although these associations were not significant when adjusted for false discovery. Geohelminth infection and intensity of geohelminth infection were both associated with reduced risk of polysensitization (OR 0.41, 95% CI 0.21–0.86), and this association remained significant with adjustment for false discovery. Reported respiratory symptoms were associated with HDM sensitization (ORs from 1.54 to 2.48), but not with parasite infection.

Conclusions and clinical relevance

Our data suggest that geohelminth infection and high geohelminth infection intensity are associated with a reduced risk of polysensitization.

Prevalence and Risk Factors Associated with Intestinal Parasitic Infection among Primary School Children in Dera District, Northwest Ethiopia

Background

Globally, over 600 million school children are living with intestinal parasites. The prevalence of intestinal parasitic infections (IPIs) among school children in Ethiopia and the Amhara region is 52% and 51%, respectively. The present study aimed to determine the prevalence and associated risk factors of IPIs among primary school children in Dera district, Northwest Ethiopia.

Methods

A school-based cross-sectional study was conducted from December 2019 to February 2020. The study used a structured pretested questionnaire and stool tests to obtain epidemiological and disease data. Data were analyzed using appropriate univariate and multivariable logistic regression methods by statistical package for social science (SPSS) version 25.0.

Results

Of the 382 students who were examined for IPIs, 238 (62.3%) (61.8% males, 62.8% females) were positive for one or more IPIs. One hundred thirty-six (35.6%), 98 (25.7%), and 4 (1.05%) were single, double, and triple infections, respectively. Out of the nine species of IPIs detected, Entamoeba sp. was the predominant species (29.6%) followed by hookworm (21.7%), Schistosoma mansoni (11.3%), Taenia sp. (9.2%), Giardia lamblia (5.2%), and Ascaris lumbricoides, Hymenolepis nana, and Enterobius vermicularis (4.2%) each, and Trichuris trichiura (0.5%). Family size greater than five (AOR = 1.8; 95% CI: 1.004, 3.13), open field school waste disposal (AOR = 15.88; 95% CI: 1.91, 132.1), and lack of knowledge about intestinal parasitic infection (AOR = 1.8; 95% CI: 1.1, 3.2) were the independent risk factors associated with the overall prevalence of IPIs.

Conclusions

The prevalence of intestinal parasitic infection was high in the Dera district. Health education, extending school-based deworming, and mass treatments are recommended.

Molecular prevalence of Cryptosporidium isolates among Egyptian children with cancer

Immunocompromised individuals especially children with cancer are at risk for acquiring cryptosporidiosis, which can result in severe morbidity and mortality. This work was conducted to evaluate the prevalence of Cryptosporidium parasite and its genotypes in children with cancer. Stool specimens were collected from 145 children in the Oncology unit of Pediatric Department, Zagazig University Hospital, Sharqiyah province, Egypt. Cryptosporidium infection was evaluated using modified Ziehl-Neelsen (MZN) staining and nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The prevalence of Cryptosporidium infection in oncological children was 29.7% using microscopy and 25.5% using nested PCR. Genotypic characterization showed that 23 (62.2%) had C. hominis, 11 (29.7%) C. parvum, and 3 specimens (8.1%) were mixed infection of both genotypes. Cryptosporidiosis was significantly associated with diarrhea. However, no statistically significant difference was detected between the age, gender, residency, animal contact and malignancy type concerning to Cryptosporidium infection. This study concluded that Cryptosporidium is a prevailing opportunistic parasite among children with cancer. It should be considered in oncological patients especially those suffering from diarrhea which requires proper management to reduce its complications.

Cryptosporidiosis is predominantly an urban, anthroponotic infectious disease among Zambian children

BACKGROUND

Cryptosporidium species are leading causes of diarrhoea in children and immunocompromised individuals. This study aimed to characterise Cryptosporidium species from children in rural and urban settings of Zambia.

METHODS

Stool samples collected from 490 children aged <5 y with diarrhoea were assessed for Cryptosporidium oocysts microscopically. A structured questionnaire was used to collect demographic and socioeconomic characteristics. Positive samples were subjected to PCR and gp60 sequence analysis.

RESULTS

The overall prevalence was 10% (50/490, 95% CI 7.8 to 13.2) with a peak in March, the late rainy season. Children who came from households where boiling water was not practised (OR=2.5, 95% CI 1.29 to 5.17; p=0.007) or who had experienced recurrent episodes of diarrhoea (OR=9.31, 95% CI 3.02 to 28.73; p=0.001) were more likely to have Cryptosporidium infection. Genotyping of 16 positive samples (14 from urban and 2 from rural sources) revealed Cryptosporidium hominis (14/16) and Cryptosporidium parvum (2/16). The Cryptosporidium hominis subtypes identified were Ia, Ib and Ie with subtype families IeAIIG3 (1), IbA9G3R2 (2), IaA31R3 (3), IbA9G3 (5), IaA27R3 (1), IaA30R3 (1) and Ia (1). Subtypes IbA9G3 and Ia were identified in children from a rural area. Cryptosporidium parvum subtypes were IIcA5G3R2 (1) and IIcA5G3a (1).

CONCLUSIONS

All isolates successfully genotyped were C. hominis or anthroponotic C. parvum, suggesting that anthroponotic transmission dominates in Lusaka and the surrounding countryside.

The risk factors for intestinal Giardia spp infection: Global systematic review and meta-analysis and meta-regression

Parasitic infections are a public health concern as they can cause aggression, growth retardation, weight loss, anemia, and other health problems. In this study, a systematic review and meta-analysis were performed to find an association between the probable social-environmental risk factors including lack of safe drinking water, no hand washing, sex, age, no access to education, no access to toilet, and Giardia spp infection. We conducted literature research among international databases including Scopus, PubMed, Web of Science and Cochrane from1 January 1995 to March 15, 2020, including 23 articles with 102 studies while the odds ratio (OR) was calculated using 2 × 2 tables or extracted. The pooled effect size with 95% confidence intervals (CIs) was estimated using a random or fixed-effects model. The results show a significant association between intestinal Giardia spp infection risk and lack of safe drinking water (OR: 1.14; 95%CI: 1.02-1.25); no access to toilet (OR: 1.22; 95%CI: 1.07-1.37); and age (2-10 vs 10-30 year) (OR: 1.42; 95%CI: 1.09-1.78). An insignificant association was observed between intestinal Giardia spp infection risk and age (<2 vs 2-10 year) (OR: 0.89; 95%CI: 0.75-1.02); no access to education (OR: 1.10; 95%CI: 0.80-1.40); Sex (male vs female) (OR: 1.04; 95%CI: 0.74-1.34); and no handwashing (OR: 1.18; 95%CI: 0.87-1.49). The results of meta-regression also indicate that intestinal Giardia spp infection has decreased over time (C= -0.024, p-value = 0.03) significantly, and also by growth of human development index (HDI) (C= - 0.42, p-value = 0.29) insignificantly. Improvement of personal hygiene, sanitation and raising public awareness can be effective in reducing Giardia spp infections.

Molecular Epidemiology of Human Cryptosporidiosis in Low- and Middle-Income Countries

Cryptosporidiosis is one of the most important causes of moderate to severe diarrhea and diarrhea-related mortality in children under 2 years of age in low- and middle-income countries. In recent decades, genotyping and subtyping tools have been used in epidemiological studies of human cryptosporidiosis. Results of these studies suggest that higher genetic diversity of Cryptosporidium spp. is present in humans in these countries at both species and subtype levels and that anthroponotic transmission plays a major role in human cryptosporidiosis. Cryptosporidium hominis is the most common Cryptosporidium species in humans in almost all the low- and middle-income countries examined, with five subtype families (namely, Ia, Ib, Id, Ie, and If) being commonly found in most regions. In addition, most Cryptosporidium parvum infections in these areas are caused by the anthroponotic IIc subtype family rather than the zoonotic IIa subtype family. There is geographic segregation in Cryptosporidium hominis subtypes, as revealed by multilocus subtyping. Concurrent and sequential infections with different Cryptosporidium species and subtypes are common, as immunity against reinfection and cross protection against different Cryptosporidium species are partial. Differences in clinical presentations have been observed among Cryptosporidium species and C. hominis subtypes. These observations suggest that WASH (water, sanitation, and hygiene)-based interventions should be implemented to prevent and control human cryptosporidiosis in low- and middle-income countries.

Cryptosporidium spp. and Giardia duodenalis emissions from humans and animals in the Three Gorges Reservoir in Chongqing, China

Cryptosporidium spp. and Giardia duodenalis are two waterborne protozoan parasites that can cause diarrhea. Human and animal feces in surface water are a major source of these pathogens. This paper presents a GloWPa-TGR-Crypto model that estimates Cryptosporidium and G. duodenalis emissions from human and animal feces in the Three Gorges Reservoir (TGR), and uses scenario analysis to predict the effects of sanitation, urbanization, and population growth on oocyst and cyst emissions for 2050. Our model estimated annual emissions of 1.6 × 10¹⁵ oocysts and 2.1 × 10¹⁵ cysts from human and animal feces, respectively. Humans were the largest contributors of oocysts and cysts, followed by pigs and poultry. Cities were hot-spots for human emissions, while districts with high livestock populations accounted for the highest animal emissions. Our model was the most sensitive to oocyst excretion rates. The results indicated that 74% and 87% of total emissions came from urban areas and humans, respectively, and 86% of total human emissions were produced by the urban population. The scenario analysis showed a potential decrease in oocyst and cyst emissions with improvements in urbanization, sanitation, wastewater treatment, and manure management, regardless of population increase. Our model can further contribute to the understanding of environmental pathways, the risk assessment of Cryptosporidium and Giardia pollution, and effective prevention and control strategies that can reduce the outbreak of waterborne diseases in the TGR and other similar watersheds.

Prevalence and Associated Risk Factors of Human Intestinal Protozoan Parasitic Infections in Ethiopia: A Systematic Review and Meta-Analysis

Background

Human intestinal protozoan parasitic infections (HIPPIs) are a series of public health problems in developing countries like Ethiopia. The overall prevalence of HIPPIs in Ethiopia is not known. Therefore, this systematic review and meta-analysis study is aimed at determining the overall prevalence of HIPPIs in Ethiopia.

Methods

Articles written in English were searched from online public databases. Searching terms used were "prevalence," "intestinal protozoan parasite," "associated factors," and "Ethiopia." We used Stata version 14 for meta-analysis and Cochran's Q test statistics and the I ² test for heterogeneity.

Result

A total of 286 articles were reviewed, but only 45 of them fulfilled the inclusion criteria. The pooled prevalence of HIPPIs in Ethiopia was 25.01% (95% CI: 20.08%-29.95%) where Entamoeba histolytica/dispar is the most prevalent (14.09%, 95% CI: 11.03%-17.14%) followed by Giardia lamblia (10.03%, 95% CI: 7.69%-12.38%) and Cryptosporidium spp. (5.93%, 95% CI: 2.95%-8.91%). This meta-analysis showed that family size (OR: 3.7, 95% CI: 1.45-5.85), source of drinking water (OR: 3.33, 95% CI: 1.30-5.36), open field defecation (OR: 2.91, 95% CI: 1.60-4.21), handwashing habit (OR: 2.82, 95% CI: 2.01-3.63), playing with soil (OR: 2.15, 95% CI: 1.01-3.29), the habit of eating raw vegetables (OR: 1.77, 95% CI: 1.03-2.51), and fingernail trimming (OR: 1.70, 95% CI: 0.89-2.25) were strongly associated with the HIPPIs in Ethiopia. High heterogeneity on the prevalence of HIPPIs was observed among studies within and among regions (I ² > 99% and P ≤ 0.01).

Conclusion

The prevalence of HIPPIs was significantly high among the Ethiopian population. Family size, source of drinking water, open field defecation, handwashing habit, the habit of eating raw vegetables, and fingernail trimming habits were significantly associated with HIPPIs.

Plants used for the treatment of diarrhoea from Mexican flora with amoebicidal and giadicidal activity, and their phytochemical constituents

ETHNOPHARMACOLOGICAL RELEVANCE

Flora of the Mexican region is represented by approximately 30,000 vascular plant species, many of which are used as traditional medicines based on knowledge compiled and refined since ancient times (e.g. Cruz-Badiano and Florentino Codexes). The traditional use of plants as medicines, including the treatment of infectious diseases such as diarrhoea, is generally practiced in communities that are geographically isolated or in human settlements where health services are scarce.

AIM OF THE STUDY

The aim of this review is to evaluate current research advances in the ethnopharmacology and phytochemistry of Mexican medicinal plants exhibiting antiprotozoal activity, used to treat diarrhoea, and to identify the gaps in this research area for future studies.

METHODS

The literature study and compilation of information relied on books and scientific journals from leading electronic databases including Scopus, Springer, SciFinder, ISI Web of Science, PubMed, and Google Scholar; the topics searched for were antiprotozoal activity, followed by Entamoeba histolytica or Giardia lamblia. Ethnopharmacological data were obtained from books regarding medicinal plants and their uses in Mexico as well as from the government databases of "Comisiòn Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO)" as "NaturaLista" and "EncicloVida".

RESULTS

A total of 80 plant species used in the Mexican traditional medicine for the treatment of diarrhoea have been evaluated as potential sources of antiprotozoal agents against E. histolytica or G. lamblia. From these samples, 150 compounds have been isolated and screened in vitro, including specialized metabolites such as flavonoids and terpenoids as well as semisynthesized derivatives. However, in vivo pharmacological studies on these substances are limited. Additional pharmacological and molecular studies of the most active compounds have also been summarized.

CONCLUSION

Research performed in the past 25 years on specialized metabolites derived from plants with antiprotozoal activity has yielded relevant findings whose results provide evidence-based support for the use of these plants in the traditional medicine of Mexico to treat diarrhoea. Toxicological and clinical trials of standardized extracts and bioactive compounds are proposed as priority future works in this research area. In addition, in vivo assays are required, of more extracts and/or pure compounds. The optimization of the pharmacological properties of the bioactive specialized metabolites through semisynthetic derivatives and computational methods could aid in developing new antiprotozoal phytomedicines and novel drugs for the treatment of these types of infections. Furthermore, elucidation of the mechanism of action of these bioactive compounds through pharmacological and molecular studies are also necessary.

Characterisation of the in vitro activity of a Nitazoxanide-N-methyl-1H-benzimidazole hybrid molecule against albendazole and nitazoxanide susceptible and resistant strains of Giardia intestinalis and its in vivo giardicidal activity

BACKGROUND

It was previously demonstrated that CMC-20, a nitazoxanide and N-methyl-1H-benzimidazole hybrid molecule, had higher in vitro activity against Giardia intestinalis WB strain than metronidazole and albendazole and similar to nitazoxanide.

OBJETIVES

To evaluate the in vitro activity of CMC-20 against G. intestinalis strains with different susceptibility/resistance to albendazole and nitazoxanide and evaluate its effect on the distribution of parasite cytoskeletal proteins and its in vivo giardicidal activity.

METHODS

CMC-20 activity was tested against two isolates from patients with chronic and acute giardiasis, an experimentally induced albendazole resistant strain and a nitazoxanide resistant clinical isolate. CMC-20 effect on the distribution of parasite cytoskeletal proteins was analysed by indirect immunofluorescence and its activity was evaluated in a murine model of giardiasis.

FINDINGS CMC-20

showed broad activity against susceptible and resistant strains to albendazole and nitaxozanide. It affected the parasite microtubule reservoir and triggered the parasite encystation. In this process, alpha-7.2 giardin co-localised with CWP-1 protein. CMC-20 reduced the infection time and cyst load in feces of G. muris infected mice similar to albendazole.

MAIN CONCLUSIONS

The in vitro and in vivo giardicidal activity of CMC-20 suggests its potential use in the treatment of giardiasis.

Intestinal parasitic infections and associated factors in children of three rural schools in Colombia. A cross-sectional study

Rural children are one of the populations that are most vulnerable to gastrointestinal parasite infections. Such diseases decrease the quality of life and result in growth and cognitive delays in the long term. This cross-sectional study was conducted to determine the frequency of intestinal parasite infections among rural schoolchildren in the municipality of Apulo, Colombia. A total of 97 stool samples from children aged between 5 and 15 years were collected and examined via direct light microscopy. Microscopic examination was repeated with sediments obtained using a fecal parasite concentrator, and the Kato–Katz test was performed. Frequency of intestinal parasite infection was 100%. Endolimax nana (77.35%), Blastocystis sp. (71.1%), Giardia intestinalis (39.1%), Entamoeba coli (25.7%), and the Entamoeba histolytica/dispar/moshkovskii complex (9.2%) were the most prevalent protozoa. Trichuris trichiura was the most prevalent helminth (12.3%), followed by Enterobius vermicularis (6.15%) and Ascaris lumbricoides (5.1%). Among the analyzed associated factors, consumption of untreated water increased the risk of acquiring pathogenic intestinal parasites. Finally, because G. intestinalis was the most prevalent pathogenic protozoan, molecular analysis was conducted to establish genetic assemblages and subassemblages of Giardia through sequence-based genotyping of the glutamate dehydrogenase, triose phosphate isomerase, and beta-giardin genes. A total of 14 G. intestinalis-positive samples were genotyped, which revealed the presence of subassemblages AI (n = 1), AII (n = 7), BIII (n = 2), BIV (n = 2), and BIII/BIV (n = 1) as well as a mixed subassemblage AII + BIII (n = 1). Our results indicate that gastrointestinal parasite infections in the tested population were mainly caused by suboptimal water quality. Moreover, molecular typing of G. intestinalis suggested contamination of water by animal- and human-derived cysts.

An exploration of the disease burden due to Cryptosporidium in consumed surface water for sub-Saharan Africa

The protozoan pathogen Cryptosporidium is an important cause of diarrhoeal disease, but in many contexts its burden remains uncertain. The Global Waterborne Pathogen model for Cryptosporidium (GloWPa-Crypto) predicts oocyst concentrations in surface water at 0.5 by 0.5° (longitude by latitude) resolution, allowing us to assess the burden specifically associated with the consumption of contaminated surface water at a large scale. In this study, data produced by the GloWPa-Crypto model were used in a quantitative microbial risk assessment (QMRA) for sub-Saharan Africa, one of the regions most severely affected by diarrhoeal disease. We first estimated the number of people consuming surface water in this region and assessed both direct consumption and consumption from a piped (treated) supply. The disease burden was expressed in disability adjusted life years (DALYs). We estimate an annual number of 4.3 × 10⁷ (95% uncertainty interval [UI] 7.4 × 10⁶-5.4 × 10⁷) cases which represent 1.6 × 10⁶ (95% UI 3.2 × 10⁵-2.3 × 10⁶) DALYs. Relative disease burden (DALYs per 100,000 persons) varies widely, ranging between 1.3 (95% UI 0.1-5.7) for Senegal and 1.0 × 10³ (95% UI 4.2 × 10²-1.4 × 10³) for Eswatini. Countries that carry the highest relative disease burden are primarily located in south and south-east sub-Saharan Africa and are characterised by a relatively high HIV/AIDS prevalence. Direct surface water consumption accounts for the vast majority of cases, but the results also point towards the importance of stable drinking water treatment performance. This is, to our knowledge, the first study to utilise modelled data on pathogen concentrations in a large scale QMRA. It demonstrates the potential value of such data in epidemiological research, particularly regarding disease aetiology.

Risk Factors and Spatial Clusters of Cryptosporidium Infection among School-Age Children in a Rural Region of Eastern China

The epidemiological features of Cryptosporidium infection among school-age children in China still remain unclear. Hereby, a cross-sectional study of 1637 children aged 3–9 years was designed to investigate the risk factors and spatial clusters of Cryptosporidium infection in a rural region of Eastern China. Stool specimens collected from participants were examined using the auramine-phenol and modified acid-fast staining. Univariable and multivariable analyses were performed to identify the risk factors of Cryptospordium infection. The spatial clusters were analyzed by a discrete Poisson model using SaTScan software. Our results showed that the overall prevalence of Cryptosporidium infection was 11‰ in the research region. At the age of 3–6 years (odds ratios (OR) = 3.072, 95% confidence intervals (CI): 1.001–9.427), not washing hands before eating and after defecation (OR = 3.003, 95% CI: 1.060–8.511) were recognized as risk factors. Furthermore, a high-risk spatial cluster (relative risk = 4.220, p = 0.025) was identified. These findings call for effective sustainable interventions including family and school-based hygienic education to reduce the prevalence of Cryptosporidium infection. Therefore, an early warning system based spatiotemporal models with risk factors is required to further improve the effectiveness and efficiency of cryptosporidiosis control in the future.