Performance evaluation of point-of-care test for detection of Cryptosporidium stool antigen in children and HIV infected adults

Occurrence of Cryptosporidium Infection and Associated Risk Factors among HIV-Infected Patients Attending ART Clinics in the Central Region of Ghana

Cryptosporidium species are intestinal protozoan parasites that infect and cause diarrhoea in animals and humans. The current study was conducted to determine the prevalence and risk factors of Cryptosporidium infection among HIV-infected patients in the Central region of Ghana. In this cross-sectional study, four hundred eighteen documented HIV-infected participants from four health facilities that provide antiretroviral therapy (ART) services across the Central region of Ghana were selected by systematic random sampling. An enzyme-linked immunosorbent assay (CoproELISA^TM, Cryptosporidium Savyon^® Diagnostics Ltd., Ashdod, Israel) was used to detect Cryptosporidium antigens in stool samples obtained from participants. Information regarding participants’ sociodemographic characteristics and clinical symptoms as well as potential environmental and behavioral risk factors were collected using a structured questionnaire. Chi-square or Fisher’s exact tests were used to determine associations between Cryptosporidium infections and explanatory variables, while risk factors were assessed using multivariate logistic regression analysis. The overall prevalence of Cryptosporidium infection among HIV-infected participants in this study was 6.2% (95% CI: 3.90–8.54). Cryptosporidium was not significantly associated with any of the sociodemographic variables, patient clinical symptoms, and environmental factors. However, the prevalence of the parasite was significantly higher 25% (95% CI: 1.17–48.83; p = 0.013) among participants who did not always wash their hands before meals and those who did not always wash vegetables before eating them, 23.5% (95% CI: 1.05–46.01; p = 0.016). Multivariate logistic regression analysis showed that participants who used public water closet facilities were approximately 9 times more likely to become infected with the parasite than those who practised open defecation (OR: 8.83; 95% CI: 1.22–64.13; p = 0.031). In conclusion, Cryptosporidium is prevalent among HIV-infected patients in the Central region of Ghana. An important risk factor identified was the use of the public water closet toilet facility. More attention should be given to ensuring cleanliness at shared water closet facilities in addition to adequate disinfection of hands after using such facilities.

Development of a low-cost copro-LAMP assay for simultaneous copro-detection of Toxocara canis and Toxocara cati

Toxocariasis is a zoonotic disease caused mainly by Toxocara canis and Toxocara cati and diagnosis in dogs and cats is an important tool for its control. For this reason, a new coprological loop-mediated isothermal amplification (LAMP) assay was developed for the simultaneous detection of these species. The primer set was designed on a region of the mitochondrial cox-1 gene. Amplification conditions were evaluated using a temperature gradient (52°C to 68°C), different incubation times (15–120 min), and different concentrations of malachite green dye (0.004–0.4% w/v). The analytical sensitivity was evaluated with serial dilutions of genomic DNA from T. canis and T. cati adult worms, and with serial dilutions of DNA extracted from feces using a low-cost in-house method. The specificity was evaluated using genomic DNA from Canis lupus familiaris, Felis catus, Escherichia coli, Toxascaris leonina, Ancylostoma caninum, Echinococcus granulosus sensu stricto and Taenia hydatigena. The LAMP assay applied to environmental fecal samples from an endemic area showed an analytical sensitivity of 10–100 fg of genomic DNA and 10−5 serial dilutions of DNA extracted from feces using the low-cost in-house method; with a specificity of 100%. Additionally, the total development of the assay was carried out in a basic laboratory and per-reaction reagent cost decreased by ~80%. This new, low-cost tool can help identify the most common agents of toxocariasis in endemic areas in order to manage prevention strategies without having to rely on a laboratory with sophisticated equipment.

First Molecular Characterization of Cryptosporidium spp. in Patients Living with HIV in Honduras

Cryptosporidiosis is one of the most important causes of gastroenteritis in the world, especially in low- and middle-income countries. It is caused by the Apicomplexan parasite Cryptosporidium spp., and mainly affects children and immunocompromised people, in whom it can pose a serious threat to their health, or even be life threatening. In Honduras, there are no data on parasite species or on molecular diversity or Cryptosporidium subtypes. Therefore, a cross-sectional study was conducted between September 2019 and March 2020 for the molecular identification of Cryptosporidium spp. in 102 patients living with HIV who attended a national hospital in Tegucigalpa. Stool samples were analyzed by direct microscopy, acid-fast stained smears, and a rapid lateral flow immunochromatographic test. All samples that tested positive were molecularly analyzed to identify the species and subtype of the parasite using three different markers: gp60, cowp, and 18Sr. PCR products were also sequenced. Four out of 102 samples (3.92%) were positive for Cryptosporidiumparvum, and all were assigned to subtype IIa. These findings suggest a possible zoonotic transmission in this population.

Performance of a rapid diagnostic test for the detection of Cryptosporidium spp. in African children admitted to hospital with diarrhea

BACKGROUND

Cryptosporidium is a protozoan parasite that causes mild to severe diarrhoeal disease in humans. To date, several commercial companies have developed rapid immunoassays for the detection of Cryptosporidium infection. However, the challenge is to identify an accurate, simple and rapid diagnostic tool for the estimation of cryptosporidiosis burden. This study aims at evaluating the accuracy of CerTest Crypto, a commercialized rapid diagnostic test (RDT) for the detection of Cryptosporidium antigens in the stool of children presenting with diarrhoea.

METHODS

A cross-sectional study was conducted in four study sites in Sub-Saharan Africa (Gabon, Ghana, Madagascar, and Tanzania), from May 2017 to April 2018. Stool samples were collected from children under 5 years with diarrhoea or a history of diarrhoea within the last 24 hours. All specimens were processed and analyzed using CerTest Crypto RDT against a composite diagnostic panel involving two polymerase chain reaction (PCR) tests (qPCR and RFLP-PCR,) as the gold standard.

RESULTS

A total of 596 stool samples were collected. Evaluation of the RDT yielded a very low overall sensitivity of 49.6% (confidence interval (CI) 40.1-59.0), a specificity of 92.5% (CI 89.8-94.7), positive predictive value of 61.3% (CI 50.6-71.2), and negative predictive value of 88.5% (85.3-91.1) when compared to the composite reference standard of qPCR and RFLP-PCR for the detection of Cryptosporidium species. Moreover, the performance of this test varied across different sites.

CONCLUSION

The weak performance of the studied RDT suggests the need to carefully evaluate available commercial RDTs before their use as standard tools in clinical trials and community survey of Cryptosporidium infections in pediatric cohorts.

Cryptosporidiosis in HIV-positive patients and related risk factors: A systematic review and meta-analysis

Cryptosporidium is one of the major causes of diarrhea in HIV-positive patients. The aim of this study is to systematically review and meta-analyze the prevalence of Cryptosporidium in these patients. PubMed, Science Direct, Google Scholar, Web of Science, Cochrane and Ovid databases were searched for relevant studies dating from the period of 1 January 2000 to 31 December 2017. Data extraction for the included studies was performed independently by two authors. The overall pooled prevalence was calculated and subgroup analysis was performed on diagnostic methods, geographical distribution and study population. Meta-regression was performed on the year of publication, proportion of patients with diarrhea, and proportion of patients with CD4 < 200 cells/mL. One hundred and sixty-one studies and 51,123 HIV-positive participants were included. The overall pooled prevalence of Cryptosporidium infection in HIV-positive patients was 11.2% (CI95%: 9.4%–13.0%). The pooled prevalence was estimated to be 10.0% (CI95%: 8.4%–11.8%) using staining methods, 13.5% (CI95%: 8.9%–19.8%) using molecular methods, and 26.3% (CI95%: 15.0%–42.0%) using antigen detection methods. The prevalence of Cryptosporidium in HIV patients was significantly associated with the country of study. Also, there were statistical differences between the diarrhea, CD4 < 200 cells/mL, and antiretroviral therapy risk factors with Cryptosporidiosis. Thus, Cryptosporidium is a common infection in HIV-positive patients, and safe water and hand-hygiene should be implemented to prevent cryptosporidiosis occurrence in these patients.

Comparison of current methods used to detect Cryptosporidium oocysts in stools

In this review all of the methods that are currently in use for the investigation of Cryptosporidium in stool material are highlighted and critically discussed. It appears that more qualifications and background knowledge in this field regarding the diagnosis of the Cryptosporidium parasite is required. Furthermore, there is no standardization for the protocols that are commonly used to either detect oocysts in faeces or to diagnose the Cryptosporidium infection. It is therefore necessary to initiate further education and research that will assist in improving the accuracy of the diagnosis of Cryptosporidium oocysts in the faecal micro-cosmos. Where ambient concentrations of oocysts are low in stool material, detection becomes a formidable task. Procedures for ring tests and the standardization of multi-laboratory testing are recommended. It is also necessary to enhance the routine surveillance capacity of cryptosporidiosis and to improve the safety against it, considering the fact that this disease is under diagnosed and under reported. This review is intended to stimulate research that could lead to future improvements and further developments in monitoring the diagnostic methodologies that will assist in harmonizing Cryptosporidium oocysts in stool diagnosis.

The global problem of childhood diarrhoeal diseases: emerging strategies in prevention and management

Acute diarrhoeal diseases remain a leading cause of global morbidity and mortality particularly among young children in resource-limited countries. Recent large studies utilizing case-control design, prospective sampling and more sensitive and broad diagnostic techniques have shed light on particular pathogens of importance and highlighted the previously under recognized impact of these infections on post-acute illness mortality and growth. Vaccination, particularly against rotavirus, has emerged as a key effective means of preventing significant morbidity and mortality from childhood diarrhoeal disease. Other candidate vaccines against leading diarrhoeal pathogens, such as enterotoxigenic Escherichia coli and Shigella spp., also hold significant promise in further ameliorating the burden of enteric infections in children. Large studies are also currently underway evaluating novel and potential easy-to-implement water, sanitation and hygiene (WASH) preventive strategies. Given the ongoing global burden of this illness, the paucity of new advances in case management over the last several decades remains a challenge. The increasing recognition of post-acute illness mortality and growth impairment has highlighted the need for interventions that go beyond management of dehydration and electrolyte disturbances. The few trials of novel promising interventions such as probiotics have mainly been conducted in high-income settings. Trials of antimicrobials have also been primarily conducted in high-income settings or in travellers from high-income settings. Bloody diarrhoea has been shown to be a poor marker of potentially treatable bacterial enteritis, and rising antimicrobial resistance has also made empiric antimicrobial therapy more challenging in many settings. Novel effective and sustainable interventions and diagnostic strategies are clearly needed to help improve case management. Diarrhoeal disease and other enteric infections remain an unmet challenge in global child health. Most promising recent developments have been focused around preventive measures, in particular vaccination. Further advances in prevention and case management including the possible use of targeted antimicrobial treatment are also required to fully address this critical burden on child health and human potential.

Practical Guidance for Clinical Microbiology Laboratories: Laboratory Diagnosis of Parasites from the Gastrointestinal Tract

This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasites from the gastrointestinal tract provides practical information for the recovery and identification of relevant human parasites. The document is based on a comprehensive literature review and expert consensus on relevant diagnostic methods. However, it does not include didactic information on human parasite life cycles, organism morphology, clinical disease, pathogenesis, treatment, or epidemiology and prevention. As greater emphasis is placed on neglected tropical diseases, it becomes highly probable that patients with gastrointestinal parasitic infections will become more widely recognized in areas where parasites are endemic and not endemic. Generally, these methods are nonautomated and require extensive bench experience for accurate performance and interpretation.

Foodborne cryptosporidiosis

Foodborne illness, the majority of which is caused by enteric infectious agents, costs global economies billions of dollars each year. The protozoan parasite Cryptosporidium is particularly suited to foodborne transmission and is responsible for >8 million cases of foodborne illness annually. Procedures have been developed for sensitive detection of Cryptosporidium oocysts on fresh produce and molecular diagnostic assays have been widely used in case linkages and infection source tracking, especially during outbreak investigations. The integrated use of advanced diagnostic techniques with conventional epidemiological studies is essential to improve our understanding of the occurrence, source and epidemiology of foodborne cryptosporidiosis. The implementation of food safety management tools such as Good Hygienic Practices (GHP), Hazard Analysis and Critical Control Points (HACCP), and Quantitative Microbial Risk Assessment (QMRA) in industrialised nations and Water, Sanitation, and Hygiene (WASH) in developing countries is central for prevention and control and foodborne cryptosporidiosis in the future.

Cryptosporidium infection in children with cancer undergoing chemotherapy: how important is the prevention of opportunistic parasitic infections in patients with malignancies?

Cryptosporidiosis is a relatively uncommon disease in healthy individuals but could be potentially worrisome in immunocompromised patients. This study aimed to evaluate Cryptosporidium infection in children with cancer undergoing chemotherapy. A case-control study was conducted in 132 children with cancer undergoing chemotherapy and 132 non-cancer controls. The modified Ziehl-Neelsen (MZN) staining and polymerase chain reaction methods were used for the detection of Cryptosporidium parasite. All positive isolates were sequenced for phylogenetic analysis. Statistical analysis was performed using the SPSS version 16 and Fisher exact test. The rate of cryptosporidiosis in children with cancer undergoing chemotherapy was 3.8%, which was higher than that of the control group. Other intestinal parasites detected in patients with cancer included Giardia lamblia (3%), Entamoeba coli (1.5%), and Chilomastix mesnili (0.8%). In the control group, only two (1.5%) cases were positive for G. lamblia. No significant difference was observed between the gender, age, residency, contact with domestic animals, stool appearance, neutropenia, chemotherapy period, and type of malignancy with regard to cryptosporidiosis. Phylogenetic analysis revealed that Cryptosporidium parvum isolates in this study relied on a branch that represents similar sequences from Iran and other countries. Although the rate of Cryptosporidium infection was relatively higher in children with cancer undergoing chemotherapy compared to the control group, any statistically significant difference has not been found between them. These findings should not be contrary to the need for healthcare to prevent opportunistic parasitic infections in malignant and immunocompromised patients.

Cryptosporidium and Giardia in Africa: current and future challenges

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Cryptosporidium and other intestinal parasitic infections among HIV patients in southern Ethiopia: significance of improved HIV-related care

Background

Intestinal parasitic infections are known to cause gastroenteritis, leading to higher morbidity and mortality, particularly in people living with HIV/AIDS. This study aimed to determine the prevalence of Cryptosporidium and other intestinal parasitic infections among HIV patients receiving care at a hospital in Ethiopia where previous available baseline data helps assess if improved HIV-related care has reduced infection rates.

Methods

A cross-sectional study was conducted at Hawassa University Hospital in southern Ethiopia from May, 2013 to March, 2014. A consecutive sample of 491 HIV- infected patients with diarrhea or a CD4 T cell count < 200 cells/μl were prospectively studied. A single stool sample was collected from each study participant and processed using direct, formol-ether concentration, and modified Ziehl-Neelsen techniques for the diagnosis of Cryptosporidium and other intestinal parasites. The study was approved by the Institutional Review Board of the College of Medicine and Health Sciences, Hawassa University. Physicians managed participants found to be infected with any pathogenic intestinal parasite.

Results

The overall prevalence of intestinal parasitic infections among the study population was 35.8 %. The most prevalent parasites were Cryptosporidium (13.2 %), followed by Entamoeba histolytica/dispar (10.2 %), and Giardia lamblia (7.9 %). The rate of single and multiple infections were 25.5 and 10.3 %, respectively. Patients with a CD4 T cell count < 200 cells/μl had a similar rate of any intestinal parasitic infection or cryptosporidiosis compared to those with counts ≥ 200 cells/μl, but with some type of diarrhea.

Conclusion

The study shows high prevalence of intestinal parasitic infections in the study population. However, the results in the current report are significantly lower compared to previous findings in the same hospital. The observed lower infection rate is encouraging and supports the need to strengthen and sustain the existing intervention measures in order to further reduce intestinal parasitic infections in people living with HIV/AIDS.