Clinical and Microbiology Profile and Outcome of Diarrhea by Coccidian Parasites in Immunocompetent Children

Spectrum and Trends of Intestinal Parasitic Infections at a Tertiary Care Hospital during Pandemic Times: A Laboratory-Based Retrospective Study

Introduction  Intestinal parasitic infections continue to loom in developing countries with low sanitation and socioeconomic conditions. Pandemic times are especially important to study the prevalence of these pathogens since the focus of all healthcare services was coronavirus disease 2019 (COVID-19). This study aimed to evaluate the prevalence and time-trend of intestinal parasitic infections in the capital region of India during the pandemic times. Methods  In this cross-sectional study, a retrospective review based on data from the past 2 years in the post-COVID-19 pandemic was used. Descriptive and time-trend analyses were applied to the data. Time series analysis was analyzed using the best fit autoregressive integrated moving average (ARIMA) model to look for seasonality in trends and forecasting. Results  A total of 7267 patients' stool samples over a 2-year pandemic period were included in the study. Intestinal parasites were detected in 11.18% (813/7276) patients. Giardia lamblia (2.28%) and Blastocystis hominis (3.78%) were the predominant ones. Time-trend analysis from 2020 to 2021 using ARIMA model predicted an increasing trend with waning of pandemic. The most prevalent infection was found in the monsoon and autumn months. Conclusion  Rates of infection with Giardia lamblia and Blastocystis hominis have increased in comparison to other protozoan infections like Entamoeba histolytica when compared with prepandemic hospital-based studies. With fading of the pandemic, further increasing trends are predicted.

Development of a new multiplex PCR to detect fecal coccidian parasite

BACKGROUND

Cryptosporidium spp., Cystoisospora belli and Cyclospora cayetanensis are common intestinal coccidian parasites causing gastroenteritis. The clinical presentation caused by each parasite is indistinguishable from each other. Uniplex polymerase chain reaction (PCR) for these three groups of intestinal coccidian parasites was developed by us in our laboratory. Thereafter, we planned to develop a single-run multiplex polymerase chain reaction (mPCR) assay to detect Cryptosporidium spp., C. belli and C. cayetanensis simultaneously from a stool sample and described it here as coccidian mPCR.

METHODS

New primers for C. belli and C. cayetanensis were designed and uniplex PCRs were standardized. The coccidian mPCR was standardized with known positive DNA control isolates. It was validated with 58 known positive and 58 known negative stool samples, which were previously identified by uniplex PCR.

RESULTS

The coccidian mPCR was standardized with earlier primers designed by us for Cryptosporidium spp. and C. cayetanensis, and a newly designed primer for the internal transcribed spacer-1 (ITS-1) gene for C. belli. The coccidian mPCR was 92.1% sensitive for Cryptosporidium spp., and 100% sensitive for C. belli and C. cayetanensis each, when tested on 116 known samples. It was 100% specific for all intestinal coccidian parasites. Two representative PCR products of the newly designed ITS-1 primer for C. belli were sequenced and submitted to the GenBank, which best match with the sequences of C. belli.

CONCLUSION

A highly sensitive, specific, cost-effective, indigenous, single-run coccidian mPCR has been developed, which can simultaneously detect Cryptosporidium spp., C. belli and C. cayetanensis.

Molecular detection of Cystoisospora belli by single-run polymerase chain reaction in stool samples

INTRODUCTION

Cystoisospora belli (C. belli) is the only pathogenic species of the Cystoisospora genus responsible for severe diarrhea in immunocompromised patients. Most common microscopic method of diagnosis is less sensitive due to intermittent shedding of oocysts. We developed a new single-run polymerase chain reaction (PCR)-based diagnostic assay for C. belli.

METHODS

A new single-run PCR-based diagnostic assay was standardized for the detection of C. belli. Diagnostic reproducibility and repeatability of the PCR assay were evaluated. A cross-sectional analytical study was done on a total of 354 stool samples collected from 331 immunocompromised patients with diarrhea. All the stool samples were tested for the presence of oocysts of C. belli and were also tested by our new PCR assay for C. belli. Three of the representative PCR products were confirmed by sequencing. Fisher's exact test was used to compare the two proportions.

RESULTS

Microscopy detected C. belli in 11/354 (3.1%) of stool samples, and the new PCR-based assay detected C. belli in 16/354 (4.5%). The new single-run PCR-based assay detected C. belli in all the stool samples which were tested positive by microscopy and additionally detected C. belli in five stool samples. The developed PCR assay detected statistically significant proportion of C. belli (p < 0.001) as compared to microscopy. The 795 base pair PCR product from one microscopy positive stool sample and two microscopy negative stool samples were confirmed by sequencing.

CONCLUSION

Our newly developed single-run PCR-based detection assay for C. belli is robust and reproducible. It may be used for molecular diagnosis of cystoisosporiasis especially in transplant, pediatrics, and human immunodeficiency virus (HIV) positive patients.

Cryptosporidiosis in children in the Indian subcontinent

Cryptosporidiosis is a leading cause of diarrheal disease among children under two in developing countries. Previous estimates have shown a high burden of cryptosporidial diarrhea in children from Sub-Saharan Africa and South Asia. Asymptomatic cryptosporidial infections which go undetected and untreated have been shown to result in significant malnutrition. In this review, we carried out a literature search of studies published on cryptosporidiosis in children in the Indian subcontinent from 1983 to 2016. Of the 154 publications identified, 54 were included for final analysis with both hospital-based and community-based studies. There were wide variations in reported prevalence rates from hospital studies and highlight the need to be carry out these studies with uniform sampling and molecular tools for detection, especially in countries with a dearth of information. Community-based studies, however, showed similarities in spite of differences in when (the late 1990s up until recently) and where (South India or Bangladesh) they were conducted. When more sensitive detection methods were used, cryptosporidial diarrhea accounted for 7%–9% of all diarrhea episodes and 20%–30% of children in these cohorts experienced at least one cryptosporidial diarrheal episode. High rates of asymptomatic infections with increased detection by serology and multiple infections (symptomatic and asymptomatic) were also documented in all cohorts. This overview brings to light the high burden of disease associated with cryptosporidiosis in children in the subcontinent and the gaps in knowledge to be addressed.

Coccidian intestinal parasites among immunocompetent children presenting with diarrhea: Are we missing them?

BACKGROUND

Diarrhoea is an important cause of both morbidity and mortality among children in India. Coccidian parasitic infections are an important cause of diarrhea in immunocompromised patients, but their investigations are rarely sought by the treating physicians in seemingly immunocompetent children. This study was aimed to find the incidence rate of coccidian parasites in all children presented with diarrhoea, irrespective of their immune status.

MATERIALS AND METHODS

Between December 2015 and May 2016, all fecal samples from children aged between 0 and 15 years presenting with diarrhoea, irrespective of their immune status, were examined using conventional wet mount and modified acid-fast staining. At the end of the study, records of their clinical history and immune status including HIV positivity were evaluated. Findings of wet-mount and modified acid-fast stained smear microscopy were analyzed in relation with clinical details.

RESULTS

During the study, samples from 200 children (single sample) with diarrhea were processed. Their mean age was 5.7 ± 3.3 years (range 4-168 months). Seventeen out of 200 (8.5%) samples were positive for acid-fast coccidian parasites. Eight (4%) samples were found to be positive for Cryptosporidium hominis, while 5 (2.5%) were positive for Cyclospora cayetonensis and 4 (2%) samples for Isospora belli oocysts. Half (50%) of the children who were tested positive for Cryptosporidium and Cyclospora were found to be otherwise immunocompetent. However, all four cases of Isosporiasis were immunocompromised patients.

CONCLUSION

We highlight the high incidence of coccidian parasites among immunocompetent children with diarrhea. The clinicians need to be aware that coccidian parasites are a potential cause of childhood diarrhea even in immunocompetent children.