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Competing Interests: There are no conflicts of interest.

Despite great efforts, intestinal protozoan infections remain a significant healthcare concern worldwide. Although many point-of-care (POC) tests are increasingly being used, microscopic examination of stool specimens remains the mainstay for their diagnosis, especially in resource-limited settings. We assessed the utility of rapid POC tests based on immunochromatography among patients from rural Northern India. A total of 78 patients were enrolled in the study. Out of nine specimens that tested positive for Giardia duodenalis on microscopy, an immunochromatographic test (ICT) could detect only five (55.55%). Entamoeba histolytica/dispar was demonstrated in two specimens on microscopy, both of which were missed by ICT. Its overall sensitivity, specificity, and positive and negative predictive value were 50%, 98.5%, 83.3%, and 93%, respectively. Its performance was considered unsatisfactory. Although ICT-based tests provide a relatively rapid and less labor-intensive alternative, they should be used to supplement and not replace stool microscopy., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Cryptosporidium species cause watery diarrhea in several vertebrate hosts, including humans. Most apparently, immunocompetent-infected individuals remain asymptomatic, whereas immunocompromised may develop severe or chronic cryptosporidiosis. We report here the case of a 6-year-old girl undergoing chemotherapy for Burkitt lymphoma who experienced multiple episodes of watery diarrhea during her hospital stay. Microscopic examination of her stool sample revealed oocysts of Cryptosporidium species. The rapid immunochromatographic test was also positive for Cryptosporidium species. She was treated with nitazoxanide for 3 weeks, which failed to provide both clinical improvement and parasitological clearance. This case highlights the importance of treatment failure in human cryptosporidiosis., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Tropical Parasitology.)

Herein, we are presenting a case of chromatinless microfilaria in a patient with chyluria., Competing Interests: Declaration of competing interest No such financial/personal competing interest is applicable pertinent to this manuscript., (Copyright © 2023 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

Intra-ocular cystic lesion in a young child can be parasitic lesion, old retinal detachment with cysts or simply a vitreous cyst. Intra-ocular localization of hydatid cysts is extremely rare accounting for less than one percent of all cases. This case describes a young child with left eye pain, redness and progressive diminution of vision with progressively enlarging intra- ocular cyst. Diagnosed as intra-ocular hydatid cyst, the radiological, intraoperative and microbiological features of same are described. Also, the management required in such a case is discussed.

Cystic echinococcosis (CE), even after several control measures, causes significant morbidity throughout the world. Besides imaging investigation technology, the serological tests are essential for both diagnosis and management of this slowly progressive disease. The present study was a hospital-based retrospective study that examined the seropositivity rate for Echinococcus granulosus sensu lato antibody in patients suspected of CE at our tertiary health care center over 8 years from 2013 to 2020. Records of new visits to hospital/clinics and associated hospital discharge constituted the denominator of calculation. All samples were tested using commercially available indirect immunoglobulin G enzyme-linked immunosorbent assay kit. A total of 925 suspected patients with a clinical diagnosis of CE were screened. The age group that commonly tested positive for CE was 20 to 39 years, and liver was the predominant organ found to be affected. The seropositive rate was 41.2%. On further year-wise analysis, it was observed that the seropositivity rate had significantly declined from 61.4% in 2013 to 33.8% in 2020. This study clearly showed that there is a by 27.6% decline of CE seropositivity rate in 8 years. This declining rate may be attributed to improved socioeconomic status and better implementation of health programs., Competing Interests: Conflict of Interest None declared., (The Indian Association of Laboratory Physicians. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)

Background: Strongyloides stercoralis (S. stercoralis) , a unique parasite, can cause mortal disease even years after the exposure. Iatrogenic use of steroids can complicate asymptomatic infections to a life-threatening hyperinfection and/or disseminated infection. Data regarding seroprevalence of strongyloidiasis remains scarce and this knowledge gap needs due attention in many endemic countries including India., Aim: The present study is aimed at assessing the seroprevalence of Strongyloides infection and the need for routine screening among individuals receiving steroid therapy., Methodology: Eighty patients receiving steroid therapy and thirty healthy volunteers who had not received any immunosuppressive drugs and/or anthelminthic therapy in last six months were enrolled as cases and controls respectively and they were screened by Strongyloides IgG ELISA., Results: Among the 80 patients on steroids, the mean cumulative prednisolone equivalent dose received was 8.2 g (±11.2 g) for a mean duration of 184 days, 16 patients (20%, 95% CI 11.9-30) had a positive Strongyloides IgG serology. Only 4 controls (4/30, 13.3%, CI 3.8-30.7) tested positive (p=0.4)., Conclusions: Our study demonstrated a Strongyloides seroprevalence of 20% in the study population emphasizing the need for screening for Strongyloides infection prior to immunosuppressive therapy in order to prevent hyperinfection or possible dissemination., Competing Interests: Conflict of interest None

The present study is an attempt to investigate the presence of Naegleria fowleri in Indian population. A total of 307 patients were enrolled and water samples were collected from both residential and surrounding areas of patients found positive for N. fowleri. The different species of Naegleria from both clinical and water samples were identified taxonomically. Recommended microbiological conventional techniques were used to identify different Naegleria stages and other free-living amoebae from the samples. PCR assays, using both genus and species specific primers were also optimized. None of the samples were positive by conventional microbiological examinations. However, PCR assays detected only three samples positive for N. fowleri. A total of 10 water bodies (ponds), that were used by Naegleria positive patients were examined. The pH and temperature of the water samples collected from water bodies ranged between 5.6-7.2 and 25-32 °C respectively. Among all the 10 water samples tested, four samples were positive for genus Naegleria by PCR assay, of which only two samples, showed positive amplification for N. fowleri. The sequence analysis of N. fowleri strain belonged to genotype II., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Objectives: Pneumocystis pneumonia (PCP) remains a debilitating cause of death among HIV-infected patients. The combination trimethoprim/sulfamethoxazole (SXT) is the most effective anti-Pneumocystis treatment and prophylaxis. However, long-term use of this combination has raised alarms about the emergence of resistant organisms. This study was performed to investigate mutations in the dihydropteroate synthase (DHPS) gene and their clinical consequences in HIV-infected patients with PCP., Methods: A total of 76 clinically suspected cases of PCP among HIV-seropositive adult patients from March 2014 to March 2017 were included. Clinical samples (bronchoalveolar lavage fluid and sputum) were investigated for the detection of Pneumocystis jirovecii using both microscopy and nested PCR. DHPS genotyping and mutational analyses were performed and the data were correlated with clinical characteristics., Results: Among the 76 enrolled HIV-positive patients, only 17 (22.4%) were positive for P. jirovecii. DHPS gene sequencing showed a novel nucleotide substitution at position 288 (Val96Ile) in three patients (3/12; 25.0%). Patients infected with the mutant P. jirovecii genotype had severe episodes of PCP, did not respond to SXT and had a fatal outcome (P=0.005). All three patients had a CD4 + T-cell count <100 cells/μL, and two also had co-infections., Conclusion: This study suggests that the emergence of a mutant P. jirovecii genotype is probably associated with drug resistance and mortality. The data also suggest that DHPS mutational analyses should be performed in HIV-seropositive patients to avoid treatment failure and death due to PCP. However, the role of underlying disease severity and co-morbidities should not be underestimated., (Copyright © 2019 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

Background: The rising incidence of obesity is one of the most serious public health issues in the developed as well as in developing countries like India. Obesity and overweight are most important risk factors for many chronic diseases, including cardiovascular diseases, diabetes and cancer. In this study the body mass index (BMI) cut off was taken as 18.5-22.9 kg/m 2 for normal, 23.0-24.9 kg/m 2 for Overweight and >25 kg/m 2 for obese as per WHO recommendation for Asian Indians, which is different for developed and developing countries. Role of gut microbiota mediated immune response in the development of obesity has been studied but the literature on Indian population are lacking. Therefore, a study was conducted to determine Toll like receptors (TLRs) in response to human gut microbiota of Indian obese and lean individuals using viable colonocytes in a Non invasive technique and Flowcytometry., Methods: A total of 20 healthy volunteer (10 obese and 10 lean) were enrolled in the study as per inclusion and exclusion criteria. Viable colonocytes were isolated from fecal samples using a Non invasive technique (SCSR Method). Toll like receptors (TLRs) and immunoglobulin (IgA &IgG) receptor concentration were measured by standard Flowcytometry methods using specific fluorochrome conjugated antibodies., Results: Average TLR2 receptor concentration was significantly higher in obese (6.35 %) as compared to lean (2.9 %) ( P = 0.01). TLR4 receptor concentration was 1.4 % in obese and 1.65 % in lean although the difference was not statistically significant ( P = 0.59). IgA & IgG receptor concentration was 49.6 % & 11.2 % in the obese and 67.15 % & 8.05 % in the lean respectively but the differences among both the group were not statistically significant., Conclusion: The results of the present study will be helpful for physicians and researchers to find some biomarkers which can determine predisposition of the obesity in Indian population and helps to use alternative therapeutics such as probiotics to maintain gut homeostasis and immune modulation to prevent obesity., Competing Interests: There are no conflicts of interest.

Data on the genetic diversity of Pneumocystis jirovecii causing Pneumocystis pneumonia (PCP) among children are still limited, and there are no available data from the Indian subcontinent, particularly associations between genotypes and clinical characteristics. A total of 37 children (62 days-12 years [median 5.5 years]) were included in this study. Pneumocystis was diagnosed by microscopy using Grocott-Gomori methenamine silver stain in 12 cases and by nested PCR using mtLSUrRNA in 25 cases. Genotyping was performed using three different genes, mitochondrial large subunit ribosomal RNA (mtLSUrRNA), dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR). mtLSUrRNA genotype 3 and novel mutations at the gene target DHFR (401 T > C) and DHPS 96/98 were frequently observed and clinically associated with severe PCP and treatment failure. Phylogenetic analyses revealed 13 unique sequence types (STs). Two STs (i) 3-DHFR 401 T > C-DHPS 96/98 - PJ1 and (ii) 3-DHFR 401 T > C-DHPS 96- PJ3 were significantly associated with treatment failure and high mortality among PCP-positive patients. In conclusion, the present study strongly suggests the emergence of virulent P. jirovecii strains or genetic polymorphisms, leading to treatment failure and high mortality. Our study is the first of its kind from the Indian subcontinent and has highlighted the genetic diversity of Pneumocystis jirovecii among children and their clinical outcomes. These findings emphasize the need to focus more on genotypes to better understand the epidemiology of Pneumocystis pneumonia.

Background: Globally, amoebic liver abscess, a common extraintestinal complication of intestinal amoebiasis. Diagnosis of hepatic amoebiasis is based on the detection of anti- Entamoeba histolytica immunoglobulin G (IgG) antibody using enzyme-linked immunosorbent assay (ELISA), because of its technique's relatively higher sensitivity and specificity (90%)., Aim: The aim of the present study was to determine the seroprevalence of hepatic amoebiasis in a referral tertiary care hospital in North India., Materials and Methods: The blood samples were tested specifically for anti- E. histolytica IgG antibody using commercially available ELISA kit (RIDASCREEN ® E. histolytica IgG [K1721] kit)., Results: A total of 879 patients ( n = 879) were evaluated, of which 78.49% (690/879) were positive for anti- E. histolytica IgG antibody. The seroprevalence rates showed a declining trend from 2010 to 2015 with rates falling from 91.4% to 66.7%. He present a study showed the decreasing trend of seroprevalence of hepatic amoebiasis from 2010 to 2015., Conclusions: This decrease may be attributed to several factors such as increase in awareness, improved hygienic practices, use of safe drinking water, better socioeconomic condition, and perhaps early treatment sought for intestinal amoebiasis., Competing Interests: There are no conflicts of interest.

Filariasis can present in many different ways and pose significant dilemma to the clinician. We report four atypical cases of filariasis which presented as abdominal mass, cervical lymph node enlargement, fever in pregnancy and nosocomial febrile illness respectively. All the four cases were treated successfully with oral antifilarial agents. It is essential to be aware of such atypical presentations of filariasis so that prompt therapy can be initiated.

Competing Interests: There are no conflicts of interest.

Three recombinant antigens viz. arginine kinase, cathepsin L-1 and TES-26 of Toxocara canis were expressed in Escherichia coli and evaluated for their potential in the detection of T. canis larval infection in human in immunoglobulin G-enzyme linked immunosorbent assay (IgG-ELISA). Results of the IgG-ELISA with the above recombinant antigens were confirmed with commercially available IgG detection kit for T. canis infection used as a standard test. All three recombinant antigens were 100% sensitive in the detection of positive cases (n = 6) of T. canis infection in human and were screened for their cross-reactivity in human patients with history of Toxoplasma gondii, Plasmodium vivax, Entamoeba histolytica, hydatid and hookworm infections. The recombinant TES-26 antigen showed higher specificity and cross-reacted with T. gondii infection sera only. However, arginine kinase and cathepsin L-1 recombinant antigens showed cross-reactions with sera of patients infected with T. gondii, P. vivax and E. histolytica but not with the patient sera infected with hydatid and hookworm. These results show that recombinant TES-26 is a potential diagnostic candidate antigen for human toxocarosis caused by migrating T. canis larvae.

Background: Leishmaniasis manifests as visceral (VL), cutaneous (CL) or a dermal sequel of VL, known as Post kala-azar dermal leishmaniasis (PKDL). The aim of the study was to analyze the clinical and laboratory features of cases diagnosed with leishmaniasis., Methods: This hospital-based retrospective study included all cases of VL, PKDL, and CL diagnosed between Jan 2011 to Jan 2016 at All India Institute of Medical Sciences, New Delhi. Clinical and laboratory profile of the diagnosed cases were analyzed in detail. All diagnosed cases were mapped according to the state and the district from which the cases originated., Results: A total of 91 VL cases and 4 PKDL cases were reviewed. Only one case of CL (1 female) and mucocutaneous leishmaniasis (1 female) were observed during the study period. Majority of the cases of VL (75/91) originated from Bihar. The most common presenting symptoms in all our patients were fever (97.8%), weight loss (40.6%) and abdominal discomfort (17.6%) while the most common presenting signs were hepatosplenomegaly (45.8%), isolated splenomegaly (23.1%) and skin pigmentation (11%). The most common laboratory abnormality was anaemia followed by thrombocytopenia and leucopenia., Conclusion: VL is globally recognized as a neglected tropical disease. Even after continued effort to bring down its transmission in India, it continues to affect the endemic states with reports from new pockets., Competing Interests: Conflict of Interests The authors declare that there is no conflict of interest.

The present study was carried out with the objectives of genotyping Pneumocystis jirovecii at three distinct loci, to identify the single nucleotide polymorphisms (SNPs), and to study its clinical implications in patients with Pneumocystis pneumonia (PCP). Analysis of genetic diversity in P. jirovecii from immunocompromised patients was carried out by genotyping at three distinct loci encoding mitochondrial large subunit rRNA (mtLSU rRNA), cytochrome b (CYB), and superoxide dismutase (SOD) using polymerase chain reaction (PCR) assays followed by direct DNA sequencing. Of the 300 patients enrolled in the present study, 31 (10.33%) were positive for PCP by a specific mtLSU rRNA nested PCR assay, whereas only 15 P. jirovecii could be amplified at the other two loci (SOD and CYB). These positives were further subjected to sequence typing. Important genotypic combinations between four SNPs (mt85, SOD110, SOD215, and CYB838) and clinical outcomes could be observed in the present study, and mt85A, mt85T, and SOD110C/SOD215T were frequently associated with "negative follow-up". These SNPs were also noted to be relatively more prevalent amongst circulating genotypes in our study population. The present study is the first of its kind from the Indian subcontinent and demonstrated that potential SNPs of P. jirovecii may possibly be attributed to the clinical outcome of PCP episodes in terms of severity or fatality in different susceptible populations likely to develop PCP during their course of illness.

Aim: Present hospital based study was carried out at our tertiary care centre with an aim to study the distribution of Cryptosporidium species subtypes in patients with complaints of diarrhea., Background: Cryptosporidium species are one of the important causative agents of parasitic diarrhea, amongst which Cryptosporidium hominis ( C.hominis ) and Cryptosporidium parvum ( C.parvum) are the two major species that are associated with human cryptosporidiosis., Methods: Four hundred and fifty (n=450) diarrheic patients complaining of different types of diarrhea were enrolled in the present study. Both microscopic and molecular diagnostic methods were used for the detection as well as for identification of Cryptosporidium species and its speciation and subtyping., Results: Forty one (n = 41) and forty three (n=43) patients were positive for Cryptosporidium species by microscopy and Polymerase chain reaction (PCR) assay respectively. Of these 43 cases, 70% (30/43) were identified as C. hominis and 21% (9/43) was as C. parvum, 7% (3/43) was as Cryptosporidium felis (C.felis) and 2% (1/43) as Cryptopsoridium viatorum ( C. viatorum ) respectively . Upon subtyping of C . hominis and C. parvum , 16 subtypes belonging to 8 different subtype families could be identified. The frequency of different families were Ia (13%, 5/39), Ib (15%, 6/39), Id (18%, 7/39), Ie (30%, 12/39) and IIa (5%, 2/39), IIc (8%, 3/39), IId (8%, 3/39) and IIe (3%, 1/39)., Conclusion: Our study results strongly suggest and reinforces the fact that most of the human cryptosporidiosis is anthroponotic and we expect that present molecular epidemiological data will provide more insight to unravel the changing clinical paradigm of human cryptosporidiosis at large., Competing Interests: The authors declare that they have no conflict of interest.

The modified acid fast staining technique is a commonly used procedure for the detection of coccidian parasites in developing countries. The morphological variations observed in these parasites play a significant role to some extent in both identification and diagnosis of these parasitic infections. A prospective cross sectional study was performed over three years. The fecal smears were stained by modified Kinyoun acid-fast staining technique and were extensively studied for morphological variations in the coccidian parasites. Out of a total of two thousand one hundred fifty one (n = 2,151) fecal samples received during the study period, 259 samples (12%) were positive for any one of the coccidian parasites. Morphological variations, especially in the staining character was noted in all the three coccidian parasites. This study was an attempt to characterize different variations in size, shape and staining characteristics of the three coccidian parasites., (© 2017 Wiley Periodicals, Inc.)

Competing Interests: There are no conflicts of interest.

The major brunt of scrub typhus is borne by developing countries like India but the disease remains neglected. The rapid progression of this infection to serious complications and associated mortality calls for improved diagnostics. The immunoglobulin (Ig)M immunofluorescence assay (IFA), with all of its limitations remains the gold standard. Of 218 suspected cases from patients enrolled in a 2-year study, 30 cases of scrub typhus were detected by IgM IFA, using a 1:64 dilution. The sensitivities of the IgM enzyme-linked immunosorbent assay, IgM rapid flow assay (RFA), and IgG RFA were found to be 97%, 87%, and 77%, respectively. Their respective specificities were 100%, 100%, and 92%, respectively. The sensitivity and specificity of a nested PCR assay targeting a gene encoding a 56-kDa protein were found to be 50% and 100%, respectively.

Background & Objectives: Human cryptosporidiosis is endemic worldwide, and at least eight species have been reported in humans; the most common being Cryptosporidium hominis and C. parvum. Detailed understanding of the epidemiology of Cryptosporidium is increasingly facilitated using standardized universal technique for species differentiation and subtyping. In this study micro- and minisatellite targets in chromosome 6 were used to assess genetic diversity of C. hominis by sequence length polymorphisms along with single nucleotide polymorphisms (SNPs)., Methods: A total of 84 Cryptosporidium positive stool specimens were subjected to speciation and genotyping using small subunit (SSU) ribosomal RNA (rRNA) as the target gene. Genetic heterogeneity amongst C. hominis isolates was assessed by sequencing minisatellites, microsatellites and polymorphic markers including genes encoding the 60 kDa glycoprotein (GP60), a 47 kDa protein (CP47), a mucin-like protein (Mucin-1), a serine repeat antigen (MSC6-7) and a 56 kDa transmembrane protein (CP56)., Results: Of the 84 Cryptosporidium positive stool specimens, 77 (92%) were positive by SSU rRNA gene polymerase chain reaction (PCR) assay. Of these 77 isolates, 54 were identified as C. hominis and 23 as C. parvum. Of all the loci studied by multilocus sequence typing (MLST), GP60 gene could reveal the highest genetic diversity. Population substructure analysis of C. hominis performed by combined sequence length and nucleotide polymorphism showed nine multilocus subtypes, all of which were distinct groups in the study population., Interpretation & Conclusions: MLST, a powerful discriminatory test, demonstrated both variations and distribution pattern of Cryptosporidium species and its subtypes.

Cryptosporidiosis is predominantly a gastrointestinal disease of humans and other animals, caused by various species of protozoan parasites representing the genus Cryptosporidium. Detection of Cryptosporidium spp. in human clinical samples is central to the prevention, surveillance and control of cryptosporidiosis, particularly given that there is presently no broadly applicable treatment regimen for this disease. A non-radioactive, genus specific DNA dot blot hybridization assay was developed using Digoxigenin (DIG) labelled probes to detect Cryptosporidium DNA in human clinical samples. Four hundred fifty (n = 450) clinical samples were subjected to microscopic examination, Polymerase Chain Reaction assay (PCR), Dot blot hybridization assay and Real Time PCR assay. A total of forty-one (n = 41) samples were positive by microscopy, forty-two (n = 42) by both PCR assay and dot blot hybridization assay and forty-three (n = 43) by Real Time PCR assay. Dot blot hybridization assay with a sensitivity of 95.5% and specificity of 99.75% could be an ideal choice for routine investigation of a large number of samples in a clinical setting as well as field., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background & Objectives: Diarrhoea is the main clinical manifestation caused by intestinal parasitic infections in patients, with special reference to transplant recipients who require careful consideration to reduce morbidity and mortality. Further, molecular characterization of some important parasites is necessary to delineate the different modes of transmission to consider appropriate management strategies. We undertook this study to investigate the intestinal parasitic infections in transplant recipients with or without diarrhoea, and the genotypes of the isolated parasites were also determined., Methods: Stool samples from 38 transplant recipients comprising 29 post-renal, two liver and seven bone marrow transplant (BMT) recipients presenting with diarrhoea and 50 transplant recipients (42 post-renal transplant, eight BMT) without diarrhoea were examined for the presence of intestinal parasites by light microscopy using wet mount, modified Ziehl-Neelsen staining for intestinal coccidia and modified trichrome staining for microsporidia. Genotypes of Cryptosporidium species were determined by multilocus genotyping using small subunit ribosomal (SSUrRNA), Cryptosporidium oocyst wall protein (COWP) and dihydrofolate reductase (DHFR) as the target genes. Assemblage study for Giardia lamblia was performed using triose phosphate isomerase (TPI) as the target gene. Samples were also screened for bacterial, fungal and viral pathogens., Results: The parasites that were detected included Cryptosporidium species (21%, 8/38), Cystoisospora (Isospora) belli (8%, 3), Cyclospora cayetanensis (5%, 2), G. lamblia (11%, 4), Hymenolepis nana (11%, 4), Strongyloides stercoralis (3%, 1) and Blastocystis hominis (3%, 1). Multilocus genotyping of Cryptosporidium species at SSUrRNA, COWP and DHFR loci could detect four isolates of C. hominis; two of C. parvum, one of mixed genotype and one could not be genotyped. All the C. hominis isolates were detected in adult post-renal transplant (PRT) recipients, whereas the C. parvum isolates included a child with BMT and an adult with PRT. Clostridium difficle, cytomegalovirus and Candida albicans were found in 2, 3 and 2 patients, respectively., Interpretation & Conclusions: In the present study, C. hominis was observed as an important parasite causing intestinal infections in transplant recipients. Multilocus genotyping of Cryptosporidium species could detect four isolates of C. hominis; two of C. parvum, one of mixed genotype and one could not be genotyped. Genotyping of G. lamblia revealed that assemblage B was most common., Competing Interests: None.