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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., (© 2021. Indian Society of Gastroenterology.)

Cystoisospora belli is a coccidian parasite that causes prolonged watery diarrhea especially among immunocompromised patients. Herein, we report a renal transplant patient who complaints of alternating diarrhea and review of literature related to cystoisosporiasis amongst the transplant recipients., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2021 Busra Betul Ozmen-Capin, Gamze Gursoy, Sema Tortop, Jabrayil Jabrayilov, Ahmet Cagkan Inkaya, Sibel Erguven.)

Multiple groups have recently reported involvement of the gallbladder mucosa of immunocompetent patients by cystoisospora organisms. However, this has recently been disproved with the support of molecular and ultrastructural studies. Here we present a summary of these events, recounting how this pseudo-Cystoisospora epidemic began and ended. This review also highlights the important role played by ancillary techniques in supplementing the morphologic diagnosis of pathogens.

Rationale: Cystoisosporiasis is an intestinal infectious disease caused by a coccidian protozoa, Cystoisospora belli (C. belli). It can cause prolonged and refractory diarrhea most commonly in immunocompromised patients, while immunocompetent individuals usually exhibit no symptoms or self-limited diarrhea., Patient Concerns: We herein report a case of chronic cystoisosporiasis in an immunocompetent patient. A 62-year-old man, who had been first diagnosed with cystoisosporiasis 15 years ago and had been treated with oral administration of trimethoprim-sulfamethoxazole (TMP-SMX), complained of persistent watery diarrhea. He was negative for anti-human immunodeficiency virus antibody and anti-human T-cell leukemia virus type 1 (HTLV-1) antibody., Diagnosis: Biopsy specimens from the duodenum revealed oocysts in the atrophic absorptive epithelium and protozoa were detected through stool examination, indicating the recurrence of cystoisosporiasis. Capsule endoscopy showed diffuse atrophic mucosa with white villi in the entire small intestine. We diagnosed him with chronic cystoisosporiasis that occurred in an immunocompetent adult., Interventions: Since oral administration of TMP-SMX and ciprofloxacin were ineffective, the intravenous administration of TMP-SMX was initiated., Outcomes: Intravenous TMP-SMX exhibited a significant improvement., Lessons: This case indicates that even immunocompetent individuals may develop recurrent and refractory cystoisosporiasis. Furthermore, intravenous treatment of antibiotic agents should be considered when the impaired absorptive ability from the small intestine is suspected., Competing Interests: The authors state that they have no conflict of interest., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Systemic isosporosis (formerly atoxoplasmosis), is a protozoal infection that causes death in nestling and fledgling passerine birds impacting ex situ breeding and reintroduction programs. Because current antemortem diagnostic tests lack sensitivity, a qPCR was developed for detection of Isospora spp. using primers and a fluorescent-tagged MGB probe targeting the large subunit (28s) ribosomal RNA gene (assay efficiency = >100%; sensitivity = <1 dsDNA copy). The assay was used to screen postmortem frozen or formalin-fixed paraffin-embedded tissue samples from passerine birds ( n = 24; 12 with confirmed systemic isosporosis), whole blood and feces ( n = 38) from live passerines, and other tissues infected with phylogenetically similar protozoa. The qPCR identified Isospora sp. DNA in tissues from 21/24 birds including 12/12 birds with cytologically-histologically confirmed infection (100% sensitivity) and 9/12 birds lacking microscopic organisms. The assay also amplified Eimeria sp. DNA; however, sequence analysis ruled out infection in the passerine cases. Blood and/or feces were positive in 30/38 birds, and in only 7/38 birds, blood and feces both contained Isospora sp. DNA. Finally, the qPCR was utilized to screen 30 consecutive daily fecal samples from live passerines ( n = 20) to determine optimal sampling protocols. One or more of the daily fecal samples were positive in all 20 birds. In individual birds, the interval between positive qPCR amplification results ranged from 0 to 23 days, with an average of 5.85 days. Simulated application of 13 potential sample collection schedules was used to identify the sensitivity of repeated testing for identification of infected birds. Increased sampling days resulted in higher sensitivity but increased both cost and animal handling requirements. Based on statistical analysis and clinical considerations, the testing recommendation for detection of fecal shedding was collection and assay of five consecutive daily fecal samples, which had an average diagnostic sensitivity of 0.86.

Objectives: There is recently reported increased prevalence of Isospora organisms in cholecystectomy specimens from immunocompetent patients, especially in acalculous cholecystectomies. We performed an ultrastructural and molecular evaluation of these specimens., Methods: From 28 gallbladders with intraepithelial inclusions, two specimens with diffuse involvement of the gallbladder epithelium were analyzed by electron microscopy. Polymerase chain reaction was performed on five samples for the ITS2 region of C belli and eukaryotic 18S region. The 18S products were sequenced by next-generation sequencing., Results: Electron microscopic analysis showed cytoplasmic condensations leading to vacuole formation. In contrast with true C belli, there were no identifiable organelles or organization. None of these cases showed amplified products other than human on molecular analysis., Conclusions: Electron microscopic analysis demonstrates that the inclusions are condensed cytoplasmic material and not true organisms., (© American Society for Clinical Pathology, 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Until the discovery of Toxoplasma gondii oocysts in cat feces in 1970, little was known of coccidiosis in cats. Until 1970, three coccidian parasites based on different sized oocysts were recognized, the parasite with large oocysts (∼40 μm long and called Isospora felis), medium sized oocysts (∼25 μm long, called Isospora rivolta), and small sized oocysts (14 μm or less, called Isospora bigemina) were known and they were considered not host-specific. Later, it was demonstrated that these parasites were host-specific and had also extra-intestinal stages. The Isospora bigemina turned out to be more than 25 organisms belonging to T. gondii, Hammondia spp., Sarcocystis spp., Besnoitia spp., and Neospora spp.; these subjects have been reviewed previously in detail. The present paper summarizes biology of Isospora felis, and I. rivolta (now transferred to genus Cystoisospora), including taxonomy, life cycle, diagnosis, and treatment. Re-excretion of T. gondii oocysts from chronically infected cats after superinfection with Cystoisospora felis oocysts is discussed. There are only two species of Cystoisospora species in cats, C. felis and C. rivolta; Isospora novocati and Cystoisospora frenkeli named for I. rivolta-like parasites of cats are considered synonym of C. rivolta. Clinical coccidiosis occurs more commonly in recently weaned kittens and C. felis infections are more prevalent than C. rivolta., (Published by Elsevier B.V.)

Good's syndrome, the adult onset hypogammaglobulinemia associated with thymoma has been explained about six decades ago. It generally presents with recurrent infections and several paraneoplastic syndromes including myasthenia gravis, pure red cell aplasia, connective tissue disorders, superior vena cava, Horner's syndrome, lichen planus and inflammatory bowel disease. Lack of B cell, dysfunction of T cell, CD4+ T cell lymphopenia, reversed CD4/CD8+ T cell ratio, autoantibodies against Th17 related cytokines have been respected as the pathogenesis of the immune dysregulation this syndrome. A 57-year-old man was admitted to our hospital with a history of thymectomy due to thymoma (Type A) 6 years ago. He developed weight loss and recurrent persistent diarrhea caused by isospora belli. His chest CT scan revealed bilateral bronchiectasis. His laboratory data showed hypogammaglobulinemia and he was treated by monthly IVIG with the diagnosis of good's syndrome. Nevertheless he referred again with left sided loss of vision because of CMV retinitis and he also developed nail candidiasis. Good's syndrome should be considered in every patient with a history of thymoma and recurrent infection. Immunologic evaluation of these patients including measurement of the serum level of immunoglobulin as well as B cell and T cell subgroups should be performed. Physicians must be aware and think about this entity in patients with adult onset immunodeficiency.

Cystoisospora belli (previously known as Isospora belli) is a tropical coccidian parasite sometimes leading to severe diarrhea in immunocompromised patients. Here we describe a fatal case of cystoisosporiasis in a non HIV-immunocompromised 71-year-old female with no recent travel history. Infection was either latent or potentially caused by the consumption of contaminated imported food from Asia. Diagnosis was made by microscopical detection of numerous C. belli oocysts in stools without specific staining. Treatment with TMP-SMZ slightly improved diarrhea within 3days, but dehydration subsequently led to acute decompensated heart failure and a fatal evolution. This report illustrates the possibility of severe cystoisosporiasis in non HIV-immunocompromised patients in a non-endemic country and highlights the risk of transmission through imported contaminated food consumption., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The aim of this study was to present three cystoisosporiasis cases diagnosed in pediatric patients of the Yuzuncu Yil University Medical Faculty. In the study, stool samples of the patients were evaluated by native-Lugol and modified acid-fast staining methods in the Parasitology Laboratory. The first case was a 4-year-old male child diagnosed with acute lymphoblastic leukemia (ALL). It was reported that the patient had abdominal pain, and permanent bloody and mucous diarrhea (8-10 times a day) was present for almost 1 week after the beginning of ALL treatment. The second case was a 10-year-old boy diagnosed with depression. The patient was brought to our hospital by his parents with complaints of abdominal pain, diarrhea, lack of appetite, weight loss, and fatigue persisting since 1 month in addition to headache, fear, sleeplessness, and waking up with cry. The third case was a 13-year-old boy who complained of abdominal pain, diarrhea (rare occasions), lack of appetite, and headache for 2 months. These patients had not traveled abroad. The cases were treated successfully with co-trimoxazole. Our results suggest that all patient groups with diarrhea and abdominal pain should also be considered in cystoisosporiasis.

Isospora suis is an intestinal protozoan parasite in pigs. The 2-3 weeks old piglets are most often infected by I. suis because their immune system is not fully developed. The infection exhibits clinical features such as diarrhea and dehydration and seriously affects the economic interests of farmers. The traditional method of identifying I. suis relies on the detection of fecal oocysts, which depends heavily on the accumulation of experience. Thus, missed detection, and false alarms often occur during detection. With the development of molecular-based detection methods, development of a simple, convenient and more sensitive method for the detection of I. suis is an urgent need. In this study, based on the 18S rRNA gene sequence, a fluorescence -based real-time loop-mediated isothermal amplification (LAMP) assay was established for the detection of I. suis. The results showed that the assay is highly specific and sensitive, with a detection limit of 2.74 × 10(2) copies/μL recombinant plasmid of I. suis, corresponding to 1 fg/μL plasmid when converted to DNA concentration. The sensitivity is about 100 times higher than conventional PCR. Additionally, DNA extracted from a certain number of oocysts was used for detection, and it showed that the LAMP assay had a detection limit of 5 oocysts, lower than that of 13 oocysts of conventional PCR. The established LAMP assay overcomes the shortage of the traditional microscopy-based method, and provides a valuable way for molecular detection of I. suis., (Copyright © 2016 Elsevier Inc. All rights reserved.)

This report describes the novel sampling of bile from the biliary endoscopic intervention for the molecular identification of parasite infection.A 63-year-old Vietnamese man underwent travel health examination in our hospital. Physical examination showed that his height was 159 cm and weight was 41 kg. He had a 15-year history of intermittent abdominal pain and frequent episodes of diarrhea. Laboratory tests revealed raised eosinophil count (23%, normal range [NR] 0-5), absolute eosinophil count (1899/μL, NR 50-350), and levels of serum immunoglobulin E (3770 IU/mL, NR < 100), aspartate transaminase (270 U/L, NR 0-37), alanine transaminase (210 U/L, NR 0-40), and total bilirubin (1.8 mg/dL, NR 0.2-1.4); however, the serum alkaline phosphatase level was normal (65 U/L, NR 28-94) and non-reactive result for serum human insufficiency virus antibody.Magnetic resonance cholangiopancreatography revealed diffuse dilatation of the biliary tree; the common hepatic and pancreatic duct diameters increased to 1.86 cm and 0.61 cm, respectively.Endoscopic retrograde cholangiopancreatography was performed and a 10-Fr model plastic biliary stent was inserted and flushed with 20 cc normal saline; thereafter, the bile was collected and sent for DNA sequencing. Isospora belli (IB) infection was identified by a polymerase chain reaction.Trimethoprim-sulfamethoxazole 800 mg q6h was administered for 1 month. Liver enzyme levels normalized and negative for concentration method of ova study. The patient was doing well and weighed 51 kg at the outpatient clinic visit 3 months later.This bile sampling with molecular identification has not been described in the literature. We believe that an acute IB infection through fecal-oral transmission may progress to chronic infection of the hepatobiliary system, leading to biliary obstruction and jaundice., Competing Interests: The authors have no funding and conflicts of interest to disclose.

Background: Diarrhea in piglets directly affects commercial swine production. The disease results from the interaction of pathogens with the host immune system and is also affected by management procedures. Several pathogenic agents such as Campylobacter spp., Clostridium perfringens, Escherichia coli, Salmonella spp., group A rotavirus (RV-A), coronaviruses (transmissible gastroenteritis virus; porcine epidemic diarrhea virus), as well as nematode and protozoan parasites, can be associated with disease cases., Results: All bacterial, viral, protozoan, and parasitic agents here investigated, with the exception of Salmonella spp. as well as both coronaviruses, were detected in varying proportions in piglet fecal samples, and positive animals were equally distributed between case and control groups. A statistically significant difference between case and control groups was found only for Cystoisospora suis (p = 0.034) and Eimeria spp. (p = 0.047). When co-infections were evaluated, a statistically significant difference was found only for C. perfringens β2 and C. suis (p = 0.014)., Conclusions: The presence of pathogens in piglets alone does not determine the occurrence of diarrhea episodes. Thus, the indiscriminate use of antibiotic and anthelminthic medication should be re-evaluated. This study also reinforces the importance of laboratory diagnosis and correct interpretation of results as well as the relevance of control and prophylactic measures.

A 47-year-old woman presented with a history of vague abdominal pain for several years, which worsened over the past 2 months, with pain more prominent in the right upper quadrant. She also had a history of peptic ulcer disease. The ultrasound scan of right upper quadrant revealed normal gallbladder and oesophagogastroduodenoscopy was unremarkable. A (99m)technetium labelled hepato iminodiacetic acid (HIDA) scan with cholecystokinin provocation demonstrated a decreased gallbladder ejection fraction (EF) of 32%. On this basis, the patient was diagnosed with biliary dyskinesia and underwent an elective laparoscopic cholecystectomy. Histopathological analysis revealed chronic cholecystitis with Cystoisospora belli identified in the gallbladder wall. Cystoisospora has been identified to cause an opportunistic acalculous cholecystitis among immunocompromised hosts, especially those with AIDS. This is the first case report of chronic cholecystitis due to C. belli in an immunocompetent patient., (2015 BMJ Publishing Group Ltd.)