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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.)

Despite the availability of many parasitological methods for detection of Cryptosporidium and Isospora (Cystoisospora) belli in fecal samples, there are uncertainties about the accuracy of these techniques in laboratory practice. In this study, 27 formalin-fixed positive stool samples for Cryptosporidium and 15 for I. belli were analyzed by 2 concentration methods, sedimentation by centrifugation (SC) and formalin-ethyl acetate (FE), and by 3 tintorial techniques, modified Ziehl-Neelsen (ZN), safranin (SF), and auramine (AR). No significant differences were observed on Cryptosporidium identification between concentration methods, while a significantly higher number of I. belli oocysts (P < 0.0001) was detected in fecal smears concentrated by the SC than by the FE method. Fecal samples processed by FE produced a median oocyst loss to the fatty ring of 34.8% for Cryptosporidium and 45.4% for I. belli. However, FE concentration provided 63% of Cryptosporidium and 100% of I. belli slides classified as superior for microscopic examination. Regarding the efficiency of staining methods, a more significant detection of Cryptosporidium oocysts was observed in fecal smears stained by ZN (P < 0.01) or AR (P < 0.05) than by the SF method. Regular to high-quality slides for microscopic examination were mostly observed in fecal smears stained with AR or ZN for Cryptosporidium and with SF or ZN for I. belli. This study suggests a great variability in oocyst power detection by routine parasitological methods, and that the most frequent intestinal coccidians in humans have specific requirements for concentration and staining.

Chronic diarrhea with a 35 kg weight loss (75 kg to 40 kg) occurred during 2 years in an alcoholic patient was diagnosed with Isospora belli infection in the Republic of Korea. The patient, a 70-year old Korean male, had been a heavy drinker for more than 30 years. He was admitted to the Seoul National University Hospital because of long-standing diarrhea and severe weight loss. He had an increased white blood cell (WBC) count with high peripheral blood eosinophilia (36.8-39.9%) and lowered protein and albumin levels but without any evidence of immunosuppression. A parasitic infection was suspected and fecal examination was repeated 3 times with negative results. Peroral endoscopy with mural biopsy was performed in the upper jejunum. The biopsy specimens revealed villous atrophy with loss of villi together with various life cycle stages of I. belli, including trophozoites, schizonts, merozoites, macrogamonts, and microgamonts. The patient was treated successfully with oral doses of trimethoprim 160-320 mg and sulfamethoxazole 800-1,600 mg daily for 4 weeks. A follow-up evaluation at 2.5 years later revealed marked improvement of body weight (68 kg), increased protein and albumin levels, and normal WBC count with low eosinophils (3.1%). This is the first clinical case of isoporiasis with demonstration of various parasitic stages in the Republic of Korea.

Diurnal periodicity is a phenomenon that has been observed in coccidian of Isospora parasites of passerines, which have been eliminated great number of oocysts at dusk. The objective of this study was to evaluate the occurrence of periodicity of oocysts presence in the green-winged-saltator Saltator similis, and its use in the diagnosis of coccidiosis in wild birds in captivity. A total of 220 fecal samples were collected from birds, apprehended from illegal trading and kept in quarantine in CETAS∕IBAMA, in the morning and late afternoon, from May to November 2010. It was observed that 1.82% of the samples collected in the morning were positive, while 31.36% of samples were positive in the late afternoon. In addition, the number of oocysts shed was greater in the afternoon. Therefore, it was concluded that the sampling in the late afternoon provided greater reliability for the diagnosis of coccidiosis in green-winged-saltators. Moreover, in this study a new isosporoid coccidian parasite from the green-winged-saltator S. similis was observed and is herein described. Isospora similisi n. sp. oocysts are spheroidal to sub-spheroidal, 27.5 × 25.9 µm, with a smooth and bi-layered wall, ∼1.2 mm. Micropyle and oocyst residuum are absent, but splinter-like or comma-like granules are present. Sporocysts are ellipsoidal or slightly ovoidal, 17.4 × 12.2 mm. A stieda body and substieda body are present. The sporocyst residuum is composed of granules of different sizes. Sporozoites are vermiform with a single refractile body and a nucleus. This is the fourth description of an isosporoid coccidium infecting S. similis and the sixth description from Cardinalidae.

We report a severe case of diarrhea in a 62-year-old female HIV-negative patient from whom Giardia lamblia and Isospora belli were isolated. Because unusual and opportunistic infections should be considered as criteria for further analysis of immunological status, laboratory investigations led to a diagnosis of common variable immunodeficiency (CVID). This is the first reported case of isosporiasis in a patient with CVID and illustrates the importance of being aware of a possible link, particularly in relation to primary immunodeficiency.

Isospora belli infection, characterized by peripheral blood eosinophilia, is often seen as an opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). It is also reported in patients with underlying lymphoproliferative disorders including lymphoma and leukemia. Eosinophil-associated gastrointestinal disorders (EGID), including eosinophilic gastroenteritis (EGE), is characterized by eosinophilic infiltration of the gastrointestinal (GI) tract with various GI symptoms. We report a case of a 50-year-old male who developed Isospora superinfection of the small bowel while receiving systemic corticosteroids for EGE. He presented with worsening diarrhea, abdominal pain, nausea and vomiting with worsening peripheral eosinophilia. I. belli infection was diagnosed by the detection of oocysts in stool samples and by the presence of the parasite on duodenal biopsy in the background of tissue eosinophilia. I. belli can cause severe chronic diarrhea in immunocompromised patients on corticosteroids. Trimethoprim-sulfamethoxazole often provided rapid cure. Even though peripheral blood eosinophilia was seen in both EGE and Isospora infection, the identification of subnuclear protozoal inclusions as a new histologic finding, as well as the absence of this finding in previous duodenal biopsies coupled with the continued presence of tissue eosinophilia, favored a parasitic superinfection in the setting of underlying EGE., (Copyright © 2011 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.)

Isospora belli is an opportunistic protozoon which should be monitored in patients with gastrointestinal complaints such as abdominal pain, nausea and diarrhoea, in both immune-compromised and immune-competent patients. Our case was a 35 year-old male patient who had received a liver transplant because of cirrhosis and hepatic fibrosis. A diarrhoeic stool sample of the patient was sent to the laboratory for microbiological and parasitological analyses. Faecal occult blood was positive and bacteriological analysis was negative. Isospora belli infection was diagnosed by detection of the oocysts in stool samples. Per oral trimethoprim-sulphamethoxazole treatment was given in 500 mg bid dose for 10 days. At the end of the treatment, no oocyst of Isospora belli was seen but non-pathogenic cysts of Entamoeba coli and vacuolar forms of Blastocystis hominis were observed. Two months later the patient had abdominal pain, fatigue and diarrhoea again and parasitological re-evaluation showed oocysts of Isospora belli.

Background: Hypokalemia of clinical significance, severe enough to cause paralysis and cardiac dysrhythmias, is an uncommon life-threatening medical disorder. Hypokalemic periodic paralysis (HPP), where an abrupt intracellular shift of potassium has occurred, must be distinguished from hypokalemic non-periodic paralysis (non-HPP), where a total body potassium deficit exists. The challenge for emergency physicians is to swiftly and accurately differentiate disease etiology and institute prompt treatment. Aggressive potassium repletion, required in non-HPP etiologies, may predispose HPP patients to dangerous and potentially fatal rebound hyperkalemia as the intracellular potassium shift resolves., Objectives: Describe the process by which HPP and non-HPP can be differentiated on clinical and laboratory grounds leading to appropriate resuscitation from severe and clinically relevant hypokalemia. Chronic diarrhea syndromes and possibly normal alkaline phosphatase levels alert the clinician to the potential for non-HPP., Case Report: A case of HIV/AIDS-associated isospora belli diarrheal illness with severe hypokalemia of the non-HPP type is presented. Historical, laboratory, and clinical findings, which assisted in the differentiation from HPP, are emphasized. Clinical progression and treatment strategies, as well as electrocardiogram findings with T-U-P fusion waves, are described in detail., Conclusion: The history, especially the time course of disease, is essential in differentiating HPP and non-HPP, allowing treatment to proceed without overcorrection and rebound hyperkalemia. Although other infectious diseases have been linked to non-HPP, to our knowledge this is the first report linking non-HPP to isospora belli diarrheal illness., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The differential diagnosis of diarrhea in immunocompromised patients encompasses many intestinal parasites including the coccidian Cystoisospora belli. Gastrointestinal infection with C. belli leads to cystoisosporiasis with diarrhea and, depending on host immune status, can cause extraintestinal disease. C. belli is usually diagnosed by examination of stool or intestinal biopsy specimens; however, the organism may be undetected using these test methods. Thus, more sensitive molecular tools for detection of pathogenic parasites are desirable. Herein is described a patient with AIDS who had persistent diarrhea of unknown cause. Microscopic examinations of stool and ileal biopsy specimens were initially unremarkable for any specific pathogen. Screening of DNA extracted from biopsy material using extended-range PCR primers recognizing conserved DNA sequences found in many fungi and parasites revealed infection with C. belli, which was confirmed at repeat histologic analysis. Extended-range PCR screening was used because the differential diagnosis was broad and other tools were not applied, yet this molecular approach led to the appropriate diagnosis and treatment of the condition. Thus, this approach offers a promising test for diagnosis of parasitic diseases that elude diagnosis using conventional methods., (Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.)

A 35-year-old male, positive for Human Immunodeficiency Virus (HIV) antibodies, was found to have heavy infestation by Isospora belli, leading to gastrointestinal opportunistic infection. Stool sample of the patient presenting with diarrhea of 2 months duration showed numerous oocysts of I. belli. His blood CD4 count was 85/cmm. The patient was from a slum area with poor sanitation. He was put on antimicrobial agent trimethoprim-sulfamethoxazole and was followed up. However, he died after 1 month of treatment.

Travel-related diarrhea is common among tourists to developing countries. We report two cases of diarrhea due to Cryptosporidium hominis and Isospora belli, respectively, in a child and an adult returning from Africa, without other associated microorganisms. We emphasize the need to detect underdiagnosed coccidiosis in diarrheic travelers with specific methods.

Isospora belli is a protozoan that only affects humans, after ingestion of Isospora's oocysts. Immunocompetent patients usually do not develop the infection. Immunocompromised hosts may have profuse diarrhea with other gastrointestinal symptoms. Treatment is based on trimethoprim-sulfamethoxazole. In 2006 we performed an isolated intestinal transplantation in a patient with ultra-short bowel syndrome. Neither rejection nor clinical problems occurred after transplant, but signs of intestinal inflammation were seen in every protocol biopsy starting at the first month post transplant. Almost 3 months after the procedure, the patient was re-admitted with diarrhea. I. belli infection was diagnosed by detection of the oocysts in stool samples. Antibiotic treatment with trimethoprim-sulfamethoxazole was initiated with excellent outcome and without relapses. To the best of our knowledge, this is the first case of isosporosis in a small bowel recipient.

Opportunistic isosporidial infection of the gastrointestinal tract is frequently encountered in patients with acquired immunodeficiency syndrome (AIDS) and is considered to be an AIDS-defining illness. Chronic severe watery diarrhea due to Isospora belli has also been reported in other immunodeficiency states. This report describes severe chronic debilitating diarrhea due to isosporiasis in a patient with mediastinal thymoma, a common tumor of the anterior mediastinum, originating from the epithelial cells of the thymus. Numerous oocysts of I. belli were detected in direct smear preparation of the diarrheic stool sample of the patient, who had an 8-month history of recurrent diarrhea. Duodenal and colonic mucosal biopsies revealed slight degrees of atrophic changes associated with infiltration of the lamina propria by an appreciable number of eosinophiles and the presence of unizoit tissue cysts of I. belli in the surface epithelium of the duodenal mucosa. The patient was first treated with trimethoprim-sulfamethoxazole and subsequently underwent complete thymectomy. Later, due to recurrence of the diarrhea, he was treated with ciprofloxacin.

Isospora belli is an intracellular protozoan parasite that causes diarrhea worldwide and is endemic in the tropics. In the United States, it is an uncommon cause of traveler's diarrhea and a relatively rare opportunistic pathogen among the immunocompromised, particularly AIDS patients. Isospora infects the small intestine, where both sexual and asexual replication occur, and oocysts are shed in the stool. Isosporiasis of the gallbladder has also been described in AIDS patients. We report a case of diffuse biliary isosporiasis in a West African man who presented with acute illness and was found to have dilated bile ducts. He had no history of hepatobiliary disease; his HIV status was unknown. Endoscopic retrograde cholangiopancreatography demonstrated markedly abnormal intrahepatic and extrahepatic bile ducts, with radiologic findings reminiscent of primary sclerosing cholangitis. However, common bile duct biopsies revealed Isospora belli, which was confirmed by both electron microscopy and polymerase chain reaction-based molecular analysis.

A 14-month-old intact, female Abyssinian cat was presented for chronic intermittent diarrhea and bilateral enlargement of the mammary glands. Gastrointestinal coccidiosis was diagnosed; therapy with sulfadi-methoxine was unsuccessful in the elimination of Isospora felis and clinical signs. Infection with Tritrichomonas foetus was diagnosed by fecal polymerase chain reaction (PCR) and successfully treated with ronidazole and dietary modification.

The modification of flotation method for the examination of diarrhoeic piglet faeces for the detection of Isospora suis oocysts was elaborated. The method was based on removing fractions of fat from the sample of faeces by centrifugation with a 25% Percoll solution. The investigations were carried out in comparison to the McMaster method. From five variants of the Percoll flotation method, the best results were obtained when 2ml of flotation liquid per 1g of faeces were used. The limit of detection in the Percoll flotation method was 160 oocysts per 1g, and was better than with the McMaster method. The efficacy of the modified method was confirmed by results obtained in the examination of the I. suis infected piglets. From all faecal samples, positive samples in the Percoll flotation method were double the results than that of the routine method. Oocysts were first detected by the Percoll flotation method on day 4 post-invasion, i.e. one-day earlier than with the McMaster method. During the experiment (except for 3 days), the extensity of I. suis invasion in the litter examined by the Percoll flotation method was higher than that with the McMaster method. The obtained results show that the modified flotation method with the use of Percoll could be applied in the diagnostics of suckling piglet isosporosis.

A real-time polymerase chain reaction (PCR) assay targeting the internal transcribed spacer 2 region of the ribosomal RNA gene was developed for the detection of Isospora belli DNA in fecal samples, including an internal control to detect inhibition during the amplification process. The assay was performed on species-specific DNA controls (n = 27) and a range of positive (n = 21) and negative (n = 120) stool samples, and achieved 100% specificity and sensitivity. The simple fecal sample collection procedure, the high-throughput potential, and the possibility of quantification makes the I. belli real-time PCR assay a powerful diagnostic tool for epidemiologic studies with possibilities for extension to other helminthes and protozoa using additional molecular targets. In addition, this Isospora PCR could augment the clinical laboratory diagnosis of isosporiasis, in particular, in patients with a travel history to developing countries.

Patients with AIDS are particularly susceptible to infection with intestinal coccidia. In this study the prevalence of infections with Cryptosporidium sp and Cystoisospora belli were evaluated among HIV/AIDS patients in the Triângulo Mineiro region, Brazil. Between July 1993 and June 2003 faecal samples from 359 patients were collected and stained by a modified Ziehl-Neelsen method, resulting in 19.7% of positivity for coccidian (8.6% with Cryptosporidium sp, 10.3% with Cystoisospora belli and 0.8% with both coccidian). Patients with diarrhoea and T CD4+ lymphocyte levels < or =200 cells/mm3 presented higher frequency of these protozoans, demonstrating the opportunistic profile of these infections and its relationship with the immunological status of the individual. It was not possible to determine the influence of HAART, since only 8.5% of the patients positive for coccidian received this therapy regularly. Parasitism by Cryptosporidium sp was more frequent between December and February and thus was characterised by a seasonal pattern of infection, which was not observed with Cystoisospora belli.

Coinfection with Ehrlichia canis, Babesia canis, Hepatozoon canis, Isospora spp., Giardia spp., and Dipylidium caninum were detected in a 6-week-old dog. The effect of multi-pathogen infection was a fatal combination of gastrointestinal and hematologic abnormalities, including diarrhea, vomiting, anorexia, distended painful abdomen, intussusception, severe thrombocytopenia, anemia, and hypoproteinemia.

Isospora belli, a coccidian parasite usually causes a self limiting illness of acute onset with fever, diarrhoea and colicky pain in a normal host. In immunocompromised patients human isosporiasis becomes chronic. We report a case of a malnourished 9 year old female child who presented with complaints of loose stools, nausea, vomiting and weight loss for the past three months. Stool examination revealed immature oocysts of Isospora belli. The patient was successfully treated with TMP-SMX.

We describe the first case of isosporiasis in a liver transplant patient. Watery diarrhea due to Isospora belli was observed in a woman who had undergone liver transplantation 8 months prior. She was successfully treated with trimethoprim-sulfamethoxazole. This parasite should be taken into consideration as an opportunistic infection in transplant patients who need increased hygienic awareness.

To assess the prevalence of intestinal parasites in a cohort of human immunodeficiency virus (HIV)-infected adults in Cameroon, a cross-sectional study was conducted. Detection of parasites was performed in 181 stool samples from 154 HIV-infected patients with a mean CD4 cell count of 238 cells/mm(3). Only 35 patients (22%) were receiving antiretroviral therapy at the time of stool sampling, and 46 (29%) had diarrhea. Opportunistic protozoa were found in 15 patients (9.7%), 8 of whom (53%) had diarrhea. Enterocytozoon bieneusi was found in eight patients, C. parvum in six patients, and Isospora belli in three patients. All E. bieneusi isolates tested belonged to the same genotype. The prevalence of opportunistic protozoa among patients with CD4 cell counts less than 50/mm(3) was 32%.