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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.

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.

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.

Isospora belli is a coccidian protozoon that can cause serious diarrhea especially in immunocompromised patients. The laboratory diagnosis depends primarily on the identification of oocysts in stool specimens by direct microscopic examination with iodine or special stains. This case is presented in order to draw attention to isosporiasis among the diarrheas that can be seen in elderly patients with several chronic diseases. A 81 year-old debilitated male, who had a history of hypertension, Alzheimer's disease, previous cerebrovascular accident and right hemiplegia, was admitted to our hospital complaining of malaise, anorexia, chills, abdominal pain, dysuria, cough, sputum and diarrhea of ten days duration. I. belli oocysts were detected by microscopic examination of the sample with iodine after concentration by formalin-ethyl acetate sedimentation. Then, modified acid-fast and trichrome stains were performed and I. belli oocysts were detected with both methods. Similar to this case, infections caused by I. belli can occur in elderly immunocompromised patients with several chronic diseases and inadequate nutrition and care. Consequently, in individuals with persistent diarrhea, examinations and tests should be carried out by taking their immune status into consideration and stool examinations should be done at frequent intervals using the concentrations methods and special stains.

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.)

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.)

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.

Isosporosis is an infection caused by parasitic protozoa of the genus Isospora, coccidia affecting various different vertebrate species, including humans. It is an uncommon infection in our country and it is not a zoonosis. We present two cases of Isospora belli infection in HIV positive patients from the Valparaiso region. We discuss the clinical events caused by this agent, its epidemiology, cases published in the local and foreign literature, as well as its treatment and prevention measures.

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.

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.

A highly sensitive diagnostic method is of great importance for detection of I. suis (Isospora suis). In the present study KSFV (combined sedimentation-flotation method) using different flotation solutions (NaCl, ZnSO4, NaCl-sucrose) was investigated regarding sensitivity, costs and expenditure of human labour in comparison to FV (flotation method) using NaCl-sucrose solution and to AM (autofluorescence microscopy). Ninety faecal samples were examined. Using AM, oocysts were detected in 83.3% of the samples. In cases of KSFV and FV, respectively, 41.1% to 53.3% of samples were tested positive. The quantity of detected oocysts was markedly higher in AM than in KSFV or FV. Therefore AM is the most sensitive of the comprised methods. The expenditure of labour is lowest in AM, time exposure is lower in FV than in KSFV. For performance of AM a fluorescence microscope is required contrary to KSFV and FV.

Isospora belli infection is frequent in immunosuppressed patients and can cause wasting diarrhea. We present the first isosporiosis case in a renal transplant recipient from Turkey. The 25-year old male patient who had had a renal transplantation due to renal failure and had received immunosuppressive therapy presented at the hospital complaining of weakness, nausea, vomiting and diarrhea that had lasted for 15 days. Isospora belli oocysts were detected in stool samples by direct microscopy, modified Ziehl-Neelsen staining methods and autofluorescence technique. Oocysts in the stool samples were also sporulated in 2.5% potassium dichromate and the sporulated oocysts were seen microscopically. The patient was treated with co-trimoxazole (trimethoprim 160 mg, sulphamethoxazole 800 mg) every 12 hours for seven days, with elimination of the symptoms at this time. After this, Isospora belli oocysts were no longer seen in stool samples.

This report describes a case of granulomatous endometritis caused by coccidiosis in an immunologically uncompromised 63 year old patient. The glandular epithelium of the endometrium contained numerous intracytoplasmic cysts, corresponding to periodic acid Schiff positive and methenamine silver negative sporoblasts. The endometrial glands revealed reactive phenomena, such as eosinophilic and squamous glandular metaplasia and intraluminal desquamation. Non-necrotising epithelioid granulomata, lacking the presence of parasites, were present in the stroma. Although not detected in the stool examination, the organisms were probably Isospora belli. There was no evidence of other foci of the disease. Coccidiosis should be differentiated from the more commonly occurring coccidiomycosis.

This report describes the presence of Isospora belli unizoic cysts in mesenteric lymph nodes and of gametocytes in the gallbladder epitelium of a 26 year-old Brazilian male patient with Acquired Immune Deficiency Syndrome. This patient had received treatment for several times with sulfamethoxazole-trimethoprim. It is discussed the significance of I. belli tissue cysts as possible foci of resistance of the parasite and their association with the infection relapse even post-treatment with anticoccidian medication.

Lacto-phenol cotton blue (LPCB) was found to be a useful stain for detection of Cyclospora and Isospora oocysts in direct wet mounts of stool. LPCB stained these parasites blue, and differentiated their internal structures clearly, thereby facilitating detection and accurate identification of these parasites. However, the LPCB staining was not found useful in the identification of Cryptosporidium. The LPCB wet mount is recommended for use in the laboratories where acid-fast staining is not performed routinely, such as in a peripheral laboratory or in a rural health centre in the developing countries.

Parasites from swine faeces were examined for autofluorescence. Oocysts of Eimeria polita, E. scabra and Isospora suis, cysts of Balantidium coli and eggs of Oesophagostomum dentatum, Strongyloides ransomi and Trichuris suis (but not those of Ascaris suum) emitted light after excitation with UV light. I. suis oocyst counts in McMaster chambers utilising autofluorescence were compared to those from conventional bright field microscopy. Similarly, faecal smears containing I. suis were examined using the same techniques. Autofluorescence was superior to bright field microscopy in detecting oocysts after flotation and was highly significantly more sensitive when direct smears were examined.

Isospora belli, a coccidian parasite in humans, has been described as causing chronic diarrhea and acalculous cholecystitis in patients with the acquired immunodeficiency syndrome (AIDS). Diagnosis can be made at the tissue level in the epithelium of the small bowel and by fecal examination. Disseminated extraintestinal forms are uncommon. We studied 118 adult patients with AIDS and chronic diarrhea using stool analysis and endoscopy with duodenal biopsy specimen collection. These samples were processed by routine histology and transmission electron microscopy. Isosporosis was diagnosed in 8 cases. In 2 of them, unizoite tissue cysts were present in the lamina propria, with negative results in stool materials. The cysts were located within a large parasitophorous vacuole. There were no structural means of differentiating the species level of Isospora based on morphology using light or electron microscopy. We believe further work should be done to determine if unizoite tissue cysts are part of the cycle of I belli or of other species of Isospora that could be pathogenic in immunocompromised hosts.

The aim of the present study was to use small-subunit (SSU)-rRNA sequences of Isospora belli to design specific primer pairs and a hybridization probe for the detection of Isospora belli in human samples by PCR and Southern blot hybridization. PCR amplification with the primer pairs produced correct DNA fragments with target DNA from samples of Isospora belli-infected patients and from cloned SSU-rRNA of Isospora belli. The nature of the PCR products was confirmed by Southern blot hybridization. No amplification was seen with template DNA extracted from other parasites. Although Isospora belli infections can be easily diagnosed using light microscopy, molecular-based techniques may prove useful as an additional diagnostic tool.