Epidemiology of isosporiasis among persons with acquired immunodeficiency syndrome in Los Angeles County

Cystoisospora belli infections in humans: the past 100 years

Cystoisospora belli is a coccidian parasite of humans, with a direct fecal-oral transmission cycle. It is globally distributed, but mainly found in tropical and subtropical areas. Many cases of C. belli infections have been reported in patients with HIV, and in patients undergoing immunosuppressive therapy for organ transplants or those treated for tumours worldwide. Unsporulated or partially sporulated oocysts of C. belli are excreted in feces. When sporulated oocysts in contaminated water or food are ingested, asexual and sexual stages of C. belli are confined to the epithelium of intestines, bile ducts and gallbladder. Monozoic tissue cysts are present in extra-intestinal organs (lamina propria of the small and large intestine, lymph nodes, spleen, and liver) of immunosuppressed humans. However, a paratenic host has not been demonstrated. Cystoisospora belli infections can be persistent, lasting for months, and relapses are common; the mechanism of relapse is unknown. Recently, the endogenous stages of C. belli were re-examined and attention was drawn to cases of misidentification of non-protozoal structures in the gallbladder of patients as C. belli. Here, we review all aspects of the biology of C. belli, including morphology, endogenous stages, prevalence, epidemiology, symptoms, diagnosis and control.

A road less travelled: Clinical comparison of HIV seropositive and seronegative patients with cystoisosporiasis - An 11-year experience from a tertiary care centre in Northern India

Background

Cystoisospora is a well-known opportunistic enteric parasite among human immunodeficiency virus (HIV) seropositive patients but there is a paucity of data among HIV negative patients. This study investigated Cystosporiasis on both HIV positive and negative patients, with or without diarrhea, presenting to a tertiary care and super specialty center of northern India.

Methodology

Oocysts of Cystoisospora were detected on light microscopy, by modified Kinyoun staining of stool specimens, over an 11-year study period.

Results

Of the 10,233 stool specimens evaluated, Cystoisospora was detected in 64 patients, 37 (57.81%) of whom were HIV positive. Year-wise analysis showed an overall declining trend of cystoisosporiasis. Maximum cases were detected in May and June in HIV positive patients and February and September among HIV negative patients. Among HIV positive patients, the mean CD4 count was 152.04 ± 81.12cells/μL, mean absolute eosinophil count (AEC) was 229.16 ± 175.62 cells/μL and 12.5% patients had mild eosinophilia. Tuberculosis was the most common co-morbidity. Dual infections of Cystoisospora with Cryptosporidium and Giardia were also seen. Among HIV negative patients, eight had primary autoimmune disorders, seven were solid organ transplant recipients and the rest had chronic bowel diseases. The mean AEC was 485.47 ± 414.88 cells/μL, with 14.81% patients showing mild and 11.11% showing marked eosinophilia. Dual infection with Giardia was seen. Recurrent cystoisosporiasis was noted, despite cotrimoxazole treatment in a single case.

Conclusion

The epidemiology of cystoisosporiasis differs between HIV seropositive and seronegative patients in terms of year-wise and month-wise trends, co-infections and most importantly, AECs.

Unexpectedly High Prevalence of Cystoisospora belli Infection in Acalculous Gallbladders of Immunocompetent Patients

Objectives

Indications for cholecystectomy have changed dramatically over the past three decades. Cystoisospora belli has been reported in cholecystectomy specimens of immunocompetent patients. The present study was designed to determine the prevalence and clinical association of C belli in the gallbladder.

Methods

The study included retrospective review of cholecystectomy specimens (n = 401) removed for various indications, and a prospective cohort of cholecystectomy specimens (n = 22) entirely submitted for histologic evaluation. Correlations of presence of C belli with age, sex, clinical indication, and abnormalities of preoperative laboratory values were assessed by Fisher exact test.

Results

C belli was identified in 39/401 (9.7%) of the retrospective cohort, and 6/22 (27.3%) of the entirely submitted specimens. The presence of C belli showed no correlation with age, sex, clinical indication, or laboratory abnormalities.

Conclusions

C belli resides in a latent state in the gallbladder and may be best considered a commensal organism.

Cystoisospora belli Gallbladder Infection in a Liver Transplant Donor

Introduction

Cystoisospora belli (previously Isospora belli) is a parasitic protozoan of the human gastrointestinal system. It rarely causes symptoms in immunocompetent hosts but can cause severe diarrhea in immunocompromised patients, with a rate of recurrence and risk of dissemination. Gallbladder infections are however rare. The treatment of choice for symptomatic patients is a 7–10-day course of trimethoprim-sulfamethoxazole.

Case

In this case, we report on an incidental finding of Cystoisospora belli organisms in the donor gallbladder following a transplant cholecystectomy. There was no report of symptoms in the donor. The recipient was treated with a course of trimethoprim-sulfamethoxazole, without evidence of cystoisosporiasis. Given the risk of recurrence in immunocompromised hosts, the patient will continue to be monitored for reactivation in the future.

Conclusion

Despite advances in transplant protocols and screening, disease transmission from the donor to recipient still occurs in about 0.2% of all organ transplants. With the increased use of organs from drug overdose victims and other high-risk donors, practitioners (including pathologists, hepatologists, and surgeons) must maintain a high index of suspicion for such potentially harmful organisms.

Prevalence of Cryptosporidium, microsporidia and Isospora infection in HIV-infected people: a global systematic review and meta-analysis

BACKGROUND

Diarrhea caused by opportunistic intestinal protozoa is a common problem in HIV infection. We aimed to establish the prevalence of Cryptosporidium, misrosporidia, and Isospora in HIV-infected people using a systematic review and meta-analysis, which is central to developing public policy and clinical services.

METHODS

We searched PubMed, ScienceDirect, Google Scholar, Embase, Chinese Web of Knowledge, Wanfang, and Chongqing VIP databases for studies reporting Cryptosporidium, microsporidia, or Isospora infection in HIV-infected people. We extracted the numbers of people with HIV and protozoa infection, and estimated the pooled prevalence of parasite infection by a random effects model.

RESULTS

Our research identified 131 studies that reported Cryptosporidium, microsporidia, and Isospora infection in HIV-infected people. We estimated the pooled prevalence to be 14.0% (3283/43,218; 95% CI: 13.0-15.0%) for Cryptosporidium, 11.8% (1090/18,006; 95% CI: 10.1-13.4%) for microsporidia, and 2.5% (788/105,922; 95% CI: 2.1-2.9%) for Isospora. A low prevalence of microsporidia and Isospora infection was found in high-income countries, and a high prevalence of Cryptosporidium and Isospora infection was found in sub-Saharan Africa. We also detected a high prevalence of Cryptosporidium, microsporidia, and Isospora infection in patients with diarrhea. Sensitivity analysis showed that three studies significantly affect the prevalence of Isospora, which was adjusted to 5.0% (469/8570; 95% CI: 4.1-5.9%) by excluding these studies.

CONCLUSIONS

Our findings suggest that HIV-infected people have a high prevalence of Cryptosporidium, microsporidia, and Isospora infection in low-income countries and patients with diarrhea, especially in sub-Saharan Africa, reinforcing the importance of routine surveillance for opportunistic intestinal protozoa in HIV-infected people.

Infections by Intestinal Coccidia and Giardia duodenalis

The coccidians Cryptosporidium spp, Cyclospora cayetanensis, and Cystoisospora belli and the flagellate Giardia duodenalis are pathogenic protozoa associated with gastrointestinal manifestations. Diagnosis relies heavily on microscopy, and although ova-and-parasite examinations can detect Giardia and Cystoisospora, Cryptosporidium and Cyclospora often require specific diagnostic requests. Approved non-microscopy methods are available for Giardia and Cryptosporidium, although negative results are frequently followed by microscopic assays. Polymerase chain reaction-based methods are not frequently used for diagnosis of Giardia and Cryptosporidium and have been used primarily for epidemiologic or outbreak investigations of Giardia and Cryptosporidium.

High prevalence of diarrhoegenic intestinal parasite infections among non-ART HIV patients in Fitche Hospital, Ethiopia

BACKGROUND

HIV infection has been modifying both the epidemiology and outcome of parasite infections. Hence, this study was undertaken to determine the prevalence of Cryptosporidium and other intestinal parasite infections among HIV positives with and without Antiretroviral Treatment(ART) and its association with CD4+ T-cell count.

METHODS

A cross-sectional study was conducted at Fitche hospital focusing on HIV positives who came to hospital for follow-ups. A total of 378 HIV positive persons with and without ART participated in the study. Data on socio-demographic factors and diarrhoea status were obtained by interviewing all 214 with ART and 164 without ART. Stool samples were collected from all patients and examined for intestinal parasites using direct, formol-ether and modified acid-fast staining techniques.

RESULTS

The prevalence of intestinal parasite infections in this study was significantly higher among HIV positive persons not on ART. Specifically, the rate of infection with Cryptosporidium species, Blastocystis spp., Giardia lamblia, and Entamoeba histolytica/E. dispar were higher, particularly in those with CD4+ T-cell counts less than 200 cells/µL. Fifty seven percent of the study participants were on ART. Out of these 164/378 (43%) of the non-ART study participants were infected with at least one intestinal parasite species. Significant association was observed between lower CD4+ T-cell count (<200 cells/µL) and the prevalence of Cryptosporidium spp. and Blastocystis spp. The two parasites were significantly more prevalent in HIV positive non-ART patients.

CONCLUSION

HIV infection increased the risk of having Cryptosporidium and other intestinal parasites and diarrhoea. Therefore, raising HIV positive's immune status and screening for intestinal parasites is important. This study showed that patients who are taking ART had a lower prevalence of diarrhoea causing parasites and Cryptosporidium suggesting that ART through improvement of immune status of the patients may have contributed to controlling diarrhoea-causing parasites in HIV positive patients.

Opportunistic and other intestinal parasites among HIV/AIDS patients attending Gambi higher clinic in Bahir Dar city, North West Ethiopia

OBJECTIVE

To determine the magnitude of opportunistic and non-opportunistic intestinal parasitic infections among HIV/AIDS patients in Bahir Dar.

METHODS

Cross-sectional study was conducted among HIV/AIDS patients attending Gambi higher clinic from April1-May 30, 2009. Convenient sampling technique was employed to identify the study subjects and hence a total of 248 subjects were included. A pre-tested structured questionnaire was used to collect socio-demographic data of patients. Stool samples were examined by direct saline, iodine wet mount, formol-ether sedimentation concentration and modified Ziehl-Neelsen staining technique.

RESULTS

Out of 248 enrolled in the study, 171(69.0%) (90 males and 81 females) were infected with one or more intestinal parasites. The highest rate of intestinal parasites were observed among HIV/AIDS patients (80.3%, 151/188), and the infection rate of HIV negative individuals was 33.3% (20/60). Cryptosporidum parvum (43.6%), Isospora belli (15.5%) and Blastocystis hominis (10.5%) were opportunistic parasites that were found only in HIV/AIDS patients.

CONCLUSIONS

Opportunistic parasite infections are common health problem among HIV/AIDS patients in the study area. Therefore, early detection and treatment of these parasites are important to improve the quality of life of HIV/AIDS patients.

Review article: the aetiology, investigation and management of diarrhoea in the HIV-positive patient

BACKGROUND

Diarrhoea is a common presentation throughout the course of HIV disease.

AIM

To review the literature relating to aetiology, investigation and management of diarrhoea in the HIV-infected adult.

METHODS

The PubMed database was searched using major subject headings 'AIDS' or 'HIV' and 'diarrhoea' or 'intestinal parasite'. The search was limited to adults and to studies with >10 patients.

RESULTS

Diarrhoea affects 40-80% of HIV-infected adults untreated with antiretroviral therapy (ART). First-line investigation is by stool microbiology. Reported yield varies with geography and methodology. Molecular and immunological methods and special stains have improved diagnostic yield. Endoscopy is diagnostic in 30-70% of cases of pathogen-negative diarrhoea and evidence supports flexible sigmoidoscopy as a first line screening procedure (80-95% sensitive for CMV colitis), followed by colonoscopy and terminal ileoscopy. Radiology is useful to assess severity, distribution, complications and to diagnose HIV-related malignancies. Side effects and compliance with ART are important considerations in assessment. There is a good evidence base for many specific therapies, but optimal treatment of cryptosporidiosis is unclear and only limited data support symptomatic treatments.

CONCLUSIONS

The immunological response to HIV infection and Antiretroviral therapy remains incompletely understood. Antiretroviral therapy regimens need to be optimised to suppress HIV while minimising side effects. Effective agents for management of cryptosporidiosis are lacking. There is an urgent need for enhanced regional diagnostic facilities in countries with a high prevalence of HIV. The ongoing roll-out of Antiretroviral therapy in low-resource settings will continue to change the aetiology and management of this problem, necessitating ongoing surveillance and study.

HIV-associated Isospora belli infection: incidence and risk factors in the French Hospital Database on HIV

OBJECTIVE

To determine the incidence of Isospora belli infection in HIV-infected patients in France, and to study risk factors.

METHODS

The French Hospital Database on HIV (FHDH) is a prospective cohort study that collects demographic, clinical and therapeutic data on patients managed in 62 hospitals. We reviewed all cases of I. belli infection recorded between 1992 and 2003. We compared the incidence in 1992-1994 [before the use of dual therapy and combination antiretroviral therapy (cART)] and in 1997-2003 (when use of cART was widespread), after stratification for CD4 cell count (< 50, 50-99, 100-199 and > 200 cells/microL).

RESULTS

A total of 164 patients had I. belli infection either at enrollment (n=71) or during follow up (n=93). During the study period, I. belli infection tended to occur less frequently during follow up, and to be diagnosed mainly at database enrollment. The incidence of I. belli infection during follow up fell by 79% [relative hazard (RH) 0.21; 95% confidence interval (CI) 0.13-0.33] in the cART period compared with the pre-cART period; no such change was noted among patients with CD4 cell counts below 50 cells/microL. In multivariable analysis, the risk of I. belli infection was significantly higher among patients from sub-Saharan Africa (RH 4.3; 95% CI 2.6-7.3). After adjustment for CD4 cell count, patients receiving cotrimoxazole prophylaxis were found to be at a lower risk of I. belli infection (RH 0.3; 95% CI 0.2-0.6).

CONCLUSIONS

In France, I. belli infection among HIV-infected patients is now mainly seen in patients from sub-Saharan Africa, who present at an advanced stage.

Parasitic colitides

Parasitic infections are a major worldwide health problem, and they account for millions of infections and deaths each year. Most of the infections as well as the morbidity and mortality from these diseases occur in the developing world in rural regions. However, these diseases have become more common in Western countries and in big cities over the past 25 years. These changing disease patterns can be attributed to emigration from the third world to developed countries and migration of rural populations to the big cities in developing nations. These parasitic infections have protean manifestations and consequences. The medical problems range from chronic asymptomatic carrier to fulminant infections and even death. Several factors such as the host immune status, the infecting organism, and the availability of treatment all play key roles in the outcomes of parasitic colitides. The two major classes of parasites causing these infections are the helminthes (ascariasis, strongyloidiasis, enterobiasis, trichuriasis, and schistosomiasis) and the protozoa (Isospora, Cryptosporidium, Cyclospora, Trypanosoma cruzi, Giardia lamblia, and Balantidium coli). This article summarizes the salient features of each parasite with respect to epidemiology, transmission, pathogenesis, clinical features, diagnosis, and treatment. The vast majority of these infections have a self-limited clinical course or are easily treated with medical management, and surgery is rarely needed.

Parasitic infections in HIV-infected patients who visited Seoul National University Hospital during the period 1995-2003

The prevalence of parasitic infections was investigated in human immunodeficiency virus (HIV)-infected patients (n = 105) who visited Seoul National University Hospital, Seoul, Korea, during the period from 1995 to 2003. Fecal samples were collected from 67 patients for intestinal parasite examinations, and sputum or bronchoalveolar lavage samples from 60 patients for examination of Pneumocystis carinii. Both samples were obtained from 22 patients. Thirty-three (31.4%) of the 105 were found to have parasitic infections; Cryptosporidium parvum (10.5%; 7/67), Isospora belli (7.5%; 5/67), Clonorchis sinensis (3.0%; 2/67), Giardia lamblia (1.5%; 1/67), Gymnophalloides seoi (1.5%; 1/67), and Pneumocystis carinii (28.3%; 17/60). The hospital records of the 11 intestinal parasite-infected patients showed that all suffered from diarrhea. This study shows that parasitic infections are important clinical complications in HIV-infected patients in the Republic of Korea.

Risk of opportunistic infection in the HAART era among HIV-infected Latinos born in the United States compared to Latinos born in Mexico and Central America

There are few studies that compare opportunistic infection (OI) rates for U.S.-born, Mexican-born, and Central American-born Latinos in the pre- or post-highly active antiretroviral therapy (HAART) era. Data on 803 Latino persons in treatment for HIV infection in Los Angeles, California, were examined to evaluate differences in risk for specific and total OIs by country of origin. In a Cox proportional hazards regression analysis that controlled for HAART use, CD4 counts, and age, U.S.-born Latino women were more likely than Central American-born Latino women to develop an OI from 1996 to 2000 (hazard ratio [HR] = 2.9, 95% confidence intervals [CIs]: 1.3, 6.5). In a Poisson regression analysis, U.S.-born Latino men and women combined were at greater risk for HIV encephalopathy (RR = 3.4, 95% CIs: 1.2, 10.0) and Kaposi's sarcoma (RR = 2.9, 95% CIs: 1.1, 7.6). In addition to underreporting that may result from the use of English-based criteria for diagnosing HIV encephalopathy among Spanish-speaking patients, these HAART era data suggest that variation in OI risk among Latinos may also be explained by acculturation factors, such as loss of social support systems and negative lifestyle changes.

Parasitic infections of the gastrointestinal tract

Parasitic infections of the gastrointestinal tract are a major cause of morbidity and mortality worldwide. Increased international travel means that gastroenterologists are now more likely to care for patients with parasitic diseases. This article reviews various aspects of the more common intestinal parasites and their infections, including epidemiology, life cycle, pathogenesis, clinical manifestations, diagnosis, and treatment.

Prevalence of intestinal parasites in Cuban acquired immunodeficiency syndrome (AIDS) patients

A coproparasitological study was carried out on 67 acquired immunodeficiency syndrome (AIDS) patients admitted at the Institute of Tropical Medicine 'Pedro Kouri'. The results were compared with 136 HIV-seronegative patients (control group) who were also hospitalised in the same period. In both groups monoparasitism was more prevalent than polyparasitism and intestinal protozoa were more prevalent than helminths. At least one intestinal parasite was found in 34 (51%) of the 67 AIDS patients and in 65 (48%) of the control group patients. Intestinal coccidia were only detected in AIDS patients; Cryptosporidium spp. was the most prevalent, with eight cases (11.9%), followed by Cyclospora cayetanensis with two cases (3.0%) and Isospora belli in one case (1.5%). The microsporidia Encephalitozoon (Septata) intestinalis and Enterocytozoon bieneusi were not detected. With regard to the prevalence of other pathogenic intestinal parasites in AIDS patients and the control group, no differences were found.

Molecular diagnosis of gastrointestinal infections associated with HIV infection

Developments in medical microbiology in the past 20 years have had a profound impact on our understanding of infectious diseases and have led the way in the development of new diagnostic techniques. Molecular diagnostic techniques are generally more sensitive, specific, and rapid than conventional methods by which infectious agents are detected. For many of the opportunistic infectious agents of the gastrointestinal tract found in HIV-infected individuals, the application of molecular diagnostic techniques to the clinical laboratory is in its infancy. In this article, methods by which these techniques can be evaluated are demonstrated, and the current status and potential future application of these techniques for each gastrointestinal opportunistic pathogen are described.

Parasites and Diarrhea. I: Protozoans and Diarrhea

Intestinal parasitism is extremely common, with approximately 70% of all people harboring one or more intestinal parasite. Parasitism and diarrhea are both hyperendemic in areas where sanitation is suboptimal. Many clinicians assume that the identification of intestinal parasites in patients with diarrhea implies that the parasites are the cause. This approach is frequently misguided. Some intestinal parasites such as Giardia lamblia and Entamoeba histolytica certainly do cause diarrhea. Others, for example Entamoeba coli and Ascaris lumbricoides, almost certainly do not. In addition, there are a number of other organisms that have been associated with diarrheal illness in some cases, which may or may not be important pathogens. In this article, we will review the role of protozoans as definite and possible causes of diarrhea. In Part II, we review the role of helminths in diarrhea.

Biology of Isospora spp. from humans, nonhuman primates, and domestic animals

Coccidial parasites of the genus Isospora cause intestinal disease in several mammalian host species. These protozoal parasites have asexual and sexual stages within intestinal cells of their hosts and produce an environmentally resistant cyst stage, the oocyst. Infections are acquired by the ingestion of infective (sporulated) oocysts in contaminated food or water. Some species of mammalian Isospora have evolved the ability to use paratenic (transport) hosts. In these cases, infections can be acquired by ingestion of an infected paratenic host. Human intestinal isosporiasis is caused by Isospora belli. Symptoms of I. belli infection in immunocompetent patients include diarrhea, steatorrhea, headache, fever, malaise, abdominal pain, vomiting, dehydration, and weight loss, blood is not usually present in the feces. The disease is often chronic, with parasites present in the feces or biopsy specimens for several months to years. Recurrences are common, Symptoms are more severe in AIDS patients, with the diarrhea being more watery. Extraintestinal stages of I. belli have been observed in AIDS patients but not immunocompetent patients. Treatment of I. belli infection with trimethoprim-sulfamethoxazole usually results in a rapid clinical response. Maintenance treatment with trimethoprim-sulfamethoxazole is needed because relapses often occur once treatment is stopped.