A multiattribute utility evaluation of different methods for the detection of enteric protozoa causing diarrhea in AIDS patients

Global prevalence and risk factors of Enterocytozoon bieneusi infection in humans: a systematic review and meta-analysis

Enterocytozoon bieneusi is one of the most important zoonotic pathogens. In this study, we present a systematic review and meta-analysis of the prevalence of human E. bieneusi infection in endemic regions and analyze the various potential risk factors. A total of 75 studies were included. Among 31,644 individuals tested, 2,291 (6.59%) were E. bieneusi-positive. The highest prevalence of E. bieneusi in the male population was 5.50%. The prevalence of E. bieneusi in different age groups was varied, with 10.97% in teenagers. The prevalence of E. bieneusi in asymptomatic patients (6.49%) is significantly lower than that in HIV-infected patients (11.49%), and in patients with diarrheal symptoms (16.45%). Rural areas had a higher rate (7.58%) than urban ones. The prevalence of E. bieneusi in humans was the highest (6.42%) at altitudes <10 m. Moreover, the temperate zone marine climate (13.55%) had the highest prevalence. A total of 69 genotypes of E. bieneusi have been found in humans. This is the first global study regarding E. bieneusi prevalence in humans. Not only people with low immunity (such as the elderly, children, people with HIV, etc.), but also people in Europe in temperate marine climates should exercise caution to prevent infection with E. bieneusi during contact process with animals.

Asymptomatic Cryptosporidiosis in Children Living with HIV

Children living with human immunodeficiency virus (HIV) have an increased risk of opportunistic Cryptosporidium infection. Cryptosporidium usually causes chronic diarrhea that may lead to impaired growth and cognitive function in children. This study aimed to estimate the prevalence of cryptosporidiosis in children, describe its clinical characteristics, and the risk factors. A cross-sectional study involving children aged 6 months to 18 years old with confirmed HIV infection was carried out in Sardjito General Hospital, Yogyakarta. Diagnosis of cryptosporidiosis was made by PCR of 18S rRNA after being screened by microscopic examination. The clinical characteristics and risk factors were obtained from medical records and structured questionnaires. A total of 52 participants were included in the final analysis. The prevalence of cryptosporidiosis was 42.3%. Approximately 68% of the HIV children with cryptosporidiosis were asymptomatic, while those who reported symptoms showed weight loss and diarrhea. Independent risk factors of cryptosporidiosis were diarrhea (AOR 6.5; 95% CI 1.16–36.67), well water as drinking water source (AOR 6.7; 95% CI 1.83–24.93), and drink untreated water (AOR 5.8; 95% CI 1.04–32.64). A high prevalence of asymptomatic cryptosporidiosis was observed among children with HIV infection and PCR screening of Cryptosporidium in high-risk children is advisable.

The implementation of the Kinyoun staining technique in a resource-limited setting is feasible and reveals a high prevalence of intestinal cryptosporidiosis in HIV patients

OBJECTIVES

In resource-limited settings, intestinal Cryptosporidia or coccidian infections are common causes of chronic diarrhoea, but usually remain undiagnosed by routine stool investigation. Here, the addition of the Kinyoun staining technique after stool concentration was evaluated as an easy and inexpensive method for diagnosis of intestinal parasitic infection in HIV-infected patients.

METHODS

This cross-sectional study investigated HIV-infected patients with diarrhoea and randomly selected HIV-infected patients without diarrhoea as controls. Stool samples were examined by wet mount microscopy and Kinyoun staining after stool concentration. Clinical, sociodemographic and behavioural data were collected. Statistical analysis was performed using Chi-squared test and multivariate regression analysis.

RESULTS

In total, 163 participants were included (62.0% female, mean age 38.2 [SD ±10.7] years). Diarrhoea was present in 52.1% (85/163). The prevalence of intestinal parasites was 18.4% (30/163). Cryptosporidia infections were more frequent among patients with diarrhoea (12.9% [11/85] vs. 1.3% [1/78], p=0.005) and in patients with CD4⁺ cell count <200 cells/µL (25.9% [7/27] vs. 3.7% [5/136], p=0.001). Risk factors for intestinal parasitic infections were diarrhoea and the habit of regularly eating uncooked food. Kinyoun staining was necessary for detection of cryptosporidiosis.

CONCLUSION

In our cohort, the prevalence of intestinal parasitic infection was high, especially after additional utilization of Kinyoun staining for detection of Cryptosporidia or intestinal coccidia. Considering its clinical relevance particularly in individuals at risk, the implementation of this technique should be considered in resource-limited settings.

Cryptosporidium spp. diagnosis and research in the 21st century

The protozoan parasite Cryptosporidium has emerged as a leading cause of diarrhoeal illness worldwide, posing a significant threat to young children and immunocompromised patients. While endemic in the vast majority of developing countries, Cryptosporidium also has the potential to cause waterborne epidemics and large scale outbreaks in both developing and developed nations. Anthroponontic and zoonotic transmission routes are well defined, with the ingestion of faecally contaminated food and water supplies a common source of infection. Microscopy, the current diagnostic mainstay, is considered by many to be suboptimal. This has prompted a shift towards alternative diagnostic techniques in the advent of the molecular era. Molecular methods, particularly PCR, are gaining traction in a diagnostic capacity over microscopy in the diagnosis of cryptosporidiosis, given the laborious and often tedious nature of the latter. Until now, developments in the field of Cryptosporidium detection and research have been somewhat hampered by the intractable nature of this parasite. However, recent advances in the field have taken the tentative first steps towards bringing Cryptosporidium research into the 21st century. Herein, we provide a review of these advances.

Cryptosporidiosis in HIV-positive patients and related risk factors: A systematic review and meta-analysis

Cryptosporidium is one of the major causes of diarrhea in HIV-positive patients. The aim of this study is to systematically review and meta-analyze the prevalence of Cryptosporidium in these patients. PubMed, Science Direct, Google Scholar, Web of Science, Cochrane and Ovid databases were searched for relevant studies dating from the period of 1 January 2000 to 31 December 2017. Data extraction for the included studies was performed independently by two authors. The overall pooled prevalence was calculated and subgroup analysis was performed on diagnostic methods, geographical distribution and study population. Meta-regression was performed on the year of publication, proportion of patients with diarrhea, and proportion of patients with CD4 < 200 cells/mL. One hundred and sixty-one studies and 51,123 HIV-positive participants were included. The overall pooled prevalence of Cryptosporidium infection in HIV-positive patients was 11.2% (CI95%: 9.4%–13.0%). The pooled prevalence was estimated to be 10.0% (CI95%: 8.4%–11.8%) using staining methods, 13.5% (CI95%: 8.9%–19.8%) using molecular methods, and 26.3% (CI95%: 15.0%–42.0%) using antigen detection methods. The prevalence of Cryptosporidium in HIV patients was significantly associated with the country of study. Also, there were statistical differences between the diarrhea, CD4 < 200 cells/mL, and antiretroviral therapy risk factors with Cryptosporidiosis. Thus, Cryptosporidium is a common infection in HIV-positive patients, and safe water and hand-hygiene should be implemented to prevent cryptosporidiosis occurrence in these patients.

Evaluation of enzyme linked immunosorbent assay for stool antigen detection for the diagnosis of cryptosporidiosis among HIV negative immunocompromised patients in a tertiary care hospital of northern India

The diagnosis of cryptosporidiosis among HIV positive patients has been the focus of many studies worldwide. However, there is a paucity of data on HIV negative immunocompromised patients like post-renal transplant recipients and those with haematological malignancies. Stool microscopy, the conventional method of diagnosis, is fraught with difficulties like cumbersome sample processing and subjective interpretation. Enzyme linked immunosorbent assay (ELISA), on the other hand, is quicker and easier. The present study was conducted in a tertiary care and super speciality hospital of north India. Stool specimens from HIV negative immunocompromised patients were subjected to both modified acid fast staining for oocysts of Cryptosporidium and ELISA for detection of Cryptosporidium copro-antigen, over a period of six years. Of the 637 specimens evaluated, 97 (15.23%) samples were positive for Cryptosporidium by both techniques; 25 (3.92%) specimens were positive by ELISA and negative by microscopy, 14 (2.20%) specimens were positive by microscopy but negative by ELISA, while 501 (78.65%) specimens were negative for Cryptosporidium by both techniques. Significant correlation was observed as a measure of agreement (Kappa test value 0.795) between modified ZN stained microscopy and ELISA for the detection of Cryptosporidium oocysts. The sensitivity, specificity, positive and negative predictive value of ELISA, keeping stool microscopy as gold standard were 87.38%, 95.25%, 87.39% and 97.28% respectively. We conclude that ELISA may be used as a reliable substitute for microscopy in setups where the case load is higher or expertise in special staining techniques is not available. The cost of the kit can be justified if the sample load is sufficiently high or if immunocompromised patients form a significant patient population.

Morphological variations on microscopy in oocysts of coccidian parasites: A prospective study from a tertiary care hospital in north India

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

Intestinal microsporidiosis in Iran: infection in immune-compromised and immunocompetent patients

Background and Purpose:

Gastroenteritis and the clinical profile caused by Microsporidia, an opportunistic pathogen, may be severe in immunocompromised individuals, especially in AIDS patients. Conventionally, it is necessary to detect the small infective spores in stained smears. However, due to the limitations of the microscopy-based methods, several DNA-based methods such as polymerase chain reaction (PCR) have recently been developed to enhance diagnosis sensitivity. Therefore, we sought to evaluate the rate of infection in immunocompromised patients as compared with immunocompetent patients in Kerman, Iran.

Materials and Methods:

We collected stool samples of 199 human subjects (116 males and 83 females), aged 1 to 69 years old. They were divided into immunocompromised (i.e., AIDS [n=72] and cancer-positive patients [n=59]) and immunocompetent (n=68) groups. We comparatively examined the fecal materials using the microscopy and PCR methods.

Results:

The overall prevalence rate of Microsporidia infection was 10.05% (20/199). Entrocytozoon bieneusi was the only species within the Microsporidia genus that was identified in 14.5% (19/131) of the immunocompromised patients and 1.47% (1/68) of the immunocompetent individuals.

Conclusion:

Considering the higher prevalence rate of microsporidiosis in patients with immunodeficiency (10.03%), we suggest performing sensitive and specific techniques such as PCR for the detection of these parasites in immunocompromised patients.

Detection of Emergence Cyclospora cayetanensis in A HIV(+) / AIDS Patient with Diarrhea from Tehran: A Case Report

Coccidian protozoa of Cyclospora cayetanensis are obligate intracellular apicomplexan parasites that infect the mucosal epithelium of the small intestine of immunocompetent and immunocompromised persons. A 25- years old woman from around, Tehran with complaint of faintness and fatigue with HIV positive/AIDS confirmed eight months ago was admitted in Imam Khomeini Hospital, Tehran, Iran in 2014. The patient suffered from intestinal and lung symptoms like watery diarrhea, flu-like symptoms. The stool was examined by direct preparation and concentration technique, stained with modified acid-fast staining method, and observed with light and then Immunofluorescence microscope. The stool cultivation was made in dichromate potassium medium and diagnosis of Cyclospora infection was finally made according to observation of Cyclospora oocysts almost 10 μm in acid-fast staining method and autofluorescence of Cyclospora under Immunofluorescence microscope. The patient was initially treated with azithromycin, tazocin and fluconazol because of lung lesions and diarrhea and relative remission was observed. Cyclospora sp. causes an intestinal infection particularly in immunocompromised patients.

Prevalence of intestinal parasites among HIV patients at the Yaoundé Central Hospital, Cameroon

Introduction

Intestinal parasites are more common in people with HIV, especially in tropical developing countries. This cross-sectional study was carried out to assess the prevalence of intestinal parasites among people with HIV at the Yaoundé Central Hospital Accredited Treatment Centre.

Methods

Structured questionnaires were used to collect clinical information after obtaining consent from the participants. Stool samples were collected from 207 HIV-positive patients for the investigation of intestinal pathogens using direct microscopy, formalin-ether concentration, ZiehlNeelsen modified and Kato-Katz methods. Data was analyzed using Epi-info version 3.4.1. and Microsoft Office Excel 2007.

Results

A total of 207 people were recruited. Eighty (38.65%) were male and 127 (61.35%) were female. The overall prevalence of intestinal parasite infections was 57.48% (119/207). The parasites detected in our study population included Entamoeba coli (22.68%), Ascaris lumbricoïdes (22.68%), Entamoeba histolytica(15.93%), Cryptosporidium spp (12.60%), Isospora belli (10.08%), Trichuris trichiura (7.60%), Strongyloïdesstercoralis (5.88%), Ancylostomaduodenale and Necatoramericanus (2.52%).

Conclusion

At the end of our study, it appears that intestinal parasites still occupy an important place among HIV-positive patients.

A comparison of nested PCR assay with conventional techniques for diagnosis of intestinal cryptosporidiosis in AIDS cases from northern India

Cryptosporidiosis is a very important opportunistic infection and is responsible for significant morbidity and mortality in HIV/AIDS patients. Although current laboratory methods are generally considered adequate to detect high concentrations of oocysts, they fail to detect cases of cryptosporidiosis in many immunocompromised patients. The present study was done to determine the diagnostic efficacy of modified Ziehl-Neelsen (ZN), antigen detection ELISA, and a nested PCR assay for detection of Cryptosporidium in 58 adult AIDS cases with diarrhea from the ART clinic of Lok Nayak Hospital, New Delhi. Cryptosporidium was detected in 17 (29.4%), 39 (67.3%), and 45 (77.5%) cases by modified ZN staining, antigen ELISA, and nested PCR assay, respectively. Taking nested PCR as the gold standard, specificity of both modified ZN staining and Cryptosporidium antigen detection ELISA was 100% while the sensitivity of the tests was 37.8% and 86.6%, respectively. PCR was more sensitive than the other two diagnostic modalities but required a more hands-on time per sample and was more expensive than microscopy. PCR, however, was very adaptable to batch analysis, reducing the costs considerably. This assay can therefore have considerable advantages in the treatment of immunosuppressed individuals like AIDS patients, allowing their early diagnosis and decreasing the morbidity and the mortality.

Assessment of parasitic pollution in the coastal seawater of Gaza city

BACKGROUND

The main objective of the study was the assessment of the prevalence and the identification of species of human gastrointestinal parasites as an indicator of the pollution of the seashore of Gaza City.

METHODS

The investigation was conducted by analysis of the parasitic contamination of seawater along the study area. A total of 52 samples of seawater were analyzed during the summer period; from June to October 2011. The study area was divided into six zones (A, B, C, D, E and F) according to specific criteria such as the presence of the wastewater discharge points and other geographical characteristics.

RESULTS

The results show that about 48% of the seawater samples from the shoreline region of Gaza City were contaminated with parasites. Zones A, B and D (mouth of Wadi Gaza, Al Sheikh Ejleen discharge and Al Shalehat discharge points respectively) have the highest level of parasitic contamination, while, zones C and E (From Al-Baydar restaurant to Khalel Alwazer Mosque and the basin of the Gaza marina respectively) had a lower level of contamination and zone F (From the northern part of the Gaza marina to the Intelligence Building) was uncontaminated. The parasitic species found were: Ascaris lumbricoides, Giardia lamblia, Strongyloides stercoralis, Hymenolepis nana, Entamoeba histolytica/dispar and Cryptosporidium parvum.

CONCLUSIONS

The present study revealed a high level of contamination with parasites at most of the points which were investigated along the Gaza City coast line.

Giardia duodenalis typing from stools: a comparison of three approaches to extracting DNA, and validation of a probe-based real-time PCR typing assay

A weighted, multi-attribute approach was used to compare three methods for direct extraction of Giardia duodenalis DNA from 15 microscopy-positive stools: (1) a QIAamp spin-column method for stools including a 10 min incubation at 95 °C, (2) method 1 preceded by five freeze–thaw cycles and (3) bead beating with guanidine thiocyanate using a FastPrep-28 machine followed by liquid-phase silica purification of DNA. The attributes compared included DNA yield measured using a new triose phosphate isomerase (tpi) gene probe-based real-time PCR, also described here. All three methods shared 100 % PCR positivity, while the bead-beating method provided the highest G. duodenalis DNA yield (P<0.01). However, when other weighted attributes, including biocontainment, resources and technical requirements, were also considered, spin-column extraction with prior freeze–thaw treatment (method 2) was deemed the most desirable and was selected for use. The tpi real-time PCR typing assay was designed to discriminate between the main human infectious assemblages of G. duodenalis (A and B) and was evaluated initially using standard isolates. Validation using microscopy-positive stools from 78 clinical giardiasis cases revealed 100 % typability; 20 (26 %) samples contained assemblage A, 56 (72 %) assemblage B and two (3 %) assemblages A and B. While the epidemiological significance of assemblage distribution will be revealed as more isolates are typed and analysed with patient demographic and exposure data, the utility of this assay and its ready application in our laboratory workflow and result turnaround margins is already evident.

Cyclospora infection in a young woman with human immunodeficiency virus in Hong Kong: a case report

Background

Cyclospora is an uncommon pathogen. The diagnosis of Cyclospora infection can be difficult because of its scarcity in developed countries, intracellular mode of life, small size of the parasite and its inability to take up routine microscopic stains. However, it is endemic in many countries in Asia, Africa, Central and South America. With the increase in travels to these areas, the number of cases is expected to increase. Moreover, it is found to be associated with numerous food-borne outbreaks.

Case presentation

We encountered a patient with human immunodeficiency virus presented with 6 months of diarrhoea. The initial investigation was unrevealing. The diagnosis of Cyclospora infection was finally made on the histological sample obtained by colonoscopy. Moreover, the initial therapy with ciprofloxacin was not effective, while trimethoprim/sulfamethoxazole resulted in final cure of the disease.

Conclusion

Travel and food histories are important for the suspicion of Cyclospora infection. Histological examination is more sensitive in making a diagnosis of Cyclospora infection of the gut than fecal microscopic examination. Trimethoprim/sulfamethoxazole is a more reliable therapy for Cyclospora infection in patients with human immunodeficiency virus.

Intestinal parasitic infection among Egyptian children with chronic liver diseases

Patients with chronic liver diseases (CLD) are often highly susceptible to parasitic infection due to a depressed immune system. The objective of this study was to detect the most commonly intestinal parasites found among Egyptian children with CLD. The present study was conducted on 50 children with CLD of different etiology (25 were having different intestinal symptoms, 25 without intestinal symptoms) and 50 non-CLD children with gastrointestinal complaints served as controls. All cases were subjected to stool examination and investigated by liver function tests. Also, anthropometric measurements were taken for all children including weight and height. It was found that the most commonly intestinal protozoa identified in the patients with CLD in order of frequency were: Entamoeba histolytica/Entamoeba dispar (16 %), Giardia lamblia (14 %), Blastocystis hominis (14 %), Cryptosporidium parvum (10 %), E. histolytica and G. lamblia (2 %), E. histolytica and B. hominis (2 %), G. lamblia and B. hominis (2 %), B. hominis and Entamoeba coli (2 %), Microsporidium (2 %) and no cases were found infected with Strongyloides stercoralis. As compared to the controls, the observed incidence of these organisms in CLD patients was significantly higher (p < 0.045) as regards stool examination by unstained techniques while, there was no significant difference between both groups as regards stool examination by stained techniques (p < 0.478). In addition, this study showed that the weight and height of studied patients were affected by parasitic infection while, there was no significant correlation between parasitic infection and liver function tests. In conclusion, chronic liver diseases affect the immunity of the patients as shown in significant increase in the incidence of intestinal parasites in cases compared to controls.

Enteric pathogens in HIV infected and HIV uninfected individuals with diarrhea in Pune

BACKGROUND

Diarrhea in HIV infected individuals is a common complication seen in about 90% of patients in developing countries. The objective of this study was to identify enteric pathogens in HIV infected and HIV uninfected individuals in Pune.

METHOD

This study was conducted from January 2009 to May 2010 on 331 consecutive patients presenting with diarrhea admitted at Naidu Municipal Corporation Hospital, Pune and processed using conventional methods.

RESULTS

Intestinal parasitic pathogens were detected in 60% (39/65) of HIV infected and 14.3 (38/266) of HIV uninfected individuals. Bacterial pathogens were detected in 34% (22/65) of HIV infected individuals and 28.2% (75/266) of the HIV uninfected individuals. The common enteric pathogens detected in HIV infected individuals were Cystoisospora belli (28%, 18/65) followed by Cryprotosporidium parvum (12%, 8/65). In HIV uninfected individuals Entamoeba histolytica (7.1%, 19/266) followed by Shigella flexnari (4.9%, 13/266) were the most common pathogens. The difference in detection of enteric parasites in HIV infected individuals and HIV uninfected individuals was found to be significant (p < 0.01).

CONCLUSIONS

Intestinal parasitic pathogens are more common in HIV infected antiretroviral therapy naïve patients. Early detection of enteric pathogens by routine examination of stool samples will help in the management and to improve the quality of life for HIV infected individuals.

R. Intestinal Cryptosporidiosis and the Profile of the CD4 Counts in a Cohort of HIV Infected Patients

BACKGROUND

Cryptosporidium is an infectious enteric pathogen which is capable of causing life-threatening illnesses in immunocompromised patients.

AIMS

This prospective study was planned to know the frequency of intestinal cryptosporidiosis in HIV infected patients and its correlation with their immune status. Also, the conventional diagnostic methods were compared with the copro-antigen detection test by using Enzyme Linked Immuno Sorbent Assay (ELISA).

SETTINGS AND DESIGN

This was a prospective cohort study.

METHODS AND MATERIAL

Three consecutive stool samples which were collected from 90 HIV seropositive patients and 50 seronegative controls were screened for cryptosporidiosis by wet mount, direct modified ZN (Ziehl Neelsen) staining, modified ZN staining with formol ether concentration and copro-antigen detection by ELISA. Their immune statuses were measured by CD4 + cell counting. Statistical Analytical Tests which were Used: Odds ratio, Chi square test, Fisher extract test.

RESULTS

Cryptosporidiosis was detected in 15 HIV seropositive cases. 13 cases had CD4 cell counts of < 100 cells/ μL. The formol ether concentration technique resulted in an increased number of oocysts/oil immersion field in 8 cases. ELISA was positive in 2 cases which were shown to be negative by modified ZN staining. All the controls were negative for cryptosporidium.

CONCLUSIONS

Cryptosporidiosis is an opportunistic infection in HIV infected people who present with diarrhoea. The wet mount technique, though it is simple and inexpensive, is insensitive for the detection of cryptosporidium. The conventional modified ZN staining and the modified ZN staining with concentration have a sensitivity and a specificity of 85.71% and 98.84% respectively. The copro antigen detection by ELISA which has a greater sensitivity and specificity, is a useful tool in epidemiological studies.

Evaluation of Ziehl-Neelsen staining, auramine phenol staining, antigen detection enzyme linked immunosorbent assay and polymerase chain reaction, for the diagnosis of intestinal cryptosporidiosis

Background and Objectives:

Cryptosporidiosis is a very important opportunistic infection and is responsible for significant morbidity and mortality in HIV/AIDS patients. The objective of this study is to evaluate Ziehl-Neelsen staining, auramine phenol staining, antigen detection enzyme linked immunosorbent assay and polymerase chain reaction, for the diagnosis of intestinal cryptosporidiosis.

Materials and Methods:

The study was designed to determine the efficacy of modified Ziehl-Neelsen (ZN), Auramine-Phenol (AP) staining, antigen detection enzyme linked immunosorbent assay (ELISA) and nested polymerase chain reaction (PCR) for detection of cryptosporidia in 671 HIV-seropositive patients, 353 HIV-seronegative patients including 198 children with diarrhea and 50 apparently healthy adults.

Results:

Cryptosporidium was detected in 26 (3.9%), 37 (5.5%), 32 (4.8%) and 40 (6%) HIV-seropositive and 8 (2.3%), 10 (2.9%), 9 (2.6%) and 9 (2.6%) HIV-seronegative patients by ZN staining, AP staining, antigen detection ELISA and PCR, respectively. None of the healthy controls were infected with Cryptosporidium. Based on criteria of ‘true positive’ samples, i.e. positive by any two of the four techniques out of ZN, AP, antigen detection ELISA and PCR, sensitivity of ZN and ELISA was 79.06% and 95.35% respectively. AP and PCR were found to be 100% sensitive. Specificity of ZN and ELISA was 100% while specificity of AP and PCR was 99.59% and 99.39% respectively.

Conclusions:

Auramine phenol staining is a rapid, sensitive and specific technique for diagnosis of intestinal cryptosporidiosis.

Enteric protozoa in the developed world: a public health perspective

Several enteric protozoa cause severe morbidity and mortality in both humans and animals worldwide. In developed settings, enteric protozoa are often ignored as a cause of diarrheal illness due to better hygiene conditions, and as such, very little effort is used toward laboratory diagnosis. Although these protozoa contribute to the high burden of infectious diseases, estimates of their true prevalence are sometimes affected by the lack of sensitive diagnostic techniques to detect them in clinical and environmental specimens. Despite recent advances in the epidemiology, molecular biology, and treatment of protozoan illnesses, gaps in knowledge still exist, requiring further research. There is evidence that climate-related changes will contribute to their burden due to displacement of ecosystems and human and animal populations, increases in atmospheric temperature, flooding and other environmental conditions suitable for transmission, and the need for the reuse of alternative water sources to meet growing population needs. This review discusses the common enteric protozoa from a public health perspective, highlighting their epidemiology, modes of transmission, prevention, and control. It also discusses the potential impact of climate changes on their epidemiology and the issues surrounding waterborne transmission and suggests a multidisciplinary approach to their prevention and control.

Comparison of three DNA extraction methods for feed products and four amplification methods for the 5'-junction fragment of Roundup Ready soybean

Three methods of DNA extraction from feed products and four detection methods for the 5'-junction fragment of genetically modified (GM) Roundup Ready soybean (RRS) were compared and evaluated. The DNA extraction methods, including cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and guanidine hydrochloride (Kit), were assessed for their yields and purity of DNA, extraction time, and reagent cost. The DNA yields of CTAB, SDS, and Kit were 52-694, 164-1750 and 23-105 ng/mg sample, and their extraction time was 2.5-3, 2-2.5, and 1.5-2 h with reagent cost about US dollar 0.24, 0.13, and 1.9 per extraction, respectively. The SDS method was generally well suited to all kinds of feed matrices tested. The limits of detection for the four amplification protocols, including loop-mediated isothermal amplification (LAMP), hyperbranched rolling circle amplification (HRCA), conventional polymerase chain reaction (PCR), and real-time PCR, were 48.5, 4.85, 485, and 9 copies of the pTLH10 plasmid, respectively. The ranked results of the four detection methods were based on multiattribute utility theory as follows (from best to worse): HRCA, LAMP, PCR, and real-time PCR. This comparative evaluation was specifically useful for selection of a highly efficient DNA extraction or amplification method for detecting different GM ingredients.

Cryptosporidium species screening using Kinyoun technique in domestic cats with diarrhea

Cryptosporidium is a coccidian that can lead to diarrhea, especially in immunosuppressed individuals. Retroviruses are considered a primary cause of immunosuppression in cats. Fecal specimens and blood collected from the 60 cats were evaluated for the presence of acid-fast cryptosporidia in three consecutive stool samples and for feline leukemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibody by ELISA testing. Five animals (8.33%) shedding oocysts were found, one was both FIV- and FeLV-negative and four were FeLV-positive.

Microsporidia as emerging pathogens and the implication for public health: a 10-year study on HIV-positive and -negative patients

Despite recent advances in the understanding and diagnosis of emerging microsporidian pathogens, more research is necessary to elucidate their complex epidemiology. In fact, studies that reflect true human-infecting microsporidian prevalence are still inadequate. The present 10-year study was undertaken to examine the occurrence of Microsporidia in 1989 stools, 69 urine and 200 pulmonary specimens from HIV-positive and HIV-negative patients using PCR and DNA sequencing. In stools, 12.0% were Microsporidia-positive. Prevalences of 13.9% and 8.5% were observed for HIV+ and HIV- samples, respectively. The percentage of children that were Microsporidia-positive (18.8%) was significantly higher than that of adults (10.2%). In stools, Enterocytozoon bieneusi (6.3%) and Vittaforma-like parasites (6.8%) were identified. Based on the internal transcribed spacer (ITS) region of E. bieneusi, Type IV (37.5%), Peru 6 (29.2%), D (12.5%), A (8.3%), C (6.3%) and PtEb II (6.3%) genotypes were identified. Microsporidia were detected in 1.5% and 1.0% of urine and pulmonary specimens, respectively. Encephalitozoonintestinalis was detected in urine. In pulmonary specimens, Encephalitozoon cuniculi and Vittaforma-like parasites were identified. An immunosuppressive condition and youth (children) appear to be risk factors for microsporidian infection. Microsporidia seems to have an important impact on public health in Portugal, highlighting the need to implement routine diagnosis.

Microsporidiosis: not just in AIDS patients

PURPOSE OF REVIEW

Microsporidia have emerged as causes of opportunistic infections associated with diarrhea and wasting in AIDS patients. This review describes recent reports of microsporidiosis in HIV-infected individuals and the growing awareness of microsporidiosis in non-HIV-infected populations.

RECENT FINDINGS

Microsporidia were only rarely recognized as causes of disease in humans until the AIDS pandemic. Implementation of combination antiretroviral therapy (cART) to curtail HIV replication and restore immune status drastically reduced the occurrence of opportunistic infections, including those due to microsporidia, in HIV-infected individuals. In developing countries where cART is not always accessible, microsporidiosis continues to be problematic. Improvement of diagnostic methods over the previous 25 years led to identification of several new species of microsporidia, many of which disseminate from enteric to systemic sites of infection and contribute to some unexpected lesions. Among non-HIV-infected but immune-suppressed individuals, microsporidia have infected organ transplant recipients, children, the elderly, and patients with malignant disease and diabetes. In otherwise healthy immune-competent HIV seronegative populations, self-limiting diarrhea occurred in travelers and as a result of a foodborne outbreak associated with contaminated cucumbers. Keratitis due to microsporidiosis has become problematic and a recent longitudinal evaluation demonstrated that non-HIV-infected individuals seropositive for microsporidia who had no clinical signs continued to intermittently shed organisms in feces and urine.

SUMMARY

Greater awareness and implementation of better diagnostic methods are demonstrating that microsporidia contribute to a wide range of clinical syndromes in HIV-infected and non-HIV-infected people. As such, microsporidia should be considered in differential diagnoses if no other cause can be defined.

Efficiency of diagnostic methods for correlation between prevalence of enteric protozoan parasites and HIV/AIDS status--an experience of a tertiary care hospital in East Delhi

Since the beginning of the AIDS pandemic, opportunistic infections have been recognized as common complications of HIV infection. Enteric protozoan parasitic infections are one of the leading causes of morbidity and mortality in HIV infected patients. The present study is, therefore, aimed to determine the prevalence of these parasites and study their association with immune status in HIV patients with emphasis on the correlation between various diagnostic techniques to give an accurate diagnosis to avoid empirical treatment. This prospective study, carried out between November 2009 and May 2010 included all HIV seropositive patients presenting with diarrhea to the ART center. A total of 64 stool samples were analyzed by wet mount examination, three different staining techniques, and antigen detection by ELISA for various enteric protozoan infections. Total prevalence of enteric protozoan parasites was 30%. Among the total cases, Cryptosporidium was seen in 12% cases followed by Giardia, E. histolytica and Isospora belli. The maximum diagnostic yield for coccidian parasites was with safranin-methylene blue staining technique. Parasitic burden contributes towards early morbidity in HIV infection. This study provides important information about prevalence of intestinal protozoan parasites in HIV infection. A combination of procedures should be carried out for the screening of stool specimens of HIV patients for better diagnosis and management.

Newer diagnostic approaches to intestinal protozoa

PURPOSE OF REVIEW

To update the reader on the latest developments in the laboratory diagnosis of intestinal protozoa.

RECENT FINDINGS

Correct identification of a diarrhoea causing pathogens is essential for the choice of treatment in an individual patient as well as to map the aetiology of diarrhoea in a variety of patient populations. Classical diagnosis of diarrhoea causing protozoa by microscopic examination of a stool sample lacks both sensitivity and specificity. Alternative diagnostic platforms are discussed.

SUMMARY

Recent literature on the diagnosis of intestinal protozoa has focused mainly on nucleic acid-based assays, in particular the specific detection of parasite DNA in stool samples using real-time PCR. In addition, the trend has been moving from single pathogen detection to a multiplex approach, allowing simultaneous identification of multiple parasites. Different combinations of targets can be used within a routine diagnostic setting, depending on the patient population, such as children, immunocompromised individuals and those who have been travelling to tropical regions. Large-scale monitoring and evaluation of control strategies become feasible due to automation and high-throughput facilities. Improved technology also has become available for differentiating protozoa subspecies, which facilitates outbreak investigations and extensive research in molecular epidemiology.

Treatment of cryptosporidiosis: do we know what we think we know?

PURPOSE OF REVIEW

The management of cryptosporidiosis is fraught with controversies. New research on diagnostics and medications has reached the field in recent years. Therefore, familiarity with key features of current management tools is important. We discuss diagnostic and therapeutic aspects of cryptosporidiosis focusing on evidence behind the medications available to date.

RECENT FINDINGS

Molecular methods provide a clearer understanding of cryptosporidiosis epidemiology. The major determinants of severity still are host immune status and parasite species. Children and immunosuppressed individuals, especially with HIV/AIDS, are disproportionately affected. Nitazoxanide is an important advance in treatment of HIV negative patients. However, recent research confirms the limited effectiveness of antiparasitic drugs to treat cryptosporidiosis in AIDS. Questions remain about using partially active drugs paromomycin and nitazoxanide for treatment. Potent antiretroviral combinations modify disease epidemiology and are key components of therapy in AIDS. However, it is unclear whether this is due solely to immune reconstitution or due in part to antiparasitic effects of HIV protease inhibitors. Newer candidate drugs are in development.

SUMMARY

There is better understanding of the epidemiology of cryptosporidiosis and promising new diagnostic methods. There are significant challenges in terms of control and treatment of cryptosporidiosis among the groups at risk.