Identification and characterization of microsporidia from fecal samples of HIV-positive patients from Lagos, Nigeria

Prevalence of Cryptosporidium and microsporidial infection in HIV-infected individuals

BACKGROUND

Microsporidia and Cryptosporidium are obligate intracellular protozoa. These medically important species are recognized as opportunistic organisms in intestinal complications in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome patients.

METHODS

The current cross-sectional study was designed and conducted from August 2016 to August 2017 to determine intestinal Cryptosporidium and microsporidia spp. in HIV-infected individuals from the Behavioral Diseases Counseling Center, Tabriz, Iran, by modified acid-fast and modified trichrome staining and nested polymerase chain reaction (PCR) and real-time PCR.

RESULTS

Of 100 HIV-infected persons, 21.0% (95% confidence interval [CI] 13.0 to 30.0) and 18.0% (95% CI 11.0 to 26.0) were identified as Cryptosporidium and microsporidia, respectively, by the microscopic method. Of these 100 HIV-infected persons, 18.0% (95% CI 11.0 to 26.0) and 14.0% (95% CI 7.0 to 22.0) were positive for Cryptosporidium and microsporidia, respectively, by the molecular method. The predominant species of microsporidia in patients was Enterocytozoon bieneusi (85.7% [95% CI 57.0 to 98.0]) and Encephalitozoon cuniculi (14.3% [95% CI 1.7 to 42.0]), which were found by quantitative real-time PCR and its high-resolution melting tool.

CONCLUSIONS

As far as we know, this study is the first to estimate the prevalence of infection with Cryptosporidium and microsporidia among HIV-infected persons in northwest of Iran. The prevalence of intestinal microsporidiosis and cryptosporidiosis in this area in HIV-infected people was higher than the global prevalence of infection among immunocompromised patients. In addition to the need for further studies to prove protozoan pathogenicity in the aforementioned group, preventive measures should be considered.

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.

Intestinal microsporidiosis among HIV/AIDS patients receiving antiretroviral therapy in Sana'a city, Yemen: first report on prevalence and predictors

Background

Intestinal microsporidiosis is an opportunistic infection associated with persistent diarrhea among HIV/AIDS patients. In Yemen, however, its epidemiology is unknown. Therefore, this study determined its prevalence and predictors among HIV/AIDS patients receiving antiretroviral therapy (ART) in Sana’a city, the capital of Yemen.

Methods

This cross-sectional study included 402 patients receiving ART at Al-Jomhori Educational Hospital in Sana’a from November 2019 to December 2020. Data about demographics, clinical characteristics and risk factors were collected using a pre-designed questionnaire. Stool samples were collected and examined for microsporidian spores using the Gram-chromotrope Kinyoun staining. Blood samples were also collected and used for CD4 cell counting by flow cytometry. Univariate analysis was used to test the association of patients’ characteristics and risk factors with intestinal microsporidiosis. Multivariable logistic regression was then used to identify the independent predictors of infection. Statistical significance was considered at P-values < 0.05.

Results

Intestinal microsporidiosis was prevalent among 14.2% (57/402) of HIV/AIDS patients and was significantly associated with diarrhea (OR 3.4, 95% CI 1.7–6.6; P = 0.001). The significant independent predictors of infection were < 200 CD4 cells/µl (AOR 3.2, 95% CI 1.5–6.9; P = 0.003), not washing hands after contacting soil (AOR 2.5, 95% CI 1.1–5.4; P = 0.026) and before eating (AOR 3.1, 95% CI 1.5–6.4; P = 0.003), eating unwashed raw produce (AOR 2.5, 95% CI 1.2–5.3; P = 0.017) and absence of indoor latrines (AOR 6.2, 95% CI 1.5–25.9; P = 0.012).

Conclusions

The prevalence of intestinal microsporidiosis among HIV/AIDS patients in Sana'a is high and comparable to that reported from several other countries, being prevalent among approximately 14.0% of patients and significantly associated with diarrhea. It could be predicted among patients who have < 200 CD4 cells/µl, have poor hand hygiene after contacting soil and before eating, usually eat unwashed raw produce, or do not possess indoor latrines. Large-scale studies on its epidemiology and predictors among HIV/AIDS patients across the country are warranted.

The largest meta-analysis on the global prevalence of microsporidia in mammals, avian and water provides insights into the epidemic features of these ubiquitous pathogens

BACKGROUND

Microsporidia are obligate intracellular parasites that can infect nearly all invertebrates and vertebrates, posing a threat to public health and causing large economic losses to animal industries such as those of honeybees, silkworms and shrimp. However, the global epidemiology of these pathogens is far from illuminated.

METHODS

Publications on microsporidian infections were obtained from PubMed, Science Direct and Web of Science and filtered according to the Newcastle-Ottawa Quality Assessment Scale. Infection data about pathogens, hosts, geography and sampling dates were manually retrieved from the publications and screened for high quality. Prevalence rates and risk factors for different pathogens and hosts were analyzed by conducting a meta-analysis. The geographic distribution and seasonal prevalence of microsporidian infections were drawn and summarized according to sampling locations and date, respectively.

RESULTS

Altogether, 287 out of 4129 publications up to 31 January 2020 were obtained and met the requirements, from which 385 epidemiological data records were retrieved and effective. The overall prevalence rates in humans, pigs, dogs, cats, cattle, sheep, nonhuman primates and fowl were 10.2% [2429/30,354; 95% confidence interval (CI) 9.2-11.2%], 39.3% (2709/5105; 95% CI 28.5-50.1%), 8.8% (228/2890; 95% CI 5.1-10.1%), 8.1% (112/1226; 95% CI 5.5-10.8%), 16.6% (2216/12,175; 95% CI 13.5-19.8%), 24.9% (1142/5967; 95% CI 18.6-31.1%), 18.5% (1388/7009; 95% CI 13.1-23.8%) and 7.8% (725/9243; 95% CI 6.4-9.2%), respectively. The higher prevalence in pigs suggests that routine detection of microsporidia in animals should be given more attention, considering their potential roles in zoonotic disease. The highest rate was detected in water, 58.5% (869/1351; 95% CI 41.6-75.5%), indicating that water is an important source of infections. Univariate regression analysis showed that CD4+ T cell counts and the living environment are significant risk factors for humans and nonhuman primates, respectively. Geographically, microsporidia have been widely found in 92 countries, among which Northern Europe and South Africa have the highest prevalence. In terms of seasonality, the most prevalent taxa, Enterocytozoon bieneusi and Encephalitozoon, display different prevalence trends, but no significant difference between seasons was observed. In addition to having a high prevalence, microsporidia are extremely divergent because 728 genotypes have been identified in 7 species. Although less investigated, microsporidia coinfections are more common with human immunodeficiency virus and Cryptosporidium than with other pathogens.

CONCLUSIONS

This study provides the largest-scale meta-analysis to date on microsporidia prevalence in mammals, birds and water worldwide. The results suggest that microsporidia are highly divergent, widespread and prevalent in some animals and water and should be further investigated to better understand their epidemic features.

Advancement in our understanding of immune response against Encephalitozoon infection

Microsporidia are a group of obligate, intracellular, spore-forming eukaryotic pathogens, which predominantly infects immunocompromised individuals worldwide. Encephalitozoon spp. is one of the most prevalent microsporidia known to infect humans. Host immune system plays a major role in combating pathogens including Encephalitozoon spp. infecting humans. Both innate and adaptive arms of host immune system work together in combating Encephalitozoon infection. Researchers are conducting studies to elucidate the role of both arms of immune system against Encephalitozoon infection. In addition to cell-mediated adaptive immunity, role of innate immunity is also being highlighted in clearance of Encephalitozoon spp. from host body. Therefore, the current review will give a clear and consolidated update on the role of innate as well as adaptive immunity in protection against Encephalitozoon spp.

Epidemiology of Cryptosporidium Infections among People Living with HIV/AIDS in Nigeria: Results of Systematic Review and Meta-analysis

PURPOSE

Cryptosporidium is implicated in diarrhea epidemics in many parts of the world and is said to be the most common protozoan cause of diarrhea among people living with HIV/AIDS (PLWHA) globally. To provide data on the burden of Cryptosporidium infections among Nigerians living with HIV/AIDS, we reported the prevalence, geographic distribution and Cryptosporidium species diversity among this population in Nigeria.

METHODS

We used the PRISMA guidelines to perform a systematic review and meta-analysis of articles published between January 1, 1995 and April 21, 2020. Pooled estimate (PE), heterogeneity, quality of each study and publication bias were determined using the random-effects model, Cochran's Q test, the 9 point Joanna Briggs Institute Critical Appraisal Instrument and the Egger's regression asymmetry test, respectively.

RESULTS

Forty-six articles reported 2612 positive cases of Cryptosporidium infections from 12,756 PLWHA examined in 20 Nigerian States and the Federal Capital Territory. Overall pooled estimate was 14.5% (95% CI 10.4-19.9) with a range of 0.3% (95% CI 0.0-1.8) to 43.7% (95% CI 35.6-52.3) across sub-groups, with the PEs in relation to CD4⁺ T cell count, species and age showing significant variations at p < 0.05. Cryptosporidium hominis was the most prevalent (3.5%, 95% CI 2.3-5.2) of the six Cryptosporidium species reported in Nigeria.

CONCLUSION

Cryptosporidium infections are moderately prevalent among PLWHA in Nigeria with the highest regional prevalence in the north-east. In addition to personal hygienic practices, the inclusion of Cryptosporidium screening as part of HIV/AIDS clinics in Nigeria will reduce the burden of the parasite among PLWHA in Nigeria.

Diagnosis and molecular typing of Enterocytozoon bieneusi: the significant role of domestic animals in transmission of human microsporidiosis

Enterocytozoon bieneusi is an obligate intracellular fungus-like parasite with high genetic diversity among mammalian and avian hosts. Based on polymorphism analysis of the ribosomal internal transcribed spacer (ITS), nearly 500 genotypes were identified within E. bieneusi. Those genotypes form several genetic groups that exhibit phenotypic differences in host specificity and zoonotic potential and probably have varying public health implications. Some of the genotypes in Group 1 (e.g., D, EbpC, and Type IV) and Group 2 (e.g., BEB4, BEB6, I, and J) are the most common ones that infect a variety of hosts including humans and thus are of public health importance. By contrast, those genotypes in other genetic groups (Groups 3-11) are mostly restricted to the hosts from which they were originally isolated, which would have unknown or limited impacts on public health. Advances on diagnosis and molecular typing of E. bieneusi are introduced in this review. Genotype distribution pattern of E. bieneusi in major domestic animal groups (pigs, cattle, sheep, goats, cats, and dogs), the role of those animals in zoonotic transmission of microsporidiosis, and food and water as potential vehicles for transmission are interpreted here as well. This review highlights the importance of including more genetic or epidemiological data obtained in the same geographical areas and using more reliable genetic markers to analyze the actual extent of host specificity in E. bieneusi, for the purpose of fully appreciating zoonotic risks of those domestic animals in close contacts with men and enhancing our understanding of the modes of transmission.

First identification of genotypes of Enterocytozoon bieneusi (Microsporidia) among symptomatic and asymptomatic children in Mozambique

Enterocytozoon bieneusi is a human pathogen with a broad range of animal hosts. Initially, E. bieneusi was considered an emerging opportunistic pathogen in immunocompromised, mainly HIV-infected patients, but it has been increasingly reported in apparently healthy individuals globally. As in other African countries, the molecular epidemiology of E. bieneusi in Mozambique remains completely unknown. Therefore, we undertook a study to investigate the occurrence and genetic diversity of E. bieneusi infections in children with gastrointestinal symptoms as well as in asymptomatic children in Mozambique. Individual stool specimens were collected from 1,247 children aged between 0 and 14 years-old living in urban and rural settings in Zambézia (n = 1,097) and Maputo (n = 150) provinces between 2016 and 2019. Samples were analysed for E. bieneusi by nested-PCR targeting the internal transcribed spacer (ITS) region of the rRNA gene. All positive amplicons were confirmed and genotyped. Penalised logistic regression (Firth) was used to evaluate risk associations. The overall prevalence of E. bieneusi in this children population was 0.7% (9/1,247). A 10-fold higher prevalence was found in Maputo (4.0%; 6/150) than in Zambézia (0.3%; 3/1,097). All E. bieneusi-positive samples were from children older than 1-year of age, and most (8/9) from asymptomatic children. Nucleotide sequence analysis of the ITS region revealed the presence of four genotypes, three previously reported (Peru11, n = 1; Type IV, n = 2, and S2, n = 2) and a novel genotype (named HhMzEb1, n = 4). Novel genotype HhMzEb1 was identified in both asymptomatic (75%, 3/4) and symptomatic (25%, 1/4) children from a rural area in Maputo province in southern Mozambique. Genotypes HhMzEb1, Peru11, S2, and Type IV belonged to the Group 1 that includes genotypes with low host specificity and the potential for zoonotic and cross-species transmission. Being infected by enteric protozoan parasites and no handwashing were identified as risk associations for E. bieneusi infection. This study reports the first investigation of E. bieneusi genotypes in Mozambique with the identification of three previously reported genotypes in humans as well as a novel genotype (HhMzEb1). Findings highlight the need to conduct additional research to elucidate the epidemiology of E. bieneusi in the country, especially in rural areas where poor hygiene conditions still prevail. Special attention should be paid to the identification of suitable animal and environmental reservoirs of this parasite and to the characterization of transmission pathways.

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.

Host Specificity of Enterocytozoon bieneusi and Public Health Implications

Enterocytozoon bieneusi is the most common cause of human microsporidiosis and it also infects a wide range of mammals and birds worldwide. The role of animals in the transmission of this parasite to humans and its public health importance remain poorly elucidated. This review summarizes all E. bieneusi genotypes identified thus far based on sequence analysis of the ribosomal internal transcribed spacer (ITS) from specimens obtained from humans, domestic and wild animals, and water sources; it examines genotypes, host and geographical distribution, analyzes inter- and intragenotype group host specificity, and interprets the public health significance of genotype groups and major zoonotic genotypes, with the goal of improving our understanding of host specificity in E. bieneusi and its implications for interspecies and zoonotic transmission.

First survey of Enterocytozoon bieneusi and dominant genotype Peru6 among ethnic minority groups in southwestern China's Yunnan Province and assessment of risk factors

BACKGROUND

Enterocytozoon bieneusi is the most common microsporidian species causing diarrhea and other intestinal disorders in humans and animals. Like other infectious diseases, microsporidiosis usually disproportionately affects poor populations. In China, some ethnic minority areas remain poor. Currently, no information of E. bieneusi infection is available in minority populations. The present aims were to understand occurrence and genetic characterizations of E. bieneusi in ethnic minority groups from a poverty-stricken ethnic township in Yunnan Province, and to assess risk factors for E. bieneusi infection.

METHODOLOGY/PRINCIPAL FINDINGS

289 fecal specimens were collected from Yao people (one specimen each) with and without diarrhea, in Yunnan Province. E. bieneusi was identified and genotyped by PCR and sequence analysis of the ITS region of the rRNA gene. An average prevalence of 8.30% (24/289) was observed and four genotypes were identified-genotype Peru6 (n = 21) and three novel genotypes (one each). Genotype Peru6 was detected in two family members in each of three families. In a phylogenetic analysis, all of four genotypes fell into group 1 with zoonotic potential. The people owning individual pit toilets had a statistically higher prevalence of E. bieneusi (16.67%, 12/72) than those using public pit toilets (6.06%, 12/198).

CONCLUSIONS/SIGNIFICANCE

This is the first report on occurrence and genetic characteristics of E. bieneusi in ethnic minority groups in China. Genotype Peru6 was found in humans in China for the first time and showed dominance in Yao people. The same genotype was found in some family members and all the genotypes fell into group 1, suggesting the possibility of anthroponotic and zoonotic transmissions. The majority (83.33%, 20/24) of E. bieneusi positive individuals did not present diarrhea. In any case, it is important to recognize their existence and the importance that asymptomatic individuals to E. bieneusi may have from an epidemiological point of view, as transmitters of this pathogen. The analysis of risk factors provides scientific evidence for the development of effective strategies for prevention and control of E. bieneusi infection.

Epidemiology of Cryptosporidium infection in different hosts in Nigeria: A meta-analysis

Cryptosporidium is a medical and veterinary significant protozoan parasite that infects all classes of vertebrates. Environmental contamination with infective oocyst increases the risk of transmission to susceptible host. Estimates of Cryptosporidium prevalence in humans and animals are lacking in Nigeria, therefore a systematic review and meta-analysis were performed to understand the epidemiology of the disease over a period of 30 years using publications from EMBASE, Ovid MEDLINE, Web of Science, AJOL and Google Scholar databases. Studies that met the inclusion criteria of Cryptosporidium infections under the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist were analysed. Point estimates prevalence and subgroup analyses based on potential risk factors and diagnostic techniques were evaluated at 95% confidence interval (CI). A total of 64 eligible studies published between 1987 and 2017 were selected for meta-analysis. The prevalence of Cryptosporidium infection using quality effects model among human, cattle, sheep, goat, pigs, laboratory animals and birds was estimated as 15.0, 26.1, 16.6, 26.0, 20.1, 9.0 and 7.2%, respectively. The high report of C. parvum subtype family IIc indicates the importance of anthroponotic transmission of Cryptosporidium in Nigeria. Heterogeneity of subgroup (regions, species) and risk factors (HIV status, age, gender, faecal type) analyses were determined. The pooled prevalence of Cryptosporidium spp. in different hosts were high and linked with several risk factors such as environmental contamination and animal contact. There is need for increased awareness on the prevalence of the disease to provide strategies that mitigate the disease in humans and animals.

Enteric Opportunistic Infection and the Impact of Antiretroviral Therapy among HIV/AIDS Patients from Tehran, Iran

BACKGROUND

Opportunistic parasites have been identified as human pathogens, especially in immunodeficient patients. Microsporidian and coccidian infections cause chronic diarrhea as common clinical manifestation in HIV positive patients. In this study, the frequency of opportunistic infections, including microsporidian and coccidian infections, was evaluated in HIV/AIDS patients from Tehran and phylogenic analysis was performed for E. bieneusi isolates from these patients.

METHODS

One hundred and two stool samples were collected from confirmed HIV/AIDS patients, referred to Consult Center of Behavior Diseases, West Health Center, Iran University of Medical Sciences in Tehran, Iran. The samples were transferred to Research Center of Pediatric Infectious Diseases, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences from Jan 2016 to Dec 2016. After conventional formalin-ether concentration, aniline blue staining method and acid-fast staining technique were used for detection of microsporidian spores and Cyclospora oocysts. DNA was extracted and nested PCR was performed.

RESULTS

Two (1.96%) cases were found to be positive for intestinal microsporidia infection using aniline blue staining method and were confirmed as E. bieneusi by nested PCR. One patient was found with Cyclospora cayetanensis infection by acid-fast staining method and PCR. Giardia lamblia and Blastocystis hominis were detected as non-opportunistic parasites in 1/102 (0.98%) and 2/102 (1.96%) of the HIV positive patients, respectively.

CONCLUSION

With respect to the use of antiretroviral therapy (ART) in HIV positive patients, we found a low frequency of infection.

Parasitic infections of the gut in children

Parasitic infections of the gut have major implications for child health, but many questions remain unanswered. Protozoal parasites, especially cryptosporidiosis and giardiasis, cause diarrhoea and contribute to impaired growth, neurocognitive development and mortality. Entamoeba histolytica causes dysentery and may have more subtle effects on child growth. Helminth infections are mostly asymptomatic, and untargeted mass deworming has not been shown to be beneficial. However, children with heavy infections certainly benefit from antihelminthic treatment. Hepatosplenic schistosomiasis is a neglected problem on a massive scale, which causes portal hypertension and lifelong morbidity in individuals who get infected in childhood. Neurocysticercosis causes epilepsy and is a significant consequence of taeniasis solium, another neglected disease which is entirely preventable. Parasitic infections of the gut contribute to child health problems on a large scale. Fresh approaches are needed to prevention and treatment.

Molecular Detection and Genotyping of Intestinal Microsporidia from Stray Dogs in Iran

BACKGROUND

Microsporidia as one of the most important pathogens in veterinary and agricultural settings, have emerged in immunocompromised patients in Iran. To date, different Enterocytozoon bieneusi genotypes have been identified in humans and animals, supporting the possibility of zoonotic zoonosis transmission potential. The aim of this study was to evaluate the distribution of E. bieneusi genotypes among overpopulated stray dogs in vicinity of Tehran, the capital city of Iran.

METHODS

Totally, 75 stool and 75 urine samples were obtained from 75 stray dogs during the time period from Mar 2015 to Oct 2015. DNA extraction was performed on all the samples and specific fragment of small subunit ribosomal RNA gene of E. bieneusi and Encephalitozoon spp. was amplified. Furthermore, specific primers targeting the internal transcribed spacer region of E. bieneusi were applied to determine the genotype of the microorganism.

RESULTS

Microsporidia was detected in 5.3% of stool samples, while none of the urine samples was positive for microsporidia species. Overall, 440 bp fragment of E. bieneusi was amplified in all the samples and there was no amplification for Encephalitozoon spp. The results of sequencing of 410 bp fragment of internal transcribed spacer region showed that all the E. bieneusi were genotype D.

CONCLUSION

E. bieneusi was the most prevalent microsporidian species in the stray dogs and all the positive isolates were characterized as genotype D.

Molecular Diagnosis of Microsporidia among Immunocompromised Patients in Kuala Lumpur, Malaysia

Microsporidia are obligate intracellular parasitic fungi causing chronic diarrhea, particularly among immunocompromised patients. The current method used for diagnosis is based on conventional microscopy, which does not differentiate parasites at the species level. The present study was carried out to identify microsporidian species in immunocompromised patients. From March 2016 to March 2017, a total of 289 archived stool samples were examined microscopically for microsporidian spores using Gram-chromotrope Kinyoun (GCK) stain. Positive stool samples by microscopy were subjected to polymerase chain reaction and sequencing for species identification. Based on microscopy examination, the overall prevalence of microsporidian infections was 32.2% (93/289; 95% CI = 27.1-37.8). Of these stool samples, 45 samples were successfully amplified and confirmed as Enterocytozoon bieneusi. No Encephalitozoon intestinalis was detected. Accurate identification of species might help clinicians to decide appropriate management strategies as dissemination risks and treatment response vary for different species, hence improving the management of microsporidian infections.

Prevalence of enteric parasitic infections among people living with HIV in Abeokuta, Nigeria

INTRODUCTION

Enteric parasitic infections have been increasingly recognized as etiology of life-threatening chronic diarrhea in PLWHA in sub-Saharan Africa. This study investigated the prevalence and burden of intestinal parasitic infection among PLWHA in Abeokuta, southwest Nigeria.

METHODS

Freshly passed stool samples were collected from PLWHA. Detection of Cryptosporidium spp and Microsporidium spp was carried out with Kinyoun's stain and Weber's Chromotrope-based stain respectively. Investigation of other intestinal parasites was done using the direct saline preparation and formol-ether concentration methods. CD4+ T cell count was measured using Partec flow cytometry technique.

RESULTS

A total of 231 (males: females 96:135; mean age 31.81±11.40 years) PLWHA were recruited into the study, among whom 84 (36.4%) were infected with at least one intestinal parasites. Fifty two (22.5%) individuals were positive for Cryptosporidium spp and a significant association between Cryptosporidium sppand diarrhea was observed (p=0.006). Seven (3.0%) were positive for Microsporidium spp. Helminths recovered included Ascaris lumbricoides (20.8%), hookworm (6.5%), Strongyloides stercoralis (4.3%), Trichuris trichiura (5.6%) and Taenia spp. (5.6%). Cryptosporidium spp, Microsporidium spp and S. stercoralis were significantly associated with CD4+ count ≥ 200 cells/mm3 (p<0.05). Cryptosporidium sppand A. lumbricoides were significantly observed among patients that are anti-retroviral therapy (ART) naive.

CONCLUSION

High prevalence of opportunistic parasitic infection was significantly correlated with diarrhea, low CD4+ count and ART naïve individuals in the study. These findings re-emphasize the need for early diagnosis of opportunistic parasites and appropriate intervention among PLWHA.

Genotype Identification and Phylogenetic Analysis of Enterocytozoon bieneusi Isolates from Stool Samples of Diarrheic Children

Among approximately 14 human-pathogenic microsporidian species, Enterocytozoon bieneusi is the most common. It can inhabit the small intestines, causing chronic diarrhea and wasting syndrome. Prevalence and genotype data for E. bieneusi in humans is available for only a few provinces of China. In the current study, 93 fecal specimens were collected from diarrheic children in Chongqing. Polymerase chain reaction amplification and sequencing of the internal transcribed spacer ( ITS) region of the E. bieneusi rDNA sequence identified 11 (11.83%) positive specimens. Among them, 8 (8.60%) are from patients of ages ranging from 2 mo to 6 yr old and 3 (3.23%) from patients 7 to 11 yr old. In total, 6 genotypes (4 novel genotypes and 2 known genotypes) were identified in this study. Phylogenetic analysis showed that all the genotypes identified in the present study belong to group 1, which previously has been described as a zoonotic group. This could mean these infections were acquired zoonotically, and it may be prudent to warn those people having close contact with animals of this potential risk.

Emerging Intestinal Microsporidia Infection in General Population in Jiroft District, Southeastern Iran: A Cross-sectional Study in 2013-2014

BACKGROUND

Microsporidia have been reported as the cause of opportunistic infections in immunocompromised patients in Iran and other countries. There is no data on prevalence of intestinal microsporidia in healthy population of Iran. This study aimed to provide preliminary data on the present status of microsporidia infection in the local healthy population in Jiroft, Kerman Province from southeastern Iran in 2013-2014.

METHODS

Fresh stool samples were randomly collected from 418 residents in rural 209 (50%) and urban 209 (50%) areas of Jiroft. All of the collected samples were concentrated with conventional formalin-ether, stained with Ryan blue. Microscopic examination was performed with high magnification on each sample separately for the demonstration of microsporidia spores.

RESULTS

Microsporidial spores were identified in 41 out of 418 (9.8%) samples including 16.41(39%) from rural areas and 25.41(61%) from urban areas. In general, there was no significant difference between sex, age, job, education, and contact with soil and livestock, water supply, gastrointestinal disorders and microsporidia infection among general population in Jiroft.

CONCLUSION

Intestinal microsporidia infection without clinical manifestations is prevalent in general population resident in southeastern Iran. Appropriate molecular methods are needed for microsporidia species identification.

Production and characterization of monoclonal antibodies against Encephalitozoon intestinalis and Encephalitozoon sp. spores and their developmental stages

Background

Microsporidia are intracellular obligate parasites traditionally associated with immunosuppressed patients; their detection in immunocompetent patients has increased, highlighting their possible importance as emerging pathogens. Detection of spores in stools, urine, body fluids and tissues is difficult and immunological techniques such as immunofluorescence have proved to be a useful and reliable tool in the diagnosis of human microsporidiosis. For this reason, we have produced and characterized monoclonal antibodies (MAbs) specific for Encephalitozoon intestinalis (the second most frequent microsporidian infecting humans), and other Encephalitozoon species, that can be used in different diagnostic techniques.

Results

Seven MAbs were selected in accordance with their optical density (OD). Four (4C4, 2C2, 2E5 and 2H2) were isotype IgG2a; two (3A5 and 3C9) isotype IgG3, and one Mab, 1D7, IgM isotype. The selected monoclonal antibody-secreting hybridomas were characterized by indirect immunofluorescence antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), Western blot, immunoelectron microscopy (Immunogold) and in vitro cultures. The study by IFAT showed different behavior depending on the MAbs studied. The MAbs 4C4, 2C2, 2E5 and 2H2 showed reactivity against epitopes in the wall of the spore (exospore and endospore) epitopes located in Encephalitozoon sp. spores, whereas the MAbs 3A5, 1D7 and 3C9 showed reactivity against internal epitopes (cytoplasmic contents or sporoplasm) of E. intestinalis spores. All MAbs recognized the developing parasites in the in vitro cultures of E. intestinalis. Additionally, 59 formalin-fixed stool samples that had been previously analyzed were screened, with 26 (44%) presenting microsporidian spores (18 samples with E. intestinalis and 8 samples with Enterocytozoon bieneusi). Detection of microsporidian spores by microscopy was performed using Calcofluor stain, Modified Trichrome, Quick-Hot Gram Chromotrope, as well as IFAT using MAbs 4C4, 2C2, 2E5 and 2H2. The 4 MAbs tested clearly recognized the larger spores corresponding to E. intestinalis, but showed no reactivity with Enterocytozoon bieneusi spores. The mass spectrometry and proteomic study revealed that the Mabs 4C4, 2C2, 2E5 and 2H2 recognized the Spore Wall Protein 1 (SWP1) as the antigenic target.

Conclusions

The IFAT-positive MAbs exhibited excellent reactivity against spores and developmental stages, permitting their use in human and animal diagnosis. The epitopes recognized (exospore, endospore and cytoplasmic contents) by the different MAbs developed need further study, and may reveal potential targets for vaccine development, immunotherapy and chemotherapy.

Infection by and genotype characteristics of Enterocytozoon bieneusi in HIV/AIDS patients from Guangxi Zhuang autonomous region, China

Background

Enterocytozoon bieneusi has been increasingly reported to infect humans and various mammals. Microsporidia cause diarrhea in HIV-infected patients worldwide. PCR amplification and sequencing based on the internal transcribed spacer region have been used to describe the genotypes of E. bieneusi and transmission of microsporidiosis.

Methods

In this study, we examined E. bieneusi infection and genotypes in HIV-positive patients in Guangxi, China. Stool specimens were collected from 285 HIV-positive patients and 303 HIV-negative individuals. E. bieneusi genotypes were characterized using nested PCR and sequencing.

Results

Thirty-three (11.58%) HIV-positive patients were infected with microsporidia, and no infection was found in the 303 healthy controls. Three new genotypes were identified and named as GX25, GX456, and GX458; four known genotypes, PigEBITS7, Type IV/K, D, and Ebpc, were also identified. Our data showed that the positive rate for microsporidia was significantly higher in the rural patients than in the other occupation groups. In addition, the positive rate for microsporidia was significantly higher in the patients who drink unboiled water than in those with other drinking water sources.

Conclusions

Our results will provide baseline data for preventing and controlling E. bieneusi infection in HIV/AIDS patients. Further studies are required to clarify the epidemiology and potential sources of microsporidia. Our study showed that microsporidium infection occurs in the HIV/AIDS patients in Guangxi, China.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2787-9) contains supplementary material, which is available to authorized users.

Genotyping of Enterocytozoon bieneusi and Subtyping of Blastocystis in Cancer Patients: Relationship to Diarrhea and Assessment of Zoonotic Transmission

Enterocytozoon bieneusi (E. bieneusi) and Blastocystis are common pathogens responsible for diarrhea in humans, especially in immunocompromised individuals. The number of cancer patients has been increasing and diarrhea is a common clinical symptom in the treatment of cancers. To understand the prevalences and genotypes/subtypes of E. bieneusi and Blastocystis in cancer patients in China, to track the infection sources, and to explore the relationships between E. bieneusi and Blastocystis infections and diarrhea, 381 fecal specimens were collected from cancer patients. Each of them was analyzed for the presence of E. bieneusi and Blastocystis by PCR amplifying and sequencing the ITS region of the rRNA gene and the barcode region of the SSU rRNA gene, respectively. 1.3 and 7.1% of cancer patients were positive for E. bieneusi and Blastocystis, respectively. No statistical differences were observed in the infection rates between the groups by age, gender, and residence. E. bieneusi and Blastocystis were both significantly more common in cancer patients with diarrhea, and significant relationship of Blastocystis to diarrhea was found in chemotherapy group. Two E. bieneusi genotypes (D and a novel one named as HLJ-CP1) and two Blastocystis subtypes (ST1 and ST3) were identified with three novel ST1 sequences. This is the first report of occurrence and molecular characterizations of E. bieneusi and Blastocystis in cancer patients in China. E. bieneusi genotype D and Blastocystis ST1 and ST3 have been identified in humans and animals while one novel E. bieneusi genotype falling into zoonotic group 1, implying a potential of zoonotic transmission.

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.

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.

Molecular testing for clinical diagnosis and epidemiological investigations of intestinal parasitic infections

Over the past few decades, nucleic acid-based methods have been developed for the diagnosis of intestinal parasitic infections. Advantages of nucleic acid-based methods are numerous; typically, these include increased sensitivity and specificity and simpler standardization of diagnostic procedures. DNA samples can also be stored and used for genetic characterization and molecular typing, providing a valuable tool for surveys and surveillance studies. A variety of technologies have been applied, and some specific and general pitfalls and limitations have been identified. This review provides an overview of the multitude of methods that have been reported for the detection of intestinal parasites and offers some guidance in applying these methods in the clinical laboratory and in epidemiological studies.

Performance of the OSOM Trichomonas Rapid Test for diagnosis of Trichomonas vaginalis infection among women in Mysore, India

Background Trichomonas vaginalis is the world's most common treatable sexually transmissible infection. Currently, wet mount microscopy and syndromic management based on vaginal discharge are the most widely used methods for diagnosing and treating trichomoniasis in resource-constrained settings. Wet mount microscopy requires equipment and trained technicians, who are in short supply. We examined the diagnostic accuracy of the OSOM Trichomonas Rapid Test for detecting T. vaginalis vaginal infection among women in Mysore, India.

METHODS

During July 2009-August 2010, 450 sexually active women over 18 years seeking care at an urban reproductive health clinic were enrolled in the study. Clinician-collected vaginal swabs were evaluated for trichomonads using wet mount microscopy, InPouch culture and the OSOM test.

RESULTS

Of the 418 samples included in the analyses, culture detected 68 (16.3%) positive samples, wet mount microscopy detected 56 of the culture-positive samples and four false positive samples. The OSOM test detected 60 of the culture-positive samples plus two false positive cases. Using the composite reference standard (CRS), defined as wet mount- or culture-positive, the sensitivities of wet mount, the OSOM test and culture were 83.3%, 86.1% and 94.4%, respectively. The positive and negative predictive values of the OSOM test were 100% and 97.1% respectively. The Cohen's kappa agreement between the OSOM test and the CRS was excellent (κ=0.94).

CONCLUSION

The OSOM test has high sensitivity, excellent specificity, and excellent positive and negative predictive value compared to a CRS. This simple test can improve screening and diagnosis of T. vaginalis infection in resource-constrained settings where microscopy and culture are unavailable.

Identification and genotyping of Enterocytozoon bieneusi among human immunodeficiency virus infected patients

Microsporidia cause diarrhea among human immunodeficiency virus (HIV) infected patients worldwide. Enterocytozoon bieneusi and Encephalitozoon intestinalis are the most common species infecting HIV patients. Various genotypes of E. bieneusi are transmitted from human to human (anthroponotic route) or from animal to human (zoonotic route). However, there is no study from India on genotypes of E. bieneusi among infected hosts. Therefore, we aimed to (a) study the prevalence, clinical symptoms, and species identification of microsporidia among HIV infected patients and (b) perform a genotypic analysis of E. bieneusi and a phylogenetic interpretation of the transmission of different genotypes among infected hosts. Two hundred and twenty-two HIV-infected patients and 220 healthy controls (HC) were tested for the presence of microsporidia using modified trichrome (MT) staining and PCR. Demographic, clinical and laboratory parameters were studied. Species identification was performed using PCR-RFLP. All E. bieneusi isolates were subjected to genotypic and phylogenetic analysis. Patients with HIV [n=222, age 37.4±10.4y, 169 (76%) male] were more commonly infected with microsporidia than the HC [n=220, age 34.5±6.5y, 156 (71%) male], using MT stain and PCR [4/222, 1.8% vs. 0/220, p=0.04]. Patients infected with microsporidia more commonly presented with diarrhea than those not infected with microsporidia [4, 100% vs. 98/218, 45%; p=0.04]. E. bieneusi was detected in all patients with microsporidia. Four novel genotypes (Ind1 to Ind4) were identified. Ind1 showed 95% similarity with genotype L (AF267142.1) reported in cats (Germany). Genotypes Ind2 to Ind4 showed 94-96% similarity to host-specific genotype A (AF101197.1) reported in humans. Phylogenetic analysis mainly showed an anthroponotic route of transmission (3/4), while the zoonotic route (1/4) was also observed. The prevalence of microsporidia among HIV-infected patients was 1.8%. Patients with microsporidia commonly present with diarrhea. E. bieneusi is the most common species infecting the study population. Four novel genotypes of E. bieneusi were identified, suggesting presumptive transmission mainly through the anthropological route.

Genotypes of Cryptosporidium spp. and Enterocytozoon bieneusi in Human Immunodeficiency Virus-Infected Patients in Lagos, Nigeria

Molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi has improved our understanding of the transmission of both organisms in humans. In this study, to infer possible infection sources, Cryptosporidium spp. and E. bieneusi in fecal specimens from 90 HIV-infected patients attending antiretroviral clinics in Lagos, Nigeria were detected and genotyped by PCR and DNA sequencing. Cryptosporidium spp. and E. bieneusi were identified in four and five patients, respectively, including the occurrence of subtype IeA11T3G3 of Cryptosporidium hominis in two patients, subtype IIcA5G3k of Cryptosporidium parvum in one patient, and Type IV of E. bieneusi in four patients. Among the remaining positive patients, one had mixed infection of Cryptosporidium meleagridis and C. hominis and one had mixed E. bieneusi genotypes. These data highlight a possible difference in major transmission routes (anthroponotic vs. zoonotic) between Cryptosporidium spp. and E. bieneusi in HIV+ patients in the study area.

Fast Technology Analysis Enables Identification of Species and Genotypes of Latent Microsporidia Infections in Healthy Native Cameroonians

Several enteric microsporidia species have been detected in humans and other vertebrates and their identifications at the genotype level are currently being elucidated. As advanced methods, reagents, and disposal kits for detecting and identifying pathogens become commercially available, it is important to test them in settings other than in laboratories with "state-of-the-art" equipment and well-trained staff members. In the present study, we sought to detect microsporidia DNA preserved and extracted from FTA (fast technology analysis) cards spotted with human fecal suspensions obtained from Cameroonian volunteers living in the capital city of Yaoundé to preclude the need for employing spore-concentrating protocols. Further, we tested whether amplicon nucleotide sequencing approaches could be used on small aliquots taken from the cards to elucidate the diversity of microsporidia species and strains infecting native residents. Of 196 samples analyzed, 12 (6.1%) were positive for microsporidia DNA; Enterocytozoon bieneusi (Type IV and KIN-1), Encephalitozoon cuniculi, and Encephalitozoon intestinalis were identified. These data demonstrate the utility of the FTA cards in identifying genotypes of microsporidia DNA in human fecal samples that may be applied to field testing for prevalence studies.

An original simple technique for diagnosis of Microsporidia using glycerol jelly direct smear

Microsporidia spp. are obligate intracellular parasites which are very minute with sizes ranging from 1 to 10 μm. They have been increasingly recognized as human pathogens in AIDS and immunocompromised patients, mainly associated with life-threatening chronic diarrhea and systemic disease. For accurate identification of Microsporidia, permanent staining techniques are used to enable the examiner to use the ×100 objective which reveals the important details needed for diagnosis. On the other hand, ×10 and ×40 objectives are of no value in detection of such a minute organism. Until now, there is no study that demonstrates a rapid satisfactory technique for routine examination of wet mount by the oil-immersion lens. Glycerol jelly (GJ) reagent was previously studied for its benefit in fixing the cover slide of direct wet mounts instantly enabling the use of oil-immersion lens in examination that magnifies its role as a rapid technique for direct examination. The aim of this research is to identify Microsporidia by wet mounts immediately, using GJ reagent that enables the examiner to use the ×100 objective and to evaluate GJ wet mount as a method of identification. Glycerol jelly reagent was prepared (7 g gelatin dissolved in 50 ml boiling water was added to 10 ml glycerol) and added to fecal wet mounts stained by iodine and methylene blue. Wet mounts were examined using the ×100 objective. Satisfactory results were achieved in spite of the small size of Microsporidia, as both iodine and methylene blue stained the cytological structures; GJ reagent fixed the cover slide, maintained the high translucency of the films, and enabled the examiner to use the ×100 oil-immersion objective. We also compared fecal wet mounts stained by iodine and methylene blue + GJ with a stool sample stained by permanent stain modified Ziehl-Neelsen without GJ, and we found that fecal wet mounts stained by iodine and methylene blue + GJ were more clear. We concluded that glycerol jelly wet mount is an easy, fast, reliable, and cheap technique for identification of Microsporidia in direct smear, using the ×100 oil-immersion objective.

Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi and other intestinal parasites in young children in Lobata province, Democratic Republic of São Tomé and Principe

Rare systemic studies concerning prevalence of intestinal parasites in children have been conducted in the second smallest country in Africa, the Democratic Republic of São Tomé and Príncipe. Fecal specimens from 348 children (214 in-hospital attending the Aires de Menezes Hospital and 134 from Agostinho Neto village) in São Tome Island were studied by parasitological and molecular methods. Of the 134 children from Agostinho Neto, 52.2% presented intestinal parasites. 32.1% and 20.2% of these children had monoparasitism and polyparasitism, respectively. Ascaris lumbricoides (27.6%), G. duodenalis (7.5%), T. trichiura (4.5%) and Entamoeba coli (10.5%) were the more frequent species identified in the children of this village. Giardia duodenalis (7.5%) and E. bieneusi (5.2%) were identified by PCR. Nested-PCR targeting G. duodenalis TPI identified Assemblage A (60%) and Assemblage B (40%). The E. bieneusi ITS-based sequence identified genotypes K (57.1%), KIN1 (28.6%) and KIN3 (14.3%). Among the 214 in-hospital children, 29.4% presented intestinal parasites. In 22.4% and 7.0% of the parasitized children, respectively, one or more species were concurrently detected. By microscopy, A. lumbricoides (10.3%) and Trichiuris trichiura (6.5%) were the most prevalent species among these children, and Cryptosporidium was detected by PCR in 8.9% of children. GP60 locus analysis identified 6.5% of C. hominis (subtypes IaA27R3 [35.7%], IaA23R3 [14.3%], IeA11G3T3 [28.6%] and IeA11G3T3R1 [21.4%]) and 2.3% of C. parvum (subtypes IIaA16G2R1 [20.0%], IIaA15G2R1 [20.0%], IIdA26G1 [40.0%] and IIdA21G1a [20.0%]). G. duodenalis and E. bieneusi were identified in 0.5% and 8.9% of the in-hospital children, respectively. G. duodenalis Assemblage B was characterized. The E. bieneusi genotypes K (52.6%), D (26.4%), A (10.5%) and KIN1 (10.5%) were identified. Although further studies are required to clarify the epidemiology of these infectious diseases in this endemic region the significance of the present results highlights that it is crucial to strength surveillance on intestinal pathogens.

Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi and other intestinal parasites in young children in Lobata province, Democratic Republic of São Tomé and Principe

Rare systemic studies concerning prevalence of intestinal parasites in children have been conducted in the second smallest country in Africa, the Democratic Republic of São Tomé and Príncipe. Fecal specimens from 348 children (214 in-hospital attending the Aires de Menezes Hospital and 134 from Agostinho Neto village) in São Tome Island were studied by parasitological and molecular methods. Of the 134 children from Agostinho Neto, 52.2% presented intestinal parasites. 32.1% and 20.2% of these children had monoparasitism and polyparasitism, respectively. Ascaris lumbricoides (27.6%), G. duodenalis (7.5%), T. trichiura (4.5%) and Entamoeba coli (10.5%) were the more frequent species identified in the children of this village. Giardia duodenalis (7.5%) and E. bieneusi (5.2%) were identified by PCR. Nested-PCR targeting G. duodenalis TPI identified Assemblage A (60%) and Assemblage B (40%). The E. bieneusi ITS-based sequence identified genotypes K (57.1%), KIN1 (28.6%) and KIN3 (14.3%). Among the 214 in-hospital children, 29.4% presented intestinal parasites. In 22.4% and 7.0% of the parasitized children, respectively, one or more species were concurrently detected. By microscopy, A. lumbricoides (10.3%) and Trichiuris trichiura (6.5%) were the most prevalent species among these children, and Cryptosporidium was detected by PCR in 8.9% of children. GP60 locus analysis identified 6.5% of C. hominis (subtypes IaA27R3 [35.7%], IaA23R3 [14.3%], IeA11G3T3 [28.6%] and IeA11G3T3R1 [21.4%]) and 2.3% of C. parvum (subtypes IIaA16G2R1 [20.0%], IIaA15G2R1 [20.0%], IIdA26G1 [40.0%] and IIdA21G1a [20.0%]). G. duodenalis and E. bieneusi were identified in 0.5% and 8.9% of the in-hospital children, respectively. G. duodenalis Assemblage B was characterized. The E. bieneusi genotypes K (52.6%), D (26.4%), A (10.5%) and KIN1 (10.5%) were identified. Although further studies are required to clarify the epidemiology of these infectious diseases in this endemic region the significance of the present results highlights that it is crucial to strength surveillance on intestinal pathogens.

Emerging Intestinal Microsporidia Infection in HIV(+)/AIDS Patients in Iran: Microscopic and Molecular Detection

BACKGROUND

Species of Microsporidia have been known as opportunistic obligate intracellular parasites particularly in immunocompromised patients. Enterocytozoon bieneusi is one of most prevalent intestinal microsporida parasites in HIV(+)/AIDS patients. In this study, intestinal microsporidia infection was determined in HIV(+)/AIDS patients using microscopic and molecular methods.

METHODS

Stool samples were collected from HIV(+)/AIDS patients during 12 months. All of the stool specimens washed with PBS (pH: 7.5). Slim slides were prepared from each sample and were examined using light microscope with 1000X magnification. DNA extraction carried out in microscopic positive samples. DNA amplification and genus/species identification also performed by Nested-PCR and sequencing techniques.

RESULTS

From 81 stool samples, 25 were infected with microsporidia species and E. bieneusi were identified in all of positive samples. No Encephalitozoon spp. was identified in 81 collected samples using specific primers.

CONCLUSION

E. bieneusi is the most prevalent intestinal microsporidia in immunocompromised patients of Iran. On the other hand, Nested-PCR using specific primers for ssu rRNA gene is an appropriate molecular method for identification of E. bieneusi.

Molecular diagnosis in clinical parasitology: When and why?

Microscopic detection and morphological identification of parasites from clinical specimens are the gold standards for the laboratory diagnosis of parasitic infections. The limitations of such diagnostic assays include insufficient sensitivity and operator dependence. Immunoassays for parasitic antigens are not available for most parasitic infections and have not significantly improved the sensitivity of laboratory detection. Advances in molecular detection by nucleic acid amplification may improve the detection in asymptomatic infections with low parasitic burden. Rapidly accumulating genomic data on parasites allow the design of polymerase chain reaction (PCR) primers directed towards multi-copy gene targets, such as the ribosomal and mitochondrial genes, which further improve the sensitivity. Parasitic cell or its free circulating parasitic DNA can be shed from parasites into blood and excreta which may allow its detection without the whole parasite being present within the portion of clinical sample used for DNA extraction. Multiplex nucleic acid amplification technology allows the simultaneous detection of many parasitic species within a single clinical specimen. In addition to improved sensitivity, nucleic acid amplification with sequencing can help to differentiate different parasitic species at different stages with similar morphology, detect and speciate parasites from fixed histopathological sections and identify anti-parasitic drug resistance. The use of consensus primer and PCR sequencing may even help to identify novel parasitic species. The key limitation of molecular detection is the technological expertise and expense which are usually lacking in the field setting at highly endemic areas. However, such tests can be useful for screening important parasitic infections in asymptomatic patients, donors or recipients coming from endemic areas in the settings of transfusion service or tertiary institutions with transplantation service. Such tests can also be used for monitoring these recipients or highly immunosuppressed patients, so that early preemptive treatment can be given for reactivated parasitic infections while the parasitic burden is still low.

Microsporidia and 'the art of living together'

Parasitism, aptly defined as one of the 'living-together' strategies (Trager, 1986), presents a dynamic system in which the parasite and its host are under evolutionary pressure to evolve new and specific adaptations, thus enabling the coexistence of the two closely interacting partners. Microsporidia are very frequently encountered obligatory intracellular protistan parasites that can infect both animals and some protists and are a consummate example of various aspects of the 'living-together' strategy. Microsporidia, relatives of fungi in the superkingdom Opisthokonta, belong to the relatively small group of parasites for which the host cell cytoplasm is the site of both reproduction and maturation. The structural and physiological reduction of their vegetative stage, together with the manipulation of host cell physiology, enables microsporidia to live in the cytosolic environment for most of their life cycle in a way resembling endocytobionts. The ability to form structurally complex spores and the invention and assembly of a unique injection mechanism enable microsporidia to disperse within host tissues and between host organisms, resulting in long-lasting infections. Microsporidia have adapted their genomes to the intracellular way of life, evolved strategies how to obtain nutrients directly from the host and how to manipulate not only the infected cells, but also the hosts themselves. The enormous variability of host organisms and their tissues provide microsporidian parasites a virtually limitless terrain for diversification and ecological expansion. This review attempts to present a general overview of microsporidia, emphasising some less known and/or more recently discovered facets of their biology.

Zoonotic Cryptosporidium species and Enterocytozoon bieneusi genotypes in HIV-positive patients on antiretroviral therapy

Molecular diagnostic tools have been used increasingly in the characterization of the transmission of cryptosporidiosis and microsporidiosis in developing countries. However, few studies have examined the distribution of Cryptosporidium species and Enterocytozoon bieneusi genotypes in AIDS patients receiving antiretroviral therapy. In the present study, 683 HIV-positive patients in the National Free Antiretroviral Therapy Program in China and 683 matched HIV-negative controls were enrolled. Cryptosporidium species and subtypes and Enterocytozoon bieneusi genotypes were detected and differentiated by PCR and DNA sequencing. The infection rates were 1.5% and 0.15% for Cryptosporidium and 5.7% and 4.2% for E. bieneusi in HIV-positive and HIV-negative participants, respectively. The majority (8/11) of Cryptosporidium cases were infections by zoonotic species, including Cryptosporidium meleagridis (5), Cryptosporidium parvum (2), and Cryptosporidium suis (1). Prevalent E. bieneusi genotypes detected, including EbpC (39), D (12), and type IV (7), were also potentially zoonotic. The common occurrence of EbpC was a feature of E. bieneusi transmission not seen in other areas. Contact with animals was a risk factor for both cryptosporidiosis and microsporidiosis. The results suggest that zoonotic transmission was significant in the epidemiology of both diseases in rural AIDS patients in China.

Epidemiology of Enterocytozoon bieneusi Infection in Humans

A review was conducted to examine published works that focus on the complex epidemiology of Enterocytozoon bieneusi infection in humans. Studies on the prevalence of these emerging microsporidian pathogens in humans, in developed and developing countries, the different clinical spectra of E. bieneusi intestinal infection in children, in different settings, and the risk factors associated with E. bieneusi infection have been reviewed. This paper also analyses the impact of the recent application of PCR-based molecular methods for species-specific identification and genotype differentiation has had in increasing the knowledge of the molecular epidemiology of E. bieneusi in humans. The advances in the epidemiology of E. bieneusi, in the last two decades, emphasize the importance of epidemiological control and prevention of E. bieneusi infections, from both the veterinary and human medical perspectives.