Improved light-microscopical detection of microsporidia spores in stool and duodenal aspirates. The Enteric Opportunistic Infections Working Group

Sero-salivary detection of H. pylori immunoglobulins and parasitic infection among healthcare individuals suffering from gastrointestinal disorders with correlation to personal hygiene

BACKGROUND

Gastrointestinal microbial infections among healthcare individuals (HCIs) are common due to several risk factors, including poor personal hygiene and socio-economic lifestyle.

OBJECTIVES

This is the first cross-sectional study that stratifies HCIs to correlate personal hygiene and socio-economic lifestyle with gastrointestinal microbial infections. Additionally, it compares serum and saliva levels of H. pylori-IgG and IgA to assess the potential of saliva as a non-invasive alternative to serum.

METHODS

Based on Fisher's formula, 200 HCIs suffering from gastritis-including hospital workers, employees, nursing students, nurses, and doctors-were enrolled. Blood, saliva, and stool samples were collected for microbial infection investigations. Personal hygiene and socio-economic factors were scored based on WHO guidelines. Parasitic infections were identified microscopically, while H. pylori antigen and antibodies were detected via ELISA, with diagnostic significance determined by ROC curve analysis.

RESULTS

A high prevalence of intestinal microbial infections was observed among HCIs. Blastocystis spp. was the most common pathogen (72%), followed by Cryptosporidium spp. (59.5%). Cases of single, double, and multiple infections were detected. H. pylori antigen was present in 36 (18%) cases, often as a co-infection with intestinal parasites. Infection rates were highest among workers and nurses (100%), followed by employees (97.4%) and nursing students (81.7%), with doctors having the lowest rate (50%). Poor personal hygiene and socio-economic lifestyle were directly linked to increased infection risk. Additionally, H. pylori-IgG was positive in 14 cases and negative in 186 cases, while H. pylori-IgA was positive in 2 cases and negative in 198 cases in both serum and saliva. These findings indicate consistency between serum and saliva levels of H. pylori immunoglobulins.

CONCLUSIONS

Poor personal hygiene and socio-economic lifestyle significantly increase the risk of gastrointestinal microbial infections among HCIs. Salivary immunoglobulins show consistency with serum levels, suggesting saliva as a viable non-invasive alternative for detecting H. pylori infection.

Natural regulatory T cells increase significantly in pediatric patients with parasitic infections: Flow cytometry study

Background

The most accepted definition of regulatory T cells (Tregs) relies on the expression of several biomarkers, including CD4, CD25, and transcription factor, Foxp3. The Tregs maintain tolerance to self-antigens and prevent autoimmune diseases.

Aim

The purpose of this study was to determine the difference in natural Treg levels in Entamoeba histolytica, Schistosoma mansoni, Giardia lamblia, Enterobius vermicularis, and Hymenolepis nana infected patients.

Setting and Design

Fifty-one pediatric subjects (29 males and 22 females) were recruited from a tertiary care hospital, and were divided into infected and non-infected (control) groups. The mean age of the subjects was 8.7 years.

Materials and Methods

Blood samples were collected from infected and non-infected groups, and change in the level of Tregs in these subjects was investigated by flow cytometry.

Statistical Analysis Used

The statistical analysis of data was performed by SPSS software. Quantitative data used in this study included mean and standard deviation. Data from the two groups were compared by the Student's t-test. The age of the patient and infection status were used for multivariate logistic regression analysis. Odds ratios (ORs) were estimated within a 95% confidence interval, and a P value of <0.05 was considered significant.

Results and Conclusions

The levels of natural regulatory T cells, indicated by the biomarkers, CD4+, CD25+, and Foxp3+, increase significantly in patients infected by Entamoeba histolytica, Schistosoma mansoni, Giardia lamblia, Enterobius vermicularis, and Hymenolepis nana as compared to controls. They also increase in cases of mixed infection as compared to infection by a single parasite.

High Prevalence of Microsporidia in the North African Hedgehog (Atelerix algirus) in the Canary Islands, Spain

Microsporidia are unicellular eukaryotic obligate intracellular parasites with a wide range of hosts reported worldwide; however, little is known about the epidemiological data on microsporidia infection in animals from the Canary Islands. Since data on microsporidia infection in hedgehog species are scarce, the aim of this study was to analyze the presence and identity of microsporidia in a group of North African hedgehogs (Atelerix algirus) using microscopic and molecular methods. From December 2020 to September 2021, a total of 36 fecal samples were collected from naturally deceased hedgehogs from Tenerife and Gran Canaria. All samples showed spore-compatible structures (100%; 36/36) under microscopic analysis, of which 61.1% (22/36) were amplified via the nested-polymerase chain reaction (PCR) targeting the partial sequence of the 16S rRNA gene, the internal transcribed spacer (ITS) region, and the partial sequence of the 5.8S rRNA gene. After Sanger sequencing and ITS analysis, Enterocytozoon bieneusi was detected in 47.2% (17/36) of the samples, identifying two novel genotypes (AAE1 and AAE2), followed by the detection of an undetermined species in 8.3% (3/36) and Encephalitozoon cuniculi genotype I in 5.6% (2/36) of the samples. This study constitutes the first report of microsporidia species in Atelerix algirus worldwide, highlighting the high prevalence of zoonotic species.

Microbial bowel infections-induced biochemical and biological abnormalities and their effects on young Egyptian swimmers

Swimmers' personal hygiene affects the spread of microbes in pools. The present study aimed to determine the incidence of microbial infections among young Egyptian swimmers and its impact on swimmers' scores. From January 2020 to June 2021, 528 public club swimmers were examined cross-sectionally. Swimmers were divided into two groups according to their star tests and their scores in the competition (group 1 with a high score and group 2 with a low score). Stool samples, biochemical and biological parameters were assessed. Microbial infections were 54% for intestinal parasitosis and 2.8% for Helicobacter pylori. The rate of intestinal parasitosis was higher among Gp2 as compared to Gp1. The results also revealed higher prevalence of Cryptosporidium spp., Giardia lamblia, Entameba histolytica, and Cyclospora among Gp2 than Gp1. Swimming frequency, and duration influenced the infectious status that induced anemia, abnormal blood pressure, and heart rate. Infected swimmers with cryptosporidiosis had higher alanine transaminase levels, white blood cells, and differential cells but lower aspartate transaminase levels. Giardiasis showed higher reduction in the biochemical markers including ferritin, lactoferrin, iron, and transferrin among Gp 2, compared to Gp 1 and thus affected the swimmers' scores. Thus, raising swimmers' hygiene awareness and targeting health education is obliged.

Environmental health aspects and microbial infections of the recreational water : Microbial Infections and Swimming pools

BACKGROUND

Swimming pools are places for practicing sports, recreation, relaxation, and socialization. However, swimming pools can expose swimmers to physicochemical and microbiological risks. Accordingly, we studied the environmental health aspects and microbial infections for such recreational water aiming to disclose the possible risks they pose on swimmers.

METHODS

26 pools in Alexandria, Egypt were checked for water quality; 13 pools were checked in winter then summer, and other 13 pools were checked in summer only. Water was collected from both the top and the bottom of each pool; a total of 78 samples were collected in sterile containers. Each sample was divided into three parts; the first part was used for assessing the bacteriological quality of water. They were tested for total colony count (TCC), total coliform (TC), fecal coliform, and E. coli. The second part was used for chemical analysis. The third part was checked for parasitological study.

RESULTS

Obtained data showed that only 7.7%, 78.2%, and 100% of the examined water samples have been found to fulfill the Egyptian standards for TCC, TC, and E. coli, respectively. Moreover, parasitic infection (PI) was noticed in 73.1% of the collected water samples; mainly Cyclospra and Isospora (37.2% each), followed by Cryptosporidium spp., Giradia lamblia, Microsporidia spp., and Blastocystis spp. (34.6%, 21.8%, 15.4%, and 14.1%, respectively). Acanthameba spp. was detected but at a lower rate (5.1%). The frequency of cleaning the swimming pools, flow rate, Cl2, and total dissolved solids are significantly affected PI, independently.

CONCLUSION

The tested water samples don't meet Egyptian bacteriological criteria. High parasitic contamination despite high residual chlorine level mainly intestinal coccidia, G. lamblia, microsporidia, and Blastocystis spp. Thus, monitoring pool's water quality and improving the disinfection system are mandatory. Consequently, Health education regarding hygienic behaviors before and during swimming should be included in governmental programs.

A Simian Immunodeficiency Virus-Infected Macaque Model of Enterocytozoon bieneusi Infection

Microsporidiosis caused by Enterocytozoon bieneusi is a common opportunistic infection in patients with HIV/AIDS and those on immunosuppressive therapy. A significant loss of mucosal or peripheral CD4+ T cells and subsequent dysfunction of the intestinal immune system may be responsible for the development of chronic microsporidiosis in these patients. We have used the Simian immunodeficiency virus (SIV)-infected macaque model to investigate this relationship. To establish the course of E. bieneusi infection in SIV-infected animals, four SIV-infected animals were experimentally challenged with E. bieneusi when their CD4+ counts dropped to less than 300 cells/μL of blood. Analysis of fecal samples by nested polymerase chain reaction revealed that three out of four E. bieneusi-infected macaques continued to shed spores for 7-24 months after infection, an indication of chronic microsporidiosis. Four other SIV-infected macaques, after having an initial negative phase, spontaneously acquired E. bieneusi infection when their CD4+ counts dropped to less than 600 cells/μL of blood and shed spores for 8-19 months. The shedding of E. bieneusi spores in the feces increased relative to decrease in peripheral blood CD4+ T cell numbers. Gut biopsies were obtained before and after challenge to phenotype the mucosal lymphocyte subsets using flow cytometry. The immunophenotypic analysis showed no restoration of CD4+ T cells after E. bieneusi infection in the intestinal cells. A slight increase in the percentage population of CD4+ T cells in peripheral blood did not have any effect on the control of E. bieneusi infection in the SIV-infected macaques. These preliminary studies demonstrate that SIV-infected macaques develop chronic E. bieneusi infections as their CD4+ counts dropped to below 300 cells/μL of blood.

Microsporidia as a Potential Threat to the Iberian Lynx (Lynx pardinus)

Simple Summary

The Iberian lynx, which inhabits the Iberian Peninsula, is one of the most endangered felines in the world. Wild Iberian lynx populations have suffered a constant regression over the past century, with a rapid decline of 90% in the last 20 years. Infectious diseases are one of the most critical threats that cause the population decline of these animals, either in the wild or captivity. Different studies have revealed positive seroprevalence against various pathogens, confirming contact and exposure to bacteria, viruses, and parasites. In this sense, searching for pathogens related to the depopulation of the Iberian lynx is vital for conserving and maintaining this threatened species. The present work confirmed the presence of microsporidia, opportunistic intracellular parasites recently related to fungi, in the lynx environment. Also, different species of microsporidia were determined for the first time in the urine, feces, and tissue samples of Lynx pardinus. Further studies are needed to establish the impact of microsporidia infection on the survival of the Iberian lynx. These studies would contribute to the endurance and conservation of this feline by implementing new prevention strategies.

Abstract

Lynx pardinus is one of the world’s most endangered felines inhabiting the Iberian Peninsula. The present study was performed to identify the presence of microsporidia due to the mortality increase in lynxes. Samples of urine (n = 124), feces (n = 52), and tissues [spleen (n = 13), brain (n = 9), liver (n = 11), and kidney (n = 10)] from 140 lynxes were studied. The determination of microsporidia was evaluated using Weber’s chromotrope stain and Real Time-PCR. Of the lynxes analyzed, stains showed 10.48% and 50% positivity in urine and feces samples, respectively. PCR confirmed that 7.69% and 65.38% belonged to microsporidia species. The imprints of the tissues showed positive results in the spleen (38.46%), brain (22.22%), and liver (27.27%), but negative results in the kidneys. PCR confirmed positive microsporidia results in 61.53%, 55.55%, 45.45%, and 50%, respectively. Seroprevalence against Encephalitozoon cuniculi was also studied in 138 serum samples with a positivity of 55.8%. For the first time, the results presented different species of microsporidia in the urine, feces, and tissue samples of Lynx pardinus. The high titers of anti-E. cuniculi antibodies in lynx sera confirmed the presence of microsporidia in the lynx environment. New studies are needed to establish the impact of microsporidia infection on the survival of the Iberian lynx.

Identification and Characterization of Three Spore Wall Proteins of Enterocytozoon Bieneusi

Enterocytozoon bieneusi is the most common microsporidian pathogen in farm animals and humans. Although several spore wall proteins (SWPs) of other human-pathogenic microsporidia have been identified, SWPs of E. bieneusi remain poorly characterized. In the present study, we identified the sequences of three E. bieneusi SWPs from whole genome sequence data, expressed them in Escherichia coli, generated a monoclonal antibody (mAb) against one of them (EbSWP1), and used the mAb in direct immunofluorescence detection of E. bieneusi spores in fecal samples. The amino acid sequence of EbSWP1 shares some identity to EbSWP2 with a BAR2 domain, while the sequence of EbSWP3 contains a MICSWaP domain. No cross-reactivity among the EbSWPs was demonstrated using the polyclonal antibodies generated against them. The mAb against EbSWP1 was shown to react with E. bieneusi spores in fecal samples. Using chromotrope 2R staining-based microscopy as the gold standard, the sensitivity and specificity of the direct immunofluorescence for the detection of E. bieneusi were 91.4 and 73.7%. Data generated from the study could be useful in the characterization of E. bieneusi and immunological detection of the pathogen.

Diagnostic Features of Blastocystis Life Cycle Forms in the Small Intestine in an HIV-Infected Patient

PURPOSE

Blastocystis spp. are parasites of the intestinal tract found in many hosts including humans. This pathogen is commonly found in immunocompetent in asymptomatic individuals and in patients with gastrointestinal and extra-intestinal symptoms. Recently, it has been implicated as an important cause of diarrheal illness in immunocompromised individuals, including HIV-infected patients. At least six life cycle stages have been described in faeces and cultures, namely vacuolar, granular, multi-vacuolar, avacuolar, ameboid and cyst forms. The aim of the present study was to describe the histological findings of Blastocystis infection in an adult HIV-infected patient with gastrointestinal symptoms.

METHODS

Parasitological techniques and PCR were applied to stool samples. Histological analysis was performed on duodenal biopsy specimens.

RESULTS

Standard parasitological methods revealed vacuolar, granular, cyst and multi-vacuolar forms of Blastocystis in faecal samples with the presence of Blastocystis DNA being confirmed by PCR. DNA sequencing revealed Blastocystis subtype ST1. Histological findings in duodenal samples showed an inflammatory infiltrate with plasma cells and lymphocytes. We identified cyst, granular, ameboid and multi-vacuolar forms in the lumen.

CONCLUSION

To our knowledge, there are no previous peer review reports describing these four different forms of Blastocystis in histological sections from the lumen and the brush border of the enterocytes.

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 Function and Structure of the Microsporidia Polar Tube

Microsporidia are obligate intracellular pathogens that were initially identified about 160 years ago. Current phylogenetic analysis suggests that they are grouped with Cryptomycota as a basal branch or sister group to the fungi. Microsporidia are found worldwide and can infect a wide range of animals from invertebrates to vertebrates, including humans. They are responsible for a variety of diseases once thought to be restricted to immunocompromised patients but also occur in immunocompetent individuals. The small oval spore containing a coiled polar filament, which is part of the extrusion and invasion apparatus that transfers the infective sporoplasm to a new host, is a defining characteristic of all microsporidia. When the spore becomes activated, the polar filament uncoils and undergoes a rapid transition into a hollow tube that will transport the sporoplasm into a new cell. The polar tube has the ability to increase its diameter from approximately 100 nm to over 600 nm to accommodate the passage of an intact sporoplasm and penetrate the plasmalemma of the new host cell. During this process, various polar tube proteins appear to be involved in polar tube attachment to host cell and can interact with host proteins. These various interactions act to promote host cell infection.

Nosema Disease of European Honey Bees

Nosematosis is currently a frequently discussed honey bee disease caused by two types of Microsporidia: Nosema apis and Nosema ceranae. Nosematosis as an intestinal disease caused by these species is one of the main factors associated with the weakening and loss of hives, with none of the stressors acting in isolation and all having an important synergistic or additive effect on the occurrence of parasitic infection. The most important factors are exposure to pesticides and nutritional stress, both worsening the immune response. Honey bees Apis mellifera become more susceptible to parasites and subsequently the disease manifests itself. Choosing the right laboratory diagnostics is important to determine the prevalence of both species. Our review summarizes the most commonly used methodologies, especially polymerase chain reaction (PCR), which is a reliable method for detecting nosematosis, as well as for distinguishing between the two species causing the disease.

Microsporidiosis in Humans

Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are about 220 genera and 1,700 species of microsporidia, which are classified based on their ultrastructural features, developmental cycle, host-parasite relationship, and molecular analysis. Phylogenetic analysis suggests that microsporidia are related to the fungi, being grouped with the Cryptomycota as a basal branch or sister group to the fungi. Microsporidia can be transmitted by food and water and are likely zoonotic, as they parasitize a wide range of invertebrate and vertebrate hosts. Infection in humans occurs in both immunocompetent and immunodeficient hosts, e.g., in patients with organ transplantation, patients with advanced human immunodeficiency virus (HIV) infection, and patients receiving immune modulatory therapy such as anti-tumor necrosis factor alpha antibody. Clusters of infections due to latent infection in transplanted organs have also been demonstrated. Gastrointestinal infection is the most common manifestation; however, microsporidia can infect virtually any organ system, and infection has resulted in keratitis, myositis, cholecystitis, sinusitis, and encephalitis. Both albendazole and fumagillin have efficacy for the treatment of various species of microsporidia; however, albendazole has limited efficacy for the treatment of Enterocytozoon bieneusi. In addition, immune restoration can lead to resolution of infection. While the prevalence rate of microsporidiosis in patients with AIDS has fallen in the United States, due to the widespread use of combination antiretroviral therapy (cART), infection continues to occur throughout the world and is still seen in the United States in the setting of cART if a low CD4 count persists.

Acid and heat fastness in microsporidia: How acid fast are acid fast microsporidium?

Microsporidia are obligate spore-forming microorganisms with strong resemblance to fungi and can affect almost every organ system in immunocompetent or immunocompromised individuals. Mixed infections are also reported in immunocompromised hosts. Microsporidial spores show marked morphological variations and the small and slender forms can resemble bacilli. Modified Zeihl Neelsen (ZN) stain, cold method demonstrates them as bright red in color, leaving several spores blue or incompletely stained; thus, they are reported as weakly or variably acid fast. Variability in staining results with ZN stain and considering the fact that Mycobacterium tuberculosis, the commoner bug in developing countries is identified by its resistance to stronger acids on ZN staining, authors wished to demonstrate acid and heat fastness in microsporidium using corneal tissue specimens. Microsporidial spores stained bright red in color with conventional ZN stain, demonstrated strong acid fastness, and interestingly the staining results improved on heating. Thus, the authors conclude that they are strongly acid and heat fast and care must be warranted so that they are not misdiagnosed as Mycobacterium or other acid-fast organisms. Careful observation of morphology, battery of special stains, and molecular diagnostics should be advocated for diagnostic confirmation. To the best of the authors' knowledge, this is the first explicit report on acid and heat fastness on microsporidial spores.

Enterocytozoon bieneusi of animals-With an 'Australian twist'

Enterocytozoon bieneusi is a microsporidian microorganism that causes intestinal disease in animals including humans. E. bieneusi is an obligate intracellular pathogen, typically causing severe or chronic diarrhoea, malabsorption and/or wasting. Currently, E. bieneusi is recognised as a fungus, although its exact classification remains contentious. The transmission of E. bieneusi can occur from person to person and/or animals to people. Transmission is usually via the faecal-oral route through E. bieneusi spore-contaminated water, environment or food, or direct contact with infected individuals. Enterocytozoon bieneusi genotypes are usually identified and classified by PCR-based sequencing of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA. To date, ~600 distinct genotypes of E. bieneusi have been recorded in ~170 species of animals, including various orders of mammals and reptiles as well as insects in >40 countries. Moreover, E. bieneusi has also been found in recreational water, irrigation water, and treated raw- and waste-waters. Although many studies have been conducted on the epidemiology of E. bieneusi, prevalence surveys of animals and humans are scant in some countries, such as Australia, and transmission routes of individual genotypes and related risk factors are poorly understood. This article/chapter reviews aspects of the taxonomy, biology and epidemiology of E. bieneusi; the diagnosis, treatment and prevention of microsporidiosis; critically appraises the naming system for E. bieneusi genotypes as well as the phylogenetic relationships of these genotypes; provides new insights into the prevalence and genetic composition of E. bieneusi populations in animals in parts of Australia using molecular epidemiological tools; and proposes some areas for future research in the E. bieneusi/microsporidiosis field.

The shrimp microsporidian Enterocytozoon hepatopenaei (EHP): Biology, pathology, diagnostics and control

Disease is a major limiting factor in the global production of cultivated shrimp. The microsporidian parasite Enterocytozoon hepatopenaei (EHP) was formally characterized in 2009 as a rare infection of the black tiger shrimp Penaeus monodon. It remained relatively unstudied until mid-2010, after which infection with EHP became increasingly common in the Pacific whiteleg shrimp Penaeus vannamei, by then the most common shrimp species farmed in Asia. EHP infects the hepatopancreas of its host, causing hepatopancreatic microsporidiosis (HPM), a condition that has been associated with slow growth of the host in aquaculture settings. Unlike other infectious disease agents that have caused economic losses in global shrimp aquaculture, EHP has proven more challenging because too little is still known about its environmental reservoirs and modes of transmission during the industrial shrimp production process. This review summarizes our current knowledge of the EHP life cycle and the molecular strategies that it employs as an obligate intracellular parasite. It also provides an analysis of available and new methodologies for diagnosis since most of the current literature on EHP focuses on that topic. We summarize current knowledge of EHP infection and transmission dynamics and currently recommended, practical control measures that are being applied to limit its negative impact on shrimp cultivation. We also point out the major gaps in knowledge that urgently need to be bridged in order to improve control measures.

Alternatives in Molecular Diagnostics of Encephalitozoon and Enterocytozoon Infections

Microsporidia are obligate intracellular pathogens that are currently considered to be most directly aligned with fungi. These fungal-related microbes cause infections in every major group of animals, both vertebrate and invertebrate, and more recently, because of AIDS, they have been identified as significant opportunistic parasites in man. The Microsporidia are ubiquitous parasites in the animal kingdom but, until recently, they have maintained relative anonymity because of the specialized nature of pathology researchers. Diagnosis of microsporidia infection from stool examination is possible and has replaced biopsy as the initial diagnostic procedure in many laboratories. These staining techniques can be difficult, however, due to the small size of the spores. The specific identification of microsporidian species has classically depended on ultrastructural examination. With the cloning of the rRNA genes from the human pathogenic microsporidia it has been possible to apply polymerase chain reaction (PCR) techniques for the diagnosis of microsporidial infection at the species and genotype level. The absence of genetic techniques for manipulating microsporidia and their complicated diagnosis hampered research. This study should provide basic insights into the development of diagnostics and the pitfalls of molecular identification of these ubiquitous intracellular pathogens that can be integrated into studies aimed at treating or controlling microsporidiosis.

Microscopic and PCR-based detection of microsporidia spores in human stool samples

Microsporidia are obligate intracellular fungi with a remarkable ability to infect a wide range of invertebrate and vertebrate hosts. Namely, Enterocytozoon bieneusi is the most frequently microsporidia reported worldwide, and mainly associated with chronic diarrhea and wasting syndrome in AIDS patients. Microscopy and PCR-based detection techniques are effective for diagnosis and identification of species and genotypes; however, these methods should be standardized in each laboratory. In this study, we performed microscopy and nested PCR techniques with PCR product sequencing to detect E. bieneusi in human stool samples. These techniques, if applied together, might prove useful for diagnosis and future epidemiological studies of intestinal microsporidiosis in Argentina.

A Narrative Review of Microsporidial Infections of the Cornea

Microsporidia are a rare and commonly misdiagnosed cause of corneal infection, accounting for approximately 0.4% of cases of microbial keratitis in some populations. Ocular microsporidiosis most often presents as either microsporidial keratoconjunctivitis (MKC) or microsporidial stromal keratitis (MSK). Though these two clinical entities exhibit similar symptomology, they are distinguished from one another by the time course for disease progression, findings on slit-lamp examination, and response to medical therapy. This review summarizes the current literature on the etiology and clinical presentation of microsporidial infections of the cornea and highlights ongoing developments in available diagnostic modalities and treatment regimens.

A new scope for orlistat: Effect of approved anti-obesity drug against experimental microsporidiosis

As the current therapies for intestinal microsporidiosis are either inconsistent in their efficacies or hampered by several adverse effects, alternative antimicrosporidial agents are being sought. The present study is the first that was designed to evaluate the potency of orlistat, an approved anti-obesity drug, against intestinal microsporidiosis caused by both Enterocytozoon bieneusi and Encephalitozoon intestinalis. Results were assessed through studying fecal and intestinal spore load, intestinal histopathological changes, viability, and infectivity of spores from treated animals. Results showed that orlistat has promising antimicrosporidia potential, with better results in E. intestinalis than E. bieneusi. The animals that received orlistat showed statistically significant decrease in the fecal and intestinal spore load, when compared to the corresponding control infected nontreated mice. The results were insignificant compared to fumagillin and albendazole. Light microscopic examination of stained intestinal sections revealed amelioration of the pathological changes and decreased inflammatory cells detected in the control infected nontreated mice. Spores encountered from stool of orlistat-treated E. bieneusi and E. intestinalis mice showed low viability and significant reduction of infectivity versus their control. Thus, considering the results of the present work, orlistat proved its effectiveness against the intestinal microsporidial infection.

Multimethodological Approach to Gastrointestinal Microsporidiosis in HIV-Infected Patients

PURPOSE

Microsporidiosis is an opportunistic infection that produces chronic diarrhoea and cholangiopathy in patients with AIDS, mainly caused by two species of microsporidia, Enterocytozoon bieneusi and Encephalitozon intestinalis. The aim of this work was to develop an integral system for the diagnosis of microsporidiosis of the intestine and biliary tract in HIV-infected patients, comprising microscopic and molecular techniques.

METHODS

The study population comprised 143 adult patients of both sexes with diagnosis of HIV infection, with chronic diarrhoea, and with or without HIV-associated cholangiopathy. Stool studies for microsporidia identification of spores were performed on each patient. A video esofagogastroduodenoscopy with biopsy collection was also carried out for routine histology and semi-thin sections stained with Azure II. Species identification was carried out by transmission electron microscopy and/or polymerase chain reaction for the species E. bieneusi and E. intestinalis.

RESULTS

Out of the 143 patients a total of 12.6% (n = 18) were infected with microsporidia. Microsporidia species identified in most cases was E. bieneusi (16/18 cases), followed by E. intestinalis (4/18), all of these last ones in coinfection with E. bieneusi.

CONCLUSIONS

Clinical, imaging, microscopic and molecular analyses, when applied in a systematic and integrated approach, allow diagnosis and identification of microsporidia at species level in AIDS patients with chronic diarrhoea, and with or without HIV-associated cholangiopathy.

Gastrointestinal Parasitic Infections and Immunological Status of HIV/AIDS Coinfected Individuals in Nigeria

BACKGROUND

Parasitic infections of the gastrointestinal tract is one of the highest causes of morbidity and mortality among HIV infected individuals. This is due to the colonization of the intestinal tract by parasites influenced by induced enteropathy caused by HIV infection. CD+4 t-lymphocytes count is a marker of the immune status of HIV infected individuals.

OBJECTIVE

This study investigated the prevalence of gastrointestinal parasitic infections among HIV coinfected individuals in relation to their immunological status.

METHODS

CD+4 t-lymphocytes count was determined using fluorescence-activated cell sorting (FACS) count system. Parasitological examination of faecal samples was conducted using direct wet mount, modified Z-N and Giemsa stain techniques. All prepared slides were examined under x10 and x40 objectives.

FINDINGS

Out of the 891 HIV seropositive participants on antiretroviral therapy that were studied, 641 (71.9%) had CD+4 counts equals to or greater than 500 cells/mm3. All other seropositive participants had CD+4 counts below 500 cells/mm3. Gastrointestinal parasitic infections were recorded in 187 (20.9%) seropositive participants, with females (n = 108, 12.1%) having more infections than males. Multiple gastrointestinal parasitic infections were recorded in 28 (3.1%) seropositive participants. Out of the 150 seronegative participants, 79 (52.7%) of them had at least one gastrointestinal parasitic infection. Female seronegative participants also accounted for higher infection rate (n = 42, 28.0%) than males (n = 37, 24.7%). Multiple infections were also recorded in 18 (12.0%) seronegative individuals. The overall prevalence rate of infection between both positive and negative individuals was 25.5%. There was statistical significant difference in the infections of Cryptosporidium parvum (p < 0.003), Cyclospora cayetanensis (p < 0.011) and Cystoisospora belli (p < 0.011) between HIV seropositive and HIV seronegative individuals. Also, there was statistical significant difference in the infections of hook worm (p < 0.002) and Trichuris trichiura (p < 0.020) between seronegative and seropositive individuals. Gastrointestinal parasitic infection rate was significantly higher among seropositive participants with CD+4 counts between 200 and 350 cells/mm3 (n = 109, 58.3%).

CONCLUSION

The study shows that HIV infected individuals continue to experience gastrointestinal infections even with antiretroviral treatment, especially those with CD+4 counts below 350 cells/mm3. Health care providers should prioritise routine screening of HIV patients for gastrointestinal parasites and provide prompt treatment. Antiparasitic drugs should also be provided as prophylaxis.

Molecular Phylodiagnosis of Enterocytozoon bieneusi and Encephalitozoon intestinalis in Children with Cancer: Microsporidia in Malignancies as an Emerging Opportunistic Infection

BACKGROUND : Microsporidia may cause infection in both immunocompromised and immunocompetent populations. The best strategy to control microsporidiosis is obtaining thorough knowledge of its outbreak and pathogenicity. PURPOSE : Because of the lack of precise estimation of microsporidia prevalence among Iranian children with cancer, the current study aimed at evaluating the rate of intestinal microsporidia in children undergoing chemotherapy.

METHODS

 Patients with cancer undergoing chemotherapy in a children's hospital in Northwestern Iran were studied; 132 stool samples were collected and stained by the Weber and Ryan-blue modified trichrome staining techniques. The extracted DNA samples were evaluated by the nested polymerase chain reaction (PCR) method. All positive isolates were sequenced for genotyping and phylogenetic analysis.

RESULTS

A total of 17 (12.8%) samples were microscopically positive for microsporidia infection, whereas only 14 (10.6%) cases were positive based on nested PCR results. In the positive samples detected with nested PCR, the frequency of Enterocytozoon bieneusi and Encephalitozoon intestinalis infections was 71.4% (n = 10) and 28.6% (n = 4), respectively. After sequencing and phylogenetic analysis, the genotype of E. bieneusi was type D and the sequences of the isolated species were similar to those of the registered ones.

CONCLUSION

E. bieneusi is a major contributor to microsporidiosis in young immunocompromised patients in Iran. Microsporidia species are well-detected when confirmatory techniques such as molecular methods are in agreement with staining. So, to ensure this, a suggestion has been made to introduce a certain diagnostic test for microsporidiosis.

Experimental horizontal transmission of Enterocytozoon hepatopenaei in post-larvae of whiteleg shrimp, Litopenaeus vannamei

Enterocytozoon hepatopenaei (EHP) is a microsporidian parasite that causes hepatopancreatic microsporidiosis (HPM) in penaeid shrimp. HPM was observed in several countries, including Thailand and India; it has become a prominent pathogen in shrimp culture. Based on observations on EHP infection in the wild, the route of transmission has been hypothesized. Identification of artificial EHP infection procedures can facilitate our understanding of EHP transmission. Experimental transmission of EHP was attempted using the immersion and oral infections of infection. In the immersion mode, post-larvae (PL) were exposed to an EHP tissue homogenate (0.2%) by immersion for 48 hr. Experimental samples were collected at various time points, and infection was confirmed using polymerase chain reaction, haematoxylin and eosin staining, transmission electron microscopy and modified trichrome staining. All test results revealed successful EHP transmission. Similar results were obtained through oral infection (oral infection). Innate immune gene expression patterns during infection were analysed; prophenoloxidase, crustin and superoxide dismutase were upregulated at 6, 6 and 48 hr post-challenge, respectively. Experimental infection procedures facilitate the development of diagnostic and prevention strategies. This is the first study demonstrating the experimental transmission of EHP in shrimp PL.

Therapeutic targets for the treatment of microsporidiosis in humans

INTRODUCTION

Microsporidia have been increasingly reported to infect humans. The most common presentation of microsporidiosis is chronic diarrhea, a significant mortality risk in immune-compromised patients. Albendazole, which inhibits tubulin, and fumagillin, which inhibits methionine aminopeptidase type 2 (MetAP2), are the two main therapeutic agents used for treatment of microsporidiosis. In addition, to their role as emerging pathogens in humans, microsporidia are important pathogens in insects, aquaculture, and veterinary medicine. New therapeutic targets and therapies have become a recent focus of attention for medicine, veterinary, and agricultural use. Areas covered: Herein, we discuss the detection and symptoms of microsporidiosis in humans and the therapeutic targets that have been utilized for the design of new drugs for the treatment of this infection, including triosephosphate isomerase, tubulin, MetAP2, topoisomerase IV, chitin synthases, and polyamines. Expert opinion: Enterocytozoon bieneusi is the most common microsporidia in human infection. Fumagillin has a broader anti-microsporidian activity than albendazole and is active against both Ent. bieneusi and Encephaliozoonidae. Microsporidia lack methionine aminopeptidase type 1 and are, therefore, dependent on MetAP2, while mammalian cells have both enzymes. Thus, MetAP2 is an essential enzyme in microsporidia and new inhibitors of this pathway have significant promise as therapeutic agents.

Prevalence of Cryptosporidium, Blastocystis, and other opportunistic infections in patients with primary and acquired immunodeficiency

Intestinal opportunistic infections are often caused by unicellular parasites. Individuals with decreased immunity are particularly susceptible to infection by said microorganisms, and when they are infected, diarrhea can be the main clinical manifestation. However, intestinal parasites have rarely been taken into account in intestinal disorders. In our study, an investigation was conducted to determine the prevalence of intestinal micro-pathogens, such as Cryptosporidium, Giardia, Blastocystis, and microsporidia, in hospitalized patients with different immunological statuses. The study at hand indicates that protozoan parasitic infections are rare among immunodeficient patients in Poland. The overall prevalence of micro-pathogens among participants was 4.6%; it was three times higher in adults (12.5%) than in children (2.3%). Cryptosporidium and Cyclospora species (Apicomplexa) were diagnosed as the main cause of heavy diarrhea. Accordingly, adult patients were positive mainly for Blastocystis and microsporidia, while children were more often infected with the Cryptosporidium species.

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.

Case Report: Ocular Microsporidiosis: Case in a Patient Returning from India and Review of the Literature

Microsporidia are protists close to the kingdom of fungi that may cause eye infections. Most cases are reported in Asia and affect both immunocompromised and immunocompetent patients. Here, we report a rare case of microsporidial keratoconjunctivitis in an immunocompetent French patient 3 weeks after returning from India. In our patient, Weber trichrome staining of conjunctival scrapings revealed rounded elements approximately 1-3 μm in size. Conventional polymerase chain reaction analysis by ribosomal RNA subunit sequencing showed 100% identity with Vittaforma corneae. Treatment by corneal debridement combined with fluoroquinolone eye drops allowed complete resolution of the lesions. Although rare, ocular microsporidiosis should be investigated in a patient who is native to Asia or has returned from an endemic area and presents with keratoconjunctivitis of undetermined etiology.

First detection of Cryptosporidium DNA in blood and cerebrospinal fluid of HIV-infected patients

Human cryptosporidiosis is an intestinal infection caused by different species belonging to the genus Cryptosporidium in both immunocompetent and immunocompromised individuals. The life cycle of Cryptosporidium sp. when affecting the digestive system is well known but the infection of other organs is less studied. Molecular methods are necessary for species and subtypes identification. The goal of this work is to propose a new approach that contributes to the diagnosis of the extra-intestinal dissemination process of Cryptosporidium infection. Cryptosporidium sp. was detected in stool and biopsy samples of two HIV-infected patients. DNA was extracted from feces, biopsy specimens, blood, and cerebrospinal fluid (CSF). All samples were analyzed by nested PCR-RFLP of the 18S rDNA, real-time PCR, and gp60 subtyping. Cryptosporidium DNA was detected in stool and tissue samples and it was also present in blood and CSF samples. Both cases were characterized as Cryptosporidium hominis subtype IeA11G3T3. This is the first report that demonstrates the presence of Cryptosporidium DNA in blood and CSF of HIV-infected patients.

Prevalence of potentially zoonotic gastrointestinal parasites in canine faeces in Ibadan, Nigeria

BACKGROUND

Humans can get infected through direct or indirect contact with infective stages of zoonotic parasites shed to the environment through dog faeces.

OBJECTIVES

This study was designed to investigate the presence of gastrointestinal parasites present in dog faeces shed on the street of Ibadan metropolis, one of the largest cities in Africa.

METHODS

Twenty-three locations were randomly selected using grid-sampling method. A total of 203 faecal samples collected from the streets of selected areas were processed for detection of helminth eggs and protozoan oocysts using flotation technique. Eggs/oocysts per gram of faeces was counted using modified McMaster technique.

RESULTS

The prevalence of gastrointestinal parasites was 43.3% (88/203). Single and multiple infections were 69 (78.4%) and 19 (21.6%) respectively. The parasites detected were Ancylostoma sp. 24.6% (50/88) Isospora sp. 14.2% (29/88), Toxocara sp. 9.8% (20/88), Uncinaria sp. 2.5% (5/88) and Strongyloides sp, 3.9% (8/88). Ancylostoma sp. (320 × 10² epg) and Uncinaria sp. (5 × 10² epg) had the highest and least intensity respectively. Streets within residential areas having markets had the highest number of positive samples. All the genera of parasites detected in this study have zoonotic potential.

CONCLUSION

The high prevalence of zoonotic parasites detected in dog faeces from Ibadan metropolis showed that infected stray dogs roam the streets and constitute potential risk to human health. This study suggests the need for enforcement of laws restraining roaming or straying dogs and proper veterinary care of dogs.

FUNDING

None declared.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Enteric parasites can disturb leptin and adiponectin levels in children

INTRODUCTION

Infection by intestinal parasites in childhood may be the main cause of many health-related problems in developed countries such as anemia, anorexia, loss of appetite, retarded growth and development. The aim of the present study was to assess the effect of different intestinal parasites on white adipose tissue hormones.

MATERIAL AND METHODS

Eighty-one children infected by different parasites and 35 apparently healthy children were enrolled in this study. All patients and controls were subjected to clinical examination, measurement of body mass index (BMI) and laboratory examination.

RESULTS

For BMI percentiles, there was a significant increase in serum leptin level (p = 0.042) and a significant decrease in serum adiponectin level (p = 0.039) in uninfected children, whereas there were no significant changes in the infected group (p = 0.068 and 0.082 respectively). A significant increase in leptin and decrease in adiponectin levels were observed for E. histolytica, Strongyloides and E. histolytica and Giardia infections compared to the control group (p = 0.047, 0.035 and 0.019 for leptin, and p = 0.025, 0.038 and 0.041 for adiponectin, respectively).

CONCLUSIONS

The infection by some intestinal parasites may deregulate the secretion of leptin and adiponectin and also affect the absorption of some nutrients which can disturb the BMI and cause anorexia.

Practical Guidance for Clinical Microbiology Laboratories: Laboratory Diagnosis of Parasites from the Gastrointestinal Tract

This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasites from the gastrointestinal tract provides practical information for the recovery and identification of relevant human parasites. The document is based on a comprehensive literature review and expert consensus on relevant diagnostic methods. However, it does not include didactic information on human parasite life cycles, organism morphology, clinical disease, pathogenesis, treatment, or epidemiology and prevention. As greater emphasis is placed on neglected tropical diseases, it becomes highly probable that patients with gastrointestinal parasitic infections will become more widely recognized in areas where parasites are endemic and not endemic. Generally, these methods are nonautomated and require extensive bench experience for accurate performance and interpretation.

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.

The importance of public health, poverty reduction programs and women's empowerment in the reduction of child stunting in rural areas of Moramanga and Morondava, Madagascar

BACKGROUND

Malnutrition accounts for 45% of mortality in children under five years old, despite a global mobilization against chronic malnutrition. In Madagascar, the most recent data show that the prevalence of stunting in children under five years old is still around 47.4%. This study aimed to identify the determinants of stunting in children in rural areas of Moramanga and Morondava districts to target the main areas for intervention.

METHODS

A case-control study was conducted in children aged from 6 to 59.9 months, in 2014-2015. We measured the height and weight of mothers and children and collected data on child, mother and household characteristics. One stool specimen was collected from each child for intestinal parasite identification. We used a multivariate logistic regression model to identify the determinants of stunting using backwards stepwise methods.

RESULTS

We included 894 and 932 children in Moramanga and in Morondava respectively. Stunting was highly prevalent in both areas, being 52.8% and 40.0% for Moramanga and Morondava, respectively. Stunting was most associated with a specific age period (12mo to 35mo) in the two study sites. Infection with Trichuris trichiura (aOR: 2.4, 95% CI: 1.1-5.3) and those belonging to poorer households (aOR: 2.3, 95% CI: 1.6-3.4) were the major risk factors in Moramanga. In Morondava, children whose mother had activities outside the household (aOR: 1.7, 95% CI: 1.2-2.5) and those perceived to be small at birth (aOR: 1.6, 95% CI: 1.1-2.1) were more likely to be stunted, whereas adequate birth spacing (≥24months) appeared protective (aOR: 0.4, 95% CI: 0.3-0.7).

CONCLUSION

Interventions that could improve children's growth in these two areas include poverty reduction, women's empowerment, public health programmes focusing on WASH and increasing acceptability, and increased coverage and quality of child/maternal health services.

Screening of protozoan and microsporidian parasites in feces of great cormorant (Phalacrocorax carbo)

The global population of great cormorants (Phalacrocorax carbo L.) is on the rise. These birds, characterized by rapid metabolism, can deposit large quantities of feces, and because they breed on the land but forage on water, both terrestrial and aquatic environments can be simultaneously affected by their activities. The contribution of great cormorants in the dispersal of bacterial and viral pathogens has been immensely studied; whereas, the occurrence of eukaryotic parasites such as protozoans and microsporidians in these birds is little known. The present study investigated the presence of dispersive stages of potentially zoonotic protozoans belonging to the genera Blastocystis, Giardia and Cryptosporidium, and Microsporidia spores in feces collected from birds inhabiting the breeding colony established at one lake island in Poland, Europe. The feces were examined by coprological techniques (staining with iron hematoxylin, Ziehl-Neelsen, and modified Weber's chromotrope 2R-based trichrome), and with immunofluorescence antibody MERIFLUOR Cryptosporidium/Giardia assay. As found, the Cryptosporidium oocysts were identified rarely in 8% of samples (2/25; 3-5 × 10³/g) and no cysts of Giardia and Blastocystis were detected. Microsporidian spores were detected in 4% of samples (1/25) but at very high frequency (4.3 × 10⁴/g). No dispersive stages of parasites were identified in water samples collected from the littoral area near the colony. Despite the profuse defecation of cormorants, their role in the dispersion of the investigated parasites may not be as high as hypothesized.

Allogeneic hematopoietic stem cell transplant recipients and parasitic diseases: A review of the literature of clinical cases and perspectives to screen and follow-up active and latent chronic infections

BACKGROUND

Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at substantial risk for a variety of infections depending upon numerous factors, such as degree of immunosuppression, host factors, and period after transplantation. Bacterial, fungal, viral, as well as parasitic infections can occur with high morbidity and mortality.

OBJECTIVES

The aim of this study was to evaluate the magnitude of the occurrence of parasitic infections in allogeneic HSCT recipients. Modalities of transmission, methods of diagnosis, treatment, donor and recipient pre-transplant screening and prevention measures of the most serious parasitic infections have also been discussed.

MATERIALS AND METHODS

We systematically reviewed literature records on post-transplant (allogeneic HSCT) parasitic infections, identified through PubMed database searching, using no language or time restrictions. Search was concluded on December 31, 2015. In the present review, we only discussed post-transplant parasitic infections in allogeneic HSCT. Only exclusion criteria were absence of sufficient information on the transmission of parasitic infection to the recipient. Autologous HSCT recipients have not been included because of the absence of a proper allogeneic transplantation even in presence of blood or blood product transfusions. The methods and findings of the present review have been reported based on the preferred reporting items for systematic reviews and meta-analysis checklist (PRISMA).

RESULTS

Regarding allogeneic HSCT recipients, from data published in the literature the real burden of parasitic infections cannot be really estimated. Nevertheless, a positive trend on publication number exists, probably because of more than one reason: (i) the increasing number of patients transplanted and then treated with immunosuppressive agents, (ii) the "population shift" resulting from immigration and travels to endemic areas, and (iii) the increasing of attention for diagnosis/notification/publication of cases.

CONCLUSIONS

Considering parasitic infections as emerging and potentially serious in their evolution, additional strategies for the prevention, careful screening and follow-up, with a high level of suspicion, identification, and preemptive therapy are necessary in transplant recipients.

PERSPECTIVES

The Authors' viewpoint in the perspective to screen and follow-up active and latent chronic parasitosis in stem cells donors and recipients: a proposal for a flow chart.

Histochemical study of Encephalitozoon cuniculi spores in the kidneys of naturally infected New Zealand rabbits

Encephalitozoon cuniculi is an important microsporidian pathogen that is considered an emergent, zoonotic, and opportunistic. It infects both domestic and laboratory rabbits, generating severe chronic interstitial and granulomatous nephritis with fibrosis and granulomatous encephalitis. Encephalitozoonosis is diagnosed in paraffin-embedded sections by examining the spores in the host tissues. The spores are difficult to observe when the samples are stained with hematoxylin and eosin (H&E), particularly when there is an inflammatory reaction and tissue damage. The spores are easily mistaken for other microorganisms, such as fungi (yeasts), protozoa, and bacteria. In our study, we used kidney samples from E. cuniculi–positive rabbits and employed 14 recommended histologic stains for detecting microsporidia spores: alcian blue, calcofluor white, Giemsa, Gram, Grocott, H&E, Luna, Luxol fast blue, Masson trichrome, modified trichrome stain (MTS), periodic acid–Schiff reaction (PAS), Van Gieson, Warthin–Starry (WS), and Ziehl–Neelsen (ZN).We concluded that MTS and Gram stain, detected by light microscopy, and calcofluor white stain, detected by ultraviolet light microscopy, are the best stains for detecting spores of E. cuniculi in paraffin-embedded tissues from infected rabbits. These stains were superior to WS, ZN, Giemsa, and PAS for identifying spores without background “noise” or monochromatic interference. Also, they allow individual spores to be discerned in paraffin-embedded tissues. MTS allows observation of the polar tube, polaroplast, and posterior vacuole, the most distinctive parts of the spore.

Laboratory cohabitation challenge model for shrimp hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP)

BACKGROUND

Enterocytozoon hepatopenaei (EHP) causes hepatopancreatic microsporidiosis (HPM) in shrimp. It is probably endemic in Australasia and was first characterized and named from the giant or black tiger shrimp Penaeus monodon from Thailand in 2009. Later, it was also found to infect exotic Penaeus vannamei imported for cultivation in Asia. HPM is not normally associated with shrimp mortality, but information from shrimp farmers indicates that it is associated with significant growth retardation that is not clearly noticeable until 2-3 months of cultivation. In order to study modes of HPM transmission and to test possible control measures, a laboratory challenge model was needed that would mimic the mode of infection in shrimp ponds.

RESULTS

We describe successful transmission in a cohabitation model with natural E. hepatopenaei (EHP)-infected shrimp in closed, perforated plastic containers placed in aquaria together with free-swimming, uninfected shrimp. After a period of 14 days all the free-swimming shrimp tested positive by PCR (approximately 60% with heavy infections evident by 1-step PCR positive test results) and gave positive histological and in situ hybridization results for E. hepatopenaei (EHP) in the hepatopancreas.

CONCLUSIONS

A laboratory cohabitation model for studying E. hepatopenaei (EHP) has been developed and used to confirm that E. hepatopenaei (EHP) can be directly transmitted horizontally among shrimp via water. The model will facilitate studies on methods to prevent the E. hepatopenaei (EHP) transmission.

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.

Genetic diversity of Cryptosporidium identified in clinical samples from cities in Brazil and Argentina

The identification and characterisation of Cryptosporidiumgenotypes and subtypes are fundamental to the study of cryptosporidiosis epidemiology, aiding in prevention and control strategies. The objective was to determine the genetic diversity ofCryptosporidium in samples obtained from hospitals of Rio de Janeiro, Brazil, and Buenos Aires, Argentina. Samples were analysed by microscopy and TaqMan polymerase chain reaction (PCR) assays forCryptosporidium detection, genotyped by nested-PCR-restriction fragment length polymorphism (RFLP) analysis of the 18S rRNA gene and subtyped by DNA sequencing of the gp60 gene. Among the 89 samples from Rio de Janeiro, Cryptosporidium spp were detected in 26 by microscopy/TaqMan PCR. In samples from Buenos Aires,Cryptosporidium was diagnosed in 15 patients of the 132 studied. The TaqMan PCR and the nested-PCR-RFLP detected Cryptosporidium parvum, Cryptosporidium hominis, and co-infections of both species. In Brazilian samples, the subtypes IbA10G2 and IIcA5G3 were observed. The subtypes found in Argentinean samples were IbA10G2, IaA10G1R4, IaA11G1R4, and IeA11G3T3, and mixed subtypes of Ia and IIa families were detected in the co-infections. C. hominis was the species more frequently detected, and subtype family Ib was reported in both countries. Subtype diversity was higher in Buenos Aires than in Rio de Janeiro and two new subtypes were described for the first time.

Comparative evaluation of staining techniques and polymerase chain reaction for diagnosis of intestinal microsporidiosis in immunocompromised patients

CONTEXT

Microsporidia, which causes chronic diarrhoea in immunocompromised hosts, are often missed. The commonest diagnostic techniques include modified trichrome (MT) stain; however, it requires expertise and does not identify the species, which is important therapeutically. Other diagnostic techniques include Calcoflour white staining and polymerase chain reaction (PCR). Data on comparative utility of different diagnostic techniques are scanty.

AIM

Comparison of Calcoflour white, MT staining and PCR for the diagnosis of intestinal microsporidiosis.

SUBJECTS AND METHODS

Fecal samples of consecutive immunocompromised patients were evaluated for Microsporidia using Calcoflour white, MT stain and PCR. Species were identified by restriction fragment length polymorphism using HindIII and HinfI. Presence of Microsporidia by two or more techniques was considered true positive. Absence of Microsporidia by all three techniques was taken as true negative.

RESULTS

Of 730 patients, Microsporidia was detected in 28 (3.8%), 250 (34.2%) and 30 (4.1%) patients by MT, Calcoflour white stains and PCR, respectively. Enterocytozoon bieneusi was identified in all 30 (4.1%) patients. 30 (4.1%) and 479 (65.6%) patients were true positive and true negative, respectively. Sensitivity and specificity of Calcoflour white, MT stains and PCR were 100%, 93.8%, 96.8% and 68.5%, 100% and 99.8%, respectively. Diagnostic accuracy of MT stain and PCR was superior to Calcoflour white (99.6% vs. 69.8%; P < 0.05).

CONCLUSIONS

Though Calcoflour white stain is a highly sensitive, but it is nonspecific technique. MT stain and PCR with high sensitivity, specificity and diagnostic accuracy are useful diagnostic techniques. Furthermore, PCR is useful for species identification, which has therapeutic implications.