The global epidemiology of Microsporidia infection in birds: A systematic review and meta-analysis

This study aimed to assess the global status and genetic diversity of Microsporidia infection in different birds. An online search was conducted in international databases from 1 January 1990 to 30 June 2022. A total of 34 articles (including 37 datasets) were included for the final meta-analysis. The pooled global prevalence of Microsporidia infection in birds was 14.6% (95% CI: 11.6-18.1). The highest prevalence of Microsporidia was found in wild waterfowl which was 54.5% (28.1-78.6). In terms of detection methods, the pooled prevalence was estimated to be 21.2% (95% CI: 12.1-34.4) and 13.4% (95% CI: 10.3-17.3) for using microscopic and molecular detection methods, respectively. Enterocytozoon bieneusi was the most common pathogen (24/31; 77.42% of the studies) according to PCR-based methods, and genotype D was the highest reported genotype (nine studies). In conclusion, designing strategies for the control and prevention of Microsporidia infection in birds should be recommended.

Opportunistic microsporidiosis unveiled by fine-needle aspiration cytology of cervical lymph node with literature review

Microsporidia are highly specialized obligate intracellular organisms closely related to fungi, traditionally linked to diarrheal diseases in acquired immunodeficiency syndrome patients. Over the past two decades, an increasing incidence of extraintestinal infections affecting various organ systems, especially in immunocompromised individuals, has been observed. The report presents a unique case of lymph node microsporidiosis in a 38-year-old male, positive for human immunodeficiency virus, with coinfections of hepatitis B and C. Fine-needle aspiration cytology (FNAC) from cervical lymph node yielded pus-like, necrotic material with periodic acid-Schiff stained smear uncovering small round to oval spores on microscopy suspicious for microsporidia. Based on polymerase chain reaction and sequencing done with aspiration material, the causative agent was identified as Vittaforma corneae. This rare encounter highlights the significance of recognizing unique morphological characteristics of infectious organisms and employing appropriate ancillary techniques for precise identification. The case underscores the crucial role of FNAC in diagnosing opportunistic infections involving the lymph nodes and the growing significance of molecular tests for specific pathogen confirmation.

Microsporidia-Associated Anterior Uveitis After Keratoconjunctivitis

OBJECTIVE

The aim of this study was to describe the clinical features and management of uveitis associated with microsporidial keratoconjunctivitis (MKC).

METHODS

The medical records of clinically diagnosed or microbiologically proven patients with MKC between July 2016 and August 2021 were reviewed. Patients with documented evidence of keratic precipitates (KPs) or anterior chamber cells were analyzed for their demography, clinical features, and treatment. Patients with microsporidial stromal keratitis and herpes simplex virus keratouveitis were excluded from the study.

RESULTS

Of the 2212 patients reviewed within the study period 171 of 172 eyes (7.7%) had documented evidence of KPs and/or anterior chamber cells. The patients' mean age was 43.8 ± 13.8 years, and there were more men (n = 120). The mean duration of appearance of KPs was 6.9 ± 5.5 days, and 28% (n = 48 of 171) appeared on the day of presentation. Superficial punctate keratitis was central and diffuse in 48 and 49 patients, respectively. The treatment was either lubricant alone (45.3%; 78 eyes) or combined with topical steroids (54.7%; 94 eyes). The mean duration of the resolution was longer in the "corticosteroid" than "no corticosteroid" group: KPs: 15.3 ± 6.5 days versus 12.3 ± 5.8 days ( P = 0.007) and superficial punctate keratitises: 15.4 ± 9.4 days versus 11.7 ± 6.2 days ( P = 0.01). The presenting visual acuity with a pinhole was 0.26 ± 0.26 (logMAR) and it improved to 0.03 ± 0.07 on resolution ( P < 0.0001, paired t test).

CONCLUSIONS

Uveitis after MKC is a self-limiting entity that often resolves without corticosteroid. One must exercise caution in using steroids in the presence of active corneal lesions.

Microscopic and Molecular Investigation of Intestinal Microsporidia in HIV + /AIDS and Cancer Patients Undergoing Chemotherapy in Mazandaran Province, North of Iran

BACKGROUND

The aim of this study was to identify Enterocytozoon bieneusi and Encephalitozoon spp. in fecal samples of HIV + /AIDS and cancer patients undergoing chemotherapy, and comparing the results to healthy individuals in Mazandaran province, north of Iran.

METHODS

Stool samples were collected from 50 HIV + /AIDS patients, 50 cancer patients, and 50 healthy samples referred to medical centers in north of Iran. Stool samples were kept in 2.5% potassium dichromate at 4 °C, and stained by modified trichrome for light microscopy examination. The multiplex/nested-PCR targeted the small subunit ribosomal RNA (SSU rRNA) gene. To characterize genotypes, the nested PCR products sequenced by Bioneer Company and was subjected to phylogenetic analyses.

RESULTS

Ten of 50 samples (20%) of HIV + /AIDS patients, 5 of 50 samples (10%) of cancer patients, and 1 of healthy individuals (2%) were microscopically positive. From 50 HIV + / AIDS patients, E. bieneusi and Encephalitozoon spp. were detected in 10 (20%) and 6 (12%) cases, respectively. Furthermore, among cancer patients, 7 (14%) and 2 (4%) cases were E. bieneusi and Encephalitozoon spp., respectively. Out of 50 samples of healthy individuals, only 3 (6%) cases of E. bieneusi were observed. The genotypes D and M were detected among positive samples of E. bieneusi.

CONCLUSIONS

E. bieneusi and then Encephalitozoon spp. are common intestinal microsporidia in HIV + /AIDS patients and cancer patients undergoing chemotherapy in Mazandaran province. E. bieneusi genotype D seems to be the predominant genotype in Mazandaran province. Due to the considerable prevalence of intestinal microsporidia, physicians are advised to pay more attention to this opportunistic infection in high-risk groups.

Investigation of the presence of Enterocytozoon bieneusi and Encephalitozoon intestinalis in immunosuppressed patients with diarrhea by IFA and real time PCR methods

PURPOSE

This study aimed to investigate the frequency of Enterocytozoon bieneusi and Encephalitozoon intestinalis in patients with diarrhea in the immunosuppressed.

METHODS

Patients between the ages of 18-85 who applied to different clinics of Muş Bulanık and Bitlis State Hospitals and were referred to the microbiology or parasitology laboratory were selected for this study. A total of 200 individuals, including 88 immunosuppressed with diarrhea patients, 38 immunocompetent with diarrhea patients, 38 immunosuppressed without diarrhea patients, and 36 immunocompetent without diarrhea individuals, were included. Collected stool samples were evaluated using IFA-MAbs and real-time PCR methods to determine the frequency of E.intestinalis and E.bieneusi.

RESULTS

E. intestinalis was detected in 59 (29.5%) of 200 samples and E. bieneusi was detected in 46 (23.0%) of them. Mixed infection was detected in 16 (8%) of the positive samples. While there was no statistically significant difference between E. intestinalis positivity and gender, age, diarrhea status and immune system status, a statistically significant relationship was determined between E. bieneusi positivity and diarrhea. When the real-time PCR method was accepted as the gold standard, the sensitivity of the IFA-MAbs method in the diagnosis of E. intestinalis was 94.54%, the specificity was 97.24, the sensitivity in the diagnosis of E. bieneusi was 95.45%, and the specificity was 98.72%. The overall accuracy of the IFA-MAbs method was 96.5% for the diagnosis of E. intestinalis and 98% for the diagnosis of E. bieneusi.

CONCLUSIONS

The findings suggest that E. intestinalis and E. bieneusi should be considered in both immunosuppressed and healthy individuals with diarrhea. IFA-MAbs method can be used in addition to the real-time PCR method to diagnose E. intestinalis and E. bieneusi.

Past, present, and prospects in microsporidial keratoconjunctivitis- A review

Ocular microsporidiosis comprises two entirely different spectra of disease as keratoconjunctivitis and stromal keratitis. Microsporidial keratoconjunctivitis (MKC) has been increasingly reported in the past two decades, probably due to raised awareness, simpler diagnostic procedures, and a better understanding of the clinical presentation. It is characterized by the presence of raised, coarse, punctate, multifocal, round to oval, greyish-white corneal epithelial lesions which usually evolve into nummular scars before resolution. Conjunctivitis seen is non-purulent and of mild-moderate intensity, with mixed papillary-follicular reaction. The mode of transmission and pathogenesis is poorly understood. Despite lack of inflammatory response, uncommon associations reported were- endotheliitis, corneal edema, limbitis, uveitis, and sub-epithelial infiltrates. There has been no consensus on the management of MKC. It varies from the use of multiple antimicrobial agents to simple lubricants. The majority of the disease goes underdiagnosed or misdiagnosed and treated as adenoviral keratoconjunctivitis, with topical steroids or anti-virals empirically. Changing trends have been noticed in the pattern of infection, possibly with increasing evidence of Vittaforma corneae as causative organisms, previously reported to cause stromal keratitis. An elaborate review of the past and present literature on MKC is provided in this review article, along with gaps in knowledge, and future directions of research.

[A case of microsporidial keratitis]

A case of keratitis caused by microsporidia infection was reported. A 57-year-old female patient, without any obvious predisposing cause, presented with eye redness, eye abrasion and vision loss for one year in the left eye. The patient was diagnosed with viral keratitis based on laboratory examinations and clinical symptoms two months ago in our hospital. He was given outpatient treatment for antivirus. Two months later, he was admitted to our hospital with worsened condition that presented with corneal ulcer. After admission, corneal scraping examination was performed for the detection of microsporidia with calcofluor white (CFW) and Ziehl-Neelsen staining, the smear revealed multiple oval spore-like structures, with acid-fast positive and showed blue fluorescence on potassium hydroxide with CFW stain, confirming a diagnosis of microsporidial keratitis in the left eye. Treatment: topical use of ofloxacin eye ointment and voriconazole eye drops was not effective, and then penetrating keratoplasty was performed, and the patient's condition was stable after surgery. At present, they are still in treatment and follow-up.

MULTI-STATE OCCUPANCY MODEL ESTIMATES PROBABILITY OF DETECTION OF AN AQUATIC PARASITE USING ENVIRONMENTAL DNA: PSEUDOLOMA NEUROPHILIA IN ZEBRAFISH AQUARIA

Detecting the presence of important parasites within a host and its environment is critical to understanding the dynamics that influence a pathogen's ability to persist, while accurate detection is also essential for the implementation of effective control strategies. Pseudoloma neurophilia is the most common pathogen reported in zebrafish (Danio rerio) research facilities. The only assays currently available for P. neurophilia are through lethal sampling, often requiring euthanasia of the entire population for accurate estimates of prevalence in small populations. We present a non-lethal screening method to detect P. neurophilia in tank water based on the detection of environmental DNA (eDNA) from this microsporidium, using a previously developed qPCR assay that was adapted to the digital PCR (dPCR) platform to complement current surveillance protocols. Using the generated dPCR data, a multi-state occupancy model was also implemented to predict the probability of detecting the microsporidium in tank water under different flow regimes and pathogen prevalence. The occupancy model revealed that samples collected in static conditions were more informative than samples collected from flow-through conditions, with a probability of detection at 80% and 47%, respectively. There was also a positive correlation between the frequency of detection in water and prevalence in fish based on qPCR.

Progression of infection and detection of Pseudoloma neurophilia in zebrafish Danio rerio Hamilton by PCR and histology

Pseudoloma neurophilia is a critical threat to the zebrafish (Danio rerio) model, as it is the most common infectious agent found in research facilities. In this study, our objectives were two-fold: (1) compare the application of diagnostic tools for P. neurophilia and (2) track the progression of infection using PCR and histology. The first experiment showed that whole-body analysis by qPCR (WB-qPCR) can be a standardized process, providing a streamlined diagnostic protocol, without the need for extraction of specific tissues. Evaluating the course of infection in experimentally infected fish, we showed key dynamics in infection. Starting with a low dose exposure of 8000 spores/fish, the prevalence remained low until 92 days post-exposure (dpe), followed by a 30%-40% prevalence by histology or 40%-90% by PCR until the end of the experiment at 334 dpe. WB-qPCR positively detected infection in more fish than histology throughout the study, as WB-qPCR detected the parasite as early as 4 dpe, whereas it was undetected by histology until 92 dpe. We also added a second slide for histologic analyses, showing an increase in detection rate from 24% to 26% when we combined all data from our experiments, but this increase was not statistically significant.

Anncaliia algerae Microsporidiosis Diagnosed by Metagenomic Next-Generation Sequencing, China

We report a case of Anncaliia algerae microsporidia infection in an immunosuppressed kidney transplant recipient in China. Light microscopy and transmission electron microscopy initially failed to identify A. algerae, which eventually was detected by metagenomic next-generation sequencing. Our case highlights the supporting role of metagenomic sequencing in early identification of uncommon pathogens.

Chlorhexidine in the treatment of microsporidial stromal keratitis and the effect of host immunity: A case series and literature review

Microsporidial stromal keratitis is an increasingly well-known vision-threatening disease. A large proportion of cases are initially misdiagnosed as herpes simplex keratitis and treated with topical steroids. In most of such cases, medical treatment failed, and corneal transplantation was required. This study reported the results of 0.02% topical chlorhexidine used to treat three cases of microsporidial stromal keratitis and reviewed the literature on the outcomes of microsporidial stromal keratitis treatment. In the first case, histopathology of a specimen from penetrating keratoplasty (PK) revealed severe chronic inflammation involving the entire stromal layer but no microorganism activity after the application of topical chlorhexidine for 10 months. The second case exhibited complete resolution of keratitis after topical chlorhexidine. The patient in the third case did not respond to medical treatment, and therapeutic PK was performed. Histopathological examination revealed numerous microsporidial spores that had colonized in the mid and deep stroma, where few inflammatory cells were observed. These findings explain the variable microsporidial susceptibility to chlorhexidine, suggesting the crucial role of host immunity. In cases of host immunity, topical chlorhexidine may represent a promising option for the treatment of microsporidial stromal keratitis.

Encephalitozoon cuniculi and Extraintestinal Microsporidiosis in Bird Owners

We identified Encephalitozoon cuniculi genotype II parasites as a cause of extraintestinal microsporidiosis in 2 owners of birds also infected with E. cuniculi. Patients experienced long-lasting nonspecific symptoms; the disease course was more progressive in a patient with diabetes. Our findings suggest direct bird-to-human transmission of this pathogen.

A case of stromal microsporidiosis: medical strategies employed for successful resolution

We describe the diagnosis and successful management of a case of stromal microsporidiosis, an important emerging ocular disease. Stromal microsporidiosis is recalcitrant and very often requires therapeutic keratoplasty for effective eradication. We successfully managed a steroid-treated case diagnosed only after 9 months, with a combination of polyhexamethyl biguanide 0.04%, chlorhexidine 0.04% and fluconazole 0.3% eye drops supplemented with tablet albendazole. However, complete resolution was achieved only after epithelial debridement. Toxicity due to the drugs was not noted. Diagnostic delays, steroid use and inappropriate therapy are commonly observed in stromal microsporidiosis. In spite of these potential disadvantages, our case responded well with complete eradication of the infection. The disease being fairly indolent and slowly progressive, medical therapy should be continued, in the absence of progression or other complications. Epithelial debridement may facilitate healing.

Molecular diagnosis of intestinal microsporidia infection in HIV/AIDS-patients in Zahedan city, Southeast of Iran

Microsporidia belong to the intracellular spore-like pathogen, that can cause infection in invertebrates and vertebrates, including humans. Encephalitozoon spp. and Enterocytozoon bieneusi, are important causes of chronic diarrhea, especially in patients with HIV/AIDS. Therefore, in this study, modified trichrome staining (MTS) and nested polymerase chain reaction (nested PCR) methods were used for the diagnosis of common intestinal microsporidia in faecal samples of patients with HIV/AIDS in Zahedan, southeastern Iran, for the first time. Stool samples were collected from 50 HIV/AIDS-infected patients with gastrointestinal symptoms whose infections were confirmed by serology test. Prepared smears from each stool sample were stained using the MTS method. Nested PCR was used to amplify 440 bp and 629 bp fragments of 16S rRNA genes in E. bieneusi and Encephalitozoon spp., respectively. Based on the MTS method and the nested PCR, 8 (16%) and 12 (24%) stool samples were positive, respectively. According to the results of nested PCR, eight, three, and one case were infected with E. bieneusi, Encephalitozoon spp., and both of them, respectively. Findings indicated microsporidiosis in HIV/AIDS-infected patients in Zahedan is an important health problem. Therefore, this opportunistic microorganism in HIV/AIDS-infected patients should be diagnosed using sensitive and accurate methods.

Diagnostic Utility of CDC DPDx for an Atypical Presentation of Infectious Crystalline Keratopathy-Like Infiltrate Secondary to Microsporidia

PURPOSE

To report a case of atypical infectious crystalline keratopathy-like stromal infection secondary to microsporidia wherein diagnosis of the causative organism was aided by use of the Center for Disease Control (CDC) DPDx program.

METHODS

We report the case of a 73-year-old woman who presented with atypical infectious crystalline keratopathy-like corneal infection without previous surgical history.

RESULTS

The patient had previously been treated for recalcitrant corneal infection with topical antibiotics and steroids at an outside provider before referral. Further treatment with topical fortified antibiotics failed to improve the infection. Corneal biopsy was performed and sent to the CDC DPDx for diagnostic confirmation for presumptive microsporidia. The patient underwent therapeutic penetrating keratoplasty without recurrence of ocular infection.

CONCLUSIONS

Utilization of the DPDx resource may help guide appropriate and timely diagnosis and management strategies in atypical presentations of infectious keratitis.

Microsporidial Stromal Keratitis: Epidemiological Features, Slit-Lamp Biomicroscopic Characteristics, and Therapy

PURPOSE

Microsporidial stromal keratitis is a rare form of infectious keratitis, with only 7 cases reported in the United States to date. This study was performed to evaluate risk factors, clinical features, and response to therapy.

METHODS

A retrospective review of the medical records of all patients diagnosed with microsporidial stromal keratitis seen in the practices of the authors between 1999 and 2020 was performed. Diagnosis was determined by cytology or histopathology in corneal specimens. Risk factors, presence or absence of distinctive clinical features, and response to medical and surgical therapies were recorded.

RESULTS

Nine patients-7M:2F, aged 7 to 99 years-with microsporidial stromal keratitis were identified. Exposures to recreational water and hymenopteran insect bites, both epidemiologically linked risk factors for systemic microsporidial infection, were identified in our patients. Presence of stromal edema with features of disciform keratitis and a distinctive granular keratitis were observed in 6 of 9 and 5 of 9 patients, respectively. Poor response to medical therapy was noted. Penetrating keratoplasty was effective in curing the infection. Final visual acuity was 20/40 or better in 6 of 9 patients.

CONCLUSIONS

In patients with slowly progressive keratitis, history of exposure to recreational water or hymenopteran insects should be sought. In patients with corneal edema consistent with disciform keratitis, with evolution to a granular keratitis, microsporidia should be considered in the differential diagnosis. In cases of established microsporidial stromal keratitis, penetrating keratoplasty should be considered if prompt response to medical therapy is not noted.

Disseminated microsporidiosis: An underdiagnosed and emerging opportunistic disease

Disseminated microsporidiosis is a life-threatening disease resulting from the haematogenous spread of microsporidia species. The diagnosis is challenging owing to its subtle nonspecific clinical presentation, which usually reflects the underlying organ involved. Therefore, a high index of suspicion is required for early diagnosis. Besides, tools for confirmatory laboratory diagnosis are limited. Currently, there is no direct diagnostic method that can detect the infection without involving invasive procedures. Clinical confirmation of disseminated microsporidiosis is usually based on light and transmission electron microscopy of infected tissue specimens. These are then followed by species detection using polymerase chain reaction (PCR). Disseminated microsporidiosis shows the potential to be cleared up by albendazole or fumagillin if they are detected and treated early. Based on a series of case reports, this review aims to present a current update on disseminated microsporidiosis with emphasis on the clinical manifestations based on the organ system infected, diagnostic approach and treatment of this devastating condition.

Renal Microsporidiosis in Pediatric Bone Marrow Transplant Recipients: A Case Series

Microsporidiosis is a rare, but emerging opportunistic infection in solid organ transplant and stem cell transplant recipients. Renal involvement in microsporidiosis is very rarely seen in these recipients. We describe two cases of pediatric renal microsporidiosis, diagnosed on renal biopsies, following bone marrow transplantation presenting as severe acute kidney injury. The first patient died, whereas the second survived due to early diagnosis based on high index of suspicion and prompt treatment with Albendazole. We believe these are the first such reported cases of renal microsporidiosis in pediatric bone marrow transplant recipients.

Intestinal parasites including Cryptosporidium, Cyclospora, Giardia, and Microsporidia, Entamoeba histolytica, Strongyloides, Schistosomiasis, and Echinococcus: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of intestinal parasites in the pre- and post-transplant period. Intestinal parasites are prevalent in the developing regions of the world. With increasing travel to and from endemic regions, changing immigration patterns, and the expansion of transplant medicine in developing countries, they are increasingly recognized as a source of morbidity and mortality in solid-organ transplant recipients. Parasitic infections may be acquired from the donor allograft, from reactivation, or from de novo acquisition post-transplantation. Gastrointestinal multiplex assays have been developed; some of the panels include testing for Cryptosporidium, Cyclospora, Entamoeba histolytica, and Giardia, and the performance is comparable to conventional methods. A polymerase chain reaction test, not yet widely available, has also been developed to detect Strongyloides in stool samples. New recommendations have been developed to minimize the risk of Strongyloides donor-derived events. Deceased donors with epidemiological risk factors should be screened for Strongyloides and recipients treated if positive as soon as the results are available. New therapeutic agents and studies addressing the optimal treatment regimen for solid-organ transplant recipients are unmet needs.

Detection of the intranuclear microsporidian Enterospora nucleophila in gilthead sea bream by in situ hybridization

Enterospora nucleophila is an intranuclear microsporidian responsible for emaciative microsporidiosis of gilthead sea bream (GSB). Its minute size and cryptic nature make it easily misdiagnosed. An in situ hybridization (ISH) technique based on antisense oligonucleotide probes specific for the parasite was developed and used in clinically infected GSB in combination with calcofluor white stain (CW) and other histopathological techniques. The ISH method was found to label very conspicuously the cells containing parasite stages, with the signal concentrating in merogonial and sporogonial plasmodia within the infected cell nuclei. Comparison with CW demonstrated limited ISH signal in cells containing mature spores, which was attributed mostly to the scarcity of probe targets present in these stages. Although spores were detected in other organs of the digestive system as well as in the peripheral blood, proliferative stages or parasite reservoirs were not found in this work outside the intestines. The study demonstrated a frequent disassociation between the presence of abundant spores and the intensity of the infections as determined by the parasite activity. The ISH allows confirmatory diagnosis of GSB microsporidiosis and estimation of infection intensity and will be a valuable tool for a more precise determination of parasite dissemination pathways and pathogeny mechanisms.

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.

Evaluation of four commercial DNA extraction kits for the detection of Microsporidia and the importance of pretreatments in DNA isolation

Microsporidia are obligate intracellular parasitic protozoa infecting the wide variety of hosts and are commonly known as a cause of chronic diarrhea particularly in immunocompromised individuals. Molecular-based tests have high sensitivity and specificity in disease diagnosis. However, these tests' performance relies on the isolation of DNA in a good concentration. The standard procedures of commercial DNA extraction kits are usually insufficient for this purpose due to the tough walls of spores. This study aimed to test the significance of pretreatments by glass beads and freeze-thawing processes in DNA isolation from microsporidia spores. The parasite was cultured in growing Vero cells and seven serial dilutions were prepared from the collected spores. DNA purification was performed according to different tissue kits and stool kit procedures with and without any pretreatment. Concentration of isolated DNA samples were evaluated by real-time PCR. As a result of this study, the detectable amount of spores is minimum 10 spores in each 100 μ! sample according to the different tissue kits' standard protocols. However, according to the DNA stool mini kit, the detectable amount of spores was found to be 1,000 spores/100 μl of stool sample when pretreated with both the freeze-thawing and glass beads methods.In conclusion, the current study demonstrated that further pretreatments are an essential process for DNA extraction from the stool specimens in order to avoid possible false negativity in the diagnosis of microsporidiosis.

Enterocytozoon bieneusi Microsporidiosis in Stem Cell Transplant Recipients Treated with Fumagillin

Enterocytozoon bieneusi microsporidiosis is an emerging disease in immunocompromised patients. We report 2 cases of this disease in allogeneic hematopoietic stem cell transplant patients successfully treated with fumagillin. Thrombocytopenia occurred but without major adverse events. Modifications of immunosuppression could be avoided when E. bieneusi is rapidly identified and fumagillin therapy is started promptly.

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.

Microsporidial keratoconjunctivitis after rugby tournament, Singapore

We investigated an outbreak of 47 probable and 6 confirmed cases of microsporidial keratoconjunctivitis involving participants of an international rugby tournament in Singapore in April 2012.The mode of transmission was eye contact with soil. Vittaforma corneae was identified in 4 of 6 corneal scrapings and in 1 of 12 soil water samples.

Microsporidial keratoconjunctivitis after rugby tournament, Singapore

We investigated an outbreak of 47 probable and 6 confirmed cases of microsporidial keratoconjunctivitis involving participants of an international rugby tournament in Singapore in April 2012.The mode of transmission was eye contact with soil. Vittaforma corneae was identified in 4 of 6 corneal scrapings and in 1 of 12 soil water samples.

Serological screening of selected microsporidia in HPV-positive women

Microsporidiosis is considered to be emerging opportunistic infection in immunocompromised individuals worldwide. The aim of this study was to identify the specific serum antibodies to intestinal microsporidia Encephalitozoon cuniculi and Encephalitozoon intestinalis in women with Human Papillomavirus HPV and without HPV by the indirect immunofluorescence (IFA). From total number of 669 examined women, 225 were HPV positive and 444 women HPV negative. Overall the study comprised of 10.8% women with positive result for presence of E. cuniculi antibodies. In group 1 (HPV-positive women) it was more than 28% and in group 2 (HPV-negative women) it was less than 2% (p<0.001). E. intestinalis infection was found in total of 4.48% women, in group 1 it was present in less than 6% and in group 2 in less than 4% of women.

Investigation of intestinal parasites in dialysis patients

OBJECTIVE

To search for the opportunistic and other pathogenic intestinal parasites in dialysis patients, and to compare the methods used for diagnosis.

METHODS

This is a randomized study, which recruited participants from the dialysis patients. The study was carried out in the Department of Microbiology, Research Hospital, School of Medicine in Kocaeli University, Kocaeli, Turkey between June 2012 and March 2013. One hundred and forty-two patients were diagnosed with an end-stage renal failure, which underwent dialysis, and 150 healthy volunteers were enrolled in the study. Native-lugol, formol ethyl acetate sedimentation method, trichrome, modified trichrome, acid fast, and Calcofluor staining methods were applied to the stool samples. For the diagnosis of Cryptosporidium spp., Giardia intestinalis (G. intestinalis), and Entamoeba histolytica (E. histolytica), commercially available ELISA kits were used, which detect antigen in the stool.

RESULTS

Parasites were found in 62 of the dialysis patients (43.7%) and 19 of the control group (12.7%). The most encountered parasitic agents in the dialysis patients were Blastocystis spp. (23.9%), G. intestinalis (8.5%), E. histolytica (2.1%), Microsporidia spp. (2.1%), and Cryptosporidium spp. (2.1%). The parasite detection rate of the formol ethyl acetate sedimentation method was found to be higher than native-lugol (p<0.05).

CONCLUSION

To protect the dialysis patients with diarrhea from parasitic infections, it is important to carry out interval stool examinations with trichrome, modified trichrome, acid fast, and Calcofluor staining methods, and the ELISA method, which detects antigen in the stool.

Vittaforma corneae keratitis in southern India: role of a novel duplex PCR

Microsporidia are obligate intracellular parasites that infect eukaryotic cells and have emerged as major opportunistic human pathogens. Due to the difficulties in definitive laboratory diagnosis and insufficient knowledge, ocular microsporidiosis is infrequently reported in India. To improve diagnostic facilities, we have developed a novel duplex PCR (dPCR) for the simultaneous identification of both genera and species of isolates with microsporidian aetiology that cause keratitis. The material scraped from the corneas of 12 clinically diagnosed microsporidial keratitis patients was subjected to routine microbiological examinations and molecular diagnosis using a novel dPCR that targeted the small-subunit rRNA gene (SSU-rRNA) of microsporidia and Vittaforma corneae using genus- and species-specific primers. Of the 12 corneal scrapes, 6 showed positive results in smears, while dPCR provided positive amplification with both pan-microsporidial and V. corneae species-specific primers for 9 corneal scrapes. The results were validated by sequencing and blast analysis. The sensitivity of this novel dPCR method was higher than that of conventional microscopy in the diagnosis of corneal microsporidial infection. dPCR with specific primers is potentially more sensitive, specific and depends less on more complicated methods for exact identification of the aetiology of microsporidial keratitis.

The first case of Enterocytozoon bieneusi infection in Poland

Microsporidia are intracellular parasites that cause opportunistic infections in humans of various immunological status. Only a few case reports exist on microsporidial infection in solid organ transplant recipients worldwide. The presented study demonstrates the first case in Poland of Enterocytozoon bieneusi infection in a liver transplant patient. Parasites were diagnosed in stool samples using both modified trichrome staining and PCR.

Treatment of microsporidial keratoconjunctivitis with repeated corneal swabbing

PURPOSE

To report the effect of repeated corneal swabbing in patients with microsporidial keratoconjunctivitis.

DESIGN

Retrospective noncomparative case series.

METHODS

Sixteen eyes of 14 healthy patients with microsporidial keratoconjunctivitis were diagnosed based on the detection of microsporidia in corneal scrapings using Gram stain, the modified Kinyoun acid-fast stain, or both. Polymerase chain reaction plus gene analysis of the microsporidian 16S ribosomal RNA had been performed in 10 patients who sought treatment between 2010 and 2011. Some of the lesions were scraped for procurement of specimens. The remaining lesions were wiped off gently by cotton swabs. Repeated swabbing was performed if infection persisted or new lesions were observed at follow-up. To prevent secondary bacterial infection, 0.3% norfloxacin or 0.25 % chloramphenicol were prescribed.

RESULTS

The mean age was 52.2 years. All patients had the characteristic disseminated, punctate, slightly elevated, white epithelial lesions. The denser white lesions could be removed easily after gentle swabbing, and most epithelium remained intact. The 10 cases with positive polymerase chain reaction results were all identified to be Vittaforma corneae. The mean number of corneal swabbing was 3.3, and the mean disease resolution time was 6.6 days. No patients had recurrence or loss of visual acuity at last follow-up.

CONCLUSIONS

Repeated swabbing effectively can eradicate corneal epithelial microsporidial lesions in approximately 1 week. It is easy to perform, less painful, and more acceptable for the patients.

Molecular identification of protozoa causing AIDS-associated cholangiopathy in Buenos Aires, Argentina

BACKGROUND

Several species of microsporidia and coccidia are protozoa parasites responsible for cholan-giopathy disease in patients infected with human immunodeficiency virus (HIV). The goals of this work were to identift opportunistic protozoa by molecular methods and describe the clinical manifestations at the gastrointestinal tract and the biliary system in patients with AIDS-associated cholangiopathy from Buenos Aires, Argentina.

MATERIAL AND METHODS

This study included 11 adult HIV-infected individuals with diagnosis ofAIDS- associated cholangiopathy. An upper gastrointestinal endoscopy with biopsy specimen collection and a stool analysis for parasites were performed on each patient. The ultrasound analysis revealed bile ducts compromise. An endoscopic retrograde cholangiopancreatography and a magnetic resonance cholangiography were carried out. The identification to the species level was performed on biopsy specimens by molecular methods.

RESULTS

Microorganisms were identified in 10 cases. The diagnosis in patients with sclerosing cholangitis was cryptosporidiosis in 3 cases, cystoisosporosis in 1 and microsporidiosis in 1. In patients with sclerosing cholangitis and papillary stenosis the diagnosis was microsporidiosis in 2 cases, cryptosporidiosis in 2 and cryptosporidiosis associated with microsporidiosis in 1. In 3 cases with cryptosporidiosis the species was Cryptosporidium hominis, 1 of them was associated with Enterocytozoon bieneusi, and the other 2 were coinfected with Cryptosporidium parvum. In the 4 cases with microsporidiosis the species was Enterocytozoon bieneusi.

CONCLUSIONS

These results suggest that molecular methods may be useful tools to identify emerging protozoa in patients with AIDS-associated cholangiopathy.

Development of a sensitive assay for the detection of Pseudoloma neurophilia in laboratory populations of the zebrafish Danio rerio

The zebrafish Danio rerio is an increasingly important biological model in many areas of research. Due to the potential for non-protocol-induced variation, diseases of zebrafish, especially those resulting in chronic, sub-lethal infections, are of great concern. The microsporidium Pseudoloma neurophilia is a common parasite of laboratory zebrafish. Current methods for detection of this parasite require lethal sampling of fish, which is often undesirable with poorly spawning mutant lines and small populations. We present here an improved molecular-based diagnostic assay using real-time polymerase chain reaction (PCR), and including sonication treatment prior to DNA extraction. Comparisons of several DNA extraction methods were performed to determine the method providing the maximum sensitivity. Sonication was found to be the most effective method for disrupting spores. Compared to previously published data on PCR-based assay using a dilution experiment, sensitivity is increased. This shows that our assay, which includes sonication, is capable of detecting parasite DNA at 1 log higher dilution than the conventional PCR-based assay, which does not include sonication. Furthermore, we demonstrate the application of this method to testing of water, eggs, and sperm, providing a potential non-lethal method for detection of this parasite in zebrafish colonies with a sensitivity of 10 spores 1(-1) of water, 2 spores per spiked egg sample, and 10 spores microl(-1) of spiked sperm sample.

Transmission, diagnosis, and recommendations for control of Pseudoloma neurophilia infections in laboratory zebrafish (Danio rerio) facilities

The microsporidium Pseudoloma neurophilia represents a considerable challenge for laboratory zebrafish (Danio rerio) facilities. In 2010, P. neurophilia infections were diagnosed in zebrafish from 74% of the facilities that submitted fish to the Zebrafish International Resource Center (ZIRC) pathology service, and this organism remains the most commonly diagnosed pathogen in submitted fish. Accordingly, many of the ZIRC pathology service consultations deal with control and prevention of microsporidiosis. Here we describe observations and experiments performed at the ZIRC elucidating aspects of P. neurophilia transmission in zebrafish colonies. We then review current knowledge about P. neurophilia transmission and diagnosis. Considering this information, we present recommendations for control of P. neurophilia in zebrafish facilities.

Latent microsporidial infection in immunocompetent individuals - a longitudinal study

BACKGROUND

Microsporidia (Fungi) have been repeatedly identified as the cause of opportunistic infections predominantly in immunodeficient individuals such as AIDS patients. However, the global epidemiology of human microsporidiosis is poorly understood and the ability of microsporidia to survive and multiply in immunocompetent hosts remains unsolved.

AIMS

To determine the presence of latent microsporidia infections in apparently healthy humans in the Czech Republic, the authors tested sera, urine and stool originating from fifteen persons within a three month period examined on a weekly basis.

METHODS

Sera, stool and urine samples originating from fifteen HIV-negative people at risk with occupational exposure to animals, aged 22-56 years, living in the Czech Republic were tested by indirect immunofluorescence assay (IFA) for the presence of specific anti-microsporidial antibodies, standard Calcofluor M2R staining for the detection of microsporidian spores in all urine sediments and stool smears and molecular methods for the microsporidial species determination.

RESULTS

Specific anti-microsporidial antibodies were detected in fourteen individuals, asymptomatic Encephalitozoon spp. infection was found in thirteen and E. bieneusi infection was detected in seven of those examined. While E. hellem 1A and E. cuniculi II were the major causative agents identified, seven different genotypes of E. bieneusi were recorded.

CONCLUSIONS

These findings clearly show that exposure to microsporidia is common and chronic microsporidiosis is not linked to any clinical manifestation in healthy population. Moreover, our results indicate much higher incidence of microsporidial infections among an apparently healthy population than previously reported. These results open the question about the potential risk of reactivation of latent microsporidiosis in cases of immunosupression causing life-threatening disease.

[On the use of FTA technology for collection, archieving, and molecular analysis of microsporidia dna from clinical stool samples]

The FTA technology was applied for sampling, archiving, and molecular analysis of the DNA isolated from stool samples to diagnose and identify microsporidia, the intracellular opportunistic parasites which induce malabsortion syndrome in immunosuppressed humans, particularly in patients with AIDS. Microsporidia DNA was successfully amplified in 6 of 50 stool samples of HIV-positive patients of the S. P. Botkin Memorial Infectious Disease Hospital (St. Petersburg) applied to FTA cards (FTA-Cars, Whatman Inc. Florham Park, NJ, USA). Amplicons (the fragments of rDNA) were directly sequenced, and microsporidia species--Encephalitozoon intestinalis, E. cuniculi, E. hellem, and Enterocytozoon bieneusi--were identified in Genbank by NCBI BLAST program. The FTA method of DNA immobilization is especially promising for epidemiological and field population studies which involve genotyping of microsporidia species and isolates.

Detection and species identification of microsporidial infections using SYBR Green real-time PCR

Diagnosis of microsporidial infections is routinely performed by light microscopy, with unequivocal non-molecular species identification achievable only through electron microscopy. This study describes a single SYBR Green real-time PCR assay for the simultaneous detection and species identification of such infections. This assay was highly sensitive, routinely detecting infections containing 400 parasites (g stool sample)(-1), whilst species identification was achieved by differential melt curves on a Corbett Life Science Rotor-Gene 3000. A modification of the QIAamp DNA tissue extraction protocol allowed the semi-automated extraction of DNA from stools for the routine diagnosis of microsporidial infection by real-time PCR. Of 168 stool samples routinely analysed for microsporidian spores, only five were positive by microscopy. By comparison, 17 were positive for microsporidial DNA by real-time analysis, comprising 14 Enterocytozoon bieneusi, one Encephalitozoon cuniculi and two separate Pleistophora species infections.

[Microsporidium spp. infection in an immunocompromised child diagnosed by polymerase chain reaction]

Microsporidium spp. may lead to a variety of clinical pictures like sinusitis, keratoconjunctivitis, hepatitis, myositis, peritonitis, nephritis, encephalitis and pneumonia in case of immune deficiencies. In this report, a case of diarrhea due to Microsporidium spp. has been presented. A four years old male patient who was followed with the diagnosis of myotonic dystrophia, was admitted to the hospital with the complaints of respiratory distress and fever. Due to the history of recurrent infections, further investigations was carried out to clarify the immunological status of the patient, and the total IgA and IgM levels were found as 14 mg/dl and 30 mg/dl, respectively (normal values were; 18-160 and 45-200 mg/dl, respectively). Following bronchoscopy done to enlighten respiratory distress, the patient developed high fever and watery diarrhea. Since bacteriological cultures of the stool yielded Shigella spp., antimicrobial therapy with ciprofloxacin was initiated. Parasitological examination of the stool done by Weber's modified trichrome dye, yielded Microsporidium spp. microscopically and albendazole was added to the treatment. Presence of Microsporidium spp. was confirmed by polymerase chain reaction with the use of C1 and C2 primers (Metabion, Germany) targeted to Microsporidium spp. and besides a 270 bp band specific for Encephalitozoon intestinalis was also obtained. This case emphasized that in case of diarrhea the stool samples of the immunocompromised patients should be evaluated in terms of Microsporidium spp. in addition to the routine parasitologic examinations.

Comparison of Chromotrope 2R and Uvitex 2B for the detection of intestinal microsporidial spores in stool specimens of HIV patients attending Nekempte Hospital, West Ethiopia

BACKGROUND

Intestinal microsporidiosis is the most common cause of chronic diarrhea in HIV/AIDS infected patients. The diagnosis of intestinal microsporidia depends on the detection of the spores by staining either with Chromotrope 2R or with fluorchrome uvitex 2B methods.

OBJECTIVE

To compare the Chromotrope-2R and Uvitex-2B in detecting intestinal microsporidial spores from HIV/ AIDS patients at Nekempte Hospital.

METHODS

A total of 120 single fresh stool samples were collected, and processed by water ether sedimentation method; stained with Uvitex-2B and observed microspridial spore under fluorescent microscope. From same stool samples, smear were prepared and stained with Chromotrope-2R method for the detection of intestinal microsporidial spores using light microscope.

RESULTS

Uvitex 2B detected 5/120 (4.2%) while Chromotrope 2R detected 4/120 (3.3%) and there was no statistical significance difference between the two methods (P>0.05). The sensitivity and specificity of the chromotrope-2R method relative to Uvitex-2B were 80% and 100%, respectively and positive and negative predictive values of Chromotrope-2R relative to the Uvitex 2B were 100% and 99%, respectively.

CONCLUSION

Based on its relative simplicity for processing, in terms of low cost materials (light microscopes compared to fluorescent microscopes) and reagents, make Chromotrope-2R to be recommended for diagnosis of microsporiadia infection in peripheral labs. Even though Uvitex-2B is superior, its application in peripheral health facilities is questionable and demanding.

[Histological orchiepididymitis discovery in a patient with AIDS]

Incidences of opportunistic infections of the epididymus and the testicule have already been reported in patients suffering from AIDS for over 10 years. Here we have reported the first description of microsporadic orchiepididymitis diagnosed at the university hospital (CHU) of Nice in 2005. We look at the epidemiology, the physiology and the treatment of this extremely rare infection.

[Research progress on the technology of microsporidian detection]

The microsporidia are obligate intracellular eukaryotic parasites. They have been paid more attention as being the emerging pathogen of human, so it is important to control microsporidiosis using fast and precise detecting technology. In order to provide a reference for controlling microsporidian infection effectively, this paper reviews the progress of studying on the detecting technology from the microscopic staining methods, immunological and molecular biology.

The utility of direct agglutination (DAT) and fast agglutination screening (FAST) tests in serodiagnosis of experimental microsporidiosis

The present study was designed to evaluate the efficiency of two serodiagnostic tests; the direct agglutination test (DAT) and the fast agglutination screening test (FAST) in the diagnosis of Microsporidia in experimentally infected mice and to differentiate between different species of the parasite. The swiss albino mice were divided into non infected control and infected experimental groups which were further subdivided into ten subgroups. Ten samples of microsporidial spores were isolated from ten human stools and each one was used to infect each subgroup of mice. Stool and sera were collected weekly from each subgroup from the 1st to the 4th week post infection (PI). DAT & FAST tests, using antigen prepared from the different species of microsporidial spores were used to detect antibodies in sera of different mice subgroups. The cross reactivity of microsporidial spores with the antibodies of Cyclospora cyatenensis and Cryptosporidium parvum was investigated by DAT & FAST. The results proved that DAT & FAST were effective in detecting microsporidial antibodies in sera of experimentally infected mice from the 2nd week PI till the end of the study, without cross reactivity with C. cyatenensis or C. parvum. They failed to differentiate between different Microspoiridia species used but, they gave good interpretation and they were specific and sensitive, and did not need sophisticated equipments.

[Multiple intracerebral enhanced lesions strongly suspected to be microsporidiosis. A case report]

This case of microsporidiosis manifested as mutiple intracranial lesions separated in space and time, and neurological and radiological findings were improved with albendazole administration. A 33-year-old man presented with headache, fever, and dysphasia. His consciousness was clear. Neurological examination revealed acalculia, agraphia, and homonymous hemianopsia. He had a past history of febrile convulsive seizures of unknown cause until 14-years-old, but no history of immunodeficiency. T1-weighted magnetic resonance (MR) imaging showed a hypointense lesion with a hyperintense part, and ring-like enhancement with gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA), in the left temporal lobe. T2-weighted and diffusion-weighted MR imaging showed the lesion surrounded by moderate hyperintense areas. He underwent gross total resection of the lesion. Histological examination demonstrated intracellular clusters of small basophilic spore-like bodies in the astrocytes, suggestive of microsporidia-infected astrocytes. However, immunohistochemical, polymerase chain reaction, and serological analyses failed to confirm the definitive diagnosis of microsporidiosis, so that he received no further treatment. Three years later, he presented with sensory disturbance in the left side of his face and left cerebellar ataxia, followed by fever, abnormal sensation in the left side of his face, and aggravated ataxia of the left upper and lower extremities on day 10 after admission. T1-weighted MR imaging with Gd-DTPA showed an enhanced lesion with irregular margin in the left cerebellar peduncle. T2-weighted MR imaging showed a diffuse hyperintense region around the lesion. Cerebrospinal fluid culture, serological analysis for autoimmune disease, and thoracic, abdominal, and pelvic computed tomography and 18F-fluorodeoxyglucose-positron emission tomography detected no abnormalities such as cancers or other lesions in the extracranial organs. No definitive diagnosis was obtained, but recurrence of microsporidiosis was the most probable cause. Administration of albendazole (600 mg/day) was started on day 15, because of rapid neurological and radiological deterioration. This treatment resulted in clinical improvement and disappearance of the lesion on MR imaging after daily administration for 4 weeks. He was discharged on foot with moderate sensory disturbance in the left side of the face and ataxia. Based on the clinical course and negative findings, the final diagnosis was microsporidiosis. This case suggests that microsporidiosis in the central nervous system can persist even in immunocompetent patients without involvement of any other organs, and that albendazole administration is likely to be effective.

Microsporidium Stromal Keratitis: In Vivo Confocal Findings

PURPOSE

To relate the clinical signs, histopathologic features, and in vivo confocal biomicroscopy findings of a case of stromal microsporidial keratitis and to describe the use of in vivo confocal microscopy to monitor treatment effect.

METHODS

An immunocompetent male patient presented with unilateral indolent stromal keratitis. Stromal microsporidiosis was confirmed after corneal biopsy. He underwent examination that used in vivo confocal microscopy (Heidelberg Retina Tomograph II and Rostock Cornea Module) before and after treatment with topical fumagillin and oral albendazole. Clinicopathologic correlation of the confocal scan was performed.

RESULTS

Corneal biopsy showed extracellular microsporidium spores aligned along keratocytes and corneal lamellae. In vivo confocal scans showed similar morphology, with bright dots aligned along keratocytes. Treatment with antimicrobials and topical steroid gave resolution of active keratitis, correlating with disappearance of the bright spores on repeat in vivo confocal scanning.

CONCLUSIONS

The in vivo confocal microscopy appearance of microsporidial keratitis corresponds to the histologic features from biopsy material. Treatment response may be monitored by using this technique, although definitive diagnosis requires corneal biopsy.

Validation of a quantitative PCR diagnostic method for detection of the microsporidian Ovipleistophora ovariae in the cyprinid fish Notemigonus crysoleucas

Microsporidian parasites are easily detected by light microscopy when infections are heavy and spores are present. However, early infections without spores, or light infections with low numbers of spores, are easily missed. This limitation has made it difficult to conduct investigations into microsporidian prevalence and transmission. In this study, we developed a quantitative TaqMan polymerase chain reaction assay to assess the presence of Ovipleistophora ovariae in the tissues of the cyprinid fish Notemigonus crysoleucas (golden shiner). The efficiency of the primer set was 100.8%, with a correlation coefficient of threshold position to copy number of 0.997 over 9 logs using a plasmid containing the cloned reaction product. No product was produced from other closely related microsporidian species (Nucleospora salmonis, Pseudoloma neurophila, Glugea stephani, Heterosporis sp., and O. mirandella). The coefficient of variation for replicate assays done on different days was 12.4%. The assay detects O. ovariae reliably at less than 10 genomic copies and 0.14 spores per reaction, but maximum sensitivity is only achieved when sonication is included as part of the DNA purification step. Using the assay, we found 4.44 x 10(1) to 7.91 x 10(6) copies microg(-1) host DNA in female golden shiners, with the spore density increasing during the spawning season. The parasite was also detected for the first time in the testes of male golden shiners at 2.60 x 10(1) to 8.62 x 102 copies microg(-1) host DNA.