Detection and differentiation of coccidian oocysts by real-time PCR and melting curve analysis

Use of selected samples to diagnose a tricky feline viral disease in a cat with uveitis and neurological signs

This case involved a 2-year-old neutered male domestic mixed-breed cat that was rescued from the street eight months earlier. The animal presented with weakness, hyporexia, progressive weight loss, fatigue, uveitis, pale mucous membranes, dehydration (7%), and pelvic limb paresis. Aqueous humor was collected for molecular analysis for the differential diagnosis of potential etiological agents [Feline coronavirus (FCoV), Feline leukemia virus (FeLV), Feline immunodeficiency virus (FIV), Toxoplasma gondii, Cryptococcus spp., Felid herpesvirus-1 (FHV-1) and Bartonella spp.] of feline uveitis. The sample was positive by real-time reverse transcription-polymerase chain reaction (RT-qPCR) for FCoV and RT-qPCR and real-time polymerase chain reaction (qPCR) for FeLV and qPCR FIV. The cat was euthanized due to poor clinical outcomes and prognosis. A cerebrospinal fluid (CSF) sample was collected and tested, and the same pathogens were found in the aqueous humor. Small-cell follicular multicenter lymphoma and multifocal pyogranulomatous meningoencephalitis were observed upon histopathological analysis. In this study, aqueous humor and cerebrospinal fluid samples were efficient for the detection of coinfection with FIV, FeLV, and FCoV.

Molecular investigation of ready-to-eat salads for Giardia duodenalis and Cryptosporidium spp. in Portugal

Foodborne outbreaks are often associated with the consumption of salads. However, published studies on the detection of foodborne pathogens in ready-to-eat salads are scarce. The aim of this study was to detect Giardia duodenalis and Cryptosporidium DNA in ready-to-eat salads, by applying techniques of molecular biology to study the frequency of contamination in salads. A total of 100 packages of ready-to-eat salads containing assorted leafy green vegetables were randomly purchased from hypermarkets located in central regions of Portugal (Coimbra and Viseu). Nested-PCR and qPCR methods were used to detect G. duodenalis and Cryptosporidium DNA. Species and assemblages of the parasites were identified by sequence analysis and PCR. Eighteen of the 100 samples (18%) were positive for G. duodenalis and twelve were sequenced and identified as assemblage A. Cryptosporidium spp. were not detected in any salads. Overall, pre-harvest and post-harvest preventive measures may be need for G. duodenalis control throughout the food production industry, from the field to consumers.

Diagnostic Approach to Enteric Disorders in Pigs

The diagnosis of enteric disorders in pigs is extremely challenging, at any age. Outbreaks of enteric disease in pigs are frequently multifactorial and multiple microorganisms can co-exist and interact. Furthermore, several pathogens, such as Clostridium perfrigens type A, Rotavirus and Lawsonia intracellularis, may be present in the gut in the absence of clinical signs. Thus, diagnosis must be based on a differential approach in order to develop a tailored control strategy, considering that treatment and control programs for enteric diseases are pathogen-specific. Correct sampling for laboratory analyses is fundamental for the diagnostic work-up of enteric disease in pigs. For example, histology is the diagnostic gold standard for several enteric disorders, and sampling must ensure the collection of representative and optimal intestinal samples. The aim of this paper is to focus on the diagnostic approach, from sampling to the aetiological diagnosis, of enteric disorders in pigs due to different pathogens during the different phases of production.

Automated enumeration of Eimeria oocysts in feces for rapid coccidiosis monitoring

Coccidiosis represents a major driver in the economic performance of poultry operations, as coccidia control is expensive, and infections can result in increased feed conversion ratios, uneven growth rates, increased co-morbidities with pathogens such as Salmonella, and mortality within flocks. Shifts in broiler production to antibiotic-free strategies, increased attention on pre-harvest food safety, and growing incidence of anti-coccidial drug resistance has created a need for increased understanding of interventional efficacy and methods of coccidia control. Conventional methods to quantify coccidia oocysts in fecal samples involve manual microscopy processes that are time and labor intensive and subject to operator error, limiting their use as a diagnostic and monitoring tool in animal parasite control. To address the need for a high-throughput, robust, and reliable method to enumerate coccidia oocysts from poultry fecal samples, a novel diagnostic tool was developed. Utilizing the PIPER instrument and MagDrive technology, the diagnostic eliminates the requirement for extensive training and manual counting which currently limits the application of conventional microscopic methods of oocysts per gram (OPG) measurement. Automated microscopy to identify and count oocysts and report OPG simplifies analysis and removes potential sources of operator error. Morphometric analysis on identified oocysts allows for the oocyst counts to be separated into 3 size categories, which were shown to discriminate the 3 most common Eimeria species in commercial broilers, E. acervulina, E. tenella, and E. maxima. For 75% of the samples tested, the counts obtained by the PIPER and hemocytometer methods were within 2-fold of each other. Additionally, the PIPER method showed less variability than the hemocytometer counting method when OPG levels were below 100,000. By automated identification and counting of oocysts from 12 individual fecal samples in less than one hour, this tool could enable routine, noninvasive diagnostic monitoring of coccidia in poultry operations. This approach can generate large, uniform, and accurate data sets that create new opportunities for understanding the epidemiology and economics of coccidia infections and interventional efficacy.

Quality control procedure for Coccidial vaccines versus different routes of immunization

Background and Aim:

Coccidiosis is an enteric infection caused by a protozoon (Eimeriatenella). Coccidiosis is known to have a negative impact on the economy. Coccidiosis is controlled using anticoccidial drugs, antibiotics, and vaccines. Various coccidial vaccines differ in application technique, attenuation method, and the species used. Coccidial vaccines can be spray or gel-based (Form). This study aimed to compare the effect of application and approaches between spray and gel vaccines for coccidiosis.

Materials and Methods:

Specific pathogen-free chicks were vaccinated with different vaccines. Fecal samples were taken on 21 days post-vaccination for vaccine take, and then a challenge test was done on day 21.

Results:

Post-vaccination oocyst counts in gel vaccinated groups were more than the spray vaccinated ones as it recorded (1400 and 2200) oocyst/g, but the gel vaccines resulted in lower post vaccinal titer which was (10000 and 12500) oocyst/g. Results of quantitative real-time polymerase chain reaction test post-vaccination were (23.72, 20.29) cycle threshold (CT) for spray vaccines and (18.75, 17.62) CT for gel vaccinated group. By challenging all the experimental groups, the microscopic and macroscopic lesion of gel vaccines resulted in score 1, while spray vaccines groups recorded score 2 and the control non-vaccinated challenged chickens showed score 4. The non-vaccinated/non-challenged group recorded a score of zero.

Conclusion:

These results can help poultry producers to decide which delivery system will provide the best results for their production system. The gel vaccines showed a better protection rate and lower shedding, which means more protection of birds and public health.

Verification and Use of the US-FDA BAM 19b Method for Detection of Cyclospora cayetanensis in a Survey of Fresh Produce by CFIA Laboratory

To facilitate the harmonized surveillance and investigation of cyclosporiasis outbreaks in the US and Canada, we adapted and verified the US-FDA’s BAM 19b method and employed it in a national produce survey. Performance was verified by spiking 200, 10, 5 or 0 C. cayetanensis oocysts onto berries (50 ± 5 g, n = 85) and 200, 10 or 0 oocysts onto green onions (25 ± 3 g, n = 24) and leafy greens (25 ± 1 g, n = 120) and testing these samples by the BAM method on Bio-Rad CFX96. Method robustness was assessed by aging (0 or 7 days) and freezing the produce and washes prior to testing, then implementing the method for the surveillance testing of 1759 imported leafy green, herb and berry samples. Diagnostic sensitivity was 100/44% and 93/30% for berries and leafy greens spiked with 200/10 oocysts, respectively. The diagnostic and analytical specificity were 100% for all matrices and related parasites tested. The proportion positive was unaffected (p = 0.22) by age or condition of produce (7d, fresh, frozen) or wash concentrate (3d, fresh, frozen); however, the Cq values were higher (p = 0.009) for raspberries aged 7d (37.46 ± 0.29) compared to fresh (35.36 ± 0.29). C. cayetanensis was detected in berries (two), herbs (two) and leafy greens (one), representing 0.28% of the tested survey samples. These results independently verified the reported performance characteristics and robustness of the BAM method for the detection of C. cayetanensis in a variety of matrices, including under adverse sample conditions, using a unique detection platform and demonstrating its routine diagnostic use in our Canadian Food Inspection Agency (CFIA) laboratory.

Equine Protozoal Myeloencephalitis associated with Neospora caninum in a USA captive bred zebra (Equus zebra)

A 6-year-old female captive zebra (Equus zebra) had a three-year history of slow progressive neurologic signs that recently worsened with hind limb ataxia, head tilt, and circling. Gross examination including the brain and spinal cord were unremarkable. On histopathology, the brain and brainstem had multiple random areas of severe lymphoplasmacytic meningoencephalitis associated with numerous 15-25 μm in diameter protozoal cysts with a discernible outer wall containing numerous 2 × 4 μm oval to crescent-shaped organisms. Immunohistochemistry and PCR identified the presence of Neospora organisms associated with the lesions. Equine protozoal myeloencephalitis (EPM) is generally associated with Sarcocystis neurona or less commonly Neospora hughesi. Molecular characterization revealed the first case of EPM associated with Neospora caninum in an equid as confirmed by DNA analysis.

Evaluation of quantitative polymerase chain reaction for the detection of Toxoplasma gondii oocysts shed by cats

Felines are definitive hosts of Toxoplasma gondii and can shed oocysts in their feces, contaminating the environment. Sporulated oocysts are highly resistant to the environment and have higher infectivity, which are attributed to many toxoplasmosis outbreaks. The aim of the present study was to evaluate a quantitative polymerase chain reaction (qPCR) technique for the detection of T. gondii oocysts shed by cats. Twelve cats from a previous vaccine experiment were challenged orally with 600 cysts of the TgDoveBr8 strain on day 72. Fecal samples were collected daily using the centrifugal flotation technique, with microscopic examination (Sheather technique) and qPCR for 20 days after the challenge. Cats from all groups shed oocysts in their feces. Five negative cats in the Sheather were positive according to qPCR on the 3rd day post-inoculation (dpi). Oocysts were detected on the 4th dpi using the Sheather; however, there was no statistical difference between the two methods (p=0.1116). In addition, there was no statistically significant difference in oocyst shedding between the groups according to the Sheather technique (p=0.6534) and qPCR (p=0.9670). In conclusion, these results demonstrate that qPCR can be used as an alternative to the Sheather to detect and quantify T. gondii oocysts.

Prevalence and infection risk factors of bovine Eimeria in China: a systematic review and meta-analysis

Eimeria spp. cause the disease coccidiosis, which results in chronic wasting of livestock and can lead to the death of the animal. The disease, common worldwide, has caused huge economic losses to the cattle industry in particular. This is the first systematic review and meta-analysis of the prevalence of bovine Eimeria in China. Our search of five databases including PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), Chongqing VIP, and Wan Fang for articles published up to February 29, 2020 on the prevalence of Eimeria in cattle in mainland China yielded 46 articles, in which the prevalence of cattle ranged from 4.6% to 87.5%. The rate of bovine Eimeria infection has been decreasing year by year, from 57.9% before 2000 to 25.0% after 2015, but it is still high. We also analyzed the region, sampling years, detection methods, feeding model, seasons, and species of bovine Eimeria. We recommend that prevention strategies should focus on strengthening detection of Eimeria in calves in the intensive farming model.

Host Range of Cyclospora Species: Zoonotic Implication

Cyclospora is an intracellular, gastrointestinal parasite found in birds and mammals worldwide. Limited accessibility of the protozoan for experimental use, scarcity, genome heterogeneity of the isolates and narrow panel of molecular markers hamper zoonotic investigations. One of the significant limitation in zoonotic studies is the lack of precise molecular tools that would be useful in linking animal vectors as a source of human infection. Strong and convincing evidence of zoonotic features will be achieved through proper typing of Cyclospora spp. taxonomic units (e.g. species or genotypes) in animal reservoirs. The most promising method that can be employ for zoonotic surveys is next-generation sequencing.

Cyclospora Cayetanensis-Major Outbreaks from Ready to Eat Fresh Fruits and Vegetables

Cyclospora cayetanensis is a coccidian protozoan that causes cyclosporiasis, a severe gastroenteric disease, especially for immunocompromised patients, children, and the elderly. The parasite is considered as an emerging organism and a major contributor of gastroenteritis worldwide. Although the global prevalence of cyclosporiasis morbidity and mortality has not been assessed, global concern has arisen since diarrheal illness and gastroenteritis significantly affect both developing countries and industrialized nations. In the last two decades, an increasing number of foodborne outbreaks has been associated with the consumption of fresh produce that is difficult to clean thoroughly and is consumed without processing. Investigations of these outbreaks have revealed the necessity to increase the awareness in clinicians of this infection, since this protozoan is often ignored by surveillance systems, and to establish control measures to reduce contamination of fresh produce. In this review, the major cyclosporiasis outbreaks linked to the consumption of ready to eat fresh fruits and vegetables are presented.

Species-level identification of trypanosomes infecting Australian wildlife by High-Resolution Melting - Real Time Quantitative Polymerase Chain Reaction (HRM-qPCR)

Conventional nested PCR and Sanger sequencing methods are currently the gold standards for detecting trypanosomes in wildlife. However, these techniques are time-consuming and can often overlook mixed infections. True trypanosome prevalence can thus be underrepresented. Here, we designed an 18S rDNA-based real-time quantitative PCR (qPCR) assay coupled with High-Resolution Melting Analysis (HRMA) to detect and discriminate three Trypanosoma species (T. copemani, T. noyesi, and T. vegrandis) commonly infecting Australian marsupials. A total of 68 genetically characterised samples from blood and tissue were used to validate the High-Resolution Melting - Real Time Quantitative Polymerase Chain Reaction (HRM-qPCR) assay. A further 87 marsupial samples consisting of blood, tissue and in vitro cultures derived from wildlife blood samples, were screened for the first time using this assay, and species identity confirmed using conventional PCR and Sanger sequencing. All three Trypanosoma species were successfully detected in pure cultures using the HRM-qPCR assay, and in samples containing mixed trypanosome infections. Of the 87 marsupial samples screened using the HRM-qPCR assay, 93.1% were positive for trypanosomes, and 8.0% contained more than one trypanosome species. In addition to the three targeted Trypanosoma species, this assay was also able to detect and identify other native and exotic trypanosomes. The turnaround time for this assay, from sample preparation to obtaining results, was less than 2 h, with a detection limit of 10 copies of the amplicon in a reaction for each of the targeted trypanosome species. This more rapid and sensitive diagnostic tool provides a high throughput platform for the detection, identification and quantification of trypanosome infections. It will also improve understanding of host diversity and parasite relationships and facilitate conservation management decisions.

A novel 5-Plex qPCR-HRM assay detecting human diarrheal parasites

Background

Intestinal parasitic diseases occur worldwide, and their diagnosis poses considerable challenges. Cryptosporidium spp., Entamoeba histolytica, Giardia intestinalis, (and, arguably, Dientamoeba fragilis and Blastocystis spp.) are among the most important and common parasitic protozoans causing diarrhea. Several multiplex real-time PCR assays have been developed for the synchronous detection of these parasites. However, most assays include the use of hydrolysis probes, increasing the cost of stool examination. In this study, we designed and evaluated a real-time PCR protocol, based on high-resolution melting (HRM) curve analysis, to simultaneously detect and differentiate five gastrointestinal parasites.

Results

Using a blinded panel of 143 clinical samples with laboratory diagnostic data to evaluate the method, we obtained a 95.8% concordance with conventional methods. Moreover, 4.2% of the samples were positive for D. fragilis and 2.8% additional Cryptosporidium infections were found with our multiplex assay. Our method is sensitive and specific for the selected parasites with the additional possibility of being run in single-plex as a backup control for mixed infections.

Conclusions

The assay is a convenient and cost-effective method that could contribute to a quicker and accurate diagnosis as well as to more targeted therapies of parasite-derived diarrhea. Finally, this new multiplex PCR assay could also be instrumental in epidemiology studies on these parasites.

Advances in Cyclosporiasis Diagnosis and Therapeutic Intervention

Cyclosporiasis is caused by the coccidian parasite Cyclospora cayetanensis and is associated with large and complex food-borne outbreaks worldwide. Associated symptoms include severe watery diarrhea, particularly in infants, and immune dysfunction. With the globalization of human food supply, the occurrence of cyclosporiasis has been increasing in both food growing and importing countries. As well as being a burden on the health of individual humans, cyclosporiasis is a global public health concern. Currently, no vaccine is available but early detection and treatment could result in a favorable clinical outcome. Clinical diagnosis is based on cardinal clinical symptoms and conventional laboratory methods, which usually involve microscopic examination of wet smears, staining tests, fluorescence microscopy, serological testing, or DNA testing for oocysts in the stool. Detection in the vehicle of infection, which can be fresh produce, water, or soil is helpful for case-linkage and source-tracking during cyclosporiasis outbreaks. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) can evidently cure C. cayetanensis infection. However, TMP-SMX is not suitable for patients having sulfonamide intolerance. In such case ciprofloxacin, although less effective than TMP-SMX, is a good option. Another drug of choice is nitazoxanide that can be used in the cases of sulfonamide intolerance and ciprofloxacin resistance. More epidemiological research investigating cyclosporiasis in humans should be conducted worldwide, to achieve a better understanding of its characteristics in this regard. It is also necessary to establish in vitro and/or in vivo protocols for cultivating C. cayetanensis, to facilitate the development of rapid, convenient, precise, and economical detection methods for diagnosis, as well as more effective tracing methods. This review focuses on the advances in clinical features, diagnosis, and therapeutic intervention of cyclosporiasis.

Intestinal Protozoan Parasitic Infections in Immunocompromised Child Patients with Diarrhea

Intestinal protozoan parasites are common causes of infectious diarrhea in children receiving anticancer therapy or undergoing transplantation. Additionally, immunosuppression therapy in such patients may exacerbate the symptoms related to these parasitic infections. The aim of this study was to evaluate the prevalence and diagnostic importance of parasitic protozoan infections in children treated for malignancies or undergoing transplantation, and to highlight the control of intestinal parasitic infections for immunosuppressed patients at a hospital in İzmir, Turkey. In total, 82 stool samples from 62 patients were analyzed by microscopic examination and polymerase chain reaction (PCR) for the presence of coccidian parasites. Our results showed that Cryptosporidium, Cyclospora, and Cystoisospora were present in 22.5% (14/62), 9.6% (6/62), and 3.2% (2/62) of the cases using either method, respectively. The prevalence of these coccidian parasites identified with both methods was 35.4% (20/62). Other intestinal parasites (Blastocystis, Giardia, and Entamoeba coli) were detected in 10 patients. PCR analysis showed the presence of all coccidian parasites in the same stool sample for one patient. Finally, both PCR and microscopic examination of the stools revealed that there is a higher prevalence of Cryptosporidium, Cyclospora, and Cystoisospora in immunocompromised children. These examinations allowed an early start of appropriate antibiotic treatments and led to an increased percentage of correctly treated patients.

A novel protocol to isolate, detect and differentiate taeniid eggs in leafy greens and berries using real-time PCR with melting curve analysis

BACKGROUND

Zoonotic taeniid cestodes are amongst the most important food-borne parasites affecting human health worldwide. Contamination of fresh produce with the eggs of Echinococcus granulosus (s.l.), Echinococcus multilocularis, and some Taenia species pose a potential food safety risk. However, very few studies have attempted to investigate the potential contamination of fresh produce with taeniid eggs and the available methods are not standardized for this purpose. Established protocols do exist for testing leafy greens and berries for contamination with protozoan parasites and are used in national surveillance programmes. This methodology could be suitable for the detection of taeniids. The objective of this project was to develop and standardize a sensitive and reliable method to detect contamination of leafy greens and berries with eggs of zoonotic taeniids and to differentiate between E. multilocularis, E. granulosus (s.l.) and Taenia spp.

METHODS

We compared the efficacy of different wash solutions to remove Taenia spp. eggs from spiked produce, assessed two DNA extraction kits for their performance on Taenia spp. eggs, and adapted a published conventional multiplex PCR into a real-time PCR with fluorescence melting curve analysis (MCA) that was optimized for use on produce washes. Analytical specificity of this protocol was assessed using non-spiked produce washes as well as a variety of other potentially contaminating parasites.

RESULTS

The protocol as established in this study had an analytical sensitivity of detecting five eggs per spiked sample for both romaine lettuce and strawberries. Unequivocal identification of E. multilocularis, E. granulosus (s.l.) and Taenia spp. was possible through MCA. Amplicon sequencing allowed identification of Taenia to the species level. The real-time PCR also amplified DNA from Dicrocoelium sp., but with a clearly discernable melting curve profile.

CONCLUSION

The new protocol for screening produce for taeniid contamination was highly sensitive. Melting curve analysis and the possibility of amplicon sequencing made this assay very specific. Once further validated, this method could be employed for surveillance of produce for contamination with taeniid parasites to assess potential risks for consumers.

Cyclospora cayetanensis infection in humans: biological characteristics, clinical features, epidemiology, detection method and treatment

Cyclospora cayetanensis, a coccidian parasite that causes protracted and relapsing gastroenteritis, has a short recorded history. At least 54 countries have documented C. cayetanensis infections and 13 of them have recorded cyclosporiasis outbreaks. Cyclospora cayetanensis infections are commonly reported in developing countries with low-socioeconomic levels or in endemic areas, although large outbreaks have also been documented in developed countries. The overall C. cayetanensis prevalence in humans worldwide is 3.55%. Among susceptible populations, the highest prevalence has been documented in immunocompetent individuals with diarrhea. Infections are markedly seasonal, occurring in the rainy season or summer. Cyclospora cayetanensis or Cyclospora-like organisms have also been detected in food, water, soil and some other animals. Detection methods based on oocyst morphology, staining and molecular testing have been developed. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) effectively cures C. cayetanensis infection, whereas ciprofloxacin is less effective than TMP-SMX, but is suitable for patients who cannot tolerate co-trimoxazole. Here, we review the biological characteristics, clinical features, epidemiology, detection methods and treatment of C. cayetanensis in humans, and assess some risk factors for infection with this pathogen.

Cystoisospora belli infections in humans: the past 100 years

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

Cyclospora cayetanensis and Cyclosporiasis: An Update

Cyclospora cayetanensis is a coccidian parasite of humans, with a direct fecal-oral transmission cycle. It is globally distributed and an important cause of foodborne outbreaks of enteric disease in many developed countries, mostly associated with the consumption of contaminated fresh produce. Because oocysts are excreted unsporulated and need to sporulate in the environment, direct person-to-person transmission is unlikely. Infection by C. cayetanensis is remarkably seasonal worldwide, although it varies by geographical regions. Most susceptible populations are children, foreigners, and immunocompromised patients in endemic countries, while in industrialized countries, C. cayetanensis affects people of any age. The risk of infection in developed countries is associated with travel to endemic areas and the domestic consumption of contaminated food, mainly fresh produce imported from endemic regions. Water and soil contaminated with fecal matter may act as a vehicle of transmission for C. cayetanensis infection. The disease is self-limiting in most immunocompetent patients, but it may present as a severe, protracted or chronic diarrhea in some cases, and may colonize extra-intestinal organs in immunocompromised patients. Trimetoprim-sulfamethoxazole is the antibiotic of choice for the treatment of cyclosporiasis, but relapses may occur. Further research is needed to understand many unknown epidemiological aspects of this parasitic disease. Here, we summarize the biology, epidemiology, outbreaks, clinical symptoms, diagnosis, treatment, control and prevention of C. cayetanensis; additionally, we outline future research needs for this parasite.

Human cyclosporiasis

Cyclospora species are socioeconomically important protistan pathogens. Cyclospora cayetanensis is usually transmitted via food or water to a human host via the faecal-oral route and can cause the gastrointestinal disease cyclosporiasis, which can be complicated by extra-intestinal disorders, particularly in immune-compromised people. Although more than 2 million children die each year from diarrhoeal diseases worldwide, it is not known to what extent cyclosporiasis is involved. Few epidemiological data are available on Cyclospora as a water-borne and food-borne pathogen in both underprivileged communities and developed countries. To gain an improved understanding of human cyclosporiasis, this Review describes the background of Cyclospora, summarises salient aspects of the pathogenesis, epidemiology, diagnosis, treatment, and control of cyclosporiasis, and explores what is known about its prevalence and geographical distribution. The findings show that the effect on human health of cyclosporiasis is likely underestimated, and recommendations are made about areas of future research and the prevention and control of this disease within an international collaborative context.

Diagnosis and control of chicken coccidiosis: a recent update

Coccidiosis is a deadly disease that hampers chicken's productivity and welfare. Thus, the disease is a major menace to the global poultry industry. Coccidiosis which is caused by the apicomplexan parasite of the genus Eimeria has seven known species which affect the different parts of the intestinal tract of chickens. The disease which occurs by ingestion of sporulated oocyst has been associated with poor poultry management system. Mixed infection among the species of this parasite contributes to both pathogenicity and misdiagnosis of the disease. A progress in identification and diagnosis approach which cuts across pathological, morphological and molecular has been reported for this parasite. Control measures which include anticoccidial drugs, vaccines and natural products have dominated literature for this disease. However, the emergence of genetic and antigenic diversity with implication on resistance to anticoccidials among different strains of Eimeria parasite has generated concerns on the effectiveness of the current anticoccidial vaccines. A new look on the control strategy therefore becomes imperative. This study reviews the current trends on the identification and control of chicken coccidiosis with focus on (1) Avian coccidiosis (2) Epidemiology of chicken coccidiosis (3) Eimeria parasite and distribution in poultry (4) Diagnosis of Eimeria parasite (5) Control measures of coccidiosis (6) Threats posed by genetic and antigenic diversity of Eimeria parasite on coccidiosis control. Genomic study on diversity of Eimeria parasite becomes imperative for effective vaccine design against coccidiosis.

Risk of environmental exposure to small coccidia from wild canid feces in rural Ohio

OBJECTIVE To determine the extent of environmental exposure to heteroxenous coccidia from wild canid feces in southeastern Ohio. SAMPLE 285 presumed wild canid fecal samples collected across an ecological system in southeastern Ohio. PROCEDURES Morphological classification and molecular analysis were used to determine the canid genus for collected fecal samples. Microscopic and molecular analysis were used to detect coccidian oocysts and DNA. Several variables were analyzed for associations with coccidian DNA detection or prevalence. RESULTS Coccidian DNA was detected in 51 of 285 (17.9%) fecal samples. Of those positive samples, 1% (95% confidence interval, 0.4% to 3%) had positive results for Hammondia heydorni and none had positive results for Neospora caninum, for an estimated environmental N caninum prevalence of 0% (95% confidence interval, 0% to 7%)/1-km² hexagonal area evaluated. Morphological classification revealed that 78.9% (225/285) of fecal samples were from coyotes and 17.2% (49/285) were from foxes. No difference in proportions of coccidian DNA-positive fecal samples was identified among canid species. Environmental temperature and fecal freshness were associated with coccidian DNA detection. Land use type, relative canid density, and cattle density were not associated with the prevalence of coccidian DNA-positive samples. CONCLUSIONS AND CLINICAL RELEVANCE The low prevalence of coccidia shed in wild canid feces in this study, including the estimated 0% environmental prevalence of N caninum, suggested that the role of the oocyst environmental phase in coccidia transmission to ruminants is likely minor in rural southeastern Ohio.

Molecular detection and genotyping of pathogenic protozoan parasites in raw and treated water samples from southwest Colombia

BACKGROUND

Protozoan parasites such as Giardia duodenalis, Cryptosporidium spp., Cyclospora cayetanensis, Toxoplasma gondii and Entamoeba histolytica represent a great challenge to the systems producing water for human consumption because their cystic forms are persistent in the environment and resist to the disinfection methods conventionally used for their control. In this study, we investigated the presence of these protozoan pathogens in both raw and treated water samples used for the production of drinking water in Nariño Department, southwest Colombia. We collected 110 water samples (10 lof each sample) and analyzed them with real-time PCR (qPCR). qPCR-positive samples were genotyped with PCR and DNA sequencing.

RESULTS

Giardia duodenalis was detected in 35/110 (31.8%) of the samples and Cryptosporidium spp. in 9/110 (8.2%) of the samples; no sample was positive for T. gondii, E. histolytica or C. cayetanensis. Giardia duodenalis was detected in samples of both raw water (Drinking Water Treatment Plants (DWTP): 47.83%;Drinking Water Rural Plants (DWRP): 18.42%) and water collected either after conventional physicochemical treatment (26.09%) or after disinfection by chlorine (50%), whereas Cryptosporidium spp. were only detected in raw waters (DWTP: 17.39%; DWRP: 13.16%). The two pathogens were detected in both types of treatment plants supplying water to urban areas and to rural zones. Analysis of gdh and tpi markers identified assemblages AI, AII and H of G. duodenalis, while analysis of the small subunit rRNA and gp60 markers of Cryptosporidium-positive samples identified C. parvum (Subtype IIcA5G3c), C. galli, C. molnari, Cryptosporidium sp. genotype II of bats and Cryptosporidium sp. genotype VIII of birds.

CONCLUSIONS

The results obtained demonstrate the presence of protozoan parasites in the water of the study region, and the need to improve the surveillance systems for these pathogens and identify the corresponding sources of contamination.

Detection of Cystoisospora suis in faeces of suckling piglets - when and how? A comparison of methods

Background

Cystoisospora suis is the causative agent of porcine neonatal coccidiosis, a diarrheal disease which affects suckling piglets in the first weeks of life. Detection of oocysts in the faeces of infected animals is frequently hampered by the short individual excretion period and the high fat content of faecal samples. We analysed oocyst excretion patterns of infected piglets, evaluated different detection methods for their detection limit and reproducibility, and propose a sampling scheme to improve the diagnosis of C. suis in faecal samples from the field using a protocol for reliable parasite detection.

Results

Based on a hypothesized model of the course of infection on a farm, three samplings (days of life 7–14-21 or 10–15-20) should be conducted including individual samples of piglets from each sampled litter. Samples can be examined by a modified McMaster method (lower detection limit: 333 oocysts per gram of faeces, OpG), by examining faecal smears under autofluorescence (lower detection limit: 10 OpG) or after carbol-fuchsin staining (lower detection limit: 100 OpG). Reproducibility and inter-test correlations were high with (R² > 0.8). A correlation of oocyst excretion with diarrhoea could not be established so samples with different faecal consistencies should be taken. Pooled samples (by litter) should be comprised of several individual samples from different animals.

Conclusions

Since oocyst excretion by C. suis-infected piglets is usually short the right timing and a sufficiently sensitive detection method are important for correct diagnosis. Oocyst detection in faecal smears of samples taken repeatedly is the method of choice to determine extent and intensity of infection on a farm, and autofluorescence microscopy provides by far the lowest detection limit. Other methods for oocyst detection in faeces are less sensitive and/or more labour- and cost intensive and their usefulness is restricted to specific applications.

Molecular detection of Cyclospora cayetanensis in human stool specimens using UNEX-based DNA extraction and real-time PCR

Cyclospora cayetanensis is a coccidian parasite associated with diarrheal illness. In the USA, foodborne outbreaks of cyclosporiasis have been documented almost every year since the mid-1990s. The typical approach used to identify this parasite in human stools is an examination of acid-fast-stained smears under bright-field microscopy. UV fluorescence microscopy of wet mounts is more sensitive and specific than acid-fast staining but requires a fluorescence microscope with a special filter not commonly available in diagnostic laboratories. In this study, we evaluated a new DNA extraction method based on the Universal Nucleic Acid Extraction (UNEX) buffer and compared the performances of four published real-time polymerase chain reaction (PCR) assays for the specific detection of C. cayetanensis in stool. The UNEX-based method had an improved capability to recover DNA from oocysts compared with the FastDNA stool extraction method. The best-performing real-time PCR assay was a C. cayetanensis-specific TaqMan PCR that targets the 18S ribosomal RNA gene. This new testing algorithm should be useful for detection of C. cayetanensis in human stool samples.

An overview of methods/techniques for the detection of Cryptosporidium in food samples

Cryptosporidium is one of the most important parasitic protozoa of concern within the food production industry, worldwide. This review describes the evolution and its development, and it monitors the methodology that has been used for Cryptosporidium in food material since 1984, when the first publication appeared regarding the detection of Cryptosporidium parvum in food materials. The methods that are currently being used for the detection of Cryptosporidium oocysts in food material (mainly vegetables) and all of the other available published methods are discussed in this review. Generating more consistent and reliable data should lead to a better understanding of the occurrence, transport and fate of the oocysts in food material. Improvements in monitoring and developing effective methodology, along with food security, offer more practical possibilities for both the developed and developing worlds.

Genotypic Identification of Cystoisospora in Immunocompromised Patients Using Tm-Variation Analysis

Cystoisospora is responsible for morbidity in immunocompromised patients. PCR is sensitive for diagnosing Cystoisospora; however, it needs reevaluation for differential molecular diagnosis of cystoisosporiasis. We aimed at evaluating melting curve analysis (MCA) after real-time PCR (qPCR) in diagnosis and genotyping of Cystoisospora as an alternative to conventional PCR. We included 293 diarrheic stool samples of patients attending the Department of Clinical Oncology and Nuclear Medicine of Cairo University Hospitals, Egypt. Samples were subjected to microscopy, nested PCR (nPCR), and qPCR targeting the internal transcribed spacer 2 region (ITS2) of the ribosomal RNA (r RNA) gene followed by melting temperatures (T_ms) analysis and comparing the results to PCR-RFLP banding patterns. Using microscopy and ITS2-nPCR, 3.1% and 5.8% of cases were Cystoisospora positive, respectively, while 10.9% were positive using qPCR. Genotyping of Cystoisospora by qPCR-MCA revealed 2 genotypes. These genotypes matched with 2 distinct melting peaks with specified T_ms at 85.8°C and 88.6°C, which indicated genetic variation among Cystoisospora isolates in Egypt. Genotype II proved to be more prevalent (65.6%). HIV-related Kaposi sarcoma and leukemic patients harbored both genotypes with a tendency to genotype II. Genotype I was more prevalent in lymphomas and mammary gland tumors while colorectal and hepatocellular tumors harbored genotype II suggesting that this genotype might be responsible for the development of cystoisosporiasis in immunocompromised patients. Direct reliable identification and differentiation of Cystoisospora species could be established using qPCR-T_ms analysis which is useful for rapid detection and screening of Cystoisospora genotypes principally in high risk groups.

Multiple identification of most important waterborne protozoa in surface water used for irrigation purposes by 18S rRNA amplicon-based metagenomics

Understanding waterborne protozoan parasites (WPPs) diversity has important implications in public health. In this study, we evaluated a NGS-based method as a detection approach to identify simultaneously most important WPPs using 18S rRNA high-throughput sequencing. A set of primers to target the V4 18S rRNA region of WPPs such as Cryptosporidium spp., Giardia sp., Blastocystis sp., Entamoeba spp, Toxoplasma sp. and free-living amoebae (FLA) was designed. In order to optimize PCR conditions before sequencing, both a mock community with a defined composition of representative WPPs and a real water sample inoculated with specific WPPs DNA were prepared. Using the method proposed in this study, we have detected the presence of Giardia intestinalis, Acanthamoeba castellanii, Toxoplasma gondii, Entamoeba histolytica and Blastocystis sp. at species level in real irrigation water samples. Our results showed that untreated surface irrigation water in open fields can provide an important source of WPPs. Therefore, the methodology proposed in this study can establish a basis for an accurate and effective diagnostic of WPPs to provide a better understanding of the risk associated to irrigation water.

2015 Outbreak of Cyclosporiasis Linked to the Consumption of Imported Sugar Snap Peas in Ontario, Canada

An outbreak of cyclosporiasis in Ontario, Canada, was investigated in the fall of 2015. Thirty-five confirmed and 10 probable cases were linked to the investigation. Epidemiological and food safety evidence implicated fresh sugar snap peas imported from Guatemala as the source of the outbreak. We describe here the first documented cyclosporiasis outbreak in Canada involving the consumption of sugar snap peas.

Parasitemia due to Sarcocystis neurona-like infection in a clinically ill domestic cat

An 8-year-old, 6-kg, male neutered Domestic Shorthair cat was presented to The Ohio State University Veterinary Medical Center (OSU-VMC) for difficulty breathing. Physical examination and thoracic radiographs indicated pneumonia, a soft-tissue mass in the left caudal lung lobe, and diffuse pleural effusion. The effusion was classified as modified transudate. Rare extracellular elongated (~5-7 μm × 1-2 μm) zoites with a central round to oval-shaped purple to deep purple vesicular nucleus with coarsely stippled chromatin and light blue cytoplasm were seen on a peripheral blood smear. Serum IgG and IgM were positive for Sarcocystis sp. antibodies and negative for Toxoplasma gondii antibodies, suggesting that the infection was acute rather than a recrudescence of prior infection. This organism was most consistent with either Sarcocystis neurona or Sarcocystis dasypi based on DNA sequence analysis of PCR products using COC ssRNA, ITS-1, snSAG2, and JNB25/JD396 primer sets. This is the first report to visualize by light microscopy circulating Sarcocystis sp. merozoites in the peripheral blood of a domestic cat. Therefore, Sarcocystis should be considered as a differential diagnosis in cats with suspected systemic protozoal infection.

Detection of Hammondia heydorni DNA in feces collected in and around an Ohio Wildlife Conservation Center

This study aimed to identify DNA attributed to Hammondia heydorni oocysts in the feces of wild canids in and around an Ohio wildlife conservation center. Two hundred and eighty-five wild canid fecal samples were analyzed using PCR with melting curve analysis to detect coccidian DNA. Coccidia-positive samples were further subjected to H. heydorni-specific and N. caninum-specific PCR assays. Samples positive by the H. heydorni-specific assay were additionally analyzed with a PCR assay to distinguish H. heydorni from Hammondia triffittae. Coccidian DNA was detected in 51 of the 285 (17.9%) wildlife samples. H. heydorni DNA was detected in three of the coccidia-positive wildlife samples (1.1%) and N. caninum was detected in none. Determining the presence of H. heydorni in wild canids will contribute to a greater understanding of the role these hosts play in the ecology of this parasite.

Identification and discrimination of Toxoplasma gondii, Sarcocystis spp., Neospora spp., and Cryptosporidium spp. by righ-resolution melting analysis

The objective of this study was to standardize the high-resolution melting method for identification and discrimination of Toxoplasma gondii, Sarcocystis spp., Neospora spp., and Cryptosporidium spp. by amplification of 18S ribosomal DNA (rDNA) using a single primer pair. The analyses were performed on individual reactions (containing DNA from a single species of a protozoan), on duplex reactions (containing DNA from two species of protozoa in each reaction), and on a multiplex reaction (containing DNA of four parasites in a single reaction). The proposed method allowed us to identify and discriminate the four species by analyzing the derivative, normalized, and difference melting curves, with high reproducibility among and within the experiments, as demonstrated by low coefficients of variation (less than 2.2% and 2.0%, respectively). This is the first study where this method is used for discrimination of these four species of protozoa in a single reaction.

Sarcocystis neurona manipulation using culture-derived merozoites for bradyzoite and sporocyst production

Equine protozoal myeloencephalitis (EPM) remains a significant central nervous system disease of horses in the American continents. Sarcocystis neurona is considered the primary causative agent and its intermediate life stages are carried by a wide host-range including raccoons (Procyon lotor) in North America. S. neurona sarcocysts mature in raccoon skeletal muscle and can produce central nervous system disease in raccoons, mirroring the clinical presentation in horses. The study aimed to develop laboratory tools whereby the life cycle and various life stages of S. neurona could be better studied and manipulated using in vitro and in vivo systems and compare the biology of two independent isolates. This study utilized culture-derived parasites from S. neurona strains derived from a raccoon or from a horse to initiate raccoon infections. Raccoon tissues, including fresh and cryopreserved tissues, were used to establish opossum (Didelphis virginiana) infections, which then shed sporocyts with retained biological activity to cause encephalitis in mice. These results demonstrate that sarcocysts can be generated using in vitro-derived S. neurona merozoites, including an isolate originally derived from a naturally infected horse with clinical EPM. This study indicates the life cycle can be significantly manipulated in the laboratory without affecting subsequent stage development, allowing further purification of strains and artificial maintenance of the life cycle.

Detection of Toxoplasma gondii DNA by qPCR in the feces of a cat that recently ingested infected prey does not necessarily imply oocyst shedding

Detection of Toxoplasma gondii DNA in cat feces is considered indicative of the presence of T. gondii oocysts. This study aims to demonstrate that the high sensitivity of qPCR can lead to T. gondii DNA detection in cat feces in the absence of oocysts. A cat immune to toxoplasmosis was fed with a mouse experimentally infected with T. gondii. Detection of DNA of this parasite was performed by qPCR on feces passed: (i) on the day the cat ingested the infected prey; (ii) during the three previous days; and (iii) during the three following days. The kinetics of qPCR results are clearly not linked to oocyst shedding and this result demonstrates that qPCR can detect T. gondii DNA related to bradyzoites from an infected prey, in the absence of oocysts. Caution is thus recommended when interpreting T. gondii qPCR results for samples of cat feces.

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

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

Multi-scale occupancy approach to estimate Toxoplasma gondii prevalence and detection probability in tissues: an application and guide for field sampling

Increasingly, birds are recognised as important hosts for the ubiquitous parasite Toxoplasma gondii, although little experimental evidence exists to determine which tissues should be tested to maximise the detection probability of T. gondii. Also, Arctic-nesting geese are suspected to be important sources of T. gondii in terrestrial Arctic ecosystems, but the parasite has not previously been reported in the tissues of these geese. Using a domestic goose model, we applied a multi-scale occupancy framework to demonstrate that the probability of detection of T. gondii was highest in the brain (0.689, 95% confidence interval=0.486, 0.839) and the heart (0.809, 95% confidence interval=0.693, 0.888). Inoculated geese had an estimated T. gondii infection probability of 0.849, (95% confidence interval=0.643, 0.946), highlighting uncertainty in the system, even under experimental conditions. Guided by these results, we tested the brains and hearts of wild Ross's Geese (Chen rossii, n=50) and Lesser Snow Geese (Chen caerulescens, n=50) from Karrak Lake, Nunavut, Canada. We detected 51 suspected positive tissue samples from 33 wild geese using real-time PCR with melt-curve analysis. The wild goose prevalence estimates generated by our multi-scale occupancy analysis were higher than the naïve estimates of prevalence, indicating that multiple PCR repetitions on the same organs and testing more than one organ could improve T. gondii detection. Genetic characterisation revealed Type III T. gondii alleles in six wild geese and Sarcocystis spp. in 25 samples. Our study demonstrates that Arctic nesting geese are capable of harbouring T. gondii in their tissues and could transport the parasite from their southern overwintering grounds into the Arctic region. We demonstrate how a multi-scale occupancy framework can be used in a domestic animal model to guide resource-limited sample collection and tissue analysis in wildlife. Secondly, we confirm the value of traditional occupancy in optimising T. gondii detection probability in tissue samples.

Wide genetic variations at 18S ribosomal RNA locus of Cyclospora cayetanensis isolated from Egyptian patients using high resolution melting curve

A variable clinical picture of cyclosporiasis including gastrointestinal tract (GIT) symptomatic or asymptomatic beside extraintestinal consequences suggests a possibility of heterogenicity of Cyclospora cayetanensis. The present work aimed to explore the possibility of genetic variation of C. cayetanensis using high-resolution melting (HRM) curve of polymerase chain reaction (PCR) amplified 18S rRNA genes. DNAs extracted from the stool samples of 70 cyclosporiasis patients were amplified and scanned by PCR/HRM curve. The results showed that there are four different genotypic profiles of C. cayetanensis with presence of mixed ones. Although Tm of all profiles was within the same range, they were discerned by plotting of the temperature-shifted florescence difference between normalized melting curves (dF/dT). Genotypic profile I was found alone in 40 % of patients and mixed with genotypic profile II and/or III in 25.7 % of patients, followed by genotypic profile II in 14.3 % then genotypic profile III and IV (10 % each). A significant relation was found between genotypic profiles and GIT symptomatic status as profile I and profile II were mostly detected in patients with acute GIT symptoms without or with chronic illness, respectively, while profile IV cases only were GIT asymptomatic. Statistical significance relations between genotypic profiles and age, gender, residence and oocyst shape index were determined. In conclusion, PCR/HRM proved a wide variation on C. cayetanensis genes that could be reflected on its pathogenic effects and explaining the variability of the clinical manifestations presented by cyclosporiasis patients.

Pervasive Environmental Contamination with Human Feces Results in High Prevalence of Zoonotic Sarcocystis Infection in Pigs in the Punjab, India

Three species of Sarcocystis-S. miescheriana, S. suihominis, and S. porcifelis-have been recorded from pigs ( Sus scrofa ). Among these 3 species, the zoonotic species S. suihominis is of paramount importance and an important food safety issue. Previous studies indicate prevalence of porcine Sarcocystis species in India, but molecular evidence, among other evidence, is required for proper species differentiation. Myocardium from 250 stray and farm pigs destined for slaughter for human consumption were collected from slaughter shops located in urban slums in Punjab, northern India. Tissues were examined for Sarcocystis by using an intact cyst isolation method, pepsin acid digestion, Sarcocystis 18S ribosomal RNA polymerase chain reaction (PCR), and real-time quantitative PCR with melting curve analysis (qPCR-MCA). The combination of primers was used for 18S rRNA PCR amplification followed by sequencing. Ten representative samples were sequenced in both the directions from which 7 readable sequences were obtained for phylogenetic analysis. Sarcocystis cysts/zoites were recorded in 146 (58.4%), 169 (67.6%), 182 (72.8%), and 191 (76.4%) of samples by using intact cyst isolation, pepsin HCl digestion, conventional PCR, and qPCR-MCA, respectively. Molecularly, 1 S. miescheriana isolate and 6 isolates of the zoonotic species S. suihominis were recorded. This is the first study providing molecular identification for the presence of zoonotic species S. suihomonis in India. The prevalence of zoonotic S. suihominis in pork in India is worrisome and warrants intervention policies to stop the practice of rearing pigs under unhygienic conditions.

Quantitative real-time PCR (qPCR) for Eimeria tenella replication--Implications for experimental refinement and animal welfare

The Eimeria species are highly pathogenic parasites of chickens. Research aimed at reducing their impact is hindered by a lack of non-subjective, quantitative, tools to measure parasite replication in the host. The time-consuming, and often time-sensitive, nature of existing approaches precludes their use in large-scale genetic, epidemiological, and evolutionary analyses. We have used quantitative real-time PCR (qPCR) to accurately quantify Eimeria tenella in chicken tissue and shown this to be more efficient and sensitive than traditional methodologies. We tested four chicken-specific reference qPCR assays and found beta-actin (actb) to be optimal for sample normalisation. In an experimental setting, chickens were inoculated with 500, 1500, or 4500 E. tenella oocysts and parasite replication and the impact of infection measured by i) qPCR analysis of DNA extracted from caecal tissues collected at five and eight days post-infection (dpi), ii) faecal oocyst counts (FOCs) on samples taken from six to eight dpi, and iii) lesion scoring on caeca collected post-mortem at five and eight dpi. Quantitative real-time PCR test results indicated a significant dose-dependent increase in parasite numbers among study groups for samples collected five dpi (i.e., prior to gametogony) (R² = 0.994) (p < 0.002) but not in those from day eight (after most oocyst shedding) (R² = 0.006) (p > 0.379). A strong dose-dependent increase in parasite replication and severity of infection was also revealed by FOC (R² = 0.997) and lesion scoring. Importantly, qPCR offers substantial improvements for animal welfare via improved statistical power and reduced group sizes in experimental studies. The described qPCR method overcomes subjective limitations of coproscopic quantification, allows reproducible medium- to high-throughput examination of tissues, faeces, and oocysts, and is a valuable tool for determining the impact of Eimeria infections in both experimental and field settings.

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Quantitative PCR indicates significant dose-dependent increases in parasites.

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More sensitive measure of parasite replication than faecal oocyst count/lesion score

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Significant implications for animal welfare and experiment refinement (3R's)

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Support studies focusing on the genetic basis of resistance/susceptibility

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Major implications for investigations of key aspects of Eimeria biology and control

Mini-FLOTAC for counting Toxoplasma gondii oocysts from cat feces--comparison with cell counting plates

Oocysts of Toxoplasma gondii represent one of the most common environmental contaminants causing the zoonotic infection toxoplasmosis. The aim of the present study was to compare the Mini-FLOTAC device with traditional cell counting plates (Kova Slide) for the detection of T. gondii oocysts from feline feces. Two types of experiments were performed: (i) purified oocysts were counted in different dilutions and (ii) specific pathogen free T. gondii-negative cat feces was inoculated with numbers of purified oocysts and counting was performed directly from feces. Our analysis showed a thousand times higher sensitivity of Mini-FLOTAC (5 × 10(2) oocysts) compared to Kova Slide (5 × 10(5) oocysts). Also, when compared by McNemar's test, counting of the purified oocysts showed a higher sensitivity of Mini-FLOTAC compared to Kova Slide, for a dilution of 10(3) oocysts/ml (chi(2) = 6.1; P < 0.05). A better sensitivity was also found with Mini-FLOTAC in dilutions of 10(5) and 10(4) oocysts/ml, when counted from feces (chi(2) = 4.2 and 8.1, respectively, P < 0.05). Our results show that Mini-FLOTAC is more sensitive than traditional methods of T. gondii oocysts detection and quantification is more accurate. Furthermore, Mini-FLOTAC simplicity and cost effectiveness allow it to be used with light microscopes in any laboratory or field conditions. We therefore recommend its use for regular screening. Further studies are needed to validate Mini-FLOTAC for the detection of oocysts in soil and water samples in field conditions.

Application of PCR-based methods for diagnosis of intestinal parasitic infections in the clinical laboratory

For many years PCR- and other DNA-based methods of pathogen detection have been available in most clinical microbiology laboratories; however, until recently these tools were not routinely exploited for the diagnosis of parasitic infections. Laboratories were initially reluctant to implement PCR as incorporation of such assays within the algorithm of tools available for the most accurate diagnosis of a large variety of parasites was unclear. With regard to diagnosis of intestinal parasitic infections, the diversity of parasites that one can expect in most settings is far less than the parasitological textbooks would have you believe, hence developing a simplified diagnostic triage is feasible. Therefore the classical algorithm based on population, patient groups, use of immuno-suppressive drugs, travel history etc. is also applicable to decide when to perform and which additional techniques are to be used, if a multiplex PCR panel is used as a first-line screening diagnostic.

A selective review of advances in coccidiosis research

Coccidiosis is a widespread and economically significant disease of livestock caused by protozoan parasites of the genus Eimeria. This disease is worldwide in occurrence and costs the animal agricultural industry many millions of dollars to control. In recent years, the modern tools of molecular biology, biochemistry, cell biology and immunology have been used to expand greatly our knowledge of these parasites and the disease they cause. Such studies are essential if we are to develop new means for the control of coccidiosis. In this chapter, selective aspects of the biology of these organisms, with emphasis on recent research in poultry, are reviewed. Topics considered include taxonomy, systematics, genetics, genomics, transcriptomics, proteomics, transfection, oocyst biogenesis, host cell invasion, immunobiology, diagnostics and control.

Application of a qPCR assay with melting curve analysis for detection and differentiation of protozoan oocysts in human fecal samples from Dominican Republic

A quantitative polymerase chain reaction assay with melt curve analysis (qPCR-MCA) was applied for the detection of protozoan oocysts in 501 human fecal samples collected in Dominican Republic. Samples were subjected to qPCR using universal coccidia primers targeting 18S rDNA to detect oocysts followed by MCA to identify oocyst species based on amplicon melting temperature. Putative positive samples were also tested by conventional PCR and microscopy. Cystoisospora belli (×3), Cryptosporidium parvum (×3), Cryptosporidium hominis (×5), Cryptosporidium meleagridis (×1), Cryptosporidium canis (×1), and Cyclospora cayetanensis (×9) were detected by qPCR-MCA and confirmed by sequencing. This assay consistently detected 10 copies of the cloned target fragment and can be considered more efficient and sensitive than microscopy flotation methods for detecting multiple species of oocysts in human feces. The qPCR-MCA is a reliable protozoan oocyst screening assay for use on clinical and environmental samples in public health, food safety and veterinary programs.

Looking for Cryptosporidium: the application of advances in detection and diagnosis

The protozoan Cryptosporidium is a major public and animal health concern. Young children, immunocompromised people, and pre-weaning animals are especially vulnerable, but treatment options are limited and there is no vaccine. A laboratory diagnosis is required to confirm cases of cryptosporidiosis, and species and genotype determination is essential in distinguishing human from non-human sources, understanding transmission, and strengthening the epidemiological evidence for causative links in outbreaks. However, testing is not consistent, as demonstrated by investigation of a significant increase in cases in some European countries during 2012. Many methods employed are laborious and time-consuming; recent advances, translated into diagnostic assays, can improve testing and facilitate typing to support clinical and environmental investigations.

Endoparasites in the feces of arctic foxes in a terrestrial ecosystem in Canada

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Few studies report the endoparasites of North American arctic foxes.

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Conventional, immunological, and molecular techniques detected parasites in arctic foxes at Karrak Lake, Nunavut.

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Karrak Lake foxes are infected with common parasites of foxes with a terrestrial diet.

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This study provides a comparison for future studies from the central Canadian Arctic.

The parasites of arctic foxes in the central Canadian Arctic have not been well described. Canada’s central Arctic is undergoing dramatic environmental change, which is predicted to cause shifts in parasite and wildlife species distributions, and trophic interactions, requiring that baselines be established to monitor future alterations. This study used conventional, immunological, and molecular fecal analysis techniques to survey the current gastrointestinal endoparasite fauna currently present in arctic foxes in central Nunavut, Canada. Ninety-five arctic fox fecal samples were collected from the terrestrial Karrak Lake ecosystem within the Queen Maud Gulf Migratory Bird Sanctuary. Samples were examined by fecal flotation to detect helminths and protozoa, immunofluorescent assay (IFA) to detect Cryptosporidium and Giardia, and quantitative PCR with melt-curve analysis (qPCR-MCA) to detect coccidia. Positive qPCR-MCA products were sequenced and analyzed phylogenetically. Arctic foxes from Karrak Lake were routinely shedding eggs from Toxascaris leonina (63%). Taeniid (15%), Capillarid (1%), and hookworm eggs (2%), Sarcocystis sp. sporocysts 3%), and Eimeria sp. (6%), and Cystoisospora sp. (5%) oocysts were present at a lower prevalence on fecal flotation. Cryptosporidium sp. (9%) and Giardia sp. (16%) were detected by IFA. PCR analysis detected Sarcocystis (15%), Cystoisospora (5%), Eimeria sp., and either Neospora sp. or Hammondia sp. (1%). Through molecular techniques and phylogenetic analysis, we identified two distinct lineages of Sarcocystis sp. present in arctic foxes, which probably derived from cervid and avian intermediate hosts. Additionally, we detected previously undescribed genotypes of Cystoisospora. Our survey of gastrointestinal endoparasites in arctic foxes from the central Canadian Arctic provides a unique record against which future comparisons can be made.

Detection of Cyclospora, Cryptosporidium, and Giardia in ready-to-eat packaged leafy greens in Ontario, Canada

Numerous foodborne outbreaks of diarrheal illness associated with the consumption of produce contaminated with protozoan parasites have been reported in North America in recent years. The present study reports on the presence of Cyclospora, Cryptosporidium, and Giardia in precut salads and leafy greens purchased at retail in Ontario, Canada. A total of 544 retail samples were collected between April 2009 and March 2010 and included a variety of salad blends and individual leafy greens. Most of these products were grown in the United States, with some from Canada and Mexico. Parasites were eluted and concentrated before detection by PCR and immunofluorescence microscopy. DNA sequences were aligned with reference sequences in GenBank. Cyclospora spp. were identified by PCR-restriction fragment length polymorphism in nine (1.7 % ) samples and by DNA sequence analysis. Cryptosporidium spp. were identified in 32 (5.9%) samples; 29 were sequenced and aligned with the zoonotic species Cryptosporidium parvum. Giardia duodenalis was identified in 10 (1.8%) samples, and of the 9 samples successfully sequenced, 7 aligned with G. duodenalis assemblage B and 2 with assemblage A, both of which are also zoonotic. The presence of Cryptosporidium oocysts and Giardia cysts was confirmed in some of the PCR-positive samples using microscopy, while Cyclospora -like oocysts were observed in most of the Cyclospora PCR-positive samples. The relatively high prevalence of these parasites in packaged salads and leafy greens establishes a baseline for further studies and suggests a need for additional research with respect to the possible sources of contamination of these foods, the determination of parasite viability and virulence, and means to reduce foodborne transmission to humans.