In part, Cyclospora cayetanensis owes its recognition as an emerging pathogen to the increased use of staining methods for detecting enteric parasites such as Cryptosporidium. First reported in patients in New Guinea in 1977 but thought to be a coccidian parasite of the genus Isospora, C. cayetanensis received little attention until it was again described in 1985 in New York and Peru. In the early 1990s, human infection associated with waterborne transmission of C. cayetanensis was suspected; foodborne transmission was likewise suggested in early studies. The parasite was associated with several disease outbreaks in the United States during 1996 and 1997. This article reviews current knowledge about C. cayetanensis (including its association with waterborne and foodborne transmission), unresolved issues, and research needs. (+info)
Cyclosporiasis: clinical and histopathologic correlates.
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Although the histopathologic changes associated with Cyclospora cayetanensis infection have been previously described, the histopathology and the appearance of various life cycle stages have not been correlated with severity, stage, and duration of clinical disease. We report a prospective clinical investigation of disease characteristics and histopathologic findings in three otherwise healthy, immunocompetent patients with symptomatic C. cayetanensis infection, the duration of which ranged from 6 to 60 days. Varying degrees of gross and microscopic gastrointestinal inflammation were seen before treatment. An electron-dense phospholipid membrane/myelin-like material was variably present both before and after treatment. The greatest amount of myelin-like material was seen in the patient with prolonged disease. The results of our study suggest that inflammatory changes associated with C. cayetanensis infection may persist beyond parasite eradication. It is intriguing to speculate that the myelin-like material is a marker for persistent inflammation, but further study and confirmation are needed. (+info)
Morphologic and molecular characterization of new Cyclospora species from Ethiopian monkeys: C. cercopitheci sp.n., C. colobi sp.n., and C. papionis sp.n.
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In recent years, human cyclosporiasis has emerged as an important infection, with large outbreaks in the United States and Canada. Understanding the biology and epidemiology of Cyclospora has been difficult and slow and has been complicated by not knowing the pathogen s origins, animal reservoirs (if any), and relationship to other coccidian parasites. This report provides morphologic and molecular characterization of three parasites isolated from primates and names each isolate: Cyclospora cercopitheci sp.n. for a species recovered from green monkeys, C. colobi sp.n. for a parasite from colobus monkeys, and C. papionis sp.n. for a species infecting baboons. These species, plus C. cayetanensis, which infects humans, increase to four the recognized species of Cyclospora infecting primates. These four species group homogeneously as a single branch intermediate between avian and mammalian Eimeria. Results of our analysis contribute toward clarification of the taxonomic position of Cyclospora and its relationship to other coccidian parasites. (+info)
Extraction-free, filter-based template preparation for rapid and sensitive PCR detection of pathogenic parasitic protozoa.
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Within the last several years, the protozoan parasites Cyclospora cayetanensis, Cryptosporidium parvum, and microsporidia have become recognized as important, rapidly emerging human pathogens in immunocompromised and immunocompetent individuals. Since the early 1990s, many of the reported outbreaks of enteric illness caused by these microorganisms have been attributed to food- and water-borne contamination. Many inherent obstacles affect the success of current surveillance and detection methods used to monitor and control levels of contamination by these pathogens. Unlike methods that incorporate preenrichment for easier and unambiguous identification of bacterial pathogens, similar methods for the detection of parasitic protozoa either are not currently available or cannot be performed in a timely manner. We have developed an extraction-free, filter-based protocol to prepare DNA templates for use in PCR to identify C. cayetanensis and C. parvum oocysts and microsporidia spores. This method requires only minimal preparation to partially purify and concentrate isolates prior to filter application. DNA template preparation is rapid, efficient, and reproducible. As few as 3 to 10 parasites could be detected by PCR from direct application to the filters. In studies, as few 10 to 50 Encephalitozoon intestinalis spores could be detected when seeded in a 100-microliter stool sample and 10 to 30 C. cayetanensis oocysts could be detected per 100 g of fresh raspberries. This protocol can easily be adapted to detect parasites from a wide variety of food, clinical, and environmental samples and can be used in multiplex PCR applications. (+info)
A gel delivery system for coccidiosis vaccine: uniformity of distribution of oocysts.
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A patented gel delivery system being used to deliver coccidiosis vaccine to poultry hatchlings is assessed. For effective vaccination, the coccidial oocysts must be uniformly suspended before exposure to birds. The uniformity of distribution within the gel was evaluated by incorporating a culture of chicken gut flora into gel sausages, placing sections of the sausage on culture plates, determining the appearance and distribution of bacterial colonies on culture plates after incubation, and verifying by cell counts. The uniformity of distribution of similarly prepared coccidial oocysts was verified by infecting birds with 40,000 Eimeria tenella oocysts delivered via the gel. Gel-inoculated birds were compared with control birds inoculated PO with 40,000 oocysts suspended in water by using cecal lesion scores. Both the appearance and colony counts of chicken gut flora from the gel were uniform. The standard deviation in the lesion scores for the gel-inoculated group and the water-inoculated groups were 0.51 and 0.69, respectively. The results indicate that a gel delivery system can provide uniform distribution of live organisms and vaccine agents to birds. (+info)
An indirect enzyme-linked immunosorbent assay for diagnosis of American canine hepatozoonosis.
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American canine hepatozoonosis (ACH), caused by Hepatozoon americanum, is an emerging tick-borne disease of dogs. An indirect enzyme-linked immunosorbent assay (ELISA) that should facilitate diagnosis of infection and study of the epidemiology of ACH has been developed using H. americanum sporozoites as antigen. Efficacy of the new test as a diagnostic tool was compared with that of skeletal muscle biopsy, the current gold standard for confirming H. americanum infection. Results show that the test is sensitive (93%) and specific (96%) and that it is as reliable as histopathologic examination of skeletal muscle for detecting infection. The ELISA would be suitable as a routine laboratory test for diagnosis of ACH. (+info)
On the current existence of a coccidial line of development in the malaria parasites: a theory.
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Most opinion favors the origin of the malaria parasites from a coccidial ancestor. It is assumed that whatever the process through which the coccidia differentiated into a Plasmodium this phenomenon very probably occurred millions of year ago, and during that differentiation process the original coccidia vanished. Therefore it has never been repeated. At the light of some experiments the existence, at the present time, of a coccidial cycle of development in the malaria parasites, is proposed. The connection routes and mechanisms through which the malaria parasite changes to a coccidial life, and the routes in reverse are exposed. Transmission of the malaria-coccidial forms is suggested. (+info)
Parasitology: United Kingdom National Quality Assessment Scheme.
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AIMS: To assess the results from parasitology laboratories taking part in a quality assessment scheme between 1986 and 1991; and to compare performance with repeat specimens. METHODS: Quality assessment of blood parasitology, including tissue parasites (n = 444; 358 UK, 86 overseas), and faecal parasitology, including extra-intestinal parasites (n = 205; 141 UK, 64 overseas), was performed. RESULTS: Overall, the standard of performance was poor. A questionnaire distributed to participants showed that a wide range of methods was used, some of which were considered inadequate to achieve reliable results. Teaching material was distributed to participants from time to time in an attempt to improve standards. CONCLUSIONS: Since the closure of the IMLS fellowship course in 1972, fewer opportunities for specialised training in parasitology are available: more training is needed. Poor performance in the detection of malarial parasites is mainly attributable to incorrect speciation, misidentification, and lack of equipment such as an eyepiece graticule. (+info)