ABSTRACT
Cyclospora cayetanensis es un protozoo coccidio con diversa prevalencia a nivel mundial que causa cuadros con diarrea acuosa y voluminosa tanto en pacientes inmunocompetentes como inmunocomprometidos. En estos últimos, además de producir cuadros entéricos más severos, puede cursar con compromisos biliares. Su distribución es cosmopolita, jugando un rol importante en su transmisión, el suelo, el agua y los alimentos contaminados, especialmente las verduras ingeridas crudas. El hombre, único reservorio constatado hasta el presente, elimina con las heces ooquistes inmaduros, que evolucionan en el ambiente transformándose en ooquistes maduros infectivos. Como otros coccidios, presenta un ciclo evolutivo complejo con formas sexuada y asexuada de reproducción en un único hospedador. El diagnóstico se basa fundamentalmente en el hallazgo de ooquistes ácido alcohol resistentes variables en materia fecal. Se han desarrollado métodos moleculares para su detección tanto en muestras fecales como ambientales y de alimentos.
Cyclospora cayetanensis is a coccidian protozoon with several prevalence worldwide that causes watery and voluminous diarrhea conditions both in immunocompetent and immunocompromised patients. In the latter, apart from originating more severe enteric diseases, it can occur with billiary involvement. Its distribution is cosmopolitan, with soil, water and contaminated food, especially consumption of raw vegetables, playing an important role in its transmission. Man, the only reservoir recorded so far, eliminates immature oocytes in feces, which evolve in the environment becoming infective- mature oocytes. Like other coccidians, it presents a complex evolutionary cycle with sexed and unsexed forms of reproduction in a single host. Diagnosis is mainly based on findings of variable acid-alcohol resistant variables in feces. Molecular methods have been developed for its detection in fecal samples and in environmental and food samples as well.
Cyclospora cayetanensis é um protozoo coccídio com diversa prevalência em nível mundial que causa quadros com diarreia aquosa e volumosa tanto em pacientes imunocompetentes como imunocomprometidos. Nestes últimos, além de produzir quadros entéricos mais severos, pode cursar com compromissos biliares. Sua distribuição é cosmopolita, tendo um papel importante na sua transmissão o solo, a água e os alimentos contaminados, especialmente as verduras ingeridas cruas. O homem, único reservatório constatado até o presente, elimina com as fezes oocistos imaturos, que evoluem no ambiente transformando-se em oocistos maduros infectivos. Como outros coccídios apresenta um ciclo evolutivo complexo com formas sexuada e assexuada de reprodução num único hospedeiro. O diagnóstico se baseia fundamentalmente no achado de oocistos ácido-álcool resistentes variáveis em matéria fecal. Foram desenvolvidos métodos moleculares para sua detecção tanto em amostras fecais quanto ambientais e de alimentos.
Subject(s)
Cyclospora/parasitology , Cyclosporiasis/diagnosis , Coccidia , Coccidiostats , Cyclosporiasis/therapyABSTRACT
Forty nine stool specimens collected from severe diarrheic patients. Eight were suffering from Hodgkin's lymphoma, and the rest were suffering from acute lymph plastic leukaemia. All were examined microscopically for protozoan parasites mainly, Cryptosporidium parvum and Cyclospora cayetanensis. Of the patients, 34 [69.4%] were positive and 15 [30.6%] were negative by both microscopy and nested PCR. An additional 12 [24.5%] who were negative by microscopy were positive by nested PCR. Stool examination revealed 16 cases with C. parvum, and 6 with C. cayetanensis, and 3 cases showed mixed infection. The results were compared with the established nested PCR assay to detect DNA directly from stool specimens. The patients <3 years old more affected by Cryptosporidium infection, unlike Cyclospora sp. Infection was in older age groups, which reflected the modes of parasite' transmission. Diarrheal illness was stronger for Cyclospora than for Cryptosporidium. After the extraction of DNA from stool, a 402-bp fragment of C. parvum, and 602 bp fragment of C. cayetanensis was amplified. The amplified products, 194-bp DNA fragment for C. parvum, and 306 bp DNA fragment of C. cayetanensis were used for the second run. This study indicated that primers were specific for DNA of C. parvum and C. cayetanensis. PCR detected a total of 22 [44.9%] positives for C. parvtim infection [6 negative by AF stool examination], and 12[24.5%] positives for C. cayetanensis. Infection [6 negative by AF stool examination], 7[14.3%] showed mixed infection [4 negative by AF stool examination], all microscopic negative specimens were positive by successive stool examination. Microscopy exhibited sensitivity of 72.7% for C. parvwn, 50% for C. cayetanensis and 100% specificity for both parasites compared to 100% sensitivity and specificity with PCR. So, PCR is more sensitive and easier to interpret but required more hands-on time to perform and is more expensive. However, PCR batch analysis reduces the cost considerably