Isosporose humana: Considerações sobre 28 casos

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Abstract
The authors report the finding of twenty-eight cases of human infection with coccidia belonging to the genus Isospora. These cases were found in 22.836 stools examination from December, 1942, through June 1950. The material was divided in two groups: the first (table 1) composed by 15 cases in which the parasite was identified as Isospora hominis (Raillet and Lucet 1891). In the second group (table 2) were included the others 13 cases in which the coccidium was identified as Isospora belli Wenyon 1923. In the first group of this series the coccidium was discharged in the faeces usually as a single sporocyst containing four vermiform sporozoites (illus. 1, 2 and drawing 1). The average size of these sporocysts corresponds to 14.8 microns in the length by 9.8 microns in breadth. Only in three cases ripe oocysts with 2 sporocysts each containing four sporozoites (illus. 3, 4) were found together with the isolated tetrazoic sporocysts.It is important to emphasize that in all these 15 cases the coccidia were discharged in the faeces in the mature stage. On the other hand, in 13 cases of the second group only the unsegmented oocysts were found in the faeces. Rarely oocysts containing two sporoblasts were found in freshly passed faeces. In this group of cases the oocysts are usually unsegmented when discharged in the faeces but in about forty eight hours at room temperatura the sporocysts containing four sporozoites have developed (illus. from 5 to 12 and drawings 2, 3). Therefore, differently of which occurs in the cases included in the first group, it is in the external medium that oocyst complete its development. The average size found for the oocysts was 28.3 microns in the length by 13.5microns in the breadth. The average size of the sporocysts correspond to 12.9 microns in length by 10 microns in breadth. After a brief discussion on the nomenclature of the coccidia of man and others comments suggested by their findings, the authors conclude that: 1) Man is infected by two species of coccidia of the genus Isospora; 2) These species are respectivelly: Isospora hominis (Raillet and Lucet 1891) and Isospora belli Wenyon 1923; 3) In spite of the morphological resemblance between Isospora hominis found in man and Isospora bigemina Stiles 1878 which parasites dogs, was not proved yet that they are identical; 4) In the material studied it was not possible to demonstrate the pathogenic action of Isospora hominis in the man, as either the clinical symptoms were absent or occurred together with other intestinal parasitosis;5) Referring to the infection by Isospora belli, in their material, the authors observed the three following possibilities: a) the presence of Isospora belli without any clinical symptoms; b) the presence of gastrointestinal symptoms which might have been credited to other coexisting parasites; c) the presence of enteric symptoms caused by Isospora belli infection. Os autores relatam o encontro de 28 casos de infecção humana por coccídeos do gênero Isospora em 22.836 exames parasitológicos de fezes, realizados no período de dezembro de 1942 a junho de 1950. O material foi subdividido em dois grupos: o 1.o constituído por 15 casos nos quais identificaram como espécie a Isospora hominis. No 2.° grupo, constante dos 13 casos restantes, o parasito encontrado foi reconhecido como sendo a Isospora belli Wenyon 1923. Nos casos incluídos no 1.o grupo o coccídeo encontrado apresentava-se sempre sob a forma de esporocistos tetrazóicos, cujas dimensões médias foram de 14,8µ x 9,8µ. Em três casos, porém, ao lado de esporocistos tetrazóicos isolados, foi verificada a ocorrência de dois esporocistos tetrazóieos justapostos um ao outro. Nos 13 casos do segundo grupo, foram encontrados nas fezes recentemente emitidas oocistos com esporoblastos que, no meio exterior, evoluíam para esporocistos tetrazóicos. Nestes casos as dimensões médias eram, para os oocistos, 28,3µ x 13,5µ e para os esporocistos, 12,9µ x 10µ. Os autores expõem num quadro as medidas obtidas para as formas evolutivas encontradas separadamente para cada um dos casos, e ilustram o seu trabalho com várias microfotografias, com as quais procuram demonstrar os fatos expostos no texto. Os autores concluem, de suas observações, que dois são os coccídeos parasitos do homem, e dão as razões pelas quais adotam as denominações de I. hominis e I. belli Wenyon 1923.

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