Os isolados de Giardia duodenalis de indivíduos assintomáticos, de pacientes e de animais apresentam diferenças e semelhanças em sua composição protéica, expressão de antígenos, proteases e isoenzimas, assim como na constituição dos ácidos nucléicos. A presente revisão analisa estas diferenças com ênfase na interação parasita e hospedeiro, e nos possíveis mecanismos de virulência do protozoário.

Giardia duodenalis isolates from asymptomatic or symptomatic patients and from animals present similarities and differences in the protein composition, antigenic profile, pattern of proteases and isoenzymes, as well as in nucleic acids analysis. In the present overview, these differences and similarities are reviewed with emphasis in the host-parasite interplay and possible mechanisms of virulence of the protozoon.

To study the frequency of Blastocystis hominis among healthy individuals, feces were collected from 153 children and 20 staff members of some municipal day-care centers. Three separate stool specimens of each individual were processed by Lutz and Faust methods. From 173 studied individuals, 60 (34.7%) showed B. hominis, frequently in association with other intestinal parasites and/or commensals. B. hominis was found mainly in adults and children between 36 and 72 months old. All positive cases were detected only by Lutz method and the use of three stool specimens increased the positivity of the parasitological diagnostic.

Estudo da prevalência de parasitas intestinais realizado em 370 indivíduos residentes na CECAP, distrito-sede de Botucatu, Estado de São Paulo, permitiu verificar que 41,62% encontravam-se infestados por uma ou mais espécies de parasitas intestinais. Foram encontrados os seguintes parasitas: Entamoeba histolytica 0,54%, E. coli 6,21%, I. butschlii 0,27%, Giardia lamblia 9,72%, Ancylostomidae 5,94%, Strongyloides stercoralis 6,75%, Trichuris trichiura 17,29%, Ascaris lumbricoides 7,56%, Enterobius vermicularis 3,78%, Hymenolepis nana 5,40% e Taenia sp. 1,62%. Apresentam-se dados sobre a distribuição dos parasitas em relação à idade e ao sexo dos indivíduos. O atributo cor não permite maiores considerações por serem os não brancos significantemente pouco numerosos. Dos indivíduos examinados, 25,67% apresentavam apenas uma espécie de parasita e entre as associações parasitárias mais freqüentes encontramos as de Ascaris lumbricoides - Trichuris trichiura e Trichuris trichiura - Giardia lamblia.

A parasitological survey among 370 persons was carried out at CECAP, Botucatu County, S. Paulo State, Brazil. It was found that 41.62% of the examinated persons were infected with one or more species of intestinal parasites. The parasite's prevalence was: Entamoeba hystolytica 0.54%, E. coli 6.21%, I. butschlii 0.27%, Giardia lamblia 9.72%, Ancylostomidae 5.94%, Strongyloide stercoralis 6.75%, Trichuris trichiura 17.29%, Ascaris lumbricoides 7.56%, Enterobius vermicularis 3.78%, Hymenolepis nana 5.40% e Taenia sp. 1.62%. Tables are presented showing the distribution of the parasites according to age and sex. Race was not considered because the number of "not white" was significantly low. Of the examinated persons, 25.67% were infected with only one species of parasite and the parasitic associations most frequently found were Ascaris lumbricoides - Trichuris tricriura and Trichuris trichiura - Giardia lamblia.

Estudo da prevalência de parasitas intestinais realizado em 370 indivíduos residentes na CECAP, distrito-sede de Botucatu, Estado de São Paulo, permitiu verificar que 41,62% encontravam-se infestados por uma ou mais espécies de parasitas intestinais. Foram encontrados os seguintes parasitas: Entamoeba histolytica 0,54%, E. coli 6,21%, I. butschlii 0,27%, Giardia lamblia 9,72%, Ancylostomidae 5,94%, Strongyloides stercoralis 6,75%, Trichuris trichiura 17,29%, Ascaris lumbricoides 7,56%, Enterobius vermicularis 3,78%, Hymenolepis nana 5,40% e Taenia sp. 1,62%. Apresentam-se dados sobre a distribuição dos parasitas em relação à idade e ao sexo dos indivíduos. O atributo cor não permite maiores considerações por serem os não brancos significantemente pouco numerosos. Dos indivíduos examinados, 25,67% apresentavam apenas uma espécie de parasita e entre as associações parasitárias mais freqüentes encontramos as de Ascaris lumbricoides - Trichuris trichiura e Trichuris trichiura - Giardia lamblia.

A parasitological survey among 370 persons was carried out at CECAP, Botucatu County, S. Paulo State, Brazil. It was found that 41.62% of the examinated persons were infected with one or more species of intestinal parasites. The parasite's prevalence was: Entamoeba hystolytica 0.54%, E. coli 6.21%, I. butschlii 0.27%, Giardia lamblia 9.72%, Ancylostomidae 5.94%, Strongyloide stercoralis 6.75%, Trichuris trichiura 17.29%, Ascaris lumbricoides 7.56%, Enterobius vermicularis 3.78%, Hymenolepis nana 5.40% e Taenia sp. 1.62%. Tables are presented showing the distribution of the parasites according to age and sex. Race was not considered because the number of "not white" was significantly low. Of the examinated persons, 25.67% were infected with only one species of parasite and the parasitic associations most frequently found were Ascaris lumbricoides - Trichuris tricriura and Trichuris trichiura - Giardia lamblia.