Transposable elements are DNA sequences present in all the large phylogenetic groups, both capable of changing position within the genome and constituting a significant part of eukaryotic genomes. The mariner family of transposons is one of the few which occurs in a wide variety of taxonomic groups, including freshwater planarians. Nevertheless, so far only five planarian species have been reported to carry mariner-like elements (MLEs), although several different species have been investigated. Regarding the number of copies of MLEs, Girardia tigrina is the only planarian species in which this has been evaluated, with an estimation of 8,000 copies of the element per haploid genome. Preliminary results obtained in our laboratory demonstrated that MLE is found in a large number of different species of planarians, including terrestrial. With this in mind, the aim was to evaluate the occurrence and estimate the number of MLE copies in different planarian species collected in south Brazil. Twenty-eight individuals from 15 planarian species were analyzed. By using PCR and the hybridization of nucleic acids, it was found that MLE was present in all the analyzed species, the number of copies being high, probably over 10³ per haploid genome.

Summary Faecal material from children aged zero to 5 years old with diagnosed GEA at one hospital in Manaus was studied through electron microscopy and enzime immunoassay. Samples were collected before any medical treatment was to be applied at the hospital. Out of 29 cases studied 12 showed positivity for rotavirus (41,4%). Out of the 29 cases studied 48,3% were treated with isolated rehydration, 31,0% with antibiotic therapy and 20,7% with chemotherapy. Out of the 12 positive cases 3 were treated with antibiotics and 3 with chemotherapy. Greater frequency of rotavirus was found to occur between zero to 12 months old children. Within this range of age the greater number of GEA and rotavirus cases was detected between the 7th and the 12th month.