Showing papers by "Oswaldo Cruz Foundation published in 1979"
118 citations
TL;DR: Since the isoenzyme patterns of a stock isolated from a patient with acute disease were similar to those of a silvatic reservoir, its recent introduction into the domiciliary cycle is postulated.
Abstract: 1. The isoenzyme patterns of four soluble enzymes in seven stocks of T. cruzi were determined by electrophoresis. According to their patterns they could be classified into four sets. 2. The isoenzyme patterns of two stocks were influenced by the number of subcultures. 3. Five stocks from man are distinct from those derived from a silvatic reservoir. 4. Since the isoenzyme patterns of a stock isolated from a patient with acute disease were similar to those of a silvatic reservoir, its recent introduction into the domiciliary cycle is postulated.
61 citations
TL;DR: It is proposed that the relatively recent arrival of Triatoma infestans initiated a domestic cycle linked to peridomestic and sylvatic cycles of Trypanosoma cruzi transmission, which might have contributed to the outbreak of human infection.
Abstract: Following reports of an unusually high incidence of acute Chagas's disease and the appearance of large numbers of Triatoma infestans in the southwestern region of the State of Bahia, triatomine bugs (Hemiptera: Reduviidae) and domestic animals in one of the affected communities were surveyed and examined for infection with Trypanosoma cruzi . Triatoma infestans was prevalent in houses and was also found in peridomestic habitats. T. sordida and T. pseudomaculata occupied peridomestic and sylvatic habitats and T. brasiliensis was found only among rocks far from houses. Panstrongylus megistus , formerly present in the region, was not found. Trypanosoma cruzi was detected in 19·5% of Triatoma infestans , 11·5% of T. sordida , 19% of dogs, 29% of cats and 100% of rats examined. A disproportionate number of early instar bugs were infected with Trypanosoma cruzi , suggesting that a rapid increase in the rate of transmission had recently occurred. The history of the domestic triatomine fauna of the region since 1912 is reviewed, and it is proposed that the relatively recent arrival of Triatoma infestans initiated a domestic cycle linked to peridomestic and sylvatic cycles of Trypanosoma cruzi transmission. Increased human mobility, the use of DDT for malaria control, and drought conditions are considered as factors which might have contributed to the outbreak of human infection.
39 citations
TL;DR: A comparative study of the Lutz, Faust, and Kato-Katz stool examination methods for parasitological diagnosis using 500 patients was conducted in this article, showing that the KatoKatz method provided higher rates of positivity than the other two techniques in the diagnosis of Ancylostomidae, T. trichiurus, and S. mansoni.
Abstract: A comparative study was of the Lutz, Faust (modified), and Kato-Katz stool examination methods for parasitological diagnosis using 500 patients. The Kato-Katz method provided higher rates of positivity than the other two techniques in the diagnosis of Ancylostomidae, T. trichiurus, and S. mansoni. No differences were observed in the diagnosis of A. lumbicoides. Nor was a statistically significant difference observed in the diagnosis of protozoosis when using the Lutz and modified Faust methods. The data obtained led to a recommendation for an association of Kato-Katz and modified Faust methods for routine parasitological diagnosis due to Us simplicity, rapidity, and efficiency.
18 citations
TL;DR: The distribution of microfilariae in the skin of the same indians and an additional volunteer, who had been treated 2 years previously, was determined and in both cases the highest densities of the parasite were found in the torso, with dorsal surface of the body and extensor surfaces of the limbs being more heavily infected than the ventral and flexor surfaces.
Abstract: A comparison was made between the mean number of microfilariae of Onchocerca volvulus ingested by 10 Simulium sanguineum feeding on 2 different areas of the body of 4 infected Yanomama indians and the mean number of mf/mg in 10 skin snips taken from the same areas. Between 2.3 and 28 times as many microfilariae were recovered from the midguts of the flies as were found in the skin snips. Using both methods, the distribution of microfilariae in the skin of the same indians and an additional volunteer, who had been treated 2 years previously, was determined. In both cases the highest densities of the parasite were found in the torso, with dorsal surfaces of the body and extensor surfaces of the limbs being more heavily infected than the ventral and flexor surfaces. The possibility of using S. sanguineum for the detection of low-density infections of O. volvulus is discussed.
15 citations
TL;DR: Infeccoes experimentais de descendentes de Biomphalaria tenagophila de Itajuba, MG (Brasil) foram realizadas utilizando-se a conhecida cepa "LE" de Schistosoma mansoni, isolada em Belo Horizonte, foram chamada a atencao para a necessidade de medidas profilaticas.
Abstract: Infeccoes experimentais de descendentes de Biomphalaria tenagophila de Itajuba, MG (Brasil) foram realizadas utilizando-se a conhecida cepa "LE" de Schistosoma mansoni, isolada em Belo Horizonte. Como controle, utilizou-se B. glabrata de Belo Horizonte, MG. Em consequencia, assinalou-se, pela primeira vez, a infeccao de B. tenagophila de Itajuba, a cepa de S. mansoni adaptada a B. glabrata de Belo Horizonte. Isto e, ao final do experimento, 5 (3,3%) entre os 149 exemplares sobreviventes, infectaram-se. Face ao atual surto industrial da regiao, com grande aporte de migrantes, foi chamada a atencao para a necessidade de medidas profilaticas, em decorrencia da possibilidade de instalacao de foco da doenca no Sul de Minas Gerais.
7 citations
TL;DR: It is believed that, under similar conditions, Pomacea haustrum - and, by extension, P. canaliculata - may be successfully used in the biological control of the intermediate hosts of S. mansoni, or, at least, of becoming predominant, with no damage to the new ecosystems.
Abstract: In the region of Baldim, MG (Brazil) - a well-known Schistosoma mansoni endemic area where transmission control had already been unsuccessfully attempted through molluscicide, sanitary education and clinical treatment - 5,421 specimens of Pomacea haustrum (Prosobranchia, Pilidae) were introduced into 5 brooks and 2 ditches where Biomphalaria glabrata (primarily) and B. straminea (secondarily) predominated. From 1968 to 1971, the infection rate of B. glabrata by S. mansoni ranged from 2.1% to 11.9%. None of the B. straminea specimens collected, however, were seen to be liberating cercariae of this trematode. After the introduction of Pilidae, only once were two positive B. glabrata specimens (1.8%) detected. A decrease in the planorbide population was observed, as well as an increase in the pomacea density to 20.0 and 121.6 specimens per square meter in the brooks and ditches, respectively. P. haustrum density was estimated by the "quadrat" method. Of the planorbides in the experiment, 65.2% (1,526) were collected from July/68 to July/72 and the rest were obtained after the introduction of the predator-competitor species, as follows: 15.0% (352) in 1976; 16.1% (377) in 1977; and 3.7% (87) in 1978. Although transferred from a lenitic medium (Sete Lagoas, MG), the pomaceae became perfectly adapted to the lotic collections of Baldim, and proved to be capable of replacing the original B. glabrata populations of several biotopes or, at least, of becoming predominant, with no damage to the new ecosystems. Based on the data presented above and the knowledge previously acquired in the study of the biology and ecology of the species, it is believed that, under similar conditions, Pomacea haustrum (Reeve, 1856) - and, by extension, P. lineata (Spix, 1827) and P. canaliculata (Lamarck, 1822), as well as other species from the same genus - may be successfully used in the biological control of the intermediate hosts of S. mansoni.
5 citations
01 Sep 1979
TL;DR: In order to elucidate the nature of the fibrous network present in Schistosoma mansoni tegument, adult worms were studied by light and electron microscopy and it was suggested that this network is formed by bundles of tubular microfibrils 10--12 nm in diameter, similar to oxytalan microfibils present in higher animals.
Abstract: In order to elucidate the nature of the fibrous network present in Schistosoma mansoni tegument, adult worms were studied by light and electron microscopy. It was suggested that this network is formed by bundles of tubular microfibrils 10--12 nm in diameter, similar to oxytalan microfibrils present in higher animals.
5 citations
TL;DR: Recommendations are made for an association of Kato-Katz and modified Faust methods for routine parasitological diagnosis due to their simplicity, rapidity, and efficiency.
Abstract: A comparative study was of the Lutz, Faust (modified), and Kato-Katz stool examination methods for parasitological diagnosis using 500 patients. The Kato-Katz method provided higher rates of positivity than the other two techniques in the diagnosis of Ancylostomidae, T. trichiurus, and S. mansoni. No differences were observed in the diagnosis of A. lumbicoides. Nor was a statistically significant difference observed in the diagnosis of protozoosis when using the Lutz and modified Faust methods. The data obtained led to a recommendation for an association of Kato-Katz and modified Faust methods for routine parasitological diagnosis due to Us simplicity, rapidity, and efficiency.
1 citations