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Biomedical subjects

M A Moraes

Publications and source records attributed to M A Moraes.

At least 19 recordsLinked to original sources
PubMed1987

The status of Simulium oyapockense and S. limbatum as vectors of human onchocerciasis in Brazilian Amazonia.

In an attempt to explain the current distribution of onchocerciasis in the forests of northern Brazil (Moraes et al., 1979, 1986), and its potential for dispersal to other areas, this study compares the vector status of Simulium oyapockense Floch and Abonnenc, 1946 in both a hypoendemic and an onchocerciasis free area with that of S. limbatum Knab, 1915 in the latter area. Both species allowed the full development of Onchocerca volvulus (Leuckart) to the infective L3 stage after experimental infection with microfilariae. Their vector competence was significantly lower than for other efficient vector species in South America and Africa because of the lethal effect of the cibarial armature on ingested microfilariae. The low vector capacity of S. oyapockense, together with the low prevalence and intensity of infection of O. volvulus, probably explains why onchocerciasis has not significantly increased in intensity over the last 10 years in the hypoendemic part of the Amazonian focus. Omnipresence of both vector species in the adjacent savanna region, however, could facilitate the spread of onchocerciasis if human population movements continue from the hyperendemic part of the onchocerciasis focus.

Animals↗
PubMed1983

The concentration of Mansonella ozzardi microfilariae in skin capillaries.

The densities of microfilariae of Mansonella ozzardi in different regions of the body of infected individuals were studied. The density in venous blood closely approximated to that found in finger capillaries, but was significantly lower than the densities in capillaries of the scapular region and buttocks. A possible explanation for this concentration of microfilariae is the lack of glomi in these two sites, which consequently have a lower flow of blood than areas where glomi occur and where microfilarial densities are lower. No relationship was found between blood and skin densities in the buttocks and scapular region, probably due to the inadequacy of the skin snip method used for the detection of this species of filaria. It was concluded that the most acceptable detection method for M. ozzardi remains the sampling of finger capillary blood. It could not be decided, due to the paucity of data, whether any relationship exists between skin microfilarial densities and the biting sites of the vectors.

Adolescent↗
PubMed1981

An epidemic of yellow fever in Central Brazil, 1972-1973. II. Ecological studies.

Results of ecological studies undertaken during the 1972-1973 epidemic of yellow fever (YF) in Goiás State, Brazil, suggest that mosquitoes of the genus Haemagogus were the only vectors infected with YF virus. Nine isolations of the agent were made from 1,688 Haemagogus spp. caught within or near forests from 27 January to 3 March 1973. Seven of these isolations cane from mosquitoes collected on the forest floor. No YF virus isolation was made from 791 Haemagogus leucocelaenus or 1,096 Sabethes chloropterus. Haemagogus were caught both in and outside houses located 500 m from the forest, although at a lower rate than in the forest. Haemagogus collection rates in a secondary growth forest were similar to or even higher than those in primary forests. YF virus was recovered from a Cebus monkey and hemagglutination-inhibition and/or neutralizing antibody to YF virus was found in seven (30.4%) of 23 primates examined. There was, however, little evidence of sick or dying monkeys. Among other wild-caught animals only a single marsupial (Caluromys) had antibodies to the virus. These data show that sylvan YF is not confined to the forest, nor always associated with conspicuous epizootics.

Animals↗
PubMed1980

Simulium species of the amazonicum group as vectors of Mansonella ozzardi in the Brazilian Amazon.

Experimental infection with Mansonella ozzardi of common haematophagous Diptera collected at a Ticuna Indian village on the upper reaches of the Solimões river in the Brazilian Amazon, showed that Simulium amazonicum and Simulium n.sp. are capable of supporting full development of the parasite. Natural infections with this filaria were found in both species including infective larvae in Simulium n.sp. No development of M. ozzardi occurred in Mansonia amazonensis, Culicoides insinuatus or Lepiselaga crassipes (Tabanidae). The dimensions of developing larvae of M. ozzardi in both species of black-fly were recorded. Infective larvae of this species may easily be distinguished from those of Onchocerca volvulus, also transmitted in the Amazon by a species closely resembling S. amazonicum, by the presence of a bifid tail and higher anal ratio in M. ozzardi.

Animals↗
PubMed1978

An epidemic of yellow fever in central Brazil. 1972-1973. I. Epidemiological studies.

An epidemic of jungle yellow fever occurred in Goiás State, Brazil, between December 1972 and March 1973. Laboratory confirmed cases were observed in 36 counties located in the central and southern parts of the State. Seventy-one cases were proved, of which 44 were fatal. The diagnosis was made on the basis of pathology, serology, and virus isolation. Besides yellow fever, malaria and viral hepatitis were present, and in two fatal cases there was malarial pigment in the liver in addition to the specific lesions associated with yellow fever virus infection. The fact that male patients strikingly outnumbered females (9:1) and that young adults were predominantly affected indicates that transmission occurred mainly inside or adjacent to the forests. The lack of cases in urban areas can be attributed to the absence of Aedes aegypti in these areas. Yellow fever complement-fixing antibody in high titers was found in 18 of 1,201 (1.4%) persons living in eight counties of the affected area. This finding suggests that at least 21,000 persons out of the 1.5 million rural inhabitants of the three districts where the epidemic occurred had been infected by the virus. The epidemic subsided following an intensive vaccination campaign, and the last four cases were observed in March 1973.

Adolescent↗
PubMed1978

Toxoplasmosis among the Ticuna Indians in the state of Amazonas, Brazil.

Results of a serologic survey for Toxoplasma gondii among 408 Ticuna Indians from five villages in western Brazil are presented and compared with the results of 61 non-Indian inhabitants of the town of Codajas, Amazonas. Indirect hemagglutination antibody titers greater than or equal to 64 were found in 39% of the Ticuna population as compared to 77% of the Codajas population. Prevalence rates of titers greater than or equal to 256 were 20.3% for Ticunas and 39.3% for Codajas. Prevalence rates of titers greater than or equal to 256 in Ticuna villages where dietary habits were most variable were higher and more similar to those of non-Indian populations than were the prevalence rates of this titer range in villages where the animal food source was predominantly fish.

Adolescent↗