Evolution of schistosomiasis in an hyperendemic area of the Minas Gerais state: two cross-sectional studies

Two cross-sectional studies on schistosomiasis mansoni were done in Comercinho, Minas Gerais (Brazil), at an interval of 7 years. In 1974 and 1981 feces examinations (KATO-KATZ method) were done in 89 and 90% of the population (about 1,500 inhabitants) and clinical examinations were done in 78 and 92% of the patients who excreted Schistosoma mansoni eggs in the feces, respectively. The rate of infection by S. mansoni did not change (69.9% in 1974 and 70.4% in 1981), but the geometrical mean of eggs per gram of feces (431 ± 4 and 334 ± 4, respectively) and the rate of splenomegaly (11 and 7%, respectively) decreased significantly in 1981, when compared to 1974. This reduction was observed only in the central zones of the town (zones 1-2) where the rate of dwellings with piped water increased from 17 to 44%. In the surroundings (zones 3-4), where the proportion of houses with piped water did not change significantly between 1974 (10%) and 1981 (7%), the geometrical mean of S. mansoni eggs and the rate of splenomegaly did not change either.

Rabies in the state of São Paulo: the rodents question

The authors looked over the epidemiological data on the aggression by rodents in the period 1976-1985 in the records of the Instituto Pasteur in the State of São Paulo (Brazil). They observed that out of 367 379 people attacked, 22 250 were victims of rodents. Mainly responsible for these accidents were urban rodents, whose capture, however, was a limiting factor for the sending of samples to the laboratory. Laboratory diagnosis carried out in 1 083 samples of rodents did not show any positive case in the period, in spite of the presence of rabies in other animals species. It is conclude that, as rabies is rare among rodents, tests are necessary for the identification of the virus whenever suspicion of a positive case occurs; in addition, in the absence of reported cases of human death caused by rabies related to rodents, possibility exists for a reduction of antirabies treatments following exposure to these animals.

Interrelation between parasitic infections and hypovitaminosis A: Schistosoma mansoni infection and the retinol blood levels in an endemic area of State of Minas Gerais (Brazil)

The interrelation between schistosomiasis and the retinol blood levels was studied in a double blind method, by comparing the serum vitamin A of the infected and non-infected group of an endemic area of Schistosoma mansoni infection. The infected group was characterized by 106 parasitized persons in the intestinal and hepatointestinal forms, who eliminated less than 500 eggs/gram of feces (Modified Kato's method); the non-infected group was characterized by 112 inhabitants of this endemic area without eggs in the stools and presenting negative intradermal reactions, and absence of previous specific treatment. The blood levels of retinol was determinated using trifluoracetic acid method, regarding the normal levels > 20,0mg/100ml. The results of this study point out the absence of correlation between S. mansoni infection and blood levels of vitamin A.

Ecological aspects of American cutaneous leishmaniasis: 6. Man-biting sandfly fauna of a patch of residual forest in the middle and north-eastern region of the São Paulo State, Brazil

This report shows the phlebotomine vectorial role in the endemic cutaneous leishmaniasis situated in the middle and north-eastern region of the São Paulo, Brazil. Analysis of information encloses a sandfly man-biting fauna of four different patches of residual forest. So, using the human-bait and Shannon trap for a period of one year we have caught 16,869 sandflies. The predominance of Lutzomyia intermedia (85,6%) was clear. Moreover, the low density of Lutzomyia whitmani and Lutzomyia pessoai and their epidemiological implications at present and in the past are discussed. Information about the daily activity of some species is given and we emphasize for the first time, the diurnal activity of Lutzomyia firmatoi in the São Paulo State.

Plasmid composition and virulence-associated factors of Yersinia pestis isolates from a plague outbreak at the Paraíba State, Brazil

Pathogenic Yersinia pestis isolates were collected during a plague outbreak at the Paraiba State in 1986. The Y. pestis isolates were investigated for the presence of virulence-associated factors and plasmid content. All strains analysed were proficient in the expression of the VW and fraction 1 antigens, pigment adsorption and pesticin-fibronolysin-coagulase production. A similar plasmid profile composed by four plasmid with molecular weight of 60, 44, 14.9, and 6.4 Megadaltons (MD) was found in all strains. DNA cleavage with EcoRI restriction enzyme further demonstrated the uniform plasmid content of the Y. pestis isolates. Seven additional Y. pestis strains, previously isolated in the same region but in an endemic state, showed the same plasmid fingerprint. The lack of any detectable difference between epidemic and endemic isolates as well as the value of plasmid fingerprints in epidemiology of Y. pestis is discussed.

Visceral larva migrans: a seroepidemiological survey in five municipalities of São Paulo State, Brazil

An enzyme-linked immunosorbent assay (ELISA), employing antigens from Toxocara canis larvae and the absortion of suspected sera with Ascaris lumbricoides extracts was used in a seroepidemiological study performed in five municipalities of São Paulo State, Brazil (São Paulo, Campinas, Santos, Marília and Presidente Prudente) in order to determine the frequency of antibodies to Toxocara. In 2,025 blood samples collected, 806 proceeded from male subjects and 1,219 from females; 483 samples were collected from subjects under 15 years of age and the remaining 1,542 from subjects aged 15 years or over. Among the 2,025 sera investigated, 3.60% had antibodies to Toxocara at significant levels. A moderate predominance of infection with Toxocara among male subjects (3.72%) was observed, although the difference was not statistically significant when this rate was compared with that for female (3.28%). Related to age, a higher frequency of positive results was detected among subjects under 15 years (6.41%) against the older group (2.53%). A trend of more elevated rates of infection was observed in municipalities with high demographic densities (São Paulo, Campinas and Santos). Nevertheless, such findings only appeared to be statistically significant in subjects younger than 15 years.

Human parasitism by Phagicola sp (Trematoda, Heterophyidae) in Cananéia, São Paulo State, Brazil

We report one case of parasitism by Phagicola sp. (Trematoda, Heterophyidae) in a 31 years-old woman who, in 1987, travelled and stayed several months in the municipality of Cananéia (SP), where she ingested, in various occasions, raw mullet (Mugil sp.). The patient refered mild intestinal pain and laboratory examinations showed eggs of Phagicola sp. in the stools and a slight increase in eosinophil blood levels (8%). After treatment with praziquantel (75 mg/kg per day for three days) all the symptoms and signs disappeared. This is, certainly, the first record of human infection by Phagicola sp. in Brazil and, perhaps, in countries other than the U.S.A. where unclear references to a few human cases were reported in the South-eastern region.

Drug susceptibility of Plasmodium falciparum in the western Amazon region, state of Acre, Brazil

Field studies in the western Amazon region (state of Acre, Brazil) indicate that the 4-aminoquinolines, as well as the combined regimen with sulfadoxine-pyrimethamine, can no longer be recomended for the treatment and prophylaxis of P. falciparum infections in this region. Quinine remains an effective drug when used correctly. However, compliance problems arise due to the often occurring side-effects during a ten day regimen. Prospects of overcoming these constraints by combining a short course of quinine with other drugs are limited, because of the lack of suitable partner compounds. For this reason quinine/clindamycin appears to be a more practical therapy of P. falciparum malaria. In vitro data from this study suggest that mefloquine is another effective alternative for the treatment of falciparum malaria in this Amazon region.

First register of Biomphalaria straminea Dunker, 1848, in Santa Catarina State

The first register of Biomphalaria straminea, vector species of schistosomiasis, in Santa Catarina State, South Brazil is described. The specimens were obtained from two ornamental aquaria of private residences. In both cases the ornamental plants and/or fishes were bought from the same supplier. The presence of this species was later confirmed in the farm where these plants and fishes are cultivated, in the city of Governador Celso Ramos, also in Santa Catarina State. The occurrence in natural environments was later detected in two different places of the Island of Santa Catarina.

Biological and morphological characteristics of Schistosoma mansoni from Ribeira Valley, State of São Paulo, Brazil: I - susceptibility of Biomphalaria tenagophila snail to sympatric S. mansoni strain

In the São Paulo State, Brazil, where the Biomphalaria tenagophila is the intermediate host, the Ribeira Valley is an important endemic schistosomiasis mansoni area. During last eleven years there has been intense control measures focusing on schistosomiasis. The efforts have been concentrated in the municipalities of Pedro de Toledo and Itariri. We determined the susceptibility of B. tenagophila to sympatric strain of S. mansoni, both recently isolated from Itariri field. In 1988, this strain was isolated and maintained in the experimental model: Swiss mice - sympatric B. tenagophila. The second generation of the worm was evaluated. The snail were divided in the three groups of 60 snails each. One group was exposed to 1 miracidium and other to 10. The third group was the control. The mortality and the shedding of cercariae were checked during 78 days. After that, the positive snails were observed until they ceased to shed cercariae. The exposed molluscs showed mortality rates of 23% and 31% and infection indexes were of 8% and 60% to 1 and 10 miracidia respectively. The mortality was of 22% in the control group. The periods of shedding cercariae in the two groups were 82 and 104 days. We can conclude that B. tenagophila is an effective intermediate host to the sympatric strain of S. mansoni sympatric strain

Intestinal parasites among Karitiana Indians from Rondônia State, Brazil

Gravity sedimentation parasitological examinations were performed in stool samples from 111 Karitiana Indians from Rondônia State, Brazilian Amazon Basin. Intestinal parasites were found in 43 samples (38.7%). Ascaris lumbricoides was the most prevalent helminth species (18.9%). Egg counts in samples positive for Ascaris suggested an overdispersed distribution of worm burdens in the host population. Age-distribution pattern of intestinal parasites among Karitiana Indians was found to be rather unusual: the highest prevalence (60.0%) was detected in the 12-to 16-year-old age group

Dengue epidemic in the state of Rio de Janeiro, Brazil: virological and epidemiological aspects

Laboratorial studies were carried out on 3178 patients with signs and symptoms suggestive of dengue infection from April 1986 to December 1987 in the State of Rio de Janeiro, Brazil. The epidemic had two peaks following the first virus isolation and affected the inhabitants of 17 counties. Both sex and all age groups were affected. Dengue virus type 1 was isolated from 1039 sera and the number of confirmed cases was increased to 1874 (59%) by MAC-ELISA. Isolation rate confirmed cases reached 80% in the specimens obtained until the 4th day after the onset of disease and viraemia ranged from 10 3.0 to 10(8.5) TCID50/ml.

The ecology of Triatoma sordida in natural environments in two different regions of the state of Minas Gerais, Brazil

A study was undertaken about T. sordida in the natural environment in two different regions of the state of Minas Gerais: Itapagipe (Triângulo), an area of cerrado modified by the formation of fields of pasture and agriculture, and Mato Verde (north) an area of transition between caatinga and cerrado with profound deforestation in the last years due to the expansion of cotton cultivation. In both regions the principal ecotopes identified were hollow trees and the bark of live or dead trees, where the occurrence of a food source is not frequent. In this environment, the triatomines utilize various food sources; opposums appear to represent an important source of infection. In the north of Minas, a greater concentration of reservoirs and vectors was observed than in the Triángulo which could explain the higher level of infection of the triatomines in the north. Close attention to the process of domiciliation of T. sordida in the north of Minas is recommended where an extensive intervention by man in the natural environment has occurred and where a rise in the population of triatomines in the peridomestic environment has been observed in recent years.