Observations on two biological races of Schistosoma mansoni

A comparative study of the BH strain of Schistosoma mansoni from Belo Horizonte, Minas Gerais state, infective to Biomphalaria glabrata from the same locality, and the SJ strain from São José dos Campos, São Paulo state, infective to B. tenagophila from the latter locality, showed the following differences: 1. Length of adult worms and size of eggs significantly larger in the BH strain. 2. Higher infection rates in the B. glabrata-BH strain association than in the B. tenagophila-SJ strain association, following exposure of each snail to 1 or 10 miracidia. 3.Longer prepatent period (from penetration of miracidium to first shedding of cercariae) in the B. tenagophila-SJ strain association. 4. Infection of both Biomphalaria species when exposed to hybrid miracidia from crosses between the two strains, at lower levels than those resulting from exposure of each snail species to miracidia of the pure sympatric strain. (Both Biomphalaria populations are practically refractory to infection with the allopatric strain). These results are interpreted as pointing to a better host-parasite adjustment in the B. glabrata-BH strain association than in the B. tenagophila-SJ association. The interfertility between the two strains, which produced viable hybrids infective to both Biomphalaria species, supports the conclusion that the observed differences are merely intraspecific, and that the two strains may be considered distinct biological races of Schistosoma mansoni.

Estudo da potencialidade de populações de Biomphalaria straminea do Estado de Minas Gerais, como hospedeiras do Schistosoma mansoni

Caramujos de Biomphalaria straminea, descendentes de exemplares coletados em nove municípios do Estado de Minas Gerais, foram infectados experimentalmente com três cepas de Schistosoma mansoni: "LE", procedente de Belo Horizonte (MG); "SJ", procedente de São José dos Campos (SP) e "AL" procedente do Nordeste (AL). As taxas de infeção variaram de 0,0 a 24,0% com a cepa "LE"; de 0,0 a 16% com a cepa "SJ" e de 2,0 a 9,0% com a cepa "AL". Os índices de infecção experimental obtidos foram semelhantes aos registrados por outros autores, para B. straminea dessa região. Comparou-se o número de cercárias de cepa "LE", eliminadas por oito exemplares de B. straminea de Baldim e oito Biomphalaria glabrata do controle, após 30 minutos de exposição à luz. O número de cercárias eliminadas por B. straminea foi de 4.550, aproximadamente cinco vezes menor que o de B. glabrata, 22.679. Discute-se a potencialidade desses moluscos como hospedeiros do S. mansoni nessa região.

Salmonella typhi: lisotipia VI e biotipificação em amostras oriundas de algumas regiões do Brasil

Fez-se uma análise da distribuicão da frequência dos lisotipos VI e dos tipos fermentativos segundo o esquema de Kristensen, em 1.150 amostras de Salmonella typhi, isoladas de diferentes regiões do Brasil (Pará, Pernambuco, Bahia, Minas Gerais, Rio de Janeiro, São Paulo e Rio Grande do Sul). No computo geral, observou-se a prevalência dos lisotipos A (38,1%); Ela (18,9%); amostras VI negativas (16,6%); D6 (8,7%) I + IV (4,6%); T (2,3%) e C1 (2,1%) e a ocorrência de alguns tipos fágicos característicos para determinadas áreas (B3, C4 e 40 na Bahia; E1b, F2, G1 e L1 em São Paulo; E4 e 28 no Rio de Janeiro). Quanto a classificacão bioquímica, 55,2% das amostras caracterizaram-se no biotipo II (xilose e arabinose negativas), 44,2% no tipo fermentativo I (xilose positiva e arabinose negativas) e 0,52% no tipo III (xilose e arabinose positivas), respectivamente.

A pilot study to control Lutzomyia umbratilis (Diptera: Psychodidae), the major vector of Leishmania brazileiensis guyanensis, in a peri-urban rainforest of Manaus, Amazonas State, Brazil

In the second half of 1980, 112 (or ca. 16%) of the inhabitants of the new settlement of São José, city of Manaus, contracted cutaneous leishmaniasis whilst clearing their properties of terra firme rainforest. With the aid of SUCAM, the authors carried out a pilot study to investigate the feasibility of reducing populations of Lutzomyia umbratilis, the local silvatic vector of Leishmania braziliensis guyanensis, by spraying insecticide on its favoured diurnal resting sites, the bases of the larger forest trees. Most manvector contact is at these resting sites and, therefore, it was encouraging to record a marked reduction of the tree-base populations of L. umbratilis for 21 days following just one application of D.D.T. emulsion in an area 200m square. Most of the treated trunks were not occupied by L. umbratilis for at least eleven months. Suggestions for extending the pilot study are made, and the need for collaboration with a clinical team is emphasized. Leishmania b. guyanensis is the aetiological agent of [quot ]pain bois[quot ], which is hyperendemic from French Guiana to central Amazônia. In the absence of proven vaccines or methods of vector control, some simple methods for limiting transmission of Le. b. guyanensis to man are listed.

Resistência de Biomphalaria schrammi de Arcos, Minas Gerais, Brasil, à infecção com duas cepas de schistosoma mansoni

Descendentes do plonorbídeo Biomphalaria schrammi Crosse, 1864, coletados na localidade de Calciolândia, município de Arcos, Minas Gerais, Brasil foram expostos a miracídios de duas cepas de Schistosoma mansoni:"LE" de Belo Horizonte, Minas Gerais e "SJ" de São José dos Campos, São Paulo, Brasil. Dentre 172 exemplares expostos, nenhum se infectou com as duas cepas deste trematôdeo. Por outro lado, 100 exemplares de Biomphalaria glabrata, dos grupos controle, apresentaram taxas de infecção de 88 e 40% com as cepas "LE" e "SJ", respectivamente. A taxa de mortalidade de B. schrammi chegou a 44% enquanto a de B. glabara não atingiu 10%.

Further experiments on susceptibility of Biomphalaria amazonica to Schistosoma mansoni

A sample of Biomphalaria amazonica from Porto Velho, Rondônia state, was exposed to miracidia of Schistosoma mansoni (SJ2 strain) from São José dos Campos, São Paulo state (five miracidia per snail). Water freshly taken from the snails' breeding place was used to make sure that its quality was compatible with hatching of miracidia and their penetration into the snails. The resulting infection rate was 3.5%, as against 45% in B. tenagophila controls. In comparison with the controls, B. amazonica, besides a lower infection rate, showed a longer prepatent period and a lower cercarial production. These characteristics seem to indicate that it is a poor host of S. mansoni, like B. straminea, but it should be considered that, this notwithstanding, the latter is admittedly a good vector of the parasite in hyperendemic areas of northeastern Brazil. These results point to the possibility of introduction of schistosomiasis mansoni into the western Amazonian region, where B. amazonica is widespread.

Potencialidade de Biomphalaria tenagophila do lago Pampulha, Belo Horizonte, MG, como hospederia do Schistosoma mansoni

Caramujos Biomphalaria tenagophila descendentes de exemplares coletados no lago da Pampulha, Belo Horizonte, Minas Gerais, foram expostos a miracídios de quatro cepas de Schistosoma mansoni: LE e HK de origem local, Belo Horizonte, AL do Estado de Alagoas e SJ, de São José dos Campos, SP. As cepas LE, AL e SJ são mantidas em laboratório e HK foi obtida de fezes de paciente que reside próximo à Pampulha. As taxas de infecção experimental foram de 4% (LE), 6% (HK), 30% (SJ) e 40% (AL). Esses indícios de infecção foram semelhantes aos obtidos por vários autores para populações de B. tenagophila de Minas Gerais. Caramujos infectados experimentalmente eliminaram número de cercárias comparável ao de B. glabrata do controle e de B. tenagophila capturada no lago, com infecção natural (cerca de 2.000 cercárias/molusco). Devido à alta densidade planorbídica atual em alguns pontos do lago, número de cercárias eliminadas por exemplares naturalmente infectados, afluxo de pessoas para pesca e lazer, contaminação das águas por dejetos humanos, os autores alertam para o risco de crescimento do foco de esquistossomose no local.

Resistência de Biomphalaria peregrina de Santa Rita do Sapucaí, Minas Gerais, a infecção com três cepas de Schistosoma mansoni

Descendentes do planorbídeo Biomphalaria peregrina, coletados em Santa Rita do Sapucaí, Minas Gerais, Brasil, foram expostos a miracídios de três cepas de Schistosoma mansoni: "LE" de Belo Horizonte, MG; "SJ" de São José dos Campos, SP e "AL" do Estado de Alagoas. Dentre 300 exemplares expostos, nenhum se infectou com as três cepas do trematódeo. Por outro lado, 300 exemplares de B. glabrata, dos grupos de controle, apresentaram taxas de infecção de 61,1 a 95,3% com as três cepas do trematódeo. As taxas de mortalidade de B. peregrina e de B. glabrata foram de 20,0 e de 28,0%, respectivamente.

Dispersão geopolítica da ocorrência de Fasciola hepatica no Estado de Santa Catarina, Brasil

During 12 years feces samples from cows, water buffaloes, sheeps and goats were examined by sequencial tamis filtration to show the occurence of Fasciola hepatica eggs. The material came from 129 municipalities of Santa Catarina State, and 5 g of feces per animal were examined. The occurrence of F. hepatica was confirmed in 64.82% of the municipalities. Considering the host, F. hepatica was confirmed in goats from Florianópolis, São José, São João Batista and Guaramirim municipalities; in sheeps from Brusque, Pomerode, Palhoça and São José; in water buffaloes from 9 and in cows from 86 municipalities. For this study, 13,762 feces samples were examined and in 3,814 the presence of eggs of F. hepatica was demonstrated. The percentage of occurence for host species was 27.86 in cows, 24.72 in water buffaloes, 16.92 in sheeps and 15.66 in goats. By the results it was demonstrated that Itajaí Valley at Southest Hidrographic Basin, in Santa Catarina State is an endemic area of F. hepatica, even though Uruguai Hidrographic Basin was not referred as a geographical record for this parasite.

Analysis of Mycobacterium avium Complex Serovars Isolated from AIDS Patients from Southeast Brazil

The purpose of this study was to assess the distribution of Mycobacterium avium serovars isolated from AIDS patients in São Paulo and Rio de Janeiro. Ninety single site or multiple site isolates from 75 patients were examined. The most frequent serovars found were 8 (39.2%), 4 (21.4%) and 1 (10.7%). The frequency of mixed infections with serovar 8 or 4 was 37.8%. Among the 90 strains examined, M. intracellulare serovars (7 strains) and M. scrofulaceum (4 strains) were found in 11 isolates (12%) indicating that M. avium (88%) was the major opportunistic species in the M. avium complex isolates in Brazilian AIDS patients

Studies on populations of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in Brazil

Studies were performed on five Brazilian populations of Lutzomyia longipalpis: Salvaterra (PA), São José do Ribamar (MA), Canindé (CE), Natal (RN) and Gruta da Lapinha, Lagoa Santa (MG). No morphological differences were observed that could distinguish between these populations. Homogeneity tests showed that the allopatric populations display a certain heterogeneity and that the sympatric populations, with different patterns of spots, are homogeneous. The Student-Newman-Keuls test, represented by Euler-Venn diagrams, showed a disjunction between the populations from the north/northeast and the one from Gruta da Lapinha. Genetic distances between the four populations (excluding the Canindé population) were within the range of intrapopulational differences. The Gruta da Lapinha population displayed a heterozygotic deficiency that could be a consequence of high levels of inbreeding due to cryptic habits of living in a small cave. These results do not favor the hypothesis of a L. longipalpis species complex in Brazil, and the species should be considered high polymorphic.

Identification of entomopathogenic Bacillus isolated from Simulium (Diptera, Simuliidae) larvae and adults

Entomopathogenic bacteria isolated from Simulium larvae and adults from breeding sites in the states of São Paulo and Rio de Janeiro, Brazil, were identified as 18 strains of Bacillus thuringiensis and one of B. sphaericus. Most of these strains were serotyped according to their flagellar antigens. However, nine of the B. thuringiensis samples, could not be serotyped and were designated as "autoagglutinating"; they were also shown to be toxic in preliminary tests against Aedes aegypti larvae. Additionally, B. sphaericus was also shown to be toxic towards Culex quinquefasciatus larvae.

First report on the presence of Biomphalaria straminea in the municipality of Jaboticatubas, State of Minas Gerais, Brazil

This is the first report on occurrence of Biomphalaria straminea in the district of São José de Almeida (municipality of Jaboticatubas) State of Minas Gerais, Brazil. The presence of B. glabrata and B. tenagophila had already been reported in this area. Such municipality is part of the metropolitan region of Belo Horizonte and comprises 60% of the Tourist Complex of Serra do Cipó. Since the 1950s throughout the 1990s, a schistosomiasis prevalence ranging from 15 to 40% has been observed. Although no B. straminea specimen has been found naturally infected in the region, descendants of these snails collected in the area, showed to be experimentally susceptible to Schistosoma mansoni infection reaching rates from 14.6 to 28.6%. Even not being found naturally infected, in the State of Minas Gerais, the possibility that the species B. straminea may keep endemicity foci of schistosomiasis should be regarded, as in the Northeastern region of Brazil where the high density of this planorbid and the social-economic and sanitary conditions enable to the transmission.

Factors associated with schistosomiasis mansoni in a population from the municipality of Jaboticatubas, State of Minas Gerais, Brazil

Jaboticatubas is a municipality in the metropolitan region of Belo Horizonte which has been a target of a wide media release as "the capital of schistosomiasis" since the 1960's. In order to give support to a work based on an integrated control, we sought to identify the disease determinants at the site. A transversal study was carried out aimed at identifying prevalence rates of the disease and factors associated with the infection in the district of São José de Almeida, and two close localities, Cipó Velho and São José da Serra, all of them located in the municipality of Jaboticatubas. A parasitological survey was performed, applying the Kato-Katz method with two slides per sample in 1186 schoolchildren which represents 77% of all registered pupils in four public schools in 2001. Among these schoolchildren a number of 101 (8.6%) prooved positive for Schistosoma mansoni eggs in their stool samples. A total of 64 families, whose schoolchildren had shown to be positive for schistosomiasis, also undertook examinations. As negative control, a random sample was collected from the 206 families, whose children had proven negative for schistosomiasis. The prevalence among 270 families (1304 people) was 12%. To assess those who continued to have contact with possibly contaminated water, 1061 (81.4%) people of the 270 families were interviewed. A multivariate analysis identified the following factors associated with the infection: time of residence in the area (short period), garbage disposal (use of deserted areas), gender (male), age (from 10 to 29 years), and water contact (daily and weekly). Further analysis of these factors revealed a close correlation between water contact and the disease, with a positive significant frequency concerning almost all those items. Depending on gender and age significant variations of water contact patterns associated with leisure and professional activities were found. A malacological survey on water collections in the area identified snails of the species Biomphalaria straminea and B. glabrata. The latter showed 17 (0.6%) specimens positive for S. mansoni. Qualitative studies have complemented such evidences, which allowed us to design a reference picture and specific indicators of the disease for the local population. Those data provided the essential information to continue the development of an already ongoing educative process, as well as projects on environmental improvements.

Kanaima Distant, 1909: descrição de uma nova espécie (Hemiptera, Auchenorrhyncha, Cercopidae, Tomaspidinae)

Kanaima Distant, 1909: description of a new species (Hemiptera, Auchenorrhyncha, Cercopidae, Tomaspidinae). A new species, Kanaima dubia, is described from São José dos Pinhais, Paraná, Brazil. It is similar, in general aspect, to Kanaima fluvialis (Lallemand, 1924).