[Aedes aegypti (l.) population in an endemic area of dengue in Southeast Brazil]. / População de Aedes aegypti (l.) em área endêmica de dengue, Sudeste do Brasil.

OBJECTIVE: A Aedes aegypti population from an area of dengue transmission was studied to determine mosquito's frequency, spatial distribution, parity, its ovarian development and midgut contents. METHODS: The study carried out in São José do Rio Preto country, São Paulo, SP, Brazil. Low and intermediate socioeconomic level regions were chosen to the study, which was carried out 1996 and 1997. Using a manual electric aspirator, captures were performed inside and outside the houses. Dissections were conducted to allow classify female mosquitoes according to their physiologic state. RESULTS: One hundred and eighty-eight males and 189 females were captured in both regions. A general index of 0.46 Ae. aegypti females per house was determined. Of the total sample, 82.4% of males and 87.3% of females were collected indoors. Greater proportions of females were found in the region of low socioeconomic level, and higher population density. One hundred and forty-eight female mosquitoes were analyzed: 27.0% were nulliparous and 10.1% parous. The rest were classified as Christophers and Mer's (C & M) phases III to V, 28.0% of which had red blood in their midgut. Of the total female population, 87.9% had bloodmeals. CONCLUSIONS: The mosquito species revealed a high degree of endophily. There was a higher proportion of nulliparous mosquitoes, although the majority of the females were classified as C & M's phases III to V. These results highlight both the great number of females who had had bloodmeals, and the lack of gonotrophic concordance.

[Infestation of S. Paulo State, Brazil, by Aedes aegypti and Aedes albopictus]. / Infestação do Estado de São Paulo por Aedes aegypti e Aedes albopictus.

OBJECTIVE: To study the influence of the distance between infested and non-infested areas in the geographical spread of Aedes aegypti and Aedes albopictuspopulations in the state of S. Paulo. Regional patterns were also studied, considering the determinants related to soil occupation. METHODS: Information related to the counties in the state of S. Paulo where were concentrations of Ae. aegypti and Ae. albopictus and counties infested up to the end of each year (1985 to 1995), both in the state of S. Paulo and in the neighboring states, were used. Four indicators were defined to analyze the infestation process. RESULTS/CONCLUSIONS: The analysis indicated the contribution of the states of Mato Grosso do Sul and Paraná for the initial Ae. aegypti infestation in the state of S. Paulo and Ae. albopictus infestation in the states of Rio de Janeiro and Minas Gerais. In the counties where there was a concentration of these species, their establishment was more frequent among those closer to the infested area. Seventy-five percent of the counties where there were established populations of Ae. aegypti and Ae. albopictus were situated up to 34 km and 60 km, respectively, from the nearest infested county. The analysis of the geographical spread rate of the Ae. aegypti revealed three different large areas with unexpected patterns: the area with greater demographic population density (east of the state) had the lower rate of geographical mosquito spread, indicating the existence of other factors with preponderant influence on the macro-regional patterns. For Ae. albopictus, there was no evidence of a relationship between their geographical spread patterns and the demographic population density.

[Changes in susceptibility of Aedes aegypti to organophosphates in municipalities in the state of São Paulo, Brazil]. / Alteração de resposta de suscetibilidade de Aedes aegypti a inseticidas organofosforados em municípios do Estado de São Paulo, Brasil.

Baseline data on susceptibility of Aedes aegypti to organophosphates detected alterations in cities of the state of S. Paulo, Brazil

A comparative epidemiologic study of specific antibodies (IgM and IgA) and parasitological findings in an endemic area of low transmission of schistosoma mansoni.

The diagnostic potential of circulating IgM and IgA antibodies against Schistosoma mansoni gut-associated antigens detected by the immunofluorescence test (IFT) on adult worm paraffin sections was evaluated comparatively to the fecal parasitological method, for epidemiological purposes in low endemic areas for schistosomiasis. Blood samples were collected on filter paper from two groups of schoolchildren living in two different localities of the municipality of Itariri (São Paulo, Brazil) with different histories and prevalences of schistosomiasis. The parasitological and serological data were compared to those obtained for another group of schoolchildren from a non-endemic area for schistosomiasis. The results showed poor sensitivity of the parasitological method in detecting individuals with low worm burden and indicate the potential of the serological method as an important tool to be incorporated into schistosomiasis control and vigilance programs for determining the real situation of schistosomiasis in low endemic areas.

Detection of IgM antibodies to Schistosoma mansoni gut-associated antigens for the study of the dynamics of schistosomiasis transmission in an endemic area with low worm burden.

For a period of 2 years, five follow-up measures of prevalence and incidence rates were estimated in a prospective study of S. mansoni infection in a group of schoolchildren who were living in a rural area of the Municipality of Itariri (São Paulo, Brazil), where schistosomiasis is transmitted by Biomphalaria tenagophila. Infection was determined by the examination of three Kato-Katz stool slides, and the parasitological findings were analyzed in comparison to serological data. In the five surveys, carried out at 6-month intervals (March-April and September-October), the prevalences were, respectively, 8.6, 6.8, 9.9, 5.8 and 17.2% by the Kato-Katz, and 56.5, 52.6, 60.8, 53.5 and 70.1% by the immunofluorescence test (IFT). Geometric mean egg counts were low: 57.8, 33.0, 35.6, 47.3 and 40.9 eggs per gram of feces, respectively. Of the total of 299 schoolchildren, who submitted five blood samples at 6-month intervals, one for each survey, 40% were IFT-positive throughout the study, and 22% were IFT-negative in all five surveys. Seroconversion from IFT negative to positive, indicating newly acquired S. mansoni infection, was observed more frequently in surveys carried out during March-April (after Summer holidays), than during September-October. Seasonal trends were not statistically significant for detection of S. mansoni eggs in stool. The results indicate that the use of IgM-IFT is superior to parasitological methods for detection of incidence of S. mansoni infection in areas with low worm burden.

[Schistosomiasis control in the State of São Paulo]. / Control.

The program of schistosomiasis control for the State of São Paulo, where only low endemicity areas occur, is discussed in this paper. Inclusion of schistosomiasis among the diseases due to obligatory notification is considered as a measure of great importance. Accordingly the search for passive cases conducted by the public health system acquired major importance in the disease surveillance. As from 1981 to 1992 only 11% of the detected cases were considered as autochthonous. The main transmission areas are located at the Litoral and Paraiba Valley regions. In the period of time under analysis, the epidemiological surveillance data suggest a decrease in the morbidity and in the autochthony tendency in the State of São Paulo.

Control of schistosomiasis transmission.

Despite the success of control programmes, schistosomiasis is still a serious public health problem in the world. More than 70 countries where 200 million individuals are evaluated to be infected of a total 600 million at risk. Though there have been important local success in the control of transmission, globally the infection has increased. Economic constrains in developing countries, environmental changes associated with migration and water resources development have been blocking the progress. The main objective of schistosomiasis control is to achieve reduction of disease due to schistosomiasis. We discussed the control measures like: health education, diagnosis and chemotherapy, safe water supplies, sanitation and snail control. We emphasized the need to give priority to school-age children and the importance of integrating the measures of control into locally available systems of health care. The control of schistosomiasis is directly related to the capacity of the preventive health services of an endemic country. The strategy of control requires long-term commitment from the international to the local level.

[Epidemiology of schistosomiasis mansoni in a low endemic area]. / Epidemiologia da esquistossomose mansônica em área de baixa endemicidade.

We discuss the epidemiological patterns of schistosomiasis mansoni in areas with low transmission in Brazil. We define as areas of low endemicity those where the prevalence is less than 10%, the number Schistosoma mansoni eggs per gram of feces (epg) is less than 96, and carriers are asymptomatic. Data are from the county of Pedro de Toledo in the Ribeira Valley (São Paulo State) and were collected randomly according to the aggregate pattern of S. mansoni within the hosts. We suggest the replacement of parasitological methods by more sensitive and specific serological techniques. The main risk factor for infection is type of leisure activity. Infection is more frequent in the 10-14, 15-19, and 20-24-year age brackets. Geometric mean epg is 58.5. Intensity of infections correlates well (rs = 0.745) with prevalence. The highest index of potential contamination is in the 5-20-year age bracket (57.6%). Autochthonous cases show close association with Biomphalaria tenagophila, which has a low infection rate (2%). Prevalence, incidence, and intensity of infection patterns are similar to those of moderate and high endemic areas. Social and cultural aspects must be studied in order to obtain a global epidemiological view of schistosomiasis.

Schistosomiasis mansoni in an area of low transmission. II. Risk factors for infection.

Risk factors for Schistosoma mansoni infection were identified using a 1:1 matched case-control design. The work was conducted in the municipality of Pedro de Toledo, São Paulo State, Brazil, an area where the snail host is Biomphalaria tenagophila. Information on water contact patterns, knowledge, attitudes and practices (kap), socioeconomic and sanitary conditions were obtained by mean of questionnaires. The crude odds ratio estimates and the adjusted odds ratio estimates using the logistic regression model are presented. Most of the examined individuals admitted recent water contacts (90.6% of the cases). The most frequent reason for contact was swimming, playing and fishing and the preferential site of contact was the river. According to the logistic regression technique, the main risk factors for infection were: a) water contact through swimming, playing and fishing; b) fording; c) bad hygiene. We concluded that recreational activities are the main reasons for schistosomiasis transmission in Pedro de Toledo and leisure alternatives should be offered to the local population.

[Epidemic outbreaks of dermatitis caused by butterflies of the genus Hylesia (Lepidoptera: Hemileucidae) in São Paulo State, Brazil]. / Surtos epidêmicos de dermatite causada por mariposas do gênero Hylesia (Lepidóptera: Hemileucidae) no Estado de São Paulo, Brasil.

Epidemic outbreaks of dermatitis caused by Hylesia sp which occurred in the coastal region of the State of S. Paulo during the period of December 1989 to December 1991 are confirmed. The incident assumed its greatest intensity in Bertioga, in Santos County, where 612 cases were registered. The outbreak also affected 12 other counties in that region and it was estimated that hundred of affected persons sought the Local Health Service Care. The majority presented with erythematous and prutiginous lesions and papula which lasted 7 to 14 days on average. Treatment consisted of systemic administration of antihistamines, and the use of topic corticosteroids and cold compresses. During the above-mentioned period, three epidemic episodes, coinciding with the rainy season (November to January), occurred. They were first observed in the northern part of the coastal area and then spread to the south. Information as to how avoid contact with the moth was the main prophylactic measure. In highly infested buildings the effectiveness of residual insecticide procedure was used in the attempt to reduce the level of moth infestation. Satisfactory results were obtained with deltametrin applied in a dosage of 50 mg/m2 of wall.

[Control of schistosomiasis mansoni in an area of low transmission]. / Controle da esquistossomose mansônica em área de baixa transmissão.

The schistosomiasis is transmitted by Biomphalaria tenagophila in our study area (Pedro de Toledo, São Paulo, Brazil). From 1980 to 1990 epidemiological surveys in a population of 4,000 inhabitants, has shown that: prevalences by Kato-Katz (KKT), immunofluorescence (FT) and intradermal (IDT) techniques were 22.8%, 55.5% and 51.8%, respectively; intensity of infection was low, 58.5 eggs per gram of faeces (epg); there were no symptomatic cases; prevalences were higher in mates, children and rural zone; index of potential contamination was 57.5% in the age group 5 to 20 years; 2/3 of patients were autochthonous; cases were no-randomly aggregated; transmission was focal and only 0.4% of snails were infected; water contacts through recreation showed the most important odds ratio; knowledge, attitudes and practices were satisfactory. From the epidemiological findings a control programme was carried out: yearly faeces exams, chemotherapy, molluscocide, health education and sanitation. Thus, the prevalence decreased sharply to 3.3% and intensity of infection to 30.3 epg; the incidence rates ranged between 0.4% and 2.5% annually; the sanitation became better and the youngsters were the main target in prophylaxis. To improve control, immunodiagnosis has to be conducted and the involvement of the population should be increase. However, we cannot forget that re-infection, therapeutic failure, etc, could play a major role in the maintenance this residual prevalence.

Seroepidemiology of schistosomiasis mansoni.

In population surveys in which the Schistosoma mansoni intensity of infection is low, or in localities where the schistosomiasis control program had success, the parasitologic methods lack in sensitivity. Despite of some limitations, the immunological methods are useful to provide valuable information in such field conditions. Thus, the prevalence of schistosomiasis in untreated population can be determined by the detection of IgG or IgM antibodies, as well as the incidence by the IgA antibodies, employing mainly immunofluorescence (IF) and immunoenzymatic (ELISA), and in some extent hemagglutination (HA) or even skin test. The true prevalence and incidence of schistosomiasis can be estimated using a probabilistic model equation, since knowing before-hand the sensitivity and specificity of employed test. The sensitivity and the specificity of serologic test become higher in low aged group, under 14. The geometric mean IF titers also gives a positive correlation with the intensity of infection. Presently, there are need of serologic tests which are economic and practical in seroepidemiologic inquiries, requiring no specialized personnel to collect population blood or serum samples, and also easily interpret the test results. The reagents for such tests are desired to be stable and reproducible. Moreover, it is expected that the tests can distinguish an active infection.

Seroepidemioplogy of schistosomiasis mansoni

In population surveys in wich the Schistosoma mansoni intensity of infection is low, or in localities where the schistosomiasis control program had success the parasitologic methods lack in sensitivity. Despite of some limitations the immunological methods are useful to provide valuable information in such field conditions. Thus, the prevalaence of schistosomiasis in untreated population can be determined by the detection of IgG or IgM antibodies, as well as the incidence by the IgA antibodies , employing mainly immunofluorescence (IF) and immunoenzymatic (ELISA), and in some extent hemagglutination (HA) or even skin test. The true prevalence and incidence of schistosomiasis can be estimated using a probabilistic model equation, since knowing before-hand the sensitivity and specificity of emploved test. The sensitivity and the specificity of serologic test become higher in low aged group, under 14. The geometric mean IF titers also gives a positive correlation with the intensity of infection. Presently there are need of serologic tests wich are economic and pratical in soroepidemiologic inquires, requiring no specialized personnel to collect population blood or serum and also easily interpret the test results. The reagents for such tests are desired to be stable and reproducible. Moreover, it is expected that the tests can distinguish an ative infection

Carcinoid tumors of the appendix.

Forty-six carcinoid tumors of the appendix, diagnosed in surgically resected specimens during an 11-year period (1965 to 1975) were reviewed to determine the features of metastasizing tumors. Of the carcinoid tumors of the appendix, 8.8% were found to metastasize to regional lymph nodes. The most reliable criterion of metastasizing tumors was the size of the primary tumor. Such tumors measured 2.0 cm or larger in greatest dimensions. Depth of invasion, extension to serosa, perineural involvement, histologic features, and location of the tumor relative to the length of the appendix were common to both the metastasizing and localized tumors. The surgical management of patients with carcinoid tumors of the appendix is controversial, ranging from a simple appendectomy to a more radical operative procedure. In the absence of distant metastases, it would appear that this group of patients with tumors 2.0 cm or more would require a right hemicolectomy rather than a simple appendectomy to accomplish removal of all disease-bearing tissue.

Emergence of a new arbovirus disease in Brazil. II. Epidemiologic studies on 1975 epidemic.

In April, 1975, an outbreak of human encephalitis caused by Rocio virus, a new flavivirus, occurred in the coastal region of southern São Paulo, Brazil. The epidemic started during the second half of March, 1975, and ended in June, 1975. A total of 465 cases with 61 deaths were recorded, and the overall attack rate was 15 per thousand population. The mortality rate was two per thousand inhabitants and the overall case-fatality rate was 13%. However, the case-fatality rate was markedly decreased when adequate hospital care was provided. The number of cases in the 15--30 years age group was higher than in the other age groups and the rate was higher in males than in females. Lack of evidence of person-to-person transmission, based on a study of families involved in the epidemic and on the antigenic relationship to other mosquito-borne flaviviruses, suggested that the virus was transmitted by a vector and that wild animals were involved in the virus cycle.