Estudos sobre o «vermelhão» do algodoeiro (III)

In several cotton crops areas of the State of S. Paulo it was observed, during the years of 1948, 1949, and 1951, the appearance of a purple color of the leaves; the color appears in the opening of the bolls and was correlated with a decrease of production. The opinions concerning the cause of such abnormality were very different and sometimes contradictory; certain investigators attributed the disease to insect attack, others to bad climatic conditions whereas others to a potassium deficiency now called "fome de potássio" (potash hunger); our ideas on the subject is another one. We think that the disease is caused by lack of a suitable supply of magnesium. This opinion is largely based on the syntomatology found in the literature. To study the problem, several experiments were carried out, namely: 1. pot experiments using soil collected in areas where the disorder had appeared; 2. pot experiments controlling the water supply; 3. sand culture experiments omitting either potassium or magnesium; 4. leaf analysis of plant matrial collected troughout the Piracicaba County; 5. plot experiments with the varieties Texas, Express, and I.A. 817 Campinas. The first four experiments were discussed elsewhere. To study the point 5 an experiment was carried out, with the following treatments : 1 - NPKCaMg (no K added) - Mg supplied as MgSO4 (a soluble form); 2 -NPKCa (no Mg added); 3 -NPKCaMg (complete) - Mg supplied as MgSO4; 4 - NPKCaMg (complete) - Mg supplied as dolomitic limestone (a slightly soluble form) as a rate 2.5 higher than in the treatment 1 and 3. Organic matter as cottonseed meal was applied in the proportion of 500 kg per hectare. The experimental design was randomized blocks with 4 replications and the results can be summarized as follows: 1 the I.A 817 variety was the most strongly affected by the physiological disorder, with severe decrease in yield; 2. the disease occurred more frequently in the minus magnesium treatment; 3. dolomitic limestone is so effective as magnesium sulfate in the control of the disease as well in the raising of the yield; 4. in the minus K treatment it was observed a marked occurrence of the typical symptoms of potassium deficiency (cotton rust); 5. magnesium was actually, in the experimental conditions the responsible for the purple color (vermelhão) of the cotton leaves.

Memoria – beca BE2005

Report for the scientific sojourn at the Centre for Interdisciplinary studies in Environment and Development (CISED), located in Bangalore (Southern India), from September to December 2005. A field-work in the South Indian city of Chennai (former Madras) was developed to analyse the mounting urban (and peri-urban) water crisis. In view of tackling this matter, the state government has done a deal to construct a 100 million litres per day seawater desalination plant. Due to its relative energy-intensiveness (compared to conventional water supply means), the fact that such a large capacity plant will be located in poor country such as India, constitutes somewhat of a surprising novelty, as most desalination facilities in the world are to be found in the oil-rich Persian Gulf countries. This work faces the environmental impact, the energy-intensive technology required, the cost and the missed water management options

Health education for children in the control of Schistosomasis

Health education for children is an important measure in the control of schistosomiasis especially considering the characteristics of the disease during childhood, such as high prevalence, high percent of treatment resistance, high rates of egg elimination and high level of reinfection, as reported in studies conducted in endemic areas. All of these facts indicate that children play a role in the maintenance and transmission of schistosomiasis. Historically in Brazil, Health Education concerning the major Brazilian endemies consists of a kind of vertical, interventionist and temporary action. An alternative would be to create a permanent health education process by assigning health education teachers to elementary schools. This would require expansion and improvement of teacher training and the development of programs taking into account: 1) the cognitive aspects of the child, the child's perception of reality and of the health/illness process; 2) the adaptation of instruction means and materials to the age group; 3) a "pedagogy of liberation" approach emphasizing the possibility of transforming life conditions since schistosomiasis is related to the lack of public services such as basic sanitation and clean domestic water supply.

Inter-Connectedness In The Scottish Economy, 1998-2004

The measurement of inter-connectedness in an economy using input-output tables is not new, however much of the previous literature has not had any explicit dynamic dimension. Studies have tried to estimate the degree of inter-relatedness for an economy at a given point in time using one inputoutput table, some have compared different economies at a point in time but few have looked at the question of how inter-connectedness within an economy changes over time. The publication in 2009 of a consistent series of inputoutput tables for Scotland offers the researcher the opportunity to track changes in the degree of inter-connectedness over the seven year period 1998 to 2004. The paper is in two parts. A simple measure of inter-connectedness is introduced in the first part of the paper and applied to the Scottish tables. It is shown that although the aggregate results might appear to indicate a degree of import substitution was taking place this result is not robust to industrial disaggregation. In the second part of the paper an extraction method is applied to an eleven sector disaggregation of the Scottish economy in order to estimate how interconnectedness has changed over time for each industrial sector. It is shown that for the majority of sectors the degree of interconnectedness with the rest of the Scottish economy has grown for others, in particular Financial Services and Energy and Water Supply it has not.

Experiences with the control of schistosomiasis mansoni in two foci in Central Africa

Experiences with population-based chemotherapy and other methods for the control of schistosomiasis mansoni in two subsaharan foci are described. In the forest area of Maniema (Zaire), intense transmission of Schistosoma mansoni, high prevalences and intensities of infection, and important morbidity have been documental. Taking into account the limited financial means and the poor logistic conditions, the control strategy has been based mainly on targeted chemotherapy of heavily infected people (>600 epg). After ten years of intervention, prevalences and intensities have hardly been affected, but the initial severe hepatosplenic morbidity has almost disappeared. In Burundi, a national research and control programme has been initiated in 1982. Prevalences, intensities and morbidity were moderate, transmission was focal and erratic in time and space. A more structural control strategy was developed, based on screening and selective therapy, health education, sanitation and domestic water supply. Prevalences and intensities have been considerably reduced, though the results show focal and unpredicatable variations. Transmission and reinfection were not signifcantly affected by chemotherapy alone, and eventual outcome of repeated selective treatment appears to be limited by the sensitivity of the screening method. Intestinal morbidity was strongly reduced by community-based selective treatment, but hepatosplenic enlargement was hardly affected; this is possibly due to the confounding impact of increasing malaria morbidity. The experiences show the importance of local structures and conditions for the development of an adapted control strategy. It is further concluded that population-based chemotherapy is a highly valid tool for the rapid control of morbidity, but should in most operational conditions not be considered as a tool for transmission control. Integration of planning, execution and surveillance in regular health services...

Some personal views on the control of schistosomiasis mansoni

Our views are based, on a recent study of a district of Uniao dos Palmares (Alagoas). Although being a very compact community (32 city blocks holding two thousand families), transmission is very uneven, the geometric mean egg counts in the various blocks ranging between extremes of 96 and 1920. (Results do not correlate with the availability of domestic water supply). We thus are led to conclude that: (a) transmission is primarily peridomestic, resulting from pollution of open ditches and other collections of water; (b) control of transmission can be done on a selective basis, requiring quite medest investments. Given the inefficacy of population-based chemotherapy, when used alone, the author insists that this alternative cannot any longer be overlooked. He also regrets the emphasis placed upon vaccine development; allegations that this would, at any rate, prevent severe morbidity can be dismissed, since-whatever the cause-morbidity due to schistosomiasis has been rapidly declining in Northeast Brazil.

Control of schistosomiasis in Brazil: perspectives and proposals

Attempts to control schistosomiasis have hitherto involved the use of one or more of the following methods, either in isolation or in combination: (1) control of the intermediate host using molluscicides or biological methods; (2) basic sanitation and clean water supply; (3) health education; (4) individual or mass treatment; (5) protection of individuals in such a way as to prevent cercariae from penetrating the skin; (6) vaccine-based strategies against schistosomiasis. None of these methods is capable, on its own, of bringing about effective control of schistosomiasis, except in populations of a very limited size or under very special conditions. Molluscicides, besides expensive and toxic, have only a temporary effect. As for biological control, there is no effective method yet. Basic sanitation and clean water supply combined with health education potentially constitute the most effective approach, but only in the mid-to-long term. Mass treatment reduces morbidity, but does not control transmission. Protection of individuals has proved to be impracticable on a large scale. Vaccine-based strategies against schistosomiasis are still in the experimental stage. Experiments carried out in Brazil in the last 20 years have shown that mass treatment with single doses of oxamniquine or praziquantel can rapidly reduce levels of Shistosoma mansoni infection and morbidity in endemic areas. They have also shown that subsequent transmission and reinfection frequently occur in defined foci or "clusters", due to human contact with water, and in inverse proportion to the number and frequency of treatments carried out. On the basis of these experiments, the author suggests a multidisciplinary strategy for schistosomiasis control.

Schistosomiasis control in China

After three decades' efforts, schistosomiasis japonica were controlled in one-third (4/12) of endemic provinces and 68.2 (259/380) of endemic counties throughout the country. The remaining 121 endemic counties are located primarily in the lake and mountainous regions. The epidemiological and ecological features of the lake and mountainous areas are different from the other endemic areas. The major schistosomiasis control efforts in China can be characterized as follows: (1) Application of centralized leadership and management, since schistosomiasis control is a task not only of the Ministry of Public Health, but also of all local governments in the endemic areas; (2) Integration of actions taken by various departments or bureaus, such as agriculture, water conservation and public health; (3) Promotion of mass participation; (4) Organization of strong professional teams; (5) Raising sufficient funds. Strategies on schistosomiasis control applied in different areas are divided into three levels: (1) In the areas where the schistosomiasis has been successfully controlled, surveillance must be maintained and immediate action should be taken where new infections occur and/or vector snails are found, so that control can be reestablished quickly; (2) In the areas where schistosomiasis has been partially controlled, any residents and/or live-stock infected should be examined and treated promptly with due care, and environment modifying and/or mollusciding must be used to eliminate the remaining snails; (3) In the areas where transmission has not been controlled, the main strategy is to control morbidity. Mass or selective chemotherapy with praziquental should be applied to both infected persosns and the live-stock, and environment modification for the snail-ridden areas should be taken but should be coordinated with agriculture where possible. Advance cases must be treated; and epidemics of Katayama fever prevented; water supply and sanitation shoud be improved and health education emphasized. Annual mass or selective chemotherapy with praziquental both reduces the prevalence rate and decreases the intensity of the infection for inhabitants and live-stock. As a consequence of the therapy a low prevalence rate can be obtained in a short time. The length of such arrangement period can be decided in accordance with the prevalence of the infection before the drug program is begun. Therefore,a maintenance phase is urgently needed. As China's ecomony expands and people's living standard rises, schistosomiasis will be controlled more effectively and successfully.

Schistosomiasis in a low prevalence area: incomplete urbanization increasing risk of infection in Paracambi, RJ, Brazil

The risk of schistosomiais infection and heavy infection in the locality of Sabugo was evaluated in relation to housing in areas with different urbanization development and to residential supply with snail-infested water. Critical sanitary conditions were found in areas of incomplete urbanization, where healthy water supply sources were scarce, and draining of sewage, without previous treatment, was made directly to the water-bodies used for domestic and leisure activities, despite being Biomphalaria tenagophila snail breeding-places. Stool examinations (Kato-Katz and Lutz methods) showed prevalence of 2.9%, mean intensity of 79 eggs per gram of stool and 47% of positive cases presenting intense infection. The use of snail-contaminated water for domestic purposes was considered a risk factor for infection. It is concluded that incomplete urbanization would facilitate transmission, probably enhancing the intensity of infection and that a low prevalence could hide a highly focal transmission. The relevance of these facts upon the efficiency of epidemiologic study methods and disease control planning are then discussed.

Schistosomiasis control in Brazil

In 1975 the Special Programme for Schistosomiasis Control was introduced in Brazil with the objective of controlling this parasitic disease in six northeastern states. The methodology applied varied largely from state to state, but was based mainly on chemotherapy, This Programme was modified about ten years after it beginning with the main goals including control of morbidity and the blockage of establishment of new foci in non-endemic areas. In two states, Bahia and Minas Gerais, the schistosomiasis control programme started in 1979 and 1983, respectively. The recently made evaluation of those two programmes is the main focus of this paper. It must also be pointed out, that the great majority of the studies performed by different researchers in Brazil, at different endemic areas, consistently found significant decrease on prevalence and incidence, when control measures are repeatedly used for several years. Significant decrease of hepatosplenic forms in the studied areas is well documented in Brazil. After more than 20 years of schistosomiasis control programmes in our country, chemotherapy has shown to be a very important tool for the control of morbidity and to decrease prevalence and incidence in endemic areas. Nevertheless, in medium and long terms, sanitation, water supply, sewage draining and health education seem to be the real tools when the aim is persistent and definitive schistosomiasis control.

Hepatitis A Outbreak in a Public School in Rio de Janeiro, Brazil

From June 1 to July 1 1999, an outbreak involving 25 cases of hepatitis A occurred in a public school in Rio de Janeiro, Brazil. Since these cases were notified to the State Health Department, the National Reference Center for Hepatitis Viruses (CNRHV) was required to investigate the extent of hepatitis A virus (HAV) dissemination. Blood samples from all students were tested for IgM and total anti-HAV antibodies using a commercial enzyme-linked immunoassay (ELISA). At the same time, a questionnaire was completed in order to identify possible risk factors for HAV infection. The environmental investigation showed that there was no fecal contamination of the water supply. The epidemiological investigation demonstrated that almost 50% of this population was susceptible to HAV infection and probably person-to-person transmission was the principal mode of virus dissemination. In this situation, a massive vaccination campaign could control the HAV infection.

Schistosomiasis mansoni in Bananal (State of São Paulo, Brazil): II. Intermediate hosts

We conducted monthly snail captures in Bananal, State of São Paulo, Brazil, between March 1998 and February 2001, to identify Schistosoma mansoni vectors, estimate seasonal population changes, and delimit foci. We also evaluated the impact of improvements in city water supply and basic sanitation facilities. We identified 28,651 vector specimens, 28,438 as Biomphalaria tenagophila, 49 of them (0.2%) infected with S. mansoni, and 213 as B. straminea, none of the latter infected. Vectors predominated in water bodies having some vegetation along their banks. Neither population density nor local vegetation could be linked to vector infection. We found the first infected snails in 1998 (from March to May). Further captures of infected snails ocurred, without exception, from July to December, when rainfall was least. Irrespective of season, overall temperature ranged from 16.5ºC to 21ºC; pH values, from 6.0 to 6.8. Neither factor was associated with snail population density. Frequent contact of people with the river result from wading across it, extracting sand from its bottom, fishing, washing animals, etc. Despite a marked reduction in contamination, cercaria shedding persists. Whatever the location along its urban course, contact with river Bananal, particularly of the unprotected skin, entails risks of infection.

Epidemiological and control aspects of schistosomiasis in Brazilian endemic areas

The present work analyzes the epidemiology of schistosomiasis in Brazil, its expansion, the attempts to control the disease, and the overall difficulties. The authors present the distribution of schistosomiasis intermediary hosts in Brazil, the migration routes of the human population, and disease distribution in highly and lowly endemic areas and isolated foci. They also analyze the controlling programs developed from 1977 to 2002, indicating the prevalence evolution and the reduction of disease morbi-mortality. In addition, the authors also evaluate controlling methods and conclude that: (a) no isolated method is able to control schistosomiasis, and every controlling program should consider the need of a multidisciplinary application of existing methods; (b) in long term, basic sanitation, potable water supply, as well as sanitary education, and community effective participation are important for infection control; (c) in short term, specific treatment at endemic areas, associated with control of intermediary hosts at epidemiologically important foci, are extremely relevant for controlling disease morbidity, although not enough for interrupting infection transmission.

The spatial distribution of Schistosoma mansoni infection before and after chemotherapy in the Jequitinhonha Valley in Brazil

Schistosomiasis prevalence and egg counts remained low one year after chemotherapy in most households in a hyperendemic rural area in northern Minas Gerais but several distinct spatial patterns could be observed in relation to IgE levels and to a lesser extent to exposure risk (TBM) and type of water supply. An inverse relationship between pre-treatment household prevalence and egg counts on the one hand and post-treatment IgE levels on the other were noted in two of the five communities. Low exposure risk was associated with the low pre-treatment infection rates in the central village but did not contribute to the decline of infection rates after chemotherapy in the study area, as indicated by the significant increase in water contact during the posttreatment period (p < 0.0001). Distance between households and the streams and socioeconomic factors were also unimportant in predicting the spatial distribution of infection. These results are consistent with the production and antiparasitic effect of high levels of IgE in Schistosoma mansoni infection.

Urban malaria in the Brazilian Western Amazon Region I: high prevalence of asymptomatic carriers in an urban riverside district is associated with a high level of clinical malaria

Cross sectional studies on malaria prevalence was performed in 2001, 2002, and 2004 in Vila Candelária, an urban riverside area of Porto Velho, Rondônia, in the Brazilian Western Amazon, followed by longitudinal surveys on malaria incidence. Vila Candelária is a working class district, provided with electricity, water supply, and basic sanitation. Previous preliminary surveys indicated high malaria incidence in this community. At the end of year 2000 regular diagnostic and treatment measures for malaria were introduced, with active search of febrile cases among residents. Despite of both rapid treatment of cases and relative good sanitary and housing conditions, the malaria incidence persisted at high levels during the following years with an annual parasite index of 150 to 300/1000 inhabitants. Parasite surveys in 2001, 2002, and 2004 achieved through microscopy and polymerase chain reaction to diagnose malaria showed a constant high prevalence of asymptomatic carriers for both Plasmodium falciparum and P. vivax parasites. It was concluded that asymptomatic carriers represent an important reservoirs of parasites and that the carriers might contribute to maintaining the high level of transmission. Comparing our findings to similar geo-demographic situations found in other important urban communities of the Brazilian Amazon, we propose that asymptomatic carriers could explain malaria's outbreaks like the one recently observed in Manaus.