The control of Chagas' disease transmission in Mambaí, Goiás-Brazil (1980-1981)

BHC application in Mambai in 1980 resulted in a significant decline but not elimination of domiciliated T. infestans. T. sordida peridomestic populations persist and could pose a threat to interupting human transmission of T. cruzi The results of one massive attack spray application alone was compared with this application plus one selective application as regards the presence of T. infestans in houses oneyear later. No significance difference could be detected. It is likely that for interruption of T. infestans transmission cheaper procedures can be devised than those currently in use. A further pilot study of a virgin community afflicted by T. infestans transmission is indicated since Mambai cannot be regarded as a representative areafor those still awaiting insecticide application.

Control of parasitic infections among school children in the peri-urban area of Botucatu, São Paulo, Brazil

Tide prevalence of intestinal parasitosis ivas investigated in a primaiy school located in Rubiâo Júnior, a peri-urban district of Botucatu, São Paulo slate, Brazil, in order to assess the effect of treatment and practical measures of prophylaxis in the control of parasitic infections among 7-to- 18-year-old school children of a low socio-economic status. The first series of parasitological examinations included 219 school children, ef which 123 (56.1 %) were found to be infected with one or more parasite species. Eighty- four children canying pathogenic parasites were submitted to various anti-parasitic treatment schedules. We re-evaluated 15 (89 %) students after 4 to 6 months post- chemotherapy. The results indicate that the combination of treatment with prophylactic measures has been successful in the control of parasitic infections, since reinfection rates were generally low (< 5-3 %), except for Giardia lamblia infections (18.6 %), and a marked reduction oti the prevalence rates was obsewed with a significant percentage of cure (> 73-1 %) in children infected with most parasite species. The reasons for the apparent failure in the control of infections caused by Hymenolepis nana and Strongyloides stercoralis are discussed.

The control of Latin American trypanosomiasis

The author presents his personal point of view on the present situation of Chagas' disease control in Latin America countries. He compares the situation with African trypanosomiasis. He comments on the existence of cases in other Continents. He emphazises the success of the fighting against domiciliated triatomine bugs by using residual inseticides. He discusses other forms of Trypanosoma cruzi transmission.

Control of intestinal helminths in schoolchildren in Low-Napo, Ecuador: impact of a two-year chemotherapy program

A school-based control program of intestinal helminths was undertaken among schoolchildren in the Low-Napo region, north-eastern Ecuador. Forty-eight percent of children were infected with one or more helminths at the first examination. The prevalence at the baseline was Ascaris 33.2% followed by hookworm 24.1% and Trichuris 6.5%. Sex was found to be a significant factor influencing the prevalence of hookworm and Trichuris. Prevalence was compared 9 months and 18 months after treatment. After 9 months, Ascaris and Trichuris prevalence had decreased but not hookworm. All of them increased after 18 months. The findings suggest that only a course of mebendazol had a minor effect on the control of helminth infections.

Low frequency of side effects following an incidental 25 times concentrated dose of yellow fever vaccine

In August/1999, a group of 14 adults from the staff of a private hospital in Contagem -- Minas Gerais State, Brazil, received unintentionally a 25 times concentrated dose of the 17-DD yellow fever vaccine (Bio-Manguinhos), due to a mistake at the reconstitution step. All patients were clinically and laboratorially evaluated at days 5, 13 and 35 post vaccination. Frequency of side effects and clinical observations of this group of individuals were not different from the observed in recipients immunized with normal doses of the vaccine. At the second and third evaluation none of the subjects reported symptoms. None of the patients presented abnormalities at the physical examination at none of the time points and in all cases the blood examination was normal, except for a reduced number of platelets that was detected in one subject at the first and second evaluation and reverted to normal at third evaluation. At the first evaluation point, 8 subjects were serum negative and 6 serum positive for yellow fever at the plaque reduction neutralization test. In 5 subjects the observed titre was 10 times higher as the baseline of 2.36 Log10 mUI/ml. The samples collected at second and third evaluation (13th and 35th days) demonstrated that all subjects responded to the vaccination with the exception of one that did not present a positive result in any of the samples collected. This evaluation confirms the safety of the 17-DD yellow fever vaccine.

Larval control of Anopheles (Nyssorhinchus) darlingiusing granular formulation of Bacillus sphaericus in abandoned gold-miners excavation pools in the Brazilian Amazon Rainforest

INTRODUCTION: Use of a Bacillus sphaericus based mosquito larvicide was evaluated as an intervention for malaria vector control at a mining site in Amapá, Brazil. Impacts on larval and adult densities of the primary vector Anopheles darlingi were measured over the course of a 52 week study period.METHODS: In Calçoene, State of Amapá, gold mining activity occurs in 19 mining sites in gold-miners of Lourenço. Large pools are formed in mining sites and naturally colonized by Anopheles darlingi. During one year, the impact of applications of VectoLex(r) CG to these larval sources was evaluated. Applications of 20kg/ha were made as needed, based on 10 immature (3rd, 4th instars and pupae) surveillance of health and established thresholds. RESULTS: One hundred percent initial control was observed 48h after each treatment. The pools received from 2-10 (5.3±1.6) treatments during the year. The average re-treatment interval in productive pools was 9.4±4.3 weeks. During weeks 3-52 of the study, mean density of late stage larvae was 78% and pupae were 93% lower in the treated pools than in untreated pools (p< 0.0001, n=51) while reduction of adult mosquitoes was 53% in comparison to the untreated area during the last five months of the study, which were the rainy season (p<0.001).CONCLUSIONS:VectoLex(r) CG reduced immature Anopheles darlingi infestation levels during the entire study period, and reduced adult mosquito populations during the rainy season.

Impact of insecticide resistance on the field control of Aedes aegypti in the State of São Paulo

IntroductionThe need to control dengue transmission by means of insecticides has led to the development of resistance to most of the products used worldwide against mosquitoes. In the State of São Paulo, the Superintendência de Controle de Endemias(SUCEN) has annually monitored the susceptibility of Aedes aegypti to insecticides since 1996; since 1999, surveys were conducted in collaboration with the National Network of Laboratories (MoReNAa Network) and were coordinated by the Ministry of Health. In this study, in addition to the biological characterization of insecticide resistance in the laboratory, the impact of resistance on field control was evaluated for vector populations that showed resistance in laboratory assays.MethodsField efficacy tests with larvicides and adulticides were performed over a 13-year period, using World Health Organization protocols.ResultsData from the field tests showed a reduction in the residual effect of temephos on populations with a resistance ratio of 3. For adults, field control was less effective in populations characterized as resistant in laboratory qualitative assays, and this was confirmed using qualitative assays and field evaluation.ConclusionsOur results indicated that management of resistance development needs to be adopted when insect populations show reduced susceptibility. The use of insecticides is a self-limiting tool that needs to be applied cautiously, and dengue control requires more sustainable strategies.

The residual effect of deltametrine in the control of Malaria as observed on fifferent types Of walls In the Brazilian Amazon 1

The residual power of deltametrine FW (25 mg 1 .a/m2) was evaluated and compared to that of DDT (2 g i.a./m2) by means of biological tests. The different kinds of material used in constructing houses in Amazonia, such as: masonry, wood, and wattle and daub, were used. Data from logistic regression showed that the drop in mortality, the inclination of the curve in relation to time, was similar for the two insecticides in the first samples. The negative coeficient for the variable, months after application, confirmed a reduction in the activity of both insecticides. Wooden and wattle walls showed positive and negative coeficiencies respectively from the beginning. The wooden walls retained a residual effect but the wattle walls were shown to be the least indicated for the application of insecticides The experiments demonstrated a more prolonged residual effect for deltametrine as compared to DDT, and that insecticides work better on brick and cement and wooden walls than they do on wattle and daub constructions. For these reasons, it would be necessary to spray brick and cement walls every 8 months, wooden ones every 9 months and wattle constructions every 7 months to control the vectors of malaria.

Adaptação transcultural da escala Locus of Control of Behaviour para o português: versão para idosos

Objetivo Apresentar a adaptação transcultural da escala Locus of Control of Behavior (LCB) para a língua portuguesa falada no Brasil. Métodos O processo de adaptação foi realizado em cinco etapas: tradução, retradução, avaliação da equivalência entre a retradução e a escala original, elaboração de uma versão pré-teste e aplicação na população-alvo composta por 16 idosos (56 a 80 anos), com quatro anos mínimos de escolaridade. Resultados A versão adaptada não gerou problemas de compreensão, aceitabilidade ou impacto emocional negativo. Conclusão Este trabalho torna disponível a primeira versão em Português da LCB, uma escala que tem sido particularmente utilizada para avaliar o tipo de locus de controle (LoC) no que concerne ao prognóstico de tratamentos em saúde mental.