Estelita Pereira Lima

Insecticide resistance in Aedes aegypti populations from Ceará, Brazil

BackgroundOrganophosphates and pyrethroids are used widely in Brazil to control Aedes aegypti, the main vector of dengue viruses, under the auspices of the National Programme for Dengue Control. Resistance to these insecticides is widespread throughout Brazil. In Ceará the vector is present in 98% of districts and resistance to temephos has been reported previously. Here we measure resistance to temephos and the pyrethroid cypermethrin in three populations from Ceará and use biochemical and molecular assays to characterise resistance mechanisms.ResultsResistance to temephos varied widely across the three studied populations, with resistance ratios (RR95) of 7.2, 30 and 192.7 in Juazeiro do Norte, Barbalha and Crato respectively. The high levels of resistance detected in Barbalha and Crato (RR95 ≥ 30) imply a reduction of temephos efficacy, and indeed in simulated field tests reduced effectiveness was observed for the Barbalha population. Two populations (Crato and Barbalha) were also resistant to cypermethrin, whilst Juazeiro do Norte showed only an altered susceptibility. The Ile1011Met kdr mutation was detected in all three populations and Val1016Ile in Crato and Juazeiro do Norte. 1011Met was significantly associated with resistance to cypermethrin in the Crato population. Biochemical tests showed that only the activity of esterases and GSTs, among the tested detoxification enzymes, was altered in these populations when compared with the Rockefeller strain.ConclusionsOur results demonstrate that two A. aegypti populations from Ceará are under strong selection pressure by temephos, compromising the field effectiveness of this organophosphate. Our results also provide evidence that the process of reducing resistance to this larvicide in the field is difficult and slow and may require more than seven years for reversal. In addition, we show resistance to cypermethrin in two of the three populations studied, and for the first time the presence of the allele 1016Ile in mosquito populations from northeastern Brazil. A significant association between 1011M et and resistance was observed in one of the populations. Target-site mechanisms seem not to be implicated in temephos resistance, reinforcing the idea that for the studied populations, detoxification enzymes most likely play a major role in the resistance to this insecticide.

Resistência do Aedes aegypti ao temefós em Municípios do Estado do Ceará

The susceptibility of Aedes aegypti to temefos was evaluated by means of samples of eggs and larvae from four large counties in the state of Ceara (Fortaleza, Barbalha, Juazeiro do Norte and Crato). The technique standardized by the World Health Organization for tests with larvicides was used. The CL50 of eight samples from populations of Aedes was determined, as were their respective resistance ratios, compared to the CL50 of the susceptible Rockefeller strain. All populations submitted to the experiment showed resistance to temefos, with resistance ratios varying between 8 and 16. Analysis of these results reinforces prior evidence regarding the dissemination of temefos resistance in different locations in the state, subjected to considerable pressure for control in recent decades. The larvicide may lose its effectiveness if an urgent attempt is not made to reestablish the susceptibility of Aedes aegypti in these areas, profoundly affecting control campaigns currently under way.

Activities of naphthoquinones against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae), vector of dengue and Biomphalaria glabrata (Say, 1818), intermediate host of Schistosoma mansoni

Larvicidal (against Aedes aegypti Linnaeus, 1762) and molluscicidal (against Biomphalaria glabrata Say, 1818) activities of several natural and synthetic naphthoquinones were measured, with significant results. The best larvicidal compound is 3-bromojuglone, while the better molluscicides are 2-bromo- and 3-bromo-5-acetoxy-1,4-naphthoquinones together with the 3-bromo-5-methoxy derivative. The present results reinforce the potential use of substituted hydroxyquinones, their salts and halogenated quinones as very promising compounds against 4th instar larves of Aedes aegypti, the vector of dengue and against adult snail of Biomphalaria glabrata.

Meta-analysis of studies on chemical, physical and biological agents in the control of Aedes aegypti

BackgroundAedes aegypti is a vector of international concern because it can transmit to humans three important arboviral diseases: yellow fever, dengue and chikungunya. Epidemics that are repeated year after year in a variety of urban centers indicate that there are control failures, allowing the vector to continue expanding.MethodsTo identify the most effective vector control strategies and the factors that contributed to the success or failure of each strategy, we carried out a systematic review with meta-analysis of articles published in 12 databases, from 1974 to the month of December 2013. We evaluated the association between the use of whatever chemical substance, mechanical agent, biological or integrated actions against A. aegypti and the control of the vector, as measured by 10 indicators.ResultsWe found 2,791 articles, but after careful selection, only 26 studies remained for analysis related to control interventions implemented in 15 countries, with 5 biological, 5 chemical, 3 mechanical and 13 integrated strategies. The comparison among all of them, indicated that the control of A. aegypti is significantly associated with the type of strategy used, and that integrated interventions consist of the most effective method for controlling A. aegypti.ConclusionsThe most effective control method was the integrated approach, considering the influence of eco-bio-social determinants in the virus-vector-man epidemiological chain, and community involvement, starting with community empowerment as active agents of vector control.

Epidemiologia e estatística: integrando ensino, pesquisa, serviço e comunidade

O novo modelo de saude brasileiro exige medicos dotados de visao social abrangente e capacitados para prestar a comunidade cuidados permanentes e resolutivos, bem como profissionais criticos diante da tomada de decisoes. Este relato descreve uma experiencia estrategica de ensino de epidemiologia e bioestatistica no curso de Medicina, cuja construcao do processo foi centrada no educando, que foi o agente dos conhecimentos adquiridos, por meio da producao de informacoes e da pesquisa na comunidade ou nos servicos de saude. Esta estrategia resultou na integracao e interdisciplinaridade academica, contribuindo para a compreensao de assuntos clinicos considerando a abordagem epidemiologica e estatistica. Os academicos despertaram para a importância da producao cientifica e da construcao do curriculo profissional ainda na fase academica, sendo capazes de identificar problemas locais e direcionar as intervencoes, e reconhecer que isto representa um dos objetivos mais importantes da pesquisa em saude. Os resultados indicam que a epidemiologia e a bioestatistica podem ser trabalhadas no curso de Medicina com o mesmo sucesso de outras disciplinas da clinica, desde que seja favorecida a aprendizagem significativa dos academicos.

Evaluation of the role of ATP-binding cassette transporters as a defence mechanism against temephos in populations of Aedes aegypti

The role of ATP-binding cassette (ABC) transporters in the efflux of the insecticide, temephos, was assessed in the larvae of Aedes aegypti. Bioassays were conducted using mosquito populations that were either susceptible or resistant to temephos by exposure to insecticide alone or in combination with sublethal doses of the ABC transporter inhibitor, verapamil (30, 35 and 40 μM). The best result in the series was obtained with the addition of verapamil (40 μM), which led to a 2x increase in the toxicity of temephos, suggesting that ABC transporters may be partially involved in conferring resistance to the populations evaluated.

Exposição a pesticidas e repercussão na saúde de agentes sanitaristas no Estado do Ceará, Brasil

Sanitary agents are the most exposed ones to the effects of insecticides in eradication campaigns since its preparation until its application inside and outside houses. The lack of protection equipment and misinformation on how to use the material properly increase the risk of intoxication. The aim of this work was to analyze the occupational history of vector control sanitary agents in Ceara State, Brazil and its effects on their health. Individual recorded interviews were done with 10 agents who verbally described their life history. The content of these interviews were analyzed through the following categories: agent profile, endemic controls, work conditions, risks and health changes. Health risk situations were described from acute and chronic intoxication to problems with alcoholism. The research showed that sanitary agents have been disrespected as human beings as well as their labor rights, showing negligence by their employers.

The HLA-DRB1 Alleles Effects on Multiple Sclerosis:a Systematic Review

Background: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that affects sensitive and motor functions. Many population studies were made with the intent of knowing better the most affected groups and the disease manifestations. These review analyses some of those studies, evaluating risk factors, especially genetic relations of Human Leukocyte Antigen DRB1 (HLADRB1) gens, for developing clinical disease. Method: We have analyzed 57 articles, published between 2009 and 2014, with the key words “multiple sclerosis”, “genetic association studies” and “HLA-DRB1 chains”, through the Scopus database. Only 18 articles were eligible for our study; they were read entirely and included in the fial analysis. Results: Most studies imply genetic and environmental factors for the incidence of MS, its age of starting and prognosis. Previous studies have shown that many gens are related in MS pathogenesis and that interactions between them are important in determining clinical manifestations. Limitations: Different results were observed when different populations were targeted in the studies. Conclusion: There is an important relation between HLA-DRB1 and MS in diverse population groups. Complementary studies are needed to know better the importance of environmental factors and its interaction with gens in the development of MS.

Prevalence of teenagers with disabilities in a medium-sized municipality

Introduction: Despite variations in the beginning and the end, adolescence is the second decade of life, 10-19 years. According to the World Report on disability among those individuals aged 0-14 years of age, 93 million had severe or moderate disabilities and 13 million severe disabilities. Therefore, this study aimed to identify adolescents with hearing, visual and physical impairment. Methods: A quantitative transversal study of a medium-sized municipality. Data was collected at interviews conducted by community health workers, with an instrument containing sociodemographic data and impairment characteristics. Data was organized in spreadsheets and analyzed for correlations between types of disabilities and other variables by chi-square test. Statistical significance was verified by a 0.05 level. Results: Physical disability prevailed over visual and auditory. An association was found between disability and level of education (p = 0.023). Conclusion: Support and incentive education policies are necessary among the disabled.

Conhecimentos em atenção pré-hospitalar e suporte básico de vida por estudantes recém-ingressos de medicina

Reconhecer sinais iminentes de morte em vitimas de trauma, acidente vascular encefalico e acidentes domesticos constitui parte do Suporte Basico de Vida (SBV), acao fundamental a pratica medica. Objetivou-se investigar o conhecimento em manobras no SBV e urgencias domiciliares entre estudantes recem-ingressos de Medicina. Estudo quantitativo, analitico e quase-experimental, realizado com estudantes do primeiro semestre 2012.2 do curso de Medicina de universidade publica do Ceara - Campus Cariri em Barbalha (CE), Brasil. Os dados foram coletados em fases. Na primeira etapa, aplicou-se um questionario com 40 perguntas de multipla escolha sobre manobras de atendimento pre-hospitalar em SBV como pre-teste de forma presencial. A segunda etapa consistiu num minicurso de 20 horas com profissional treinado. Na terceira fase, utilizou-se pos-teste para comparar as questoes acertadas antes e depois do curso. Quanto aos conhecimentos adquiridos, houve acrescimo nos temas traumatismo raquimedular, liberacao de vias aereas e cuidados domiciliares. Ha necessidade de realizar cursos com maior carga horaria para fundamentar uma pratica medica centrada nos temas de menor rendimento dos estudantes.