[Hearing health of workers exposed to noise and insecticides]

Effect of delayed mating on reproductive performance and life-history parameters of dengue vector Aedes aegypti

Dengue is a fast-spreading mosquito-borne viral disease in the world. The primary vector of the disease is Aedes aegypti of the family Culicidae. It is a container breeder. Since a vaccine or a drug has not been developed against dengue, vector control appears to be the best method so far to control dengue. The current study was conducted to determine the effect of delayed mating on fecundity, fertility, life-history parameters, and longevity of Ae. aegypti, because such information can help formulate integrated vector control strategies involving the release of sub-fertile males into the environment. During this study, mating was delayed by 0, 2, 5, and 8 days after emergence. Males and females were separated by hand at the pupal stage using the apparent size difference of the sexes. The separated pupae were kept in separate cages until emergence. When mating was delayed for 8 days, the number of eggs laid by the female declined by 38%, and the percentage number of eggs that hatched reduced by 24%. However, the percentage of larval mortality, duration of the larval and pupal periods, and adult longevity were not significantly affected. The current results indicate that delayed mating has a negative effect on the reproductive performance of vector mosquitoes.

Exploring the effects and mechanisms of organophosphorus pesticide exposure and hearing loss

Many environmental factors, such as noise, chemicals, and heavy metals, are mostly produced by human activities and easily induce acquired hearing loss. Organophosphorus pesticides (OPs) constitute a large variety of chemicals and have high usage with potentiate damage to human health. Moreover, their metabolites also show a serious potential contamination of soil, water, and air, leading to a serious impact on people's health. Hearing loss affects 430 million people (5.5% of the global population), bringing a heavy burden to individual patients and their families and society. However, the potential risk of hearing damage by OPs has not been taken seriously. In this study, we summarized the effects of OPs on hearing loss from epidemiological population studies and animal experiments. Furthermore, the possible mechanisms of OP-induced hearing loss are elucidated from oxidative stress, DNA damage, and inflammatory response. Overall, this review provides an overview of OP exposure alone or with noise that leads to hearing loss in human and experimental animals.

Findings on the Central Auditory Functions of Endemic Disease Control Agents

This study aimed to assess the central auditory functions of endemic disease control agents. This cross-sectional cohort study comprised two groups: the exposed group, with 38 male endemic disease control agents with simultaneous occupational noise and pesticide exposure; and the control group, with 18 age- and sex-matched workers without occupational noise and/or pesticide exposure. All participants underwent pure-tone audiometry, brainstem auditory evoked potentials, dichotic digits test, and transient-evoked otoacoustic emissions suppression effect. There was a significant inter-group difference in waves III and V absolute latencies, and interpeak I-III and I-V latencies bilaterally, with worse results found in the exposed group. Abnormal dichotic digits test results occurred more often in the exposed group, with a significant association between pesticide- and noise-exposure and the abnormal results (p = 0.0099). The transient-evoked otoacoustic emissions with suppression effect did not yield significant inter-group differences. It was concluded that pesticide and noise exposure induce harmful effects on the central auditory functions, particularly on the brainstem and figure-ground speech-sound auditory skills.

The coexistence of fast and slow diffusion processes in the life cycle of Aedes aegypti mosquitoes

A new model that describes the life cycle of mosquitoes of the species Aedes aegypti, main carriers of vector-borne diseases, is proposed. The novelty is to include in the model the coexistence of two independent diffusion processes, one fast which obeys the constitutive Fick’s law, the other slow which satisfies the Cattaneo evolution equation. The analysis of the corresponding ODE model shows the overall stability of the Mosquitoes-Free Equilibrium (MFE), together with the local stability of the other equilibrium point admitted by the system. Traveling wave type solutions have been investigated, providing an estimate of the minimal speed for which there are monotone waves that connect the homogeneous equilibria allowed by the system. A special section is dedicated to the analysis of the hyperbolic model obtained neglecting the fast diffusive contribution. This particular case is suitable to describe the biological process as it overcomes the paradox of infinite speed propagation, typical of parabolic systems. Several numerical simulations compare the existing models in the literature with those presented in this discussion, showing that although the generalized model is parabolic, the associated wave velocity admits upper bound represented by the speed of the waves linked to the classic parabolic model present in the published literature, so the presence of a slow flux together with a fast one slows down the speed with which a population spreads.

Effects of subchronic inhalation exposure to an organophosphorus insecticide compound containing dichlorvos on wistar rats' otoacoustic emissions

Introduction

Considering that previous studies suggest that pesticides may cause hearing disorders in humans, as well as the lack of studies proving the specific mechanisms of injury and the difficulty of separating concomitant etiological factors of the hearing damage, such as noise and vibration, it is important to develop studies using animal models to elucidate the effects of exposure to those substances isolated from other hearing damage etiologies.

Objective

To evaluate if the exposure to a dichlorvos based organophosphorus insecticide may induce ototoxicity.

Methods

36 male Wistar rats were assigned to 3 groups (12 rats/group): control (exposed to water), positive control (treated with cisplatin to induce hearing damage) and experimental (exposed to dichlorvos based organophosphorus insecticide). The amplitude of distortion product otoacoustic emissions in the frequencies of 4, 6, 8, 10 and 12 kHz was evaluated before and after exposure, as well as systemic toxicity signs, body mass gain and plasma cholinesterase. Open field and plus maze tests were performed in 24 rats: experimental (n = 8), control (n = 8) and positive control group (n = 8 introduced new rats to induce anxiolytic activity) to evaluate the locomotor activity and anxiety, respectively.

Results

There was no significant change in body mass gain and plasma cholinesterase in the dichlorvos based organophosphorus insecticide group, however, the animals showed transient piloerection, depression and dyspnea during exposure. The behavior was not affected in any group. The frequencies of 8 and 10 kHz were significantly affected bilaterally in the insecticide group, which also showed a significant difference of the control in 10 kHz on the right and 8 and 10 kHz on the left ear.

Conclusion

Subchronic inhalation exposure to dichlorvos based organophosphorus insecticide induced ototoxicity in the cochlear function of rats without relevant systemic toxicity.

[High frequency hearing among rural workers exposed to pesticides]

Pesticides may cause a number of health problems and are considered oto-agressive agents. The objective of this study was to investigate the high frequency hearing characteristics of workers both with and without exposure to pesticides, that presented normal conventional audiometry. It involved a cross-sectional study with 87 workers, of both genders, between 19 and 59 years, with formal or informal jobs and some of whom worked with family agriculture, either using pesticides or not, who had taken High-Frequency Audiometry tests. The use of glyphosate was reported by 73% of workers and several pesticide mixtures occurred in 78% of them. There were no cases of proper use of personal protective equipment recommended for the activity. The workers exposed to pesticides had worse results in High-Frequency Audiometry tests in comparison with those who had no contact with pesticides (p < 0.0001). High-Frequency Audiometry has proved to be a useful and effective tool in the early detection of hearing loss caused by pesticides.

Study on hearing loss and its relationship with work in pesticide-exposed tobacco growers

ABSTRACT The Purpose of this case report is to present four cases of tobacco growers with hearing loss due to occupational exposure to pesticides. A qualitative case study comprising three cases of sensorineural hearing loss with causal nexus (Cases 1, 2 and 4), and one (Case 3) of sensorineural hearing loss compatible with ototoxicity by pesticides, with causal nexus mainly based on minor neuropsychiatric disorders. The sample was composed of rural workers with health problems, in working age, having started working early in life, exposed to various pesticides, including organophosphates. The auditory and neurovegetative symptoms reported were noise discomfort (n = 2), speech perception difficulty (n = 3), dizziness (n = 2), and imbalance (n = 2). The pure-tone audiometry revealed a sensorineural hearing loss in one or more high frequencies, and one of the cases presented alteration in the brainstem auditory evoked potentials. There is evidence, in this study, of an association between hearing loss and work in tobacco growers exposed to pesticides, with peripheral auditory damage in four cases, and central damage in one of them. Thus, the need for a complete audiological evaluation of pesticide-exposed populations is highlighted.

Ototoxicity of cypermethrin in Wistar rats

Introduction

This study presents the effect of cypermethrin on the cochlear function in Wistar rats post-subchronic inhalation exposure. Worldwide several pesticides are described as causing health disorders. Cypermethrin is currently one of the most commonly used, however, little is known about its harmful effects, especially related to hearing. Human studies have associated pesticides with hearing disorders, but they present limited conclusions due to the multiple factors to which the population is exposed, such as noise.

Objective

Mimic human exposure to cypermethrin and to verify the effects on cochlear function.

Methods

It is a subchronic inhalation animal study (6 weeks, 4 hours/day), using 36 male Wistar aged 60 day. Rats were randomly assigned into three groups: Control (12 rats exposed to inhalation of water); Positive Control for auditory lesion (12 rats administrated with 24 mg/kg intraperitoneal cisplatin); Experimental (12 rats exposed to inhalation of cypermethrin – 0.25 mg/L). Animals were evaluated by distortion product otoacoustic emissions pre- and post-exposure.

Results

The frequencies of 8, 10 and 12 kHz in both ears (right p = 0.003; 0.004; 0.008 and left 0.003; 0.016; 0.005 respectively) and at frequencies 4 and 6 in the right ear (p = 0.007 and 0.015, respectively) in the animals exposed to cypermethrin resulted in reduction.

Conclusion

Subchronic inhalation exposure to cypermethrin provided ototoxicity in rats.

The Importance of Otoneurological Evaluation in Brazilian Workers Exposed to Pesticides: A Preliminary Study

Introduction  Agrochemicals, also known as pesticides, are widely used in agriculture and in public health. They are organic and inorganic chemical substances with a high level of toxicity not only for the environment, but also for human health.

Objective To verify findings on labyrinthine assessment in endemic disease control agents, and to recommend the inclusion of the vestibular exam in the set of tests for pesticide-exposed populations.

Methods  Descriptive, prospective, cross-sectional study with a sample comprising 15 endemic disease control agents, males, mean age of 51.6 years old (standard deviation [SD] = 5.9). All of the participants were submitted to anamnesis, otorhinolaryngological screening, and vestibular assessment.

Results  Regarding the most reported complaints, dizziness (73.4%), headache (60%), and tingling in the extremities (53.4%) were observed. The findings of the vestibular exams were normal in 53.3%, while 46.7% showed peripheral vestibular disorder, of which 26.7% were of deficitary type, and 20% of the irritative type.

Conclusions:  Alteration in the vestibular system was verified in 50% of the workers, with a greater prevalence in the caloric testing. Several disorders related to pesticides intoxication are scientifically known. Actions promoting knowledge and qualification of this population for the proper handling of chemicals are suggested, in addition to the elaboration and inclusion of protocols of vestibular assessment in hearing health programs for the prevention, diagnosis and treatment of vestibular disorders.

Performance of machine-learning algorithms to pattern recognition and classification of hearing impairment in Brazilian farmers exposed to pesticide and/or cigarette smoke

The use of pesticides has been increasing in agriculture, leading to a public health problem. The aim of this study was to evaluate ototoxic effects in farmers who were exposed to cigarette smoke and/or pesticides and to identify possible classification patterns in the exposure groups. The sample included 127 participants of both sexes aged between 18 and 39, who were divided into the following four groups: control group (CG), smoking group (SG), pesticide group (PG), and smoking + pesticide group (SPG). Meatoscopy, pure tone audiometry, logoaudiometry, high-frequency thresholds, and immittance testing were performed. Data were evaluated by artificial neural network (ANN), K-nearest neighbors (K-NN), and support vector machine (SVM). There was symmetry between the right and left ears, an increase in the incidence of hearing loss at high frequency and of downward sloping audiometric curve configuration, and alteration of stapedial reflex in the three exposed groups. The machine-learning classifiers achieved good classification performance (control and exposed). The best classification results occur in high type (I and II) datasets (about 90% accuracy) in k-NN test. It is concluded that both xenobiotic substances have ototoxic potential; however, their combined use does not present additive or potentiating effects recognizable by the algorithms.

Adverse effects of pesticides on central auditory functions in tobacco growers

OBJECTIVE

To investigate the effects of exposure to pesticides on the central auditory functions (CAF) of Brazilian tobacco growers.

DESIGN

This was a cross-sectional study carried out between 2010 and 2012. Participants were evaluated with two behavioural procedures to investigate CAF, the random gap detection test (RGDT) and the dichotic digit test in Portuguese (DDT).

STUDY SAMPLE

A total of 22 growers exposed to pesticides (study group) and 21 subjects who were not exposed to pesticides (control group) were selected.

RESULTS

No significant differences between groups were observed for pure-tone thresholds. A significant association between pesticide exposure and the results for RGDT and DDT was found. Significant differences between pesticide-exposed and nonexposed subjects were found for RGDT frequency average and DDT binaural average, when including age and hearing level as covariates. Age was significantly associated with RGDT frequency average, DDT left ear score, DDT binaural average and DDT right ear advantage. Hearing levels were not significantly associated with any of the test scores. The relative risk of failing the DDT and RGDT for the study group was 1.88 (95% CI: 1.10-3.20) and 1.74 (95% CI: 1.06-2.86), respectively, as compared with the control group.

CONCLUSIONS

The results showed that tobacco growers exposed to pesticides exhibited signs of central auditory dysfunction characterised by decrements in temporal processing and binaural integration processes/abilities.

Prenatal exposure to multiple pesticides is associated with auditory brainstem response at 9months in a cohort study of Chinese infants

BACKGROUND

Pesticides are associated with poorer neurodevelopmental outcomes, but little is known about the effects on sensory functioning.

METHODS

Auditory brainstem response (ABR) and pesticide data were available for 27 healthy, full-term 9-month-old infants participating in a larger study of early iron deficiency and neurodevelopment. Cord blood was analyzed by gas chromatography-mass spectrometry for levels of 20 common pesticides. The ABR forward-masking condition consisted of a click stimulus (masker) delivered via ear canal transducers followed by an identical stimulus delayed by 8, 16, or 64 milliseconds (ms). ABR peak latencies were evaluated as a function of masker-stimulus time interval. Shorter wave latencies reflect faster neural conduction, more mature auditory pathways, and greater degree of myelination. Linear regression models were used to evaluate associations between total number of pesticides detected and ABR outcomes. We considered an additive or synergistic effect of poor iron status by stratifying our analysis by newborn ferritin (based on median split).

RESULTS

Infants in the sample were highly exposed to pesticides; a mean of 4.1 pesticides were detected (range 0-9). ABR Wave V latency and central conduction time (CCT) were associated with the number of pesticides detected in cord blood for the 64ms and non-masker conditions. A similar pattern seen for CCT from the 8ms and 16ms conditions, although statistical significance was not reached. Increased pesticide exposure was associated with longer latency. The relation between number of pesticides detected in cord blood and CCT depended on the infant's cord blood ferritin level. Specifically, the relation was present in the lower cord blood ferritin group but not the higher cord blood ferritin group.

CONCLUSIONS

ABR processing was slower in infants with greater prenatal pesticide exposure, indicating impaired neuromaturation. Infants with lower cord blood ferritin appeared to be more sensitive to the effects of prenatal pesticide exposure on ABR latency delay, suggesting an additive or multiplicative effect.

Avaliação funcional do sistema vestibular de cobaias intoxicadas agudamente por organofosforado por meio da prova calórica

OBJETIVO:avaliar o funcionamento do sistema vestibular de cobaias expostas ao organofosforado clorpirifós, de forma aguda, por meio da prova calórica da eletronistagmografia.MÉTODOS:a pesquisa do tipo experimental realizou a eletronistagmografia de cobaias expostas a organofosforado durante 10 dias consecutivos, nas doses 0,5mg/kg/dia e 1,0mg/kg/dia por via intraperitoneal e comparadas com grupo controle que recebeu administração de água destilada. Foi realizada prova calórica gelada (10ºC) e comparadas as variáveis frequência de aparecimento de nistagmos em 10 segundos (u/s) e velocidade angular da componente lenta (º/s).RESULTADOS:os resultados não demonstraram diferença estatisticamente significante na comparação das variáveis entre os grupos.CONCLUSÃO:conclui-se que nas doses testadas o agrotóxico organofosforado clorpirifós não causou danos funcionais detectáveis na prova calórica.

Hearing profile of brazilian forestry workers' noise exposure

Introduction Researchers studying the hearing health of forestry workers have revealed the presence of a noise-induced hearing loss (NIHL) in this population and have concluded that the vibration of the equipment, the carbon monoxide released by motors, and pesticides might also contribute to NIHL.

Objective To analyze the noise exposure in the Brazilian forestry industry workers and the effects on hearing.

Methods The study sample comprised 109 employees of a company that specialized in reforestation. Their participants' mean age was 35.5 years (21 to 54 years), mean tenure at the company was 3.9 years (1 to 13 years), and mean total duration of noise exposure was 12.3 years (1 to 30 years). The existing documentation reporting on the jobs risk analysis was examined, noise level was measured, and pure tone audiometry was performed in all participants. Participants were divided into three groups according to their noise exposure levels in their current job.

Results Of the participants who were exposed to noise levels less than 85 dBA (decibels with A-weighting filter), 23.8% had hearing loss, and 5.5% of the participants who were exposed to noise ranging from 85 to 89.9 dBA and 11% of the participants who were exposed to noise greater than 90 dBA had audiogram results suggestive of NIHL.

Conclusion The implementation of a hearing loss prevention program tailored to forestry workers is needed.

Avaliação do sistema auditivo em agricultores expostos à agrotóxicos

Objetivos avaliar o sistema auditivo periférico, por meio de audiometria tonal, em agricultores residentes em área de intenso uso de agrotóxicos no Estado do Rio de Janeiro. Métodos foram avaliados 70 indivíduos, de ambos os gêneros, moradores de Campos dos Goytacazes, com idade variando entre 25 e 59 anos, sendo 35 agricultores e 35 não agricultores. Todos os indivíduos tiveram sua audição periférica avaliada, por meio de audiometria tonal nas frequências de 250, 500, 1.000, 2.000, 3.000, 4.000, 6.000 e 8.000Hz. Foram excluídos indivíduos com alteração de orelha externa e média e/ou com alguma queixa otológica. Além disso, foi realizada anamnese com questões relacionadas à saúde, situação sócio-econômica, educação e exposição ao agrotóxico. Foi considerada perda auditiva, os limiares maiores ou iguais a 25dB em qualquer das frequências testadas. Resultados o Odds Ratio de perda auditiva foi 3,67 vezes (IC95%: 2,08-6,48) maior entre agricultores (94,3%), quando comparados aos não agricultores (25,7%). Além disso, a maior parte das alterações auditivas foi observada nas frequências mais agudas. Conclusão o presente estudo sugere que a atividade agrícola e possivelmente a exposição a agrotóxicos aumenta o risco de perda auditiva.

Relação da perda auditiva induzida por ruído e o uso de tabaco em trabalhadores de uma indústria alimentícia

Objetivo verificar se o uso do tabaco potencializa os efeitos do ruído causados na audição. Métodos 153 trabalhadores de ambos os sexos, fumantes e não-fumantes, de uma indústria do ramo alimentício, escolhidos aleatoriamente dentre 14 setores da empresa, cuja faixa de ruído apresentada teve uma variação de 85 a 109 dBNA, responderam a um questionário sobre tempo e exposição ao ruído bem como hábitos sobre fumo e passaram por exame de audiometria. Resultados os limiares auditivos da via aérea nas frequências de 4.000 Hz e 6.000Hz foram significantemente mais altos no grupo de fumantes/ex-fumantes quando comparados aos não-fumantes tanto na orelha direita quanto na orelha esquerda; limiares estes, característicos da perda auditiva induzida por ruído. Essas diferenças se mantiveram significantes após o ajuste pela idade e pelo tempo de exposição. Conclusão por meio dos resultados obtidos, concluiu-se que o uso do tabaco pode potencializar os danos causados pelo ruído à audição.

Saúde auditiva e qualidade de vida em trabalhadores expostos a agrotóxicos

O objetivo deste estudo foi determinar a relação entre a exposição ao agrotóxico e a ocorrência de perda auditiva nos trabalhadores rurais do Povoado Colônia Treze, Lagarto (SE). Foram selecionados 351 trabalhadores adultos na faixa etária de 18 a 59 anos, com atividade laboral atual ou pregressa na área rural, com ou sem uso de agrotóxico. A avaliação audiológica foi composta de ficha para registro dos limiares tonais aéreos pelo critério de normalidade preconizado por Merluzzi 1979. O instrumento usado para a avaliação da qualidade de vida foi a versão brasileira do Short Form 36 (SF-36). Foi realizada análise estatística (testes qui-quadrado χ², não paramétrico de Kruskal-Wallis, V de Cramer e d de Cohen) com nível de significância de 95% (p < 0,05). Os resultados relacionaram o uso de agrotóxico com o grau de toxicidade, com a presença de perda auditiva e com os índices de qualidade de vida (p < 0,001). Este estudo pode comprovar que os agricultores, usuários de agrotóxicos apresentaram piores níveis de qualidade de vida quando comparados com aqueles que não os utilizaram. O uso de agrotóxico e sua classe toxicológica interferiram de maneira mais impactante na classificação de perda auditiva apresentada nos mesmos e novos estudos são recomendados para avaliar outros impactos nesta população.

Genetic Control of Mosquitoes: population suppression strategies

Over the last two decades, morbidity and mortality from malaria and dengue fever among other pathogens are an increasing Public Health problem. The increase in the geographic distribution of vectors is accompanied by the emergence of viruses and diseases in new areas. There are insufficient specific therapeutic drugs available and there are no reliable vaccines for malaria or dengue, although some progress has been achieved, there is still a long way between its development and actual field use. Most mosquito control measures have failed to achieve their goals, mostly because of the mosquito's great reproductive capacity and genomic flexibility. Chemical control is increasingly restricted due to potential human toxicity, mortality in no target organisms, insecticide resistance, and other environmental impacts. Other strategies for mosquito control are desperately needed. The Sterile Insect Technique (SIT) is a species-specific and environmentally benign method for insect population suppression, it is based on mass rearing, radiation mediated sterilization, and release of a large number of male insects. Releasing of Insects carrying a dominant lethal gene (RIDL) offers a solution to many of the drawbacks of traditional SIT that have limited its application in mosquitoes while maintaining its environmentally friendly and species-specific utility. The self-limiting nature of sterile mosquitoes tends to make the issues related to field use of these somewhat less challenging than for self-spreading systems characteristic of population replacement strategies. They also are closer to field use, so might be appropriate to consider first. The prospect of genetic control methods against mosquito vectored human diseases is rapidly becoming a reality, many decisions will need to be made on a national, regional and international level regarding the biosafety, social, cultural and ethical aspects of the use and deployment of these vector control methods.

Prevalence of tinnitus in workers exposed to noise and organophosphates

INTRODUCTION

 Research on the workplace has emphasized the effects of noise exposure on workers' hearing, but has not considered the effects of agrochemicals.

AIM

 To evaluate and correlate the hearing level and tinnitus of workers exposed simultaneously to noise and organophosphates in their workplace and to measure tinnitus distress on their quality of life.

METHOD

 A retrospective clinical study. We evaluated 82 organophosphate sprinklers from the São Paulo State Regional Superintendence who were active in the fight against dengue and who were exposed to noise and organophosphates. We performed pure tone audiometry and applied the translated THI (Tinnitus Handicap Inventory) questionnaire.

RESULTS

 Of the sample, 28.05% reported current tinnitus or had presented tinnitus, and the workers with tinnitus had an increased incidence of abnormal audiometry. The average hearing threshold for the 4-8-kHz frequency range of the workers with current tinnitus was higher than that of the others, and was most affected at the 4-kHz frequency. The THI score ranged 0-84, with an average score of 13.1. Twelve (52.17%) workers had THI scores consistent with discrete handicap.

CONCLUSION

 There is an increased incidence of abnormal pure tone audiometry in workers with tinnitus, and its impact on the workers' quality of life was discrete. The correlation between average hearing threshold and tinnitus distress was weak.

Noise-induced hearing loss and associated factors among vector control workers in a Malaysian state

This study aims to determine the prevalence and associated factors of noise-induced hearing loss (NIHL) among vector control workers in the state of Negeri Sembilan, Malaysia. This was an analytical cross-sectional study conducted on 181 vector control workers who were working in district health offices in a state in Malaysia. Data were collected using a self-administered questionnaire and audiometry. Prevalence of NIHL was 26% among this group of workers. NIHL was significantly associated with the age-group of 40 years and older, length of service of 10 or more years, current occupational noise exposure, listening to loud music, history of firearms use, and history of mumps/measles infection. Following logistic regression, age of more than 40 years and noise exposure in current occupation were associated with NIHL with an odds ratio of 3.45 (95% confidence interval = 1.68-7.07) and 6.87 (95% confidence interval = 1.54-30.69), respectively, among this group of vector control workers.

Genetic elimination of dengue vector mosquitoes

An approach based on mosquitoes carrying a conditional dominant lethal gene (release of insects carrying a dominant lethal, RIDL) is being developed to control the transmission of dengue viruses by vector population suppression. A transgenic strain, designated OX3604C, of the major dengue vector, Aedes aegypti, was engineered to have a repressible female-specific flightless phenotype. This strain circumvents the need for radiation-induced sterilization, allows genetic sexing resulting in male-only releases, and permits the release of eggs instead of adult mosquitoes. OX3604C males introduced weekly into large laboratory cages containing stable target mosquito populations at initial ratios of 8.5-101 OX3604Ctarget eliminated the populations within 10-20 weeks. These data support the further testing of this strain in contained or confined field trials to evaluate mating competitiveness and environmental and other effects. Successful completion of the field trials should facilitate incorporation of this approach into area-wide dengue control or elimination efforts as a component of an integrated vector management strategy.

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

Os agentes sanitaristas são os trabalhadores mais expostos aos efeitos dos inseticidas nas campanhas antivetoriais, desde o preparo da calda até a aplicação nas áreas intra ou peridomiciliares. Fatores como falta de equipamentos de proteção individual ou desconhecimento da forma correta de manipulação de cada produto aumentam os riscos de intoxicação. O objetivo deste trabalho foi analisar a história ocupacional de agentes sanitaristas sobre o controle dos vetores no Estado do Ceará e sua repercussão na saúde destes trabalhadores. As histórias de vida ocupacionais foram relatadas por dez agentes, através de entrevistas individuais gravadas. O conteúdo foi analisado a partir da construção de categorias como: perfil dos agentes, controle de endemias, condições de trabalho, riscos e alterações na saúde. Os depoimentos revelaram condições de trabalho geradoras de risco à saúde dos agentes, desde intoxicações agudas a crônicas, além de outros problemas, como o alcoolismo. Constatou-se que os profissionais foram desrespeitados como seres humanos e que houve descumprimento dos direitos trabalhistas, evidenciando-se o descaso por parte dos seus superiores e instituição contratante.

Ototoxicity study in workers exposed to organophosphate

Occupational and environmental exposure to agricultural pesticides represent an important health care problem in our country. Among the symptoms presented, dizziness stands out, because of a probable toxic action.

AIM

The goal of our study was to characterize vestibular test results from rural workers occupationally and environmentally exposed to organophosphates used in agricultural pesticides.

MATERIALS AND METHODS

We carried out a cohort cross-sectional study with 18 rural workers from Teresópolis, RJ. Age ranged between 16 and 59 years, with a mean value of 39.6 years, 5 were males and 13 females. We used three questionnaires with questions associated with general and auditory health, and more specific questions about dizziness and its association with work. All workers underwent clinical evaluation, audiometry and vectoelectronystagmography.

RESULTS

Results showed that 16 workers had irritative peripheral body balance disorder and 7 workers had sensorineural hearing loss, thus suggesting that agricultural pesticides cause vestibular alterations through a slow and silent intoxication.

CONCLUSIONS

Medical care for this population exposed to neurotoxic substances require an interdisciplinary approach, to guarantee efficient preventive and therapeutic measures.

Estudo da ototoxicidade em trabalhadores expostos a organofosforados

A exposição ocupacional e ambiental aos agrotóxicos evidencia-se como um grave problema de Saúde Pública em nosso país. Entre os sintomas apresentados, a tonteira se destaca, em decorrência de uma provável ação tóxica. OBJETIVO: O objetivo do estudo é caracterizar os resultados do exame vestibular de trabalhadores rurais expostos ocupacionalmente e ambientalmente aos agrotóxicos organofosforados. MATERIAL E MÉTODO: Foi realizado um estudo de coorte com corte transversal em 18 trabalhadores rurais de Teresópolis, RJ. A faixa etária variou de 16 a 59 anos com uma média de 39,6 anos, sendo 5 trabalhadores do sexo masculino e 13 do sexo feminino. Foram utilizados três questionários com perguntas relacionadas à saúde geral e auditiva e perguntas específicas à tonteira e suas relações com o trabalho. Todos os trabalhadores passaram por uma avaliação clínica e realizaram os exames vectoeletronistagmografia e audiometria. RESULTADOS: Os resultados mostraram que 16 trabalhadores apresentaram alterações do equilíbrio corporal de tipo periférico irritativo e 7 trabalhadores apresentaram perdas auditivas do tipo neurossensorial, sugerindo que os agrotóxicos induzem alterações do sistema vestibular através de uma intoxicação lenta e silenciosa. CONCLUSÕES: O olhar clínico sobre esta população exposta a substâncias neuro-ototóxicas requer uma abordagem interdisciplinar, assegurando uma intervenção terapêutica e preventiva eficaz.

Auditory monitoring in ototoxicity

Some pharmaceutical products are capable of damaging the human auditory system. Technological progress has provided numerous resources to monitor hearing but there still is some controversy regarding the selection of the most sensitive and specific tests.

OBJECTIVE

to analyze audiological procedures used in the auditory monitoring of individuals exposed to ototoxic medication.

METHODS

we searched the MEDLINE and LILACS literature databases, using terms pertinent to audiological monitoring, ototoxicity and cancer. The pertaining literature analysis identified two procedures often used worldwide for the early detection of auditory lesions induced by ototoxic pharmaceutical drugs: high-frequency audiometry and evoked otoacoustic emissions. Both allow early identification of hearing disorders before changes are seen in conventional pure-tone audiometry and, consequently, before speech understanding is compromised.

CONCLUSION

we suggest a hearing monitoring protocol, considering the patients capability to respond to behavioral tests and monitoring timing (first test/follow up). For cancer patients, hearing monitoring should be performed in the patients treatment venue.

Perda auditiva neurossensorial por exposição continuada a níveis elevados de pressão sonora em trabalhadores de manutenção de aeronaves de asas rotativas

A exposição continuada à pressão sonora elevada em trabalhadores ligados à aviação pode acarretar ao longo dos anos perda de audição ao nível da orelha interna. Este estudo teve como principal objetivo avaliar a prevalência do dano auditivo em todos os trabalhadores do setor de manutenção de aeronaves de asas rotativas de uma unidade da Força Aérea Brasileira. A metodologia incluiu a aplicação de questionários individuais e a realização de audiometrias em todos esses trabalhadores. Dos 74 trabalhadores estudados, a prevalência de perda auditiva sugestiva de ser neurossensorial por exposição continuada a níveis elevados de pressão sonora foi elevada, alcançando 32,4%, e sendo relacionada com as variáveis: tempo de trabalho (p < 0,05; RP = 2,11; IC95%: 1,03-4,32) e faixa etária entre 41 e 50 anos (p = 0,00; RP = 3,94; IC95%: 2,04-7,62). Não foram observadas diferenças significativas entre os grupos com ou sem perda auditiva para possíveis variáveis de confusão selecionadas. Enfatizou-se a implementação do Programa de Conservação Auditiva para prevenção e progressão desse tipo de lesão.