Strategies to minimize dengue transmission commonly rely on vector control, which aims to maintain Ae. aegypti density below a theoretical threshold. Mosquito abundance is traditionally estimated from mark-release-recapture (MRR) experiments, which lack proper analysis regarding accurate vector spatial distribution and population density. Recently proposed strategies to control vector-borne diseases involve replacing the susceptible wild population by genetically modified individuals’ refractory to the infection by the pathogen. Accurate measurements of mosquito abundance in time and space are required to optimize the success of such interventions. In this paper, we present a hierarchical probabilistic model for the estimation of population abundance and spatial distribution from typical mosquito MRR experiments, with direct application to the planning of these new control strategies. We perform a Bayesian analysis using the model and data from two MRR experiments performed in a neighborhood of Rio de Janeiro, Brazil, during both low- and high-dengue transmission seasons. The hierarchical model indicates that mosquito spatial distribution is clustered during the winter (0.99 mosquitoes/premise 95% CI: 0.80–1.23) and more homogeneous during the high abundance period (5.2 mosquitoes/premise 95% CI: 4.3–5.9). The hierarchical model also performed better than the commonly used Fisher-Ford’s method, when using simulated data. The proposed model provides a formal treatment of the sources of uncertainty associated with the estimation of mosquito abundance imposed by the sampling design. Our approach is useful in strategies such as population suppression or the displacement of wild vector populations by refractory Wolbachia-infected mosquitoes, since the invasion dynamics have been shown to follow threshold conditions dictated by mosquito abundance. The presence of spatially distributed abundance hotspots is also formally addressed under this modeling framework and its knowledge deemed crucial to predict the fate of transmission control strategies based on the replacement of vector populations.
Introdução:O vírus ZIKA atualmente está disseminado em países da África, Ásia e Américas. Os sintomas são semelhantes aos de Dengue. Entretanto, após sua emergência no Brasil, observou-se o aumento de casos de microcefalia e síndrome de Guillain-Barré. Ao nível de diagnóstico, recomenda-se o Teste de Neutralização por Placas de Lise (PRNT, do inglês Plaque Reduction Neutralization Test) como teste confirmatório ao ELISA, uma vez que este método é considerado padrão ouro para quantificação de anticorpos neutralizantes. Entretanto, estudos preliminares demonstram a ocorrência de falsos positivos em pacientes que apresentaram infecção prévia por outros flavivírus. Sendo assim, avaliar estratégias para minimizar reações cruzadas é indispensável para a obtenção de um resultado confiável.
Objetivo:O principal objetivo do estudo é minimizar reações cruzadas com flavivírus no PRNT de ZIKA, a partir da análise de endpoint , 50% e 90%, e do tempo de neutralização do teste.
Metodologia:Para esta avaliação foram utilizadas quinze amostras, divididas em grupos, sendo: duas amostras positivas para ZIKA e negativas para Dengue (Z+/D-); duas amostras positivas para ZIKA e Dengue (Z+/D+); onze amostras coletadas no período anterior à circulação do vírus no Brasil, logo, negativas para ZIKA, porém entre estas, oito são positivas para Dengue (Z-/D+) e três são negativas para estes dois flavivírus , no entanto, positivas para Febre Amarela (Z-/D-/F+). Esses grupos foram todos previamente testados por PRNT de Dengue, e Febre Amarela no caso do último grupo. Além disso, os grupos positivos para ZIKA foram selecionados por quadros clínicos característicos e confirmados por PRNT.
1Fiocruz/Bio-Manguinhos; 2Fiocruz/INI.Introdução: Dengue is an important arbovirus that is currently a serious public health problem in Brazil and in the world. The Dengue virus has been circulating in the country for several decades and it has been responsible for epidemics since its reintroduction. However, the epidemiological pattern has undergone changes in the age distribution and worsening of clinical symptoms in infants, which may be associated with the presence of maternal anti-Dengue antibodies in neonates. Despite that, the studies including this population group are unfrequently. In this context, a prospective study has been conducted with pregnant and infants from community of Manguinhos between 2012 and 2014.Objective: The main objective was to verify the immunological profile against Dengue virus (for all serotypes) in a maternal-infant cohort, as well as to evaluate the efficiency of maternal neutralizing antibodies transfer to the neonates. Kinetics of the neutralizing antibodies during the first year of life was also evaluated to determine the "seroreversion" time of maternal antibodies for each serotype (DENV1-4).Methodology: Blood samples were collected from 502 pregnant woman in the last trimester of pregnancy, from 298 umbilical cord and from 298 childrens during the first year of life (at least three colection per children). We tested the samples for presence of neutralizing antibodies to all Dengue virus serotypes by Plaque Reduction Neutralization Test (PRNT).
Results:We observed that 89% of pregnant women had previous immunity to Dengue. In addition, we verified that there was an efficient transfer of maternal antibodies to all serotypes, and that maternal neutralizing antibodies seroreversion occurred between the 10th and 12th month of life. During the follow-up of the kinetics of maternal antibody decay, some infants presented increasing levels of neutralizing antibodies. For DENV-1 and DENV-2, there was an increase from the 6th month, in 31% and 20% of the following infants, respectively. For DENV-4, it was observed in 14% of the infants between 2nd and 6th month age. For DENV-3, there was no increasing.
Conclusion:Our results indicate high transmissibility of DENV, evidencing that an expressive portion of the infants in the studied area are exposed to infection, although they still have circulating maternal antibodies. Thus, additional studies to investigate serotype-specific immunity in the pregnant population and the incidence of dengue in the first years of life are necessary. It is important to understand the dynamics of these neutralizing antibodies in children in this age group in order to define future vaccination regimen.
ResumoOs autores apresentam um caso bem-sucedido no tratamento conservador da camptodactilia de tipo III em paciente com síndrome de Beals-Hecht. A camptodactilia é uma deformidade em flexão da articulação interfalangeana proximal (IFP), no sentido anteroposterior, indolor, e bilateral em 2/3 dos casos. A de tipo III é a forma mais grave e incapacitante, pois geralmente acomete vários dedos e está associada a síndromes e outras malformações. O caso apresentado teve a correção alcançada com o uso sistemático de órteses estáticas iniciado aos 7 meses de idade e concluído após 23 meses e meio de intervenção.
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