Developing new approaches for detecting and preventing Aedes aegypti population outbreaks: basis for surveillance, alert and control system

A new approach to dengue vector surveillance based on permanent egg-collection using a modified ovitrap and Bacillus thuringiensis israelensis(Bti) was evaluated in different urban landscapes in Recife, Northeast Brazil. From April 2004 to April 2005, 13 egg-collection cycles of four weeks were carried out. Geo-referenced ovitraps containing grass infusion, Bti and three paddles were placed at fixed sampling stations distributed over five selected sites. Continuous egg-collections yielded more than four million eggs laid into 464 sentinel-ovitraps over one year. The overall positive ovitrap index was 98.5 percent (over 5,616 trap observations). The egg density index ranged from 100 to 2,500 eggs per trap-cycle, indicating a wide spread and high density of Aedes aegypti (Diptera: Culicidae) breeding populations in all sites. Fluctuations in population density over time were observed, particularly a marked increase from January on, or later, according to site. Massive egg-collection carried out at one of the sites prevented such a population outbreak. At intra-site level, egg counts made it possible to identify spots where the vector population is consistently concentrated over the time, pinpointing areas that should be considered high priority for control activities. The results indicate that these could be promising strategies for detecting and preventing Ae. aegypti population outbreaks.

Precisão do diagnóstico clínico da síndrome do desconforto respiratório agudo quando comparado a achados de necropsia / Accuracy of clinical diagnosis of acute respiratory distress syndrome in comparison with autopsy findings

OBJETIVO: Comparar a definição de síndrome do desconforto respiratório agudo (SDRA) estabelecida pela American-European Consensus Conference (AECC, Conferência Americano-Européia) com achados de necropsia. MÉTODOS: Avaliaram-se todos os pacientes que morreram na unidade de terapia intensiva do Hospital Universitário da Universidade Federal de Juiz de Fora entre 1995 e 2003 e que foram submetidos à necropsia. Seus prontuários foram revisados para estabelecer a presença ou não dos critérios clínicos de SDRA, cujo diagnóstico histológico foi definido pela presença de dano alveolar difuso (DAD). RESULTADOS: No período, 592 pacientes faleceram e 22 foram submetidos à necropsia. Destes, 10 pacientes (45 por cento) preencheram os critérios de SDRA pela AECC e sete (32 por cento) preencheram os critérios histopatológicos de DAD. A sensibilidade da definição clínica foi de 71 por cento (IC95 por cento: 36-92 por cento) e a especificidade foi de 67 por cento (IC95 por cento: 42-85 por cento). Os valores preditivos positivo e negativo foram, respectivamente, 50 e 83 por cento; e as razões de verossimilhança positiva e negativa foram, respectivamente, 2,33 e 0,47. Os achados histopatológicos nos cinco pacientes que preencheram os critérios clínicos de SDRA, mas não apresentavam DAD, foram pneumonia (n = 2), embolia pulmonar (n = 1), tuberculose (n = 1) e criptococose (n = 1). CONCLUSÃO: A precisão dos critérios da AECC para diagnóstico de SDRA não é tão boa. Em função do baixo valor preditivo positivo e da baixa razão de verossimilhança positiva do diagnóstico clínico, outras hipóteses devem ser consideradas quando há suspeita de SDRA.

OBJECTIVE: To compare the American-European Consensus Conference (AECC) definition of acute respiratory distress syndrome (ARDS) to autopsy findings. METHODS: All patients who died in the intensive care unit of the Federal University of Juiz de Fora University Hospital between 1995 and 2003 and were submitted to autopsy were included in the study. Patient clinical charts were reviewed to establish whether cases met the AECC criteria for a diagnosis of ARDS, histologically defined as the presence of diffuse alveolar damage (DAD). RESULTS: During the study period, 592 patients died, and 22 were submitted to autopsy. Of those 22 patients, 10 (45 percent) met the AECC criteria, and 7 (32 percent) met the histopathological criteria for DAD. The AECC clinical criteria presented a sensitivity of 71 percent (95 percentCI: 36-92 percent) and a specificity of 67 percent (95 percentCI: 42-85 percent). The positive and negative predictive values were, respectively, 50 and 83 percent, whereas the positive and negative likelihood ratios were, respectively, 2.33 and 0.47. The histopathological findings in the 5 patients who met AECC criteria but did not present DAD were pneumonia (n = 2), pulmonary embolism (n = 1), tuberculosis (n = 1), and cryptococcosis (n = 1). CONCLUSION: The accuracy of the AECC definition of ARDS was godless than satisfactory. Due to the low positive predictive value and the low positive likelihood ratio, other hypotheses must be considered when ARDS is suspected.