海南省2006年登革热传播媒介监测分析

目的了解海南省登革热传播媒介的种群分布、密度及带毒情况，为制定登革热防制措施提供依据。方法2006年在既往登革热流行区的儋州市、临高县、陵水县设立监测点，全年每月定时定点定人监测媒介幼虫密度和成蚊种群、密度；6～10月份监测雌性伊蚊登革病毒携带状况。结果各监测点全年均有媒介伊蚊活动，布雷图指数每月均高于5，儋州市2个哨点全年有11个月指数均≥20，其中港口村8月达168为最高指数；除儋州市港口村、临高县宫花村有明显4～8月季节高峰外，其他各点无明显季节高峰。各监测点伊蚊幼虫孳生环境也有所不同，儋州市以永久性容器孳生为主，临高县和陵水县以暂时性容器孳生占多数。三个监测点全年捕获的埃及伊蚊与白纹伊蚊总数的种群分布比，儋州市为138：15，临高县为0：64，陵水县为42：113，存在明显的种群分布差异。对188只雌性伊蚊进行登革病毒分离，结果均为阴性。结论海南省既往登革热流行区广泛存在传播媒介，全年活动，且密度均较高，存在发生登革热爆发或流行的潜在危险。     

Extensive fever workup produces low yield in determining infectious etiology

OBJECTIVE: The study was undertaken to evaluate the use of a fever workup in women undergoing benign gynecologic procedures. STUDY DESIGN: A retrospective chart review was performed at Jackson Memorial Hospital between 1994 and 2000. Information was abstracted from hospital and clinic records. Fever criteria was defined as 1 temperature equal to or greater than 101.5, or 2 equal to or greater than 100.4, at least 4 hours apart within a 24-hour period. Patients undergoing additional intraoperative procedures leading to increased febrile morbidity were excluded. Data abstracted included patient demographics, procedure, complications, antibiotic use, and extent of fever workup. Statistical analysis used was 2-sample t tests, Wilcoxon rank test, chi2 test, and multivariate logistic regression. Alpha level = .05. RESULTS: The charts of 505 patients were reviewed, and 147 patients met fever criteria. All patients underwent surgery for benign conditions, abdominal hysterectomy being the most common (90%). The study population was divided into 2 groups: the noninfectious group and infectious group. These groups were determined by wound infection, pelvic abscess, blood or urine culture, ultrasound, and chest roentgen. Both groups were found to be similar with respect to demographics, surgical procedures, and postoperative complications, with the exception of body mass index (28.4 vs 31.7) and length of hospital stay (3.9 vs 5.3). Results from fever workups included positive results blood cultures (9.7%), urine culture (18.8%), and chest roentgens (14%) in this study population. We found no association between positive urine analysis and urine culture. When comparing both groups, a statistically significant difference was found with regard to maximum temperature elevation, number of days febrile, and postoperative day of maximum temperature (P < .05). CONCLUSION: The extensive fever workup was not frequently positive in this study population. Its use and cost-effectiveness should be questioned. Therefore, the fever workup should be tailored to the individual patient.     

A Laboratory Investigation into Oviposition Responses of Aedes aegypti to Some Common Household Substances and Water from Conspecific Larvae

Background

The surveillance of Dengue vector – Aedes aegypti, is routinely done by using ovitraps (a dark container filled with water and a wooden paddle/towel cloth provided as a oviposition substrate), which indicates the extent of Aedes activity in an area.

Method

The study evaluated the oviposition responses of laboratory bred gravid Aedes aegypti to commonly available household substances by use of ovitrap method.

Results

Oviposition avoidance or deterrence was exhibited by gravid Aedes to ovitraps baited with salt, fenugreek, vinegar, lime juice, hibiscus leaves, radish and curry leaves, whereas positive oviposition response was noticed to waters from conspecific (of the same species) larvae and cumin seeds baited ovitraps.

Conclusion

The study findings may be utilized by researchers for further chemical analysis of the active ingredients of the substances found promising with a view to explore the possibility of their use by community and individuals for Aedes surveillance and control.Key Words: Aedes, Dengue, Oviposition deterrence/attraction     

Impact of fever-range thermal stress on lymphocyte-endothelial adhesion and lymphocyte trafficking

The evolutionarily conserved febrile response has been associated with improved survival during infection in endothermic and ectothermic species although its protective mechanism of action is not fully understood. Temperatures within the range of physiologic fever influence multiple parameters of the immune response including lymphocyte proliferation and cytotoxic activity, neutrophil and dendritic cell migration, and production or bioactivity of proinflammatory cytokines. This review focuses on the emerging role of fever-range thermal stress in promoting lymphocyte trafficking to secondary lymphoid organs that are major sites for launching effective immune responses during infection or inflammation. Specific emphasis will be on the molecular basis of thermal control of lymphocyte-endothelial adhesion, a critical checkpoint controlling lymphocyte extravasation, as well as the contribution of interleukin-6 (IL-6) trans-signaling to thermal activities. New results are presented indicating that thermal stimulation of lymphocyte homing potential is evident in evolutionarily distant endothermic vertebrate species. These observations support the view that the evolutionarily conserved febrile response contributes to immune protection and host survival by amplifying lymphocyte access to peripheral lymphoid organs.     

Dengue and dengue hemorrhagic fever, Brazil, 1981-2002

In the last 5 years, Brazil has accounted for approximately 70% of reported dengue fever cases in the Americas. We analyzed trends of dengue and dengue hemorrhagic fever (DHF) from the early 1980s to 2002 by using surveillance data from the Brazilian Ministry of Health. Two distinct epidemiologic patterns for dengue were observed: localized epidemics (1986-1993), and endemic and epidemic virus circulation countrywide (1994-2002). Currently, serotypes 1, 2, and 3 cocirculate in 22 of 27 states. Dengue and DHF affected mainly adults; however, an increase in occurrence of DHF among children has been recently detected in northern Brazil, which suggests a shift in the occurrence of severe disease to younger age groups. In 2002, hospitalizations increased, which points out the change in disease severity compared to that seen in the 1990s. We describe the epidemiology of dengue in Brazil, characterizing the changing patterns of it and DHF during the last 20 years.     

Early activation of natural killer and B cells in response to primary dengue virus infection in A/J mice

Dengue virus (DEN) causes the most prevalent arthropod-borne viral illness in humans worldwide. Immune mechanisms that are involved in protection and pathogenesis of DEN infection have not been fully elucidated due largely to the lack of an adequate animal model. Therefore, as a first step, we characterized the primary immune response in immunocompetent inbred A/J mice that were infected intravenously with a non-mouse-adapted DEN type 2 (DEN2) strain. A subset (55%) of infected mice developed paralysis by 14 days post-infection (p.i.), harbored infectious DEN in the central nervous system (CNS), and had an elevated hematocrit and a decreased white blood cell (WBC) count. Immunologic studies detected (i). increased numbers of CD69(+) splenic natural killer (NK) and B cells at day 3 p.i., (ii). DEN-specific IgM and IgG responses by days 3 and 7 p.i., respectively, and (iii). splenocyte production of IFNgamma at day 14 p.i. We conclude that the early activities of NK cells, B cells and IgM, and later actions of IFNgamma and IgG likely play a role in the defense against DEN infection.     

Dengue virus infection in travellers returning to Berlin, Germany: clinical, laboratory, and diagnostic aspects

BACKGROUND: Dengue is a mosquito-borne viral infection endemic throughout the tropics and subtropics. The global prevalence of dengue has grown dramatically in recent years and it has been recognized as a potential hazard to tourists. OBJECTIVE: In this study, we analyzed the epidemiology, clinical manifestations, laboratory features and serological/virological results in a series of German travellers returning to Berlin with acute dengue virus infection. STUDY DESIGN: Laboratory-confirmed dengue virus infections among German travellers returning to Berlin were studied retrospectively during the period of 1993-2001. Seventy-one patients tested positive for dengue fever and were included in this study. RESULTS: The majority of patients (77.5%) contracted the disease in South Central and South East Asia. The most important clinical characteristics were fever and prostration (100%), headache, predominantly frontal or retroorbital (86%), arthralgia (79%), morbilliform rash (66%) and myalgia (48%). The most meaningful laboratory results were: marked leucopenia (72%), thrombocytopenia (70-89%), hyponatremia (41%) and increased hepatic enzymes ALAT (41%), ASAT (45%) and LDH (62%). Dengue virus infection was diagnosed by means of a matching clinico-epidemiological history and positivity of specific serology and/or virus isolation. Hemorrhagic phenomena appeared in 10 of the 71 patients (14%), out of which one was diagnosed with DHF according to WHO criteria. All patients recovered fully. CONCLUSION: Pretravel advice should be given to all travellers to dengue-endemic areas. DF must be included in the differential diagnosis of patients returning febrile from tropical areas.     

Human transportation influences Aedes aegypti gene flow in Southeast Asia

Estimates of population genetic organization and gene flow of Aedes aegypti, the main vector of dengue viruses, have provided insights into dengue epidemiology. To assess the role of the vector in the changing pattern of dengue in Southeast Asia, extensive studies on the genetic differentiation of Aedes aegypti have been carried out. Among them, vector differentiation has been estimated for Cambodia, Thailand and South Vietnam using microsatellite markers. Analysis showed that there was less genetic differentiation between mosquito populations from Ho Chi Minh City and Phnom Penh than from either of them and Thailand, suggesting that passive migrations through human transportation help to explain this pattern of differentiation.     

Inflammatory parameters after pleurodesis in recurrent malignant pleural effusions and their predictive value

Recurrent pleural malignant effusion is a common problem which can be treated by inducing symphysis of the pleural sheets. Many different drugs administered into the pleural space can be used to achieve this. The drugs cause an inflammatory response, which in turn is believed to cause the symphysis. Comparatively little has been published on the degree of pleural inflammation and the systemic response and whether this will affect the outcome. The aim of this study was to describe the systemic inflammatory reaction following instillation of a chemical agent into the pleura and to investigate whether this had any predictive value for the outcome (i.e. the pleurodesis). The markers investigated were simple ones: erythrocyte sedimentation rate, C-reactive protein, and leukocyte count from venous blood samples, and the fever reaction. Eighty-nine prospective patients with malignant pleural effusion who underwent pleurodesis with either talc (48 patients) or quinacrine (41 patients) were included in the study. Symphysis was achieved in 82 patients (92 per cent) and all had a prominent transitional elevation of the inflammatory parameters. The unsuccessful attempts caused negligible or very small elevations, but due to the small numbers only the degree of fever after 8 and 48 h showed a statistically significant difference. In conclusion, pleurodesis causes a systemic inflammation and there is a tendency to a correlation between the success of pleurodesis and the degree of inflammation. High fever and high inflammatory parameters including CRP are due to this inflammatory response and do not indicate infection.     

The effects of prostaglandin E2 on the firing rate activity of thermosensitive and temperature insensitive neurons in the ventromedial preoptic area of the rat hypothalamus

In response to an immune system challenge with lipopolysaccharide (LPS), recent work has shown that Fos immunoreactivity is displayed by neurons in the ventromedial preoptic area of the hypothalamus (VMPO). In addition, neurons in this region show distinct axonal projections to the anterior perifornical area (APFx) and the paraventricular nucleus (PVN). It has been hypothesized that neurons within the VMPO integrate their local responses to temperature with changes in firing activity that result from LPS induced production of prostaglandin E(2) (PGE(2)). This may be an important mechanism by which the set-point regulation of thermoeffector neurons in the APFx and PVN is altered, resulting in hyperthermia. To characterize the firing rate activity of VMPO neurons, single-unit recordings were made of neuronal extracellular activity in rat hypothalamic tissue slices. Based on the slope of firing rate as a function of tissue temperature, neurons were classified as either warm sensitive or temperature insensitive. Neurons were then treated with PGE(2) (200 nM) while tissue temperature was held at a constant level ( approximately 36 degrees C). The majority of temperature insensitive neurons responded to PGE(2) with an increase in firing rate activity, while warm sensitive neurons showed a reduction in firing rate. This suggests that both warm sensitive and temperature insensitive neurons in the VMPO may play critical and contrasting roles in the production of a fever during an acute phase response to infection.