Distribution of dengue virus types in Aedes aegypti in dengue endemic districts of Rajasthan, India.

Background & objectives: Dengue haemorrhagic fever (DHF) is the major cause of sustained morbidity/ mortality among human cases of dengue in dengue endemic areas of Rajasthan. Screening of mosquitoes collected from disease endemic settings and typing the virus could provide signifi cant epidemiological information for prospective risk of DHF. We therefore carried out a study on different dengue virus types as occurring in fi eld collected Aedes aegypti mosquitoes from four dengue endemic districts of Rajasthan, India. Methods: Adult Ae. aegypti were collected from the human dwellings of urban, peri-were collected from the human dwellings of urban, urban and rural settings of four dengue endemic districts of Rajasthan, India. The fi eld collected adults were fed on 4 per cent glucose solution and kept in the laboratory for 3-4 days. The adult fi eld collected Ae. aegypti, were subjected to indirect fl uorescence antibody test (IFAT) following standard procedure. Commercially acquired monoclonal antibodies against DEN types 1, 2, 3 and 4 were used. The remnants of IFA test subjected mosquitoes were made into viral suspension which was inoculated into the cell culture medium and mouse brain to confi rm the presence of virus as shown by IFA test. Results: Of the 498 adult Ae. aegypti tested, 78 (15.6%) were positive by IFA test. Among urban areas, desert area (Jodhpur) showed highest (21.6%) mosquito infectivity followed by 7.1 per cent in forest and river area (Kota) and least (3.2%) in semi-arid area (Jaipur). Among rural settings also, desert area showed maximum (25.0%) natural infection in mosquitoes followed by rural setting-1 of semi-arid area (24.1%). Among urban setting of desert area, all the four dengue types viz., DEN-1, 2, 3 and 4 were detected. In semi-arid area, urban settings showed presence of DEN-3, whereas among rural settings, rural-1 showed all the four DEN types, rural-2 showed DEN-1 and DEN-3, rural-4 showed DEN-3 and DEN-4, and rural-3 showed no mosquito infections. In forest and river area, among urban settings only, three DEN types, 1, 2 and 4 were observed. Interpretation & conclusion: In desert and semi-arid areas of Rajasthan, where people possess tendency of over- and sustained storage of domestic water, present observations on occurrence of all four dengue virus types may have important bearing on the epidemiology of DHF in the area.

Acciones en el control y la eliminación de un brote de dengue en Santiago de Cuba, 2001 / Actions aimed at control and eradication of a dengue outbreak in Santiago de Cuba in 2001

Evaluar los resultados de las acciones de control y eliminación de un brote de dengue en Santiago de Cuba en septiembre de 2001. Se realizó un estudio descriptivo transversal retrospectivo para describir el brote de dengue y las acciones en su control y eliminación. Este brote aportó 38 casos confirmados serológicamente, así como otros 16 casos en otras ßreas de salud. La implementación de medidas rápidas y efectivas en la lucha antivectorial, la organización de la detección y el manejo de casos, así como la participación comunitaria y de los organismos del estado, permitieron localizar este episodio y lograr su eliminación en 45 d. Las experiencias en la lucha antivectorial y el empleo precoz del tratamiento con insecticidas de acción residual resultaron elementos claves en el control del brote.

To asses result of the actions aimed at control and eradication of a dengue outbreak in Santiago de Cuba in september 2001. A descriptive retrospective cross-sectional study was performed in order to describe the dengue outbreak and the actions aimed at control and eradication. This outbreak gave rise to 38 serologically confirmed cases as well as other 16 cases in other health areas. The implementation of rapid and effective actions as part of the anti-vector fight, the organized detection and management of cases as well as the community and central state bodies involvement made it possible to eradicate this outbreak in 45 days. The experiences accumulated in the anti-vector fight and the early use of residual action pesticide treatments were key elements for the control of this dengue outbreak.

Aedes aegypti, Aedes albopictus, and dengue in Argentina: current knowledge and future directions

Since the reinfestation of South American countries by Ae. aegypti, dengue fever (DF) and dengue hemorrhagic fever (DHF) have become a major public health concern. The aim of this paper was to review the information related with Aedes vectors and dengue in Argentina since the reintroduction of Ae. aegypti in 1986. The geographic distribution of Ae. albopictus is restricted to the Northeast, and that of Ae. aegypti has expanded towards the South and the West in comparison with the records during the eradication campaign in the 1960s. Since 1998, 4,718 DF cases have been reported concentrated in the provinces of Salta, Formosa, Misiones, Jujuy and Corrientes. Despite the circulation of three dengue virus serotypes (DENV-1, -2 and -3) in the North of the country, DHF has not occurred until the present. The information published over the last two decades regarding mosquito abundance, temporal variations, habitat characteristics, competition, and chemical and biological control, was reviewed. Considering the available information, issues pending in Argentina are discussed. The presence of three DENV, the potential spread of Ae. albopictus, and the predicted climate change suggest that dengue situation will get worse in the region. Research efforts should be increased in the Northern provinces, where DHF is currently an actual risk.

El dengue y el dengue hemorrágico: prioridades de investigación / Dengue and dengue hemorrhagic fever: research priorities

Dengue is one of the most important infectious diseases in tropical and subtropical countries. At present, the only strategy available to reduce the incidence of dengue is vector control. The World Health Organization and the Pan American Health Organization have called on all nations to take the needed steps to help diminish the burden of this disease and its medical and socioeconomic impact. It is hoped that it will be possible to reverse the increase in dengue and help control its spread through a coordinated, effective international response, along with epidemiological, clinical, and virological research that brings together the most advanced methods and techniques. This piece summarizes the most up-to-date information on dengue, analyzes current epidemiologic trends in the Region of the Americas, discusses the main global and Western Hemisphere initiatives to control the disease, and presents the main areas of research that should be developed in the immediate future.

Vulnerabilidad espacial al dengue: una aplicación de los sistemas de información geográfica en el municipio Playa de Ciudad de La Habana / Spatial vulnerability to dengue: an applications of the geographic informations systems in Havana city

Durante la década de los años noventa, se ha extendido el uso de los sistemas de información geográfica en salud (SIG). Por otra parte el dengue reemerge con particular intensidad en este período, y progresa el uso de las herramientas SIG en su estudio. La presente investigación tiene como objetivos identificar la diferenciación espacial de la vulnerabilidad para la ocurrencia de dengue en el municipio Playa de Ciudad de La Habana, y contrastar los estratos identificados con la espacialidad de los casos notificados durante el brote reportado en el año 2000. Se confeccionó una base de datos digital a escala 1: 25 000, que define como polígonos las manzanas, y como atributos aquellos asociados a los macrofactores y microfactores de transmisión, y a la introducción del virus. Para los análisis espaciales se emplearon los softwares Mapinfo 5.0., Sig Epi 2000 y el SPSS 8.0. Se determinaron 3 grupos de manzanas según similitud de los valores de las variables, categorizadas en estratos espaciales de vulnerabilidad a la transmisión, como poco vulnerable, medianamente vulnerable y muy vulnerable. Se comprueba la solidez de los hallazgos, por su asociación con la espacialidad de los casos notificados

Detection of dengue virus from field Aedes aegypti and Aedes albopictus adults and larvae.

Mosquito adults and larvae were collected from dengue high risk areas and transported to the laboratory for identification. Identified mosquitos were pooled according to the species, date and locality and stored at -70 degrees C. A total of 1,385 pools of Aedes albopictus and 267 pools of Ae. Aegypti were collected from major towns in 12 states in Peninsular Malaysia. Virus isolation was carried out using cell culture (C6/36 clone) of Ae. albopictus and detection of dengue virus by the peroxidase anti-peroxidase staining. All positive isolations were further re-confirmed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Most of the pools were negative with PAP staining and RT-PCR. However, 11 mosquito pools were positive with PAP staining. On the other hand, samples from Terengganu, Pulau Pinang and Johor were positive using both methods.