An outbreak of dengue fever in Peri Urban slums of Chandigarh, India, with special reference to entomological and climatic factors
Dengue viral infection is one of the most important public health problem in tropical countries. An outbreak of dengue fever was investigated in a periurban slum area of Chandigarh, India, during September to December, 2002. Blood samples from 218 patients and 30 apparently healthy contacts were tested for dengue-specific immunoglobulin M (IgM) and IgG antibodies including 80 acute samples collected within 5 days of illness were subjected for virus isolation in newborn mice. The average temperature, rainfall, and humidity of the epidemic year were compared with the number of dengue cases. statistical significance was found out using c2-test. A total of 76 cases were positive by either dengue IgM capture assay (n = 57) or virus isolation (n = 17) or both (n = 2). Fifteen of nineteen viral isolates subjected for typing by type-specific multiplex reverse transcription-polymerase chain reaction were found to be of dengue virus. High rainfall and humidity with the temperature range from 21 degrees C to 33 degrees C during the months of August and September might have favored the breeding of mosquitoes, thus leading to an increase in the number of dengue cases in October and November, 2002. The present outbreak thus emphasizes the need for continuous sero epidemiological and entomological surveillance for the timely implementation of effective dengue control programme.
[Show abstract] [Hide abstract] ABSTRACT: Porcelain and plastic materials constitute bulk of household wastes. Owing to resistibility and slow degradability that accounts for higher residence time, these materials qualify as potential hazardous wastes. Retention of water permits these wastes to form a congenial biotope for the breeding of different vector mosquitoes. Thus porcelain and plastic wastes pose a risk from public health viewpoint. This proposition was validated through the study on the porcelain and plastic household wastes as larval habitats of Dengue vectors (Aedes spp.) in rural and urban areas around Kolkata, India. The wastes were characterized in terms of larval productivity, seasonal variation and a comparison between urban and rural areas was made using data of two subsequent years. The number of wastes positive as larval habitats and their productivity of Aedes spp. varied among the types of household wastes with reference to months and location. Multivariate analysis revealed significant differences in the larval productivity of the household wastes based on the materials, season, and urban-rural context. Results of Discriminant Analysis indicated differences in abundance of Ae. aegypti and Ae. albopictus for the urban and rural areas. The porcelain and plastic wastes were more productive in urban areas compared to the rural areas, indicating a possible difference in the household waste generation. A link between household wastes with Aedes productivity is expected to increase the risk of dengue epidemics if waste generation is continued without appropriate measures to limit addition to the environment. Perhaps, alternative strategies and replacement of materials with low persistence time can reduce this problem of waste and mosquito production.0Comments 0Citations
- "Thus vector control strategies should incorporate the rural and suburban areas for regulation Aedes mosquito abundance. While only few discrete studies in rural areas of North India [19,43,45] record the occurrence of the dengue vectors, planned dengue vector control strategies are yet to be employed. In majority instances in India and other tropical regions, dengue vector control is restricted to urban populated sites [4,45, 49]. "
- "These high-density, high-transmission intensity environments have also been shown to be of particular importance for dengue persistence (Cummings et al., 2004; Almeida et al., 2007). Several studies have linked poverty or wealth to dengue (Lifson, 1996; Ratho et al., 2005; Flauzino et al., 2009; Mena et al., 2011), while others have found only transitory associations (Heukelbach et al., 2001; Mondini and Chiaravalloti Neto, 2007 ), highlighting the complexity of this relationship. It is possible that using relative poverty instead of absolute poverty might better discriminate between levels of economic disadvantage and detect disparities not only between urban and rural environments, but also within them. "
[Show abstract] [Hide abstract] ABSTRACT: Introduction:Dengue is one of the most important arboviral infections caused by one of the four dengue serotypes, 1-4.Objective:To study the applicability of different diagnostic methods in diagnosis of dengue viral infection.Materials and Methods:A total of 2101 blood samples were collected for confirmation of dengue viral infection. All the samples were tested by dengue-specific IgM ELISA, of which 111 were also tested for NS1 antigen detection and 27 acute samples (≤5 days) were further subjected for viral RNA detection by RT-PCR and isolation in C6/36 cell line. To detect the sensitivity of NS1 antigen for different dengue virus serotypes, four dengue serotype 1 and 12 dengue 3 were subjected for the NS1 antigen assay.Results:Most common age group affected was 16-45 years, with male to female ratio of 2.8:1. During first 3 days of illness virus isolation and RT-PCR were the most sensitive (83%) followed by NS1 antigen detection (75%) and IgM detection (37.5%). The positivity of IgM detection was found to be significantly higher as compared to NS1 detection during 4 to 5 days and also after 5 days of illness (P < 0.05). Dengue serotypes 1 and 3 were found to be co-circulated, dengue 1 being the predominant serotype.Conclusion:Virus isolation and RT-PCR were the most sensitive tests during the early period of illness whereas beyond third day, IgM antibody detection was found to be the most sensitive method of dengue diagnosis.0Comments 1Citation
- "NS1 antigen detection (P < 0.05). The early appearance of IgM antibody has been reported in secondary dengue infections as compared to primary dengue infection.  As Chandigarh is known for its endemo-epidemic status for dengue virus infection with sero-prevalence more than 70%, majority of dengue cases are considered to be secondary infections.  Secondly, the lower positivity of NS1 antigen after 3 days of illness in the present study could also be due to the secondary nature of dengue infection in this region due to endemicity. High titers of pre-existing IgG antibodies have been attributed to the lower positivity of NS1 antigen detection in acute secondary dengue infection as"