The effects of climatic factors on the distribution and abundance of japanese encephalitis vectors in Kurnool district of Andhra Pradesh, India.

Background & objectives: Climatic attributes have been associated with relative mosquito abundance and transmission of mosquito borne infections in many parts of the world, especially in warm and tropical climatic regions. The main objectives of this study were to assess the change in seasonal pattern of Japanese encephalitis (JE) vectors, their density, to elucidate whether the lagged climate variables (precipitation, temperature and humidity) are associated with JE vector density, and to determine if temperature and precipitation are similarly important for the rise in the number of potential mosquito vectors for JE virus in the temperate climate of Andhra Pradesh, India. Methods: Mosquito samples were collected from Kurnool district of Andhra Pradesh using hand catch and light-trap methods during 2002 to 2006. The type and abundance of recovered species were compared to ecological correlates. In each geographic area, temperature and precipitation are the two possible proxy variables for mosquito density, in conjunction with other seasonal factors for JE epidemics. Results: Out of the various mosquito species collected, Culex gelidus and Cx. tritaeniorhynchus were noticed in high numbers. There was considerably high prevalence of Cx. gelidus (68.05%) in urban area than in rural areas whereas, Cx. tritaeniorhynchus (57.51%) was found to be more in rural areas than in the urban area. It is noticed that the factors such as rainfall and temperature were found to be correlated with the per man hour (PMH) density, whereas the humidity was inversely correlated with the PMH. Interpretation & conclusion: The environmental and eco-climatic factors are assisting in enhancing the breeding of these mosquitoes in Kurnool district of Andhra Pradesh, India. Both Cx. tritaeniorhyncus and Cx. gelidus are quite adaptable to these environmental conditions and this necessitates immediate control measures in both rural and urban areas of Kurnool district.

Impact of different housing structures on filarial transmission in rural areas of southern India.

The aim of the present investigation was to assess the filarial transmission levels in houses of different structure in rural areas of Andhra Pradesh, India. During this study, ecologically-similar households were selected for entomological study. The per-man-hour density (PMHD), infection and infectivity rates, were recorded in different ranges ie, 16.1 to 77.6, 0-31.2% and 0-5.6%, respectively.

A baseline study of rural Bancroftian filariasis in southern India.

Night mass blood surveys were carried out for parasitological evidence of Bancroftian filariasis in 45 rural areas belonging to 9 National Filaria Control Program (NFCP) zones of East Godavari and West Godavari districts of Andhra Pradesh, India during the period 1998 to 2001. Mf prevalence range between 2.9 to 10.2%, and mf intensities in 20 mm3 blood samples ranged from 1-281. The present study explains the trend of microfilaria dynamics in the rural population, where mass drug delivery has been implemented since 1997, and anti-larivicidal and adulticidal control measures have not been adopted.

Relative abundance of Culex quinquefasciatus (Diptera: Culicidae) with reference to infection and infectivity rate from the rural and urban areas of East and West Godavari districts of Andhra Pradesh, India.

This paper describes the seasonal abundance of Culex quinquefasciatus in the rural and urban areas of the East and West Godavari districts (EGDT and WGDT) of Andhra Pradesh, India. The per man-hour density (PMHD) was collected from seven units in EGDT and two units in WGDT, which comprised rural and urban areas. The highest infection and infectivity rates were found in the rural areas of Rajahmundry (43.6%) and Amalapuram (13.2%) respectively. In urban areas, the highest infection and infectivity rates were found in Rajahmundry: 7.5% and 3.6% respectively. There was considerable difference in the infection rate and infectivity rates between the rural areas and urban areas in each unit.