Population Ecology ofPhlebotomus argentipes(Diptera: Psychodidae) in West Bengal, India

Abstract

The population abundance of Phlebotomus argentipes Annandale & Brunetti was studied between January 1986 and December 1987 at 2 sites in West Bengal, India, in relation to 8 ecological parameters (air temperature, rainfall, windspeed, relative humidity, soil moisture, soil temperature, soil pH, and soil organic carbon). Sand flies were present throughout the year with minimum abundance in winter months and maximum during monsoon and postmonsoon months. Correlation analysis examined pairwise relationships among the 8 ecological parameters and P. argentipes abundance. Multiple linear regression of sand fly abundance on the 8 parameters showed that average soil temperature and soil moisture, both recorded 1 mo earlier, were associated positively with sand fly abundance. These findings have important implications for Indian kala-azar disease control and prevention. Effective vector management programs are needed most when weather conditions favor increased sand fly abundance, given that greater sand fly abundance increases the likelihood of host-vector contact and the transmission of Leishmania.

Seasonal relationship between normalized difference vegetation index and abundance of the Phlebotomus kala-azar vector in an endemic focus in Bihar, India

“…soil moisture, temperature, humidity, land use/land cover and topography, etc.) contribute to P. argentipes abundance (Ghosh et al, 1999;Kishore et al, 2006;Guernaoui and Boumezzough, 2009;Bhunia et al, 2010b) and may also influence vector seasonality (Dinesh et al, 2001;Picado et al, 2010). However, if the minimum NDVI values are produced by water-bodies instead of empty land, these readings could be an indication of the relative humidity and damp surfaces favoured by P. argentipes for its egg and larvae, rather than signifying barren land (Bern et al, 2000;Sharma and Singh, 2008;Bhunia et al, 2011).…”

“…The poor efficacy of vector control programmes is associated with logistic problems, mainly due to poor understanding of vector ecology. Indeed, knowledge of breeding sites, host preferences and seasonality of P. argentipes is crucial when designing effective vector control strategies (Ghosh et al, 1999;Picado et al, 2010). Kala-azar has become particularly common in the north-eastern part of India and is currently considered one of the most severe public health problems of the country (Ashford, 2000;Redhu et al, 2006).…”

Progress in the Mathematical Modelling of Visceral Leishmaniasis

“…In tropical regions, sandflies are usually present in every month, but with up to a 10-fold variation in sandfly numbers across the year. On the ISC, numbers are lowest in December and January, when temperatures are lowest, and typically highest in summer and the post-Monsoon period; numbers correlate positively with temperature, but correlations with rainfall are more variable (Ghosh et al, 1999;Picado et al, 2010a). In Amazon Brazil, sandfly numbers peak at the end of the dry season, and this variation in population size is reflected in a marked variation in the incidence of canine infection across the year Kelly et al, 1997).…”

Understanding Visceral Leishmaniasis Disease Transmission and its Control—A Study Based on Mathematical Modeling

“…A significant positive correlation between sandfly density and rainfall is known for the sandfly species Phlebotomus papatasi [45]. Further, sandfly abundance is known to the highest in monsoon and post-monsoon seasons [46]. With respect to this information, it is palpable that seasonal fluctuations like rainfall affect the existence of effective sandfly population.…”