Ecological dynamics and multidimensional analysis of phlebotomine sandflies in potentially prone communities in southeastern Nigeria

Abstract

This study investigates the spatial and temporal dynamics of sandfly specie abundance in some selected communities in Nigeria using multidimensional approach, including entomological survey, soil analysis and Inverse Distance Weighting (IDW) spatial interpolation. The Centre for Disease Control (CDC) light and sticky paper trap method was installed three times repeatedly in a month between 6.30 am to 6.30 pm over a period of eight (8) months (August 2022 – March 2023) while Human baits was deployed once monthly. A total of 909 insects were captured to determine the spatio-temporal abundances and 525 sandflies were caught using the human baits and for estimate of the Monthly Biting Rates (MBR). The Inverse Distance Weighted (IDW) technique was deployed for spatial mapping of specie abundance. The finding reveals distinct patterns in sandfly abundance across various months, highlighting specific trends in variability and skewness. Notably, the month of August exhibits higher variability with a wider interquartile range (IQR), indicating a dynamic ecological environment. In September, a left-skewed distribution suggests consistently higher and more stable sandfly abundance. November and March present right-skewed patterns while October and December were without significant fluctuation. January and February were left-skewed and right-skewed respectively. The spatial interpolation maps generated reveals a stronger correlation between sandfly abundance and land use types; particularly during the rainy season with values of 18.6% for Umuoba and Amuzu while 26.5% for Ihube in contrast to 6.1%, 7.0% and 13.2% for Umuoba, Amuzu and Ihube in dry season respectively. This suggests a spatial pattern aligning with land use types at different location, influenced by environmental conditions and microclimate. Soil analysis results revealed that sulphate ion appeared to be associated with favoured breeding sites for these sandflies. This breeding pattern is suggestive of intense biting activities observed during the early mornings and evenings of the rainy season as against reduced biting activity in the dry season. Ihube community recorded higher specie abundance oscillating between August and October. This study underscores the value of multidimensional approach in understanding sandfly ecology, with implications for vector control and public health intervention strategies.