Effect of Abiotic Factors on Seasonal Population Dynamics of <I>Lutzomyia longipalpis</I> (Diptera: Psychodidae) in Northeastern Brazil

Abstract

The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz and Neiva) (Diptera: Psychodidae), the vector of Leishmania infantum, the causative agent of visceral leishmaniasis in Brazil. Sand flies were captured in peridomestic habitats biweekly for 3 yr. Cross-correlation tests and spectral analysis were used to analyze the simultaneous and lag-time correlations between Lu. longipalpis population densities and abiotic factors of temperature, relative humidity, wind velocity, and rainfall. Distinct seasonal patterns were observed for males and females, with intervals of 6 mo between population peaks for males and 12 mo for females. Peak female population densities lagged 3 mo behind the maximum annual temperature. Female population density was negatively correlated with relative humidity. An increase in average wind velocity was followed by a decrease in the number of females for 2 wk. Understanding the relationship between the seasonal population dynamics of Lu. longipalpis and abiotic factors will contribute to the design of better control measures to decrease transmission of L. infantum and consequently the incidence of leishmaniasis.

Spatiotemporal dynamics of Lutzomyia longipalpis and macro‐habitat characterization using satellite images in a leishmaniasis‐endemic city in Argentina

“…The increases in L. longipalpis abundance and distribution during mid‐spring and summer and its persistence until the beginning of autumn indicate that this period represents the time of greatest risk for human–vector and reservoir–vector contact. Similar temporal dynamics of L. longipalpis populations have been recorded in other regions (de Melo Ximenes et al ., ; da Paixão Sevá et al ., ; Gómez‐Bravo et al ., ). In a longitudinal study carried out in Mato Grosso do Sul, L. longipalpis was associated with NDVI (Oliveira et al ., ).…”

Lutzomyia longipalpis, Gone with the Wind and Other Variables

“…Regarding annual modality and climate variables lag times, Lu. longipalpis was trimodal in Mato Grosso do Sul and Colombia (Morrison et al 1995a, Brilhante et al 2015; in Natal, the males were bimodal correlated with relative humidity and wind up to 6 weeks earlier, and females were unimodal peaking 3 months after peak of temperature and 2 weeks after the increase of wind, but with a lag of 11 weeks with relative humidity (Ximenes et al 2006).…”

“…On the other hand, the time intervals between the peaks of Lu. longipalpis and the peaks of human or canine AVL cases, on this annual time scale, are also shifted from each other, as the latter are related to the incubation period of the parasites in the mammalian host (de Ximenes et al 2006). Thus, simultaneous surveys of vectors and infection can link different seasons of transmission, the vectors peak related to the next AVL incidence rate, and the host infection prevalence related with the previous vector peak although they may have a similar but displaced pattern (Michalsky et al 2009, Silva et al 2014.…”

“…With regard to moonlight, it was not correlated with the abundance of Lu. longipalpis by one study (Ximenes et al 2006), but different wavelengths showed different attractiveness yet barely no alteration of the sex ratio (Lima-Neto et al 2018).…”

“…The microscale temporal distribution, the hourly pattern, also varies between places and habitats, showing peaks in the evening in rural peridomiciles (Morrison et al 1995b), at 10 or 11 PM according to the sex (Ximenes et al 2006), at midnight in intradomiciles (Rebêlo et al 2001), or bimodal in the twilight hours of dusk and dawn (Infran et al 2017). The hourly activity seems more related to the light cycles, sunset time, and even artificial lighting than to internal clocks, since in the photic zone of caves nocturnal activity is 33 times greater than diurnal activity, while in the aphotic area it is only 0.66 times (Campos et al 2017).…”