Hourly Activity and Natural Infection of Sandflies (Diptera: Psychodidae) Captured from the Aphotic Zone of a Cave, Minas Gerais State, Brazil

Abstract

Sandflies are holometabolous insects that are of great epidemiological importance in the neotropical region as vectors of leishmaniases. Caves are ecotopes that significantly differ from external environments and, among the insects that live or visit their internal area and adjacent environment, sandflies are commonly found. Based on this context, the objective of this work was to examine the period of activity of sandflies in the cave environment in the aphotic zone. Thus, four sandfly captures were conducted, one in each season of the year, in a cave where studies on the bioecological aspects of sandfly fauna have been conducted since 2008. In this same study, we have also noticed the presence of flagellates in some captured females. Catches were carried out for 24 hours using a Shannon trap, light bait, and cave walls were actively searched. We collected a total of 638 sandflies, representing 11 species. The most abundant species and with more intense period of activity were, in descending order: Lu. cavernicola (62%), Ev. spelunca (16%) and Ev. sallesi (14%). A total of 69 females were dissected to check for natural infection, and in five specimens we found living flagellated forms: two Ev. spelunca, two Ev. sallesi and one Sc. sordellii. This study shows that the activity of some species caught in the aphotic zone of the cave, especially Lu. cavernicola, differs from what has already been reported in previous sandfly captures, which are almost always conducted at night and during twilight. The existence of sandflies that were naturally infected with flagellates and the lack of awareness regarding the behaviour of sandflies in cave environments are strong indicators of the need for further study on this group of insects in this ecotope, as a safety measure to protect the visitors of such environment.

Ecological Aspects of Phlebotomine Sandflies (Diptera: Psychodidae) from a Cave of the Speleological Province of Bambuí, Brazil

“…Other recent published study describes the hourly activity of sandflies captured over 24-hours in the same cave [46]. With this data, it became clear that some species presented differences in the circadian cycle and, consequently, a different period of activity compared with sandflies trapped in the external environment.…”

Knowledge of the Population about Visceral Leishmaniasis Transmission in Endemic Areas near the Banks of the Mossoró River in Northeastern Brazil

“…Because few dogs living in the study areas wear collars with repellent action, dogs in the study area may be at risk of infection by VL. Another factor that draws attention is the habit that some have to walk their dogs at night, which is a risk to animals because L. longipalpis activity occurs from dusk to dawn [ 34 ]. Dogs that are walked when vector activity is high have a higher susceptibility of infection due to the possibility of contact with sandflies in the environment.…”

Monthly Distribution of Phlebotomine Sand Flies, and Biotic and Abiotic Factors Related to Their Abundance, in an Urban Area to Which Visceral Leishmaniasis Is Endemic in Corumbá, Brazil

“…corumbaensis not being found to be naturally infected by Leishmania . However, the other 3 species of the complex have been found naturally infected with Leishmania , or Leishmania DNA, in wild-caught female, has been detected [57–59]. These facts may indicate the importance of the complex in maintaining the wild cycle of Leishmania .…”