A systematic review and global analysis of the seasonal activity of Phlebotomus (Paraphlebotomus) sergenti, the primary vectors of L. tropica

Abstract

Background Phlebotomus (Paraphlebotomus) sergenti is a widespread proven vector of Leishmania pathogens causing anthroponotic cutaneous leishmaniasis (ACL), due to L. tropica, in the old world. The activity of P. (Par.) sergenti is seasonal and sensitive to general variations in climate. Phenological data sets can thus provide a baseline for continuing investigations on P. (Par.) sergenti population dynamics that may impact future leishmaniasis transmission and control scenarios. Methods/Principal finding A systematic review of the seasonality of P. (Par.) sergenti was undertaken globally. Sixty-eight scientific papers were identified, and data were extracted from 35 ones, with informative data on sand fly seasonal dynamics on trapping performed from 1992 to December 2021 on 63 sites from 12 countries. Morocco, Saudi Arabia, Iraq, Iran, Pakistan, Palestine, Turkey, Spain, Portugal, Italy, Cyprus, and Georgia. The data extracted from the literature survey were further normalized. Our analysis recorded that the highest P.(Par.) sergenti activity occurs during the hot and dry seasons, primarily in July and August, whatever the location studied. We noticed a relationship between the latitude of sites and sand fly presence (from early April to June) and the type of density trend, varying from a single peak to multiple peaks. On a geographical scale, P. (Par.) sergenti concentrates between 32–37° in latitude in a large interval following the longitude and the highest number of sites with high P. (Par.) sergenti activity is located at the latitude 32°. We also quoted a similar seasonal dynamic and geographic distribution with Phlebotomus (Phlebotomus) papatasi, a proven vector of L. major that causes cutaneous infection. No apparent risk for ACL occurred from December to March, at least in the years and geographic areas considered in this survey. Altogether, knowing that high P. (Par.) sergenti activity would be linked with an increased risk of leishmaniasis transmission, and our study provides information that can be used for control programs on ACL transmission. Conclusions Despite variations, we found a relatively homogeneous pattern of P. (Par.) sergenti potential behavior in sites whose data are published. A higher risk for L. tropica transmission was identified in the June-October period. Still, such risk was not equally distributed throughout the area since density waves of adults occurred earlier and were more frequent in some territories, like Saudi Arabia.

Entomological, parasitological and molecular investigations in a new focus of cutaneous leishmaniasis in Youssoufia region, Morocco

“…Indeed, factors influencing spatial and temporal dynamics depend on rodent population dynamics, vector dispersal, climate change, and human activities (Riyad et al., 2013). In fact, entomological investigations in the three localities confirmed the prevalence of P. papatasi , the vector of L. major responsible for zoonotic CL (40); P. sergenti , the proven vector of L. tropica , agent of the anthroponotic form of CL in the Old World (Karmaoui et al., 2022), particularly in Morocco (Daoudi et al., 2022), and the presence of P. longicuspis which increases the risk of transmission of L. infantum causing CL and VL (Zarrouk et al., 2022).…”

“…Sand flies were collected using miniature CDC light traps and sticky traps (20–20‐cm pieces of paper coated with castor oil; Boussaa et al., 2009), set up one night at dusk and collected early the next morning. These CDC light traps, were placed approximately 1.5 m above the ground (Mhaidi et al., 2022), inside houses, in stables for domestic animal; however sticky traps were placed outside near garbage and sewage, in areas of wild vegetation away from human habitations, in caves, roadside drainage holes (“barbacans”), old walls, rock crevices, and ruins (Karmaoui et al., 2022). The collection period was between April and October 2021, corresponding to the activity period of sand fly in the region.…”

Knock, knock, knocking on Europe’s door: Threat of leishmaniasis in Europe with a focus on Turkey

“…Climate change, another influential factor, has impacted the epidemiology of leishmaniasis in Turkey ( Özbel et al, 2022 ). Alterations in temperature and rainfall patterns, as well as environmental modifications, can influence the distribution and abundance of sand fly vectors, thereby affecting the transmission dynamics of the disease ( Karmaoui et al, 2022 ). As climate change continues to reshape ecological conditions, regions that were previously unaffected by leishmaniasis may become suitable habitats for sand fly populations, potentially leading to the introduction and establishment of the disease in new areas ( Van der Auwera et al, 2022 ).…”