Early detection of Sergentomyia minuta (Diptera: Phlebotominae) in Madrid, Spain An early warning for the temporal dynamic modi�cation of leishmaniosis’ epidemiology?

Global changes, such as climate change, represent a worldwide risk for the management of leishmaniosis. The transmission pro�le can be modi�ed by several mechanisms, mainly through the distribution and ecology of the vectors, causing direct effects on their survival, generation time, reproduction rate and population size. Sergentomyia minuta is an endemic species of the Old World, considered the most abundant in some areas of Spain. Even though S. minuta has traditionally been seen as herpetophilic, several recent research suggest this species to play a potential role in Leishmania infantum transmission. Furthermore, the Toscana virus has previously been detected in S. minuta and the potential role of this species in the epidemiology of this emerging arbovirus is still uncertain and needs further research. At the end of April 2023, a total of 10 individuals of S. minuta were collected in Torrelodones (Madrid, Central Spain), this being the �rst collection of sand�ies of any species during the month of April in this region. While it is known that climate change can have a signi�cant impact on sand �y distribution and behavior, little is known about the microscale effect of this variation on vector biology and ecology. The early detection of S. minuta in an endemic area of leishmaniosis such as the Madrid region suggests the potential impact on the epidemiology of these diseases. Furthermore, this early detection may act as an early warning of the risk of temporal dynamic changes in Phlebotomus species in response to global change.


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Although global change may cause the emergence and reemergence of vector-borne diseases, such as leishmaniosis (Ready 2008), there are many knowledge gaps concerning this topic.Due to the medical and veterinary importance of such diseases, further research is needed to better understand the epidemiological interactions between the environment, parasites, and vectors (da Costa et al. 2018; Reisen 2010).
In the face of climate change (Field et al. 2014), the distribution and ecology of vectors are expected to be signi cantly in uenced, increasing the generation time, survival, reproduction rate and consequent increase in its population and range of distribution (Alten et al. 2016;Negev et al. 2015).As such, global change also poses a worldwide risk for visceral leishmaniosis management (Kamhawi 2017;Wamai et al. 2020 (Grimm et al. 1993;Poeppl et al. 2013), while Mediterranean Basin countries may also become climatically suitable for new Phlebotomus species.Also, other species such as P. ariasi, based on prediction models, are expected to reduce their populations in their current distribution areas of Southern Europe, such as is the case of Spain (Koch et al. 2017).This hypothesis is supported by the evidence that P. arasi in Central Spain is mostly restricted to sampling sites above 700 meters above sea level (Gálvez et al. 2010).
Sergentomyia minuta Rondani, 1843 is an endemic species from the Old World, considered the most abundant in some areas of Spain (Aransay et al. 2004).Traditionally seen as herpetophilic (Jaouadi et al. 2013), it is considered the main vector of Leishmania (Sauroleishmania) tarentolae, a non-pathogenic protozoan for humans (Mendoza-Roldan et al. 2022), which had been previously detected in the Iberian Peninsula (Bravo-Barriga et al. 2016).Nevertheless, S. minuta has been implied to pose a public health risk, as it has been suggested to play some role in Le. infantum transmission (González et al. 2020;Latrofa et al. 2018).Although it supposedly prefers to feed on reptiles, several studies point to a more generalist feeding pattern.Both in vitro and eld blood meal analyses have con rmed the capacity of S. minuta to feed on mammals' blood ( (Aransay et al. 2004).Also, it should be noted that Le. tarentolae has been found in human blood in eld studies, and even though its potential for causing virulence is supposedly limited due to the absence of several virulence factors associated with viralization (Pombi et al. 2020), its capacity to infect human phagocytes has been proven through in vitro analysis (Taylor et al. 2010).Nevertheless, the potential interactions of Le. tarentolae in endemic areas with Le. infantum and its associated potential risks should be further explored (Mendoza-Roldan et al. 2022).Lastly, the recent rst detection of Le. major DNA in S. minuta in Europe was reported, in the Mediterranean region, once again challenging the idea that this species is an exclusive vector of reptilian leishmaniosis (Campino et al. 2013).Also, sand ies are vectors of several arboviruses, being the Phlebovirus the most studied.Nevertheless, other lesser-known viruses have also been identi ed in phlebotomine sand ies (Jancarova et al. 2023).Among the Phlebovirus, the Toscana virus (Bunyaviridae: Phlebovirus) is the most clinically relevant, being considered a major cause of meningitis and encephalitis in the Mediterranean region (Charrel et al. 2005).Phlebotomus perniciosus was identi ed as a potential vector species in the region of Madrid, Central Spain (Remoli et al. 2016).However, the wider geographic distribution of the Toscana virus in the Mediterranean region suggests the existence of greater varieties of sand y vectors, which could include S. minuta (Ayhan et al. 2020).Toscana virus has previously been detected in S. minuta (Charrel et al. 2006), and the potential role of this species in the epidemiology of this emerging arbovirus is still uncertain and needs further research.
At the end of April 2023 (27, 28 and 29 th ) a total of 10 S. minuta individuals (6 males; 4 females) were collected in the Animal Shelter of Torrelodones (Madrid, Central Spain), an area characterized by showing the highest phlebotomine sand ies' densities of the municipality (Prieto et al. 2021).The study area shows an arid Meso-Mediterranean climate (Martínez 1983) and it has established phlebotomine sand ies' populations, as shown by previous studies (López-de-Felipe et al. 2023; Gálvez et al. 2022).CDC light traps were installed 0.5m above the ground and placed from 20:00h to 08:00h.The animal shelter is situated in the periurban area of the municipality, close to low grasses elds and trees (Quercus ilex, Pinus pinea and Cupressus sp.) over sandy clays substrate.Sand ies were collected, morphologically identi ed to species level, and placed in 1.5 mL Eppendorf tubes with ethanol 70%.Species of S. minuta were identi ed according to Fierro et al. (2014).
In Central mainland Spain, sand y activity normally occurs between late May and October, with population peaks in June and September (Alten et al. 2016;Gálvez et al. 2010).Phlebotomus perniciosus shows a biphasic seasonal trend with two abundance peaks in July and September, while P. ariasi shows a monophasic trend with a single peak in August (Gálvez et al. 2010).To our knowledge, this was the rst collection of sand ies of any species during the month of April in the Madrid region.April 2023 has been characterized by being extremely dry and hot, reaching temperatures above 28ºC (minimum, 13ºC; maximum, 29ºC; mean, 20.7ºC) (Meteoblue 2023).The seasonal activity of sand ies explains, in part, an equally seasonal pattern in relation to cases of leishmaniosis, with important variations caused by environmental factors (Alten et al. 2016).Even though climate change is known to potentially have a signi cant impact on the distribution and behavior of sand ies, little is understood of the microscale effect of this variation on the vector's biology and ecology (Booth 2018;Peterson & Shaw 2003) The early detection of S. minuta in a leishmaniosis endemic area such as the Madrid region suggests the potential impact on the epidemiology of these diseases.Even though the spatial alterations of phlebotomine sand ies in response to climate change, both in latitudinal and altitudinal ranges, are heavily addressed in the literature (Gálvez et al. 2010;Medlock et al. 2014), seasonal trends alterations for these vectors are scarcer (Halimi et al. 2017).Nevertheless, the modi cations on phlebotomine sand ies' spatial dynamics may play a key role in future leishmaniosis prophylactic campaigns, as recommendations given by veterinary or public health practicians should be modi ed according to the species' new phenologies.Surveillance services must be aware of such changes to carry out adequate monitoring programs.Although S. minuta is not a proven vector of Le. infantum, its ability to feed on human blood suggests the need for further studies to better understand its role in the spread of leishmaniosis and arbovrisues.Also, and most importantly, this early detection may act as an early warning of the risk for Phlebotomus species temporal dynamics alterations, in response to global change.