Courtship behaviour of <it>Phlebotomus papatasi</it> the sand fly vector of cutaneous leishmaniasis

<p>Abstract</p> <p>Background</p> <p>The sand fly <it>Phlebotomus papatasi</it> is an Old World vector of <it>Leishmania major</it>, the etiologic agent of zoonotic cutaneous leishmaniasis. This study describes the courtship behaviour of <it>P. papatasi</it> and compares it with that of <it>Lutzomyia longipalpis</it>, the New World vector of visceral leishmaniasis. Understanding the details of courtship behaviour in <it>P. papatasi</it> may help us to understand the role of sex pheromones in this important vector.</p> <p>Results</p> <p><it>P. papatasi</it> courtship was found to start with the female touching the male, leading him to begin abdomen bending and wing flapping. Following a period of leg rubbing and facing, the male flaps his wings while approaching the female. The female then briefly flaps her wings in response, to indicate that she is willing to mate, thereby signaling the male to begin copulation. Male <it>P. papatasi</it> did not engage in parading behaviour, which is performed by male <it>L. longipalpis</it> to mark out individual territories during lekking (the establishment and maintenance of mating aggregations), or wing-flap during copulation, believed to function in the production of audio signals important to mate recognition. In <it>P. papatasi</it> the only predictor of mating success for males was previous copulation attempts and for females stationary wing-flapping. By contrast, male <it>L. longipalpis</it> mating success is predicted by male approach-flapping and semi-circling behaviour and for females stationary wing-flapping.</p> <p>Conclusions</p> <p>The results show that there are important differences between the mating behaviours of <it>P. papatasi</it> and <it>L. longipalpis</it>. Abdomen bending, which does not occur in <it>L. longipalpis</it>, may act in the release of sex pheromone from an as yet unidentified site in the male abdomen. In male <it>L. longipalpis</it> wing-flapping is believed to be associated with distribution of male pheromone. These different behaviours are likely to signify significant differences in how pheromone is used, an observation that is consistent with field and laboratory observations.</p

Investigation of the Sandfly Fauna of Central Arid Areas and Northern Humid Regions of Tunisia, with Morphological and Molecular Identification of the Recently Established Population of Phlebotomus (Larroussius) perfiliewi

International audiencePhlebotomus perfiliewi is one of the main vectors of Leishmania infantum, etiologic agent of zoonotic visceral leishmaniasis (ZVL), in the Western Mediterranean basin including Tunisia. Phlebotomus perfiliewi, originally endemic only in Northern humid bio-climatic zones, became established in a highly irrigated area of the central arid bioclimatic zone. Therefore, surveillance of sandfly vectors is a cornerstone for the establishment of control strategies. An entomological survey was carried out using light traps in a humid and in a highly irrigated arid bio-climatic zone located in northern and central Tunisia, respectively. Collected sandflies were identified based on morphological criteria, and identification of Ph. perfiliewi was confirmed by molecular tools. Results indicated that Ph. perfiliewi is the most abundant sandfly species in both sites and it is genetically variable. Thus, surveillance and control of sandflies is highly needed to limit the incidence of sandfly-borne disease

Colonization of <it>Phlebotomus papatasi </it>changes the effect of pre-immunization with saliva from lack of protection towards protection against experimental challenge with <it>Leishmania major </it>and saliva

Abstract Background Sand fly saliva has been postulated as a potential vaccine or as a vaccine component within multi component vaccine against leishmaniasis. It is important to note that these studies were performed using long-term colonized Phlebotomus papatasi. The effect of sand flies colonization on the outcome of Leishmania infection is reported. Results While pre-immunization of mice with salivary gland homogenate (SGH) of long-term colonized (F5 and beyond) female Phlebotomus papatasi induced protection against Leishmania major co-inoculated with the same type of SGH, pre-immunization of mice with SGH of recently colonized (F2 and F3) female P. papatasi did not confer protection against L. major co-inoculated with the same type of SGH. Our data showed for the first time that a shift from lack of protection to protection occurs at the fourth generation (F4) during the colonization process of P. papatasi. Conclusion For the development of a sand fly saliva-based vaccine, inferences based on long-term colonized populations of sand flies should be treated with caution as colonization of P. papatasi appears to modulate the outcome of L. major infection from lack of protection to protection.</p

Independent Circulation of Leishmania major and Leishmania tropica in Their Respective Sandfly Vectors for Transmission of Zoonotic and Chronic Cutaneous Leishmaniasis Co-Existing in a Mixed Focus of Central Tunisia

Zoonotic cutaneous leishmaniasis (ZCL) and chronic cutaneous leishmaniasis (CCL) are known to overlap in Central Tunisia. Sandflies were collected using sticky traps and CDC light-traps set in rodent burrows at the ecotones surrounding the village, in houses, and in animal shelters during July&ndash;October 2017, 2018, and 2019. A total of 17,175 sandflies were collected during the three sandfly seasons and identified morphologically to species level. Of a total of 18 sandfly species reported in Tunisia, 16 were identified in this mixed focus of ZCL and CCL. Except for the rocky mountainous areas, Phlebotomus papatasi was the most abundant sandfly species in all biotopes. In the mountainous areas, Phlebotomus sergenti is the most abundant sandfly species belonging to the genus Phlebotomus. Female sandflies were tested for the presence of Leishmania species by PCR. The overall infection prevalence of sandflies with Leishmania major and Leishmania tropica was 0.42% and 0.065%, respectively. The sequencing of PCR-amplified ITS1 products showed that L. major is the predominant species in all biotopes and transmitted mostly by P. papaptasi followed by Phlebotomus longicuspis and Sergentomyia species. Leishmania tropica was detected in Phlebotomus sergenti and in Phlebotomus longicuspis collected in bedrooms and in the ecotone of rocky mountainous areas. Our results provided strong evidence that the proximity of human settlements to biotopes of rodent reservoir hosts of L. major and of L. tropica resulted into the cocirculation of both Leishmania species leading to a mixed focus of ZCL and CCL. The epidemiology of leishmaniases in North Africa is highly complex by the high diversity of sandfly vectors and their associated Leishmania species, leading to a mixed form of cutaneous leishmaniasis. It is of major epidemiological importance to point to the risk of spillover from rural to urban areas leading to the anthroponization of cutaneous leishmaniasis. Therefore, efficient control to reduce the indoor abundance of sandfly vectors in order to reduce the incidence of leishmaniases is urgently needed

Transmission Dynamics of Punique Virus in Tunisia

A novel phlebovirus, Punique virus (PUNV), was discovered and isolated in 2008 from sandflies from Northern Tunisia. PUNV is now classified as a unique member of the Punique phlebovirus species within the Phlebovirus genus in the Phenuiviridae family (order bunyavirales). In this study, we aimed to investigate the transmission dynamics of PUNV in Tunisia. Sandflies were collected during two consecutive years, 2009 and 2010, by CDC light traps. In 2009, a total of 873 sandflies were collected and identified to the species level. Phlebotomus perniciosus was the most abundant species. One pool of P. perniciosus females collected in autumn contained PUNV RNA, yielding an infection rate of 0.11%. The population densities of circulating sandfly species were assessed during May–November 2010 in Northern Tunisia by using sticky traps. Phlebotomus (Larroussius) perniciosus (71.74%) was the most abundant species, followed by Phlebotumus (Larroussius) longicuspis (17.47%), and Phlebotumus (Larroussius) perfiliewi (8.82%). The densities of dominant sandfly species were found to peak in early spring and again in the autumn. In 2010, species identification was not performed, and sandflies were only discriminated on the basis of sex and collection date. Out of 249 pools, three contained PUNV RNA. Each positive pool allowed virus isolation. The three pools of female sandflies containing PUNV RNA were collected in autumn with an infection rate of 0.05%. These findings provide further evidence that P. perniciosus is the main vector of PUNV in Tunisia, and this phlebovirus is endemic in Tunisia. Our findings provided strong evidence of intensive circulation of PUNV in sandflies and hosts through a viral infection buildup process between sandfly vectors and hosts starting at the beginning of the activity of sandflies in spring to reach a maximum during the second main peak in autumn

Colonization of Phlebotomus papatasi changes the effect of pre-immunization with saliva from lack of protection towards protection against experimental challenge with Leishmania major and saliva.

International audienceBACKGROUND: Sand fly saliva has been postulated as a potential vaccine or as a vaccine component within multi component vaccine against leishmaniasis. It is important to note that these studies were performed using long-term colonized Phlebotomus papatasi. The effect of sand flies colonization on the outcome of Leishmania infection is reported. RESULTS: While pre-immunization of mice with salivary gland homogenate (SGH) of long-term colonized (F5 and beyond) female Phlebotomus papatasi induced protection against Leishmania major co-inoculated with the same type of SGH, pre-immunization of mice with SGH of recently colonized (F2 and F3) female P. papatasi did not confer protection against L. major co-inoculated with the same type of SGH. Our data showed for the first time that a shift from lack of protection to protection occurs at the fourth generation (F4) during the colonization process of P. papatasi. CONCLUSION: For the development of a sand fly saliva-based vaccine, inferences based on long-term colonized populations of sand flies should be treated with caution as colonization of P. papatasi appears to modulate the outcome of L. major infection from lack of protection to protection