Rotation of male genitalia in various species of phlebotomine sandfly.

Phlebotomine sandflies, vectors of Leishmania (Kinetoplastida: Trypanosomatidae) parasites that affect millions of people worldwide, breed in terrestrial biotopes. As immature stages are rarely accessible, the detection of their natural breeding sites is primarily based on findings of juvenile males with unrotated external genitalia. In males, permanent 180° rotation on the longitudinal body axis occurs soon after eclosion; however, no study has as yet addressed this aspect in detail. The present study describes the timing and duration of the rotation of male external genitalia in eight highly medically important sandfly species belonging to the genera Sergentomyia, Lutzomyia and Phlebotomus (all: Diptera: Psychodidae), kept under controlled laboratory conditions. The average duration of rotation was species-specific and varied from 12 h in Sergentomyia schwetzi to 33 h in Phlebotomus sergenti. Significant differences in rotation times were found among species, even between two closely related species of the subgenus Larroussius, Phlebotomus orientalis and Phlebotomus tobbi. The rotation of genitalia in all three studied genera was randomly oriented and similar numbers of clockwise and counter-clockwise events were observed. The study also addresses the effects of some external factors. In all species studied, rotation was not affected by the time of day of eclosion. Similarly, no differences in total rotation time were found between Phlebotomus papatasi males maintained at 25 and 20 °C, respectively. The present findings will assist in the search for natural breeding sites and in studies aimed at elucidating strategies for integrated sandfly and leishmaniasis control.

Establishment and maintenance of sand fly colonies.

Sand flies used to have a reputation for being difficult and labour-intensive to breed. Here we summarize our experience with establishment and maintenance of sand fly colonies and their use for infective experiments: techniques for collection and handling wild-caught females, rearing larvae and adults and experimental infections of sand flies by Leishmania using membrane feeding. In addition, we compare major life cycle parameters between various colonies maintained under standard laboratory conditions. The sand fly rearing is tricky but some species can be reared in large numbers with a minimum of space and equipment. Initiation of new colonies from endemic sites is a prerequisite for accurate studies on parasite-vector interaction but it is more difficult step than routine maintenance of colonies already established in laboratory for many generations.

Repellent efficacy of a combination containing imidacloprid and permethrin against sand flies (Phlebotomus papatasi) in dogs.

Infection in dogs and humans with the protozoan parasite Leishmania are widespread in tropical and subtropical countries around the globe. Sand flies of the order Phlebotomus in the Old World and Lutzomyia in the New World function as the vector of this disease. In dogs, skin lesions are the most prominent signs of canine leishmaniasis, besides other complex underlying manifestations. To prevent dogs from sand fly bites and thus transmission of Leishmania, an imidacloprid 10% w/v / permethrin 50% w/v combination was evaluated for its insecticidal and repellent efficacy. Treated and untreated control dogs were exposed weekly to about 200 female Phlebotomus papatasi for a period of four weeks. Dead and alive sand flies were counted for surviving rate evaluation and feeding rate was determined for repellency evaluation. The repellent efficacy was 94.6% (day 1), 93.3% (day 8), 80.0% (day 15), 72.8% (day 22) and 55.9% (day 29).The insecticidal efficacy was 60.0% (day 1), 46.2% (day 8), 42.6% (day 15), 35.2% (day 22) and 29.3% (day 29). The study demonstrated the high repellent potential of the imidacloprid / permethrin combination, thus protecting dogs from sand fly bites.