Besides being a nuisance, sand flies and their feeding are especially of importance for the transmission of Leishmania spp. Thus, prevention of sand fly feeding is essential for the control of leishmaniosis.
Transmission of metacyclic promastigotes of Leishmania spp. to dogs occurs immediately after the sand fly bite. Consequently, the main way to avoid Leishmania spp. infection, is to use topical insecticides with proven activity for bite prevention. These formulations have the dual effect of both warding off and killing sand flies, when they contact a protected dog, for example. This killing effect identifies the insecticidal efficacy, while the ability to ward off sand flies is a combination of contact repellency and anti-feeding effect (Miró et al., 2017).
Prevention of canine leishmaniosis should include the application of a long-acting topical insecticide throughout the period of sand fly activity. Additionally, vaccination should be considered as a multimodal approach (www.leishvet.org).
Different insecticide applications are available:
Spot on formulations
The application of repellent (anti-feeding) treatments is proven to be highly effective against sand flies. Formulations with permethrin have a repellent and killing effect and prevent biting of sand flies.
There are two different active ingredients used in collars which show repellent efficacy against sand flies: deltamethrin and flumethrin.
In endemic areas a multimodal approach combining the use of repellents and vaccination should be considered for an optimal prevention against infection with Leishmania spp. and development of clinical disease (www.leishvet.org).
Environmental vector control
Additional measures exist beyond topical treatment, to control and reduce sand fly numbers in the dogs’ environment. These include protecting windows and doors of homes, shelters, or dog kennels using mesh with size ranging between 0.3 and 0.4 mm2. In addition, removal of sand fly breeding locations (e.g., compost, pruning scraps, bins, and woodpiles) and favourable areas close to inhabited zones, is important to decrease the risk of sand fly bite. Use of residual insecticides or permethrin-treated screens in dwellings and surrounding areas in hyperendemic regions can also serve to reduce the number of infectious bites. Lastly, keeping dogs indoors from dusk to dawn, when female sand flies are questing for blood meals, during high-risk seasons, is also important to prevent infection (Miró et al., 2017).
Miró G, Petersen C, Cardoso L, et al.: Novel areas for prevention and control of canine leishmaniosis. Trends Parasitol. 2017, 33, 718-30