Laboratory assessment of the anti-feeding effect for up to 12 months of a slow release deltamethrin collar (Scalibor®) against the sand fly Phlebotomus perniciosus in dogs

Abstract

BackgroundLeishmaniosis/leishmaniasis consists of a wide group of diseases, caused by different Leishmania species and having different hosts. Leishmaniosis caused by Leishmania infantum, a disease primarily of dogs and humans, occurs after susceptible hosts are exposed to the feeding behavior of infected sand flies. A one-year laboratory study in dogs was designed to determine the 364-day anti-feeding efficacy of a slow release deltamethrin collar against the sand fly P. perniciosus, a common host of L. infantum in the Mediterranean basin.MethodsIn this assessor-blinded study, 16 Beagle dogs were randomized into two groups using P. perniciosus engorgement rates from a Day -7 challenge. On Day 0, dogs in Group 1 received a placebo collar, while dogs in Group 2 received a deltamethrin collar (Scalibor® Protector Band). All dogs were caged, sedated and then exposed for 1 h to 85 (± 10) female and 15 (± 5) male P. perniciosus on Day 7 and every 28 days through Day 364. All flies, alive and dead, were aspirated from cages and from dogs, immediately counted and then frozen for assessment of blood engorgement. Anti-feeding efficacy was determined by comparing the arithmetic means of engorged female flies (alive, dead and moribund) in the deltamethrin group to the control group means. Insecticidal efficacy at the time flies were retrieved was assessed by comparisons between groups of mean live female fly counts.ResultsIn the deltamethrin group, relative to the control group, there was a significant reduction in arithmetic mean numbers of engorged P. perniciosus of 94–98% from Day 7 through Day 364. On Day 28, in the treated group relative to the control group, there was a 74% reduction in mean live fly counts, with between-group differences significant from Days 7 through 196, although insecticidal activity remained less than 50% from Day 56.ConclusionDeltamethrin collar application to dogs reduced sand fly feeding by ≥ 94%, relative to unprotected control dogs, for 364 days. Thus, one collar applied to a dog can prevent or reduce the risk of sand fly transmission of Leishmania for one full year.

Insecticide–impregnated dog collars reduce infantile clinical visceral leishmaniasis under operational conditions in NW Iran: A community–wide cluster randomised trial

“…Scalibor collars release deltamethrin into dermal secretions, resulting in reduced sand fly blood–feeding by >90%, and increased mortality in blood–fed sand flies by 35%–100% over 8 months[ 25 , 26 ]. More recent studies suggest that Scalibor collars offer 94–98% protection against Phlebotomous perniciosus sand fly bites for up to 12 months[ 49 ]. These effects reduce the likelihood of a collared dog acquiring infection and being a source for onward transmission, thus, they are expected to reduce the number of infectious bites on humans.…”

Sand fly synthetic sex-aggregation pheromone co-located with insecticide reduces the incidence of infection in the canine reservoir of visceral leishmaniasis: A stratified cluster randomised trial

“…The veterinary team fitted and replaced any lost collars, promoted their correct use to dog owners, and recorded any adverse reactions and reasons for collar losses. Scalibor collars have an activity period of 5–6 months against sand flies according to the product label, though longer durations of >10 months are experimentally demonstrated[35–37]. Collars were routinely replaced on 5 occasions at an average interval of 182 (S.D.…”

Vaccination against canine leishmaniasis in Brazil

“…For decades, the public health authorities have attempted to reduce the incidence of VL through the mass elimination of seropositive dogs, with no apparent success. The available scientific data support the community-wide use of insecticide-impregnated collars, rather than vaccination, to reduce the risk of infection in dogs and humans (Gavgani et al, 2002;Brianti et al, 2014Brianti et al, , 2016Paulin et al, 2018;Courtenay et al, 2019). This conclusion is supported by others.…”

“…That study showed Seresto ® to prevent 88.3% incident canine infections compared to 61.8% by Scalibor ® (Brianti et al, 2016). Moreover, Seresto ® provide 8 months of protection against sand flies, whereas for Scalibor ® is labelled for 4 months in Brazil and 5 months in Europe, though a recent laboratory study demonstrated a sustained anti-feeding efficacy of >94% for 12 months against Phlebotomus perniciosus (Paulin et al, 2018). As a follow up consequence of this study, the Ministry of Health of Italy authorized the extension of the label recommendation of Scalibor ® for 12 months (Ministero della Salute, 2018).…”