Efficacy of a slow-release imidacloprid (10%)/flumethrin (4.5%) collar for the prevention of canine leishmaniosis.

BACKGROUND: The efficacy of a slow-release insecticidal and repellent collar containing 10% imidacloprid and 4.5% flumethrin (Seresto, Bayer Animal Health) in preventing Leishmania infantum infection was evaluated in a large population of dogs living in a hyper-endemic area of Sicily (Italy). METHODS: A total of 219 dogs, negative for L. infantum were enrolled in a multicentre, controlled study. Dogs were divided into two homogeneous groups, defined as G1 (n = 102) and G2 (n = 117). Before the start of the sand fly season, dogs in G1 were treated with the collar while animals in G2 were left untreated, serving as negative controls. Dogs were serially sampled on day D90, D180, D210 and D300 in order to assess Leishmania infection by IFAT, PCR on skin (D210-D300) and bone marrow (D300) and cytology on bone marrow aspirate (D300). RESULTS: Three dogs (2.9%) in G1 and 41 (40.2%) in G2 became positive for L. infantum in at least one of the diagnostic tests employed in the study. The number of seropositive dogs in G2 increased in the course of the study from 15 (D90) to 41 (D300), with some of them also positive in other diagnostic tests. Eight (19.6%) of the seropositive dogs in G2 showed an increase in antibody titers ranging from 1:160 to 1:1,280. At the last follow-up, some of dogs in G2 displayed overt clinical signs suggestive of leishmaniosis. The mean incidence density rate at the final follow-up was 4.0% for G1 and 60.7% for G2, leading to a mean efficacy of the collar in protecting dogs at both sites of 93.4%. CONCLUSIONS: The slow-release collar tested in this study was shown to be safe and highly effective in preventing L. infantum infection in a large population of dogs. Protection conferred by a single collar (up to eight months) spanned an entire sand fly season in a hyper-endemic area of southern Italy. The regular use of collars, at least during the sand fly season, may represent a reliable and sustainable strategy for the prevention of leishmaniosis in dogs living in or travelling to an endemic area.

Ecology of phlebotomine sand flies and Leishmania infantum infection in a rural area of southern Italy.

Phlebotomine sand flies are insects of major medico-veterinary significance in the Mediterranean region, as they may transmit pathogens to animals and humans, including viruses and protozoa. The present study was conducted in southern Italy, in an area where visceral leishmaniasis caused by Leishmania infantum is endemic. Insects were collected monthly during two consecutive years using light traps set in five different ecologic contexts (i.e., a stonewall near a woodhouse, a tree near volcanic rocks in a high-altitude area, a tree trunk in a meadow habitat, a sheep stable, and a chicken coop) and weekly in one site (the garage of a private house). A total of 13,087 specimens were collected and six species identified (i.e., Phlebotomus perfiliewi, Phlebotomus perniciosus, Phlebotomus neglectus, Phlebotomus papatasi, Phlebotomus mascittii, and Sergentomyia minuta), representing 75% of the total number of phlebotomine species found in Italy. P. perfiliewi was the most abundant species, comprising 88.14% of the specimens identified. The greatest species diversity and abundance was recorded in human dwellings and in animal sheds. Sand flies were active from June to October, peaking in July-August in 2010 and July-September in 2011. Part of the females (n=8865) was grouped into 617 pools (range, 1-10 insects each) according to species, feeding status, day and site of collection. A total of four pools (10 non-engorged specimens each) and one engorged female of P. perfiliewi were positive for L. infantum. This study confirms that phlebotomine vectors in southern Italy are highly adapted to human-modified environments (e.g., animal sheds) and that P. perfiliewi is a major vector of L. infantum in some regions of southern Italy.

Effect of night time-intervals, height of traps and lunar phases on sand fly collection in a highly endemic area for canine leishmaniasis.

The activity of phlebotomine sand flies was monitored in a sub-urban area of Sicily in order to acquire data on seasonality and to elucidate the effect of the night time-intervals, height of traps from ground and lunar phases on the abundance of the capture. The study was conducted in the farm of the University of Messina (Italy). Light traps were placed as in the following: biweekly, from dusk to dawn, and from May to November; for three consecutive nights from 18:00 to 6:00, with the net bag being changed every 2h; for 30 days, at different heights from 18:00 to 6:00. A total of five species (i.e., Phlebotomus perniciosus, Phlebotomus neglectus, Phlebotomus sergenti, Phlebotomus perfiliewi, and Sergentomyia minuta), three of which are proven vectors of Leishmania infantum, were captured. The most abundant species was P. perniciosus (73.3%) followed by S. minuta (23.3%). The highest number of phlebotomine sand flies was collected in August and September with a peak of collection recorded in the evening (i.e., from 20:01 to 22.00). The number of phlebotomine sand flies collected at 50cm above the ground was significantly higher (P=0.041) than that captured at 150cm. Results of this study shed light on the ecology of main phlebotomine species in the Mediterranean area, and on the influence of some factors, such as time and height of traps, on the light trap capture efficiency.

Prevention of canine leishmaniosis in a hyper-endemic area using a combination of 10% imidacloprid/4.5% flumethrin.

BACKGROUND: Dogs are the main reservoir hosts of Leishmania infantum, the agent of human zoonotic visceral leishmaniosis. This study investigated the efficacy of a polymer matrix collar containing a combination of 10% imidacloprid and 4.5% flumethrin as a novel prophylactic measure to prevent L. infantum infections in young dogs from a hyper-endemic area of southern Italy, with a view towards enhancing current control strategies against both human and canine leishmaniosis. METHODOLOGY/PRINCIPAL FINDINGS: The study was carried out on 124 young dogs, of which 63 were collared (Group A) while 61 were left untreated (Group B), from March-April 2011 until March 2012. Blood and skin samples were collected at baseline (April 2011) and at the first, second, third and fourth follow-up time points (July, September 2011 and November 2011, and March 2012, respectively). Bone marrow and conjunctiva were sampled at baseline and at the fourth follow-up. Serological, cytological and molecular tests were performed to detect the presence of L. infantum in the different tissues collected. At the end of the trial, no dog from Group A proved positive for L. infantum at any follow-up, whereas 22 dogs from Group B were infected (incidence density rate = 45.1%); therefore, the combination of 10% imidacloprid and 4.5% flumethrin was 100% efficacious for the prevention of L. infantum infection in young dogs prior to their first exposure to the parasite in a hyper-endemic area for CanL. CONCLUSIONS: The use of collars containing 10% imidacloprid and 4.5% flumethrin conferred long-term protection against infection by L. infantum to dogs located in a hyper-endemic area, thus representing a reliable and sustainable strategy to decrease the frequency and spread of this disease among the canine population which will ultimately result in the reduction of associated risks to human health.

Phlebotomine sand fly population dynamics in a leishmaniasis endemic peri-urban area in southern Italy.

A 2-year survey was carried out from May to November 2008 and 2009 to study the sand fly species composition, its seasonal phenology and density in Apulia region (southern, Italy). The study was conducted in a dog shelter located in a new residential urban district where Leishmania infantum is endemic. Sand flies were collected using sticky traps from May to November, at about 7-day intervals. Temperature and relative humidity were recorded daily. In December 2008, general environmental improvements (e.g., the ground was covered with gravel and the vegetation present inside the cages was removed to facilitate cleaning) were made in the study area. The most diffused species during the whole study period were Phlebotomus perniciosus (2008, n=248, 49.4%; 2009, n=254, 50.6%) followed by Phlebotomus neglectus (2008, n=76, 39.8%; 2009, n=115, 60.2%) and Phlebotomus papatasi (2008, n=5, 50.0%; 2009, n=5, 50.0%). Four specimens of Phlebotomus perfiliewi were collected only in the first year. The number of Sergentomyia minuta specimens collected increased considerably in the second (n=548, 86.2%) in comparison to the first year (n=88, 13.8%). The highest number of phlebotomine sand flies was collected in July and August when a mean temperature from 27.09 to 28.02°C and mean relative humidity from 47.28 to 56.36% were recorded. The variations in phlebotomine sand fly species diversity and abundance recorded in this study were related to climatic and environmental factors. Data here presented confirm that sand flies easily adapt to the urban environments and that the may represent a public health concern for L. infantum and other pathogen transmission also in similar urban environment of southern Europe.

Efficacy of Amitraz plus Metaflumizone for the treatment of canine demodicosis associated with Malassezia pachydermatis.

This case reports the efficacy of metaflumizone plus amitraz spot-on formulation (ProMeris Duo(R); Fort Dodge) against generalized demodectic mange. A two year-old male dog presented at clinical examination with poor general condition, diffused alopecia, crusted lesions, pruritus, skin scales and pustules. Demodex mites, Malassezia pachydermatis yeasts and bacteria were diagnosed. The dog was treated with cephalexin and topically with metaflumizone plus amitraz spot on formulation at two weeks intervals until two consecutive skin scrapings resulted negative for mites. The number of adult mites statistically decreased at follow-up with a reduction of approximately 42 and 94% at +14 and +28 days post treatment (p.t.) respectively. Nymphs and larvae could not be detected from +28 day p.t. while eggs were no longer present +42 day p.t. The dog was negative for both bacteria and M. pachydermatis at 14 days p.t., coinciding with improved general clinical conditions, recovering skin lesions and no further signs of pruritus. These results show that metaflumizone plus amitraz associated with the antibiotic therapy is highly effective for treating generalized demodectic mange and could also be effective toward controlling M. pachydermatis opportunistic infections.