Comparative Evaluation of the Efficacy of Two Ectoparasiticides in Preventing the Acquisition of Borrelia burgdorferi by Ixodes scapularis and Ixodes ricinus: A Canine Ex Vivo Model.

In dogs, tick infestation can cause damage ranging from a simple skin irritation to severe diseases and/or paralysis leading to animal death. For example, Ixodes ricinus and I. scapularis are among the tick species incriminated the most in the transmission of Borrelia burgdorferi, the agent of human and canine Lyme borreliosis (LB). In this study, we aimed to compare the efficacy of two products designed for dogs-an oral systemic ectoparasiticide and a topical repellent ectoparasiticide-against the acquisition of B. burgdorferi by adult I. scapularis and I. ricinus using an ex vivo model. Thirty-two beagle dogs were included in a parallel-group-designed, randomized, single-center, negative-controlled efficacy study. The dogs were allocated to three groups based on gender and body weight: a fluralaner (F, Bravecto®) treatment group (n = 8), administered a single oral treatment on day 0 at the recommended dose; a dinotefuran-permethrin-pyriproxyfen (DPP, Vectra® 3D) treatment group (n = 8), topically treated on day 56 at the recommended dose; and an untreated control group (n = 16). Blood and hair were collected from each dog on days 58, 63, 70, 77, and 84. Hair was added to the silicone-based membrane separating two glass chambers forming the feeding unit (FU). Chamber 1 was filled with blood spiked with B. burgdorferi sensu stricto, strain B31 (105 cells/mL). Chamber 2, glued below chamber 1, was seeded with 20 adult I. scapularis or I. ricinus. The FUs (n = 240) were incubated at 37 °C with a humidity >90%. Tick survival, attachment, and feces presence were observed from 1 h up to 72 h after tick seeding. The uptake of B. burgdorferi was determined in ticks using nested polymerase chain reaction (nPCR). The acaricidal efficacy of DPP-treated hair was 100% within 1 h of tick release on every study day for both I. ricinus and I. scapularis. The speed of kill associated with DPP was sufficiently fast to prevent tick attachment and engorgement, and, consequently, to prevent the acquisition of B. burgdorferi. In the F-treated group, the acaricidal efficacy observed at 12 h, throughout the study, was <20% and <28% for I. scapularis and I. ricinus, respectively. Furthermore, tick feces were observed in the FUs, and several female ticks (I. scapularis (n = 55) and I. ricinus (n = 94)) tested positive for B. burgdorferi. The results provide proof of concept for the use of an ex vivo model based on an artificial feeding system to compare two ectoparasiticides against the acquisition of B. burgdorferi by I. ricinus and I. scapularis. In addition, our results demonstrate the superiority of DPP compared to F in the speed of acaricidal activity against ticks, as well as in preventing the acquisition of B. burgdorferi.

Snakes and Souks: Zoonotic pathogens associated to reptiles in the Marrakech markets, Morocco.

The world-famous markets of Marrakech, also known in Arabic as souks, harbor a vast diversity of reptiles that are sold for medicinal/magic/pet purposes or used for snake charming. This unique epidemiological context has never been studied considering the interactions of humans, reptiles, and zoonotic pathogens. Thus, the aim of this study was to identify the parasites and pathogens present in blood and feces associated with handled reptiles in the markets of Marrakech to assess the risk of zoonotic transmission within the reptile-human interface. Privately owned reptiles (n = 118), coming from vendors or snake charmers, were examined and blood and feces sampled. DNA was extracted and molecular screening (cPCR, nPCR, qPCR, dqPCR) was performed aiming to identify potentially zoonotic pathogens (i.e., Anaplasma/Ehrlichia spp., Rickettsia spp., Borrelia burgdorferi sensu lato, Coxiella burnetii, Babesia/Theileria spp., Cryptosporidium spp., Giardia spp., Leishmania spp., Cestoda). Overall, 28.9% (34/118) of reptiles were positive for at least one pathogen. In blood, Anaplasma spp. were detected in four snakes, with two Montpellier snakes positive for Anaplasma phagocytophilum, while Rickettsia spp. were detected in one Mediterranean chameleon and four puff adders. Leishmania tarentolae was molecularly detected in a Mediterranean chameleon and a Montpellier snake. In feces, the cox1 gene generated a myriad of sequences for nematodes, cestodes, fungi and bacteria. Importantly, Proteus vulgaris was identified from a Mediterranean chameleon. Cryptosporidium spp. nPCR yielded a positive sample (i.e., Cryptosporidium sp. apodemus genotype I) from a Moroccan worm lizard, as well as for bacteria such as Pseudomonas aeruginosa in an Egyptian cobra, and Morganella morganii from a puff adder. Results from this study demonstrated the risk of zoonotic transmission of microorganisms and parasites present in blood and feces from reptiles that are brought to the souks in Marrakech, Morocco, to be sold for medicinal purposes or used for snake charming, being in direct and straight contact with humans.

Sustained efficacy of collars containing 10% w/w imidacloprid and 4.5% w/w flumethrin (Seresto®) in dogs against laboratory challenge with Haemaphysalis longicornis (Neumann, 1901) ticks.

BACKGROUND: Haemaphysalis longicornis ticks are reported on dogs from an increasing geographic range. This study aimed to determine the sustained efficacy of Seresto® collars (imidacloprid/flumethrin) against experimental infestations of H. longicornis in dogs. METHODS: Twenty-four Beagle dogs previously assessed for their suitability to harbor ticks were included in the study and randomized into three groups of eight dogs each. Two of the groups were treated with collars at different time points: at the first tick infestation, dogs in group 1 had already worn collars for 92 days, while dogs in group 2 had received collars only on the previous day, thus allowing evaluation of two different treatment durations at the same point in time. Infestation of the treated groups was conducted at 1, 7, 28, and 56 days (group 2) and 92, 119, 147, 168, 196, 227, and 238 days (group 1) after collar placement. Group 3 served as untreated control and was infested whenever the dogs of the other two groups were infested. Infestations were conducted using 50 viable, adult, unfed female ticks of a US isolate of H. longicornis per dog. Ticks were removed and counted 48 h after each infestation. Health and body weight of the dogs were monitored throughout the study. The efficacy against ticks was calculated for groups 1 and 2 based on arithmetic mean values at each assessment day according to Abbott's formula. The mean post-treatment H. longicornis tick counts were compared statistically between treatments, using an analysis of variance with a treatment effect untransformed tick count. RESULTS: Dogs in the control group were adequately infested at all tick counts. Efficacy was 88.2% on day 3, however well above 90% (i.e., 98.3 to 100%) at all other time points up to day 240. Statistical analysis confirmed significantly different live tick counts (P < 0.001) between the treated groups and the control group at all time points. CONCLUSIONS: The 8-month sustained acaricidal efficacy demonstrated by the Seresto® collar (imidacloprid/flumethrin) provides a reliable strategy against H. longicornis infestations in dogs.

Insecticidal efficacy against Phlebotomus perniciosus in dogs treated orally with fluralaner in two different parallel-group, negative-control, random and masked trials.

BACKGROUND: Dogs are the reservoir host of Leishmania infantum, the agent of zoonotic visceral leishmaniasis (VL), which is transmitted by the bite of phlebotomine sand flies. The sand fly Phlebotomus perniciosus is the main vector of zoonotic VL in the western Mediterranean region. Fluralaner has been shown to effectively kill this vector. The aim of this study was to evaluate the insecticidal efficacy of oral fluralaner in dogs bitten by P. perniciosus. METHODS: Two parallel-group, negative-controlled, randomized, masked laboratory trials with equivalent designs were performed in two different locations using two different pathogen-free laboratory-bred P. perniciosus strains for the challenge. In each trial, 12 purpose-bred beagles, initially ranked on natural attractiveness to sand flies, were randomly allocated to two groups (6 animals/group). Dogs in one group received fluralaner orally at the approved dose on day 0, and dogs in the control group were not treated. Each dog was subsequently exposed to an average of 70 unfed live sand fly females on days 1, 28, 56 and 84. Viability of blood-fed females was then evaluated for up to 96 h after exposure, and insecticidal efficacy was measured as the survival rate of flies fed on the fluralaner-treated dogs versus that of dogs in the control group. Significance was calculated for the proportion of live fed sand fly counts from treated versus control group dogs. RESULTS: Comparison of the survival proportions between treated and control groups showed that fluralaner insecticidal efficacy was highly significant in both trials (P < 0.001 or P < 0.01 in different assessments) through to day 56. In the first trial, efficacy reached 100% on days 1 and 28, and 99.1% on day 56; in the second trial, the insecticidal efficacy was 98.5, 100 and 85.9%, respectively on the same days. On day 84, efficacy was in the range of 53-57% (P < 0.05) in the first trial and 0% in the second trial. CONCLUSION: A single oral fluralaner administration to dogs under laboratory conditions results in strong and reproducible insecticidal efficacy against P. perniciosus for at least 8 weeks.

Aedes (Stegomyia) aegypti mosquito bite hypersensitivity in a dog: a case report.

BACKGROUND: Mosquitoes are vectors of several pathogens of considerable importance to humans and companion animals, including nematode helminths such as Dirofilaria immitis and Dirofilaria repens that cause heartworm disease and subcutaneous dirofilariosis, respectively. In addition to mosquito-borne pathogen transmission, mosquito bites can cause discomfort and irritation in pets, and even lead to severe hypersensitivity reactions. In the present study, we report an acute local hypersensitivity reaction in a dog following experimental exposure to Aedes (Stegomyia) aegypti. CASE PRESENTATION: A healthy six-year-old male beagle was included in an efficacy study in which dogs (n = 28) were exposed to Ae. aegypti mosquitoes. On Day - 6, the dog was allocated to one of the study groups, consisting of seven dogs to be treated on Day 0 with an imidacloprid/flumethrin collar. After sedation, animals were exposed to approximately 50 females of Ae. aegypti for 60 (± 5) minutes on Days - 6, 1, 7, 14, 21, 28, 55, and 83. On Day - 6, no allergic reaction to the mosquito bites was observed. However, on Day 1, corresponding to the second challenge, the dog demonstrated an acute allergic reaction characterized by swelling of the face (especially in the base of the muzzle and around the eyes), redness of the eyes, and conjunctival edema of the right eye was also observed. The dog was immediately treated with an intramuscular injection of a commercially available antihistamine treatment, Pen-Hista-Strep® containing a suspension of benzylpenicillin, chlorphenamine, dexamethasone, dihydrostreptomycin, and procaine at a dosage of 1 mL per 10 kg. A few hours after treatment, the dog showed noticeable improvement. CONCLUSIONS: This case provides the first evidence of canine acute local hypersensitivity reaction to mosquito bites under laboratory conditions. This observation suggests that invasive mosquito species such as Aedes spp. may affect the health and comfort of our companion animals, especially for pets with outdoor access without individual protective measures against insect bites.