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c Bartonella henselae (Rhizobiales: Bartonellaceae) is a Gram-negative fastidious bacterium of veterinary and zoonotic importance. The cat flea Ctenocephalides felis (Siphonaptera: Pulicidae) is the main recognized vector of B. henselae, and transmission among cats and humans occurs mainly through infected flea feces. The present study documents the use of a quantitative molecular approach to follow the daily kinetics of B. henselae within the cat flea and its excreted feces after exposure to infected blood for 48 h in an artificial membrane system. B. henselae DNA was detected in both fleas and feces for the entire life span of the fleas (i.e., 12 days) starting from 24 h after initiation of the blood meal. Bartonella henselae is a Gram-negative facultative intracellular bacterium of veterinary and zoonotic importance distributed worldwide (1). At present, its major competent vector is the cat flea, Ctenocephalides felis (2). Viable B. henselae or its DNA has also been detected in several other blood-feeding arthropods, such as ticks (Dermacentor spp., Ixodes spp.) (3-6) and biting flies (Haematobia spp., Stomoxys spp.) (7); however, no evidence of the role of these insects as competent vectors exists. Cats, particularly kittens, represent the major reservoir of B. henselae (8). Infected cats are usually asymptomatic but experience chronic recurring bacteremia (9). Clinical signs observed after experimental infection of cats include febrile illness, transient anemia, neurological dysfunction, and endocarditis (10-12).In humans, B. henselae is the causative agent of cat scratch disease (CSD), a syndrome characterized by a persistent regional lymphadenopathy that is usually self-limiting within 2 to 4 months in immunocompetent patients (13). However, infected immunocompromised individuals (such as those with AIDS or organ transplant recipients) can develop severe vasoproliferative tumors known as bacillary angiomatosis and bacillary peliosis (13,14,15).Although the prevalence of B. henselae infection in cats fluctuates significantly, the highest levels of infection occur in temperate regions where conditions are most favorable for the development of C. felis (1,16,17). The seroprevalence of antibodies against B. henselae in healthy cat populations ranges from 25 to 45% throughout the world (17). Nonetheless, in North America, where C. felis is endemic, seroprevalence was reported to reach up to more than 90% in some cat colonies (18). Fleas acquire B. henselae during their blood meal on highly bacteremic cats (16). Once in the arthropod vector, the bacterium seems to replicate within the gut and is then excreted in the feces (19,20). While transmission by flea saliva still requires further investigation (21), the exposure to infected flea feces appears to be the main route of infection for cats and, accidentally, humans (22-24). B. henselae can also be inoculated into the skin of a naive host via scratching or biting by a flea-contaminated carrier animal (16,20,25).Knowledge of the kinetics of B. henselae in C. f...

A spot-on formulation combining permethrin, dinotefuran and pyriproxyfen (Vectra 3D™ spot-on solution for dogs - one 10-25 kg pipette contains 196 mg dinotefuran, 1429 mg permethrin and 17 mg pyriproxyfen) was evaluated in adult Beagle dogs in a study designed to measure its efficacy to control Aedes aegypti (anti-feeding effect and mortality effect). The trial was performed according to Animal Welfare and Good Clinical Practice. Twelve dogs (five males and seven female, >3 years old, weighing 8.8-13.0 kg) were randomly allocated to treatment groups on pre-treatment mosquito counts: six dogs served as untreated controls, and six dogs were treated with the test formulation. Treatment consisted of applying a combination formulation to deliver at least 46.6 mg kg(-1) permethrin, 6.40 mg kg(-1) dinotefuran and 0.57 mg kg(-1) pyriproxyfen. The combination is designed to control fleas, ticks, sand flies and mosquitoes. Each dog was infested with approximately 100 adult unfed A. aegypti once before treatment (day 6) then at 1, 7, 14, 21 and 28 days post-treatment. Counts and engorgement determination of dead and live mosquitoes were performed after 1h exposure period. In the treated group (group A), the repellency effect of the product based on engorgement status (anti-feeding effect), was 91.5%, 94%, 94.7%, 94% and 87% at 1, 7, 14, 21 and 28 days post-treatment. Mortality effect or insecticidal efficacy calculated at the end of the 1-h exposure was almost identical when calculated 24h after the 1-h exposure and remained above 93% until the end of the in-life phase. No adverse events were observed following treatment, including observations conducted 2, 4 and 24h after the last dog was treated.

African swine fever (ASF) is one of the most important diseases in Suidae due to its significant health and socioeconomic consequences and represents a major threat to the European pig industry, especially in the absence of any available treatment or vaccine. In fact, with its high mortality rate and the subsequent trade restrictions imposed on affected countries, ASF can dramatically disrupt the pig industry in afflicted countries. In September 2018, ASF was unexpectedly identified in wild boars from southern Belgium in the province of Luxembourg, not far from the Franco-Belgian border. The French authorities rapidly commissioned an expert opinion on the risk of ASF introduction and dissemination into metropolitan France. In Europe, the main transmission routes of the virus comprise direct contact between infected and susceptible animals and indirect transmission through contaminated material or feed. However, the seasonality of the disease in some pig farms in Baltic countries, including outbreaks in farms with high biosecurity levels, have led to questions on the possible involvement of arthropods in the transmission of the virus. This review explores the current body of knowledge on the most common arthropod families present in metropolitan France. We examine their potential role in spreading ASF—by active biological or mechanical transmission or by passive transport or ingestion—in relation to their bio-ecological properties. It also highlights the existence of significant gaps in our knowledge on vector ecology in domestic and wild boar environments and in vector competence for ASFV transmission. Filling these gaps is essential to further understanding ASF transmission in order to thus implement appropriate management measures.

Cattle besnoitiosis due to the cyst-forming coccidian parasite Besnoitia besnoiti has recently been reported in expansion in Europe since the end of the twentieth century. The B. besnoiti life cycle and many epidemiological traits are still poorly known. Hematophagous flies, including the worldwide-distributed Stomoxys calcitrans, could be mechanical vectors in the contamination of mouthparts after the puncture of cutaneous cysts or ingestion of infected blood. In this study, a protocol is presented to assess more deeply the role of S. calcitrans, reared in laboratory conditions, in parasite transmission. A preliminary trial showed that stable flies could transmit tachyzoites from bovine artificially parasite-enriched blood to B. besnoiti-free blood using glass feeders. Evidence of transmission was provided by the detection of parasite DNA with Ct values ranging between 32 and 37 in the blood recipient. In a second time, a B. besnoiti-infected heifer harboring many cysts in its dermis was used as a donor of B. besnoiti. An interruption of the blood meal taken by 300 stable flies from this heifer was performed. Immediately after the blood meal was interrupted, they were transferred to a glass feeder containing B. besnoiti-free blood from a non-infected heifer. Quantitative PCR and modified direct fluorescence antibody test (dFAT) were used to detect B. besnoiti DNA and entire parasites, respectively, in the blood recipient, the mouthparts, and the gut contents of S. calcitrans at two time intervals: 1 and 24 h after the interrupted blood meal. Parasite DNA was detected at both time intervals (1 and 24 h) in all samples (blood recipient, mouthparts, and gut contents of stable flies) while entire parasites by dFAT were only found in the abdominal compartment 1 h after the interrupted blood meal. Then, S. calcitrans were able to carry B. besnoiti from chronically infected cattle to an artificial recipient in the conditions of the protocol.

Summary :A controlled clinical trial was performed to determine the duration of efficacy of a new oral insecticide formulation of spinosad for the control of experimentally induced Ctenocephalides canis infestations in dogs. Twelve Beagle dogs (two groups of six) were used in the study. Dogs in the treated group received spinosad tablets per os on D0 at the commercial dosage. All dogs were infested with 100 fleas on 7, 14, 21, 28 and 35. The dogs were combed four hours after each infestation and fleas were counted and replaced on the coat. 24 hours after each infestation fleas were combed, counted and removed. The efficacy of the formulation was calculated four and 24 hours after the treatment and then four and 24 hours after each new infestation. The mean number of fleas on the control dogs was respectively between 65.1 and 83.3 at four hour counts and between 58.3 and 75.3 at 24 hour counts. The product was well tolerated. The treatment controlled the fleas already present on the skin with 81 % efficacy at four hours and 100 % efficacy at 24 hours. For the weekly infestations, the speed of action of the product was high: at four hours the efficacy was 100 % at D7, 96 % at D14, 74 % at D21, 42 % at D28, 12.90 % at D35 and 12.8 % at D42. The efficacy evaluated 24 hours after each infestation was approximately 100 % during three weeks then 90 % at D39, 81.4 % at D36 and 80.4 % at D43. A single dose of the new spinosad tablet formulation should control flea populations in dogs for four weeks as indicated in the claim (evaluation performed at 48 h for the registration). Spinosad tablet is the first product administered per os which acts so long and so quickly against adult fleas. Résumé

Bartonella are hemotropic bacteria responsible for emerging zoonoses. These heme auxotroph alphaproteobacteria must import heme for their growth, since they cannot synthesize it. To import exogenous heme, Bartonella genomes encode for a complete heme uptake system enabling transportation of this compound into the cytoplasm and degrading it to release iron. In addition, these bacteria encode for four or five outer membrane heme binding proteins (Hbps). The structural genes of these highly homologous proteins are expressed differently depending on oxygen, temperature and heme concentrations. These proteins were hypothesized as being involved in various cellular processes according to their ability to bind heme and their regulation profile. In this report, we investigated the roles of the four Hbps of Bartonella henselae, responsible for cat scratch disease. We show that Hbps can bind heme in vitro. They are able to enhance the efficiency of heme uptake when co-expressed with a heme transporter in Escherichia coli. Using B. henselae Hbp knockdown mutants, we show that these proteins are involved in defense against the oxidative stress, colonization of human endothelial cell and survival in the flea.

Bionomic aspects of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae) were studied under laboratory conditions. For this reason, laboratory-rearing techniques were optimized at the National Veterinary School of Toulouse. The colony was maintained at 25 ± 2 °C, 50 ± 10% RH under a 12-hour light cycle and observed daily. The size of each adult cage is 30 x 30 x 30 cm and designed to house about 500-1,000 flies. The average cycle from egg to adult was 19.2 ± 1.7 days. The mean longevity of imagos was 9.3 ± 5.8 days and not significantly different between sexes. Stable flies were split into two groups; the first was fed with blood, honey and water, and the second was fed only with honey and water. The mean weight of a blood meal was 11.1 ± 3.8 mg with no significant differences between males and females. The mean longevity of non-blood fed flies was found to be significantly higher (10.4 ± 3.9 days) than those fed with blood. The maximum lifespan was shorter for non-blood fed males (17 days) and females (18 days) than for those fed with blood (females: 24 days, males: 23 days). Under these laboratory conditions, S. calcitrans rearing was successfully established. In the end, the number of expected generations of S. calcitrans and the net reproduction rate were estimated to be 11.8 generations/year and 16.2 living females per female respectively.