Emmanuel Liénard

Assessment of persistence of Bartonella henselae in Ctenocephalides felis

ABSTRACT 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.

No detection of Besnoitia besnoiti DNA in the semen of chronically infected bulls

Bovine besnoitiosis is a chronic and debilitating disease observed in many European countries that may cause important economic losses in cattle. The recent widespread of the parasite in Europe had led the European Food Safety Authority to declare bovine besnoitiosis as a re-emerging disease in Europe. Many aspects of the epidemiology of bovine besnoitiosis such as the main routes of transmission are still unclear and need to be further studied. Among the different hypotheses, a sexual transmission has not yet been investigated. Therefore, the aim of this study was to evaluate the presence of Besnoitia besnoiti DNA in the semen of naturally infected bulls by using a highly sensitive method (real-time qPCR). Both pre-sperm and sperm fractions of 40 bulls, including seronegative (n = 11), seropositive subclinically (n = 17), and seropositive clinically (n = 12) infected animals, were collected by electroejaculation and analyzed by real-time qPCR. No B. besnoiti DNA was detected in 27 pre-sperm and 28 sperm fractions of the 40 examined bulls, suggesting that the transmission of B. besnoiti infection by the semen of chronically infected bulls is very unlikely.

Efficacy of permethrin, dinotefuran and pyriproxyfen on adult fleas, flea eggs collection, and flea egg development following transplantation of mature female fleas (Ctenocephalides felis felis) from cats to dogs.

A novel spot-on formulation combining permethrin, pyriproxifen and dinotefuran (Vectra 3D™ spot-on solution for dogs) was evaluated in adult Beagle dogs in a study to determine adulticidal efficacy, egg laying inhibition and viability of Ctenocephalides felis felis eggs (development and emergence of fleas from the collected eggs). Prior to treatment sixteen dogs were checked for their ability to keep fleas 24 hours after infestation and were allocated to treatment groups: 8 dogs served as untreated controls, and 8 dogs were treated once with the tested formulation. The spot on was administered respecting the laboratory recommendations at a dosage of 65-126 mg/kg of permethrin; 8.9-17.4 mg/kg of dinotefuran and 0.8-1.5mg/kg of pyriproxyfen. Each dog was infested with 100 adult cat fleas ready to lay eggs after 72 hours spent feeding on cats. Dogs were infested 24 hours after treatment and then weekly during 63 days. Eggs were collected and counted 24 hours after each infestation and dogs were combed 48 hours after each infestation. Fleas were counted and removed. Collected eggs were placed in incubator to study their development in larvae and into newly emerged adults. A single treatment provided 99.7% adulticidal efficacy on fleas within 48 hours after treatment and controlled re-infestations for up to 30 days (efficacy >96.20%, p<0.05). The egg laying inhibition was over 92.3% for up to 29 days (p<0.05). The adult emergence inhibition remained 100% during 8 weeks after treatment and was 99.8% nine weeks after treatment (p<0.001).

Does bovine besnoitiosis affect the sexual function of chronically infected bulls

Bovine besnoitiosis is a reemerging disease in Europe. The clinically Besnoitia besnoiti infection in bulls is characterized by fever, nasal discharge, and orchitis in the acute phase and by scleroderma in the chronic phase. However, in many bulls, B besnoiti infection remains at a subclinical stage. Bull infertility is an economically relevant consequence of besnoitiosis infection. It is not clear, however, if semen quality returns to normal levels when infected animals have clinically recovered. The aim of this study was to examine the relationship between chronic besnoitiosis and bull sexual function in a region of eastern France, where the disease is reemerging, by comparing semen quality and genital lesions in 11 uninfected, 17 subclinically infected, and 12 clinically infected bulls. The presence of anti-B besnoiti antibodies was detected by Western blot test. Semen was collected by electroejaculation. Bulls clinically infected with B besnoiti showed significantly more genital tract alterations than uninfected or subclinically infected bulls. No relationship was evidenced between besnoitiosis infectious status and semen quality, whereas a significant relationship was noted between genital lesions and semen score. This means that in the absence of moderate to severe genital lesions, chronic bovine besnoitiosis is unlikely to alter semen quality. However, as the presence of infected animals could lead to spread of the disease, culling or separation of clinically infected bulls from the remaining healthy animals is strongly recommended.

Repellent and insecticidal efficacy of a combination of dinotefuran, pyriproxyfen and permethrin (Vectra® 3D) against Culex pipiens in dogs

Culex pipiens is an important vector of pathogens of substantial medical and veterinary importance such as Dirofilaria immitis and Dirofilaria repens or the West Nile Virus. The control of these mosquitoes is therefore essential to control the transmission of mosquito-borne agents to humans and animals. A combination of dinotefuran, permethrin and pyriproxyfen (Vectra® 3D) has already shown its efficacy against Aedes aegypti. The aim of this study was to confirm the efficacy of this combination in repelling and killing another species of mosquito, Culex pipiens, after a single topical application to dogs. Twelve adult Beagle dogs with an equal receptivity to mosquitoes were included in the study and divided in two groups of six dogs: an untreated control group and a group treated with a combination containing 54 mg/mL dinotefuran + 4.84 mg/mL pyriproxyfen + 397 mg/mL permethrin (Vectra® 3D). All dogs were challenged with 80 Culex pipiens females for 90 ± 5 min on Days - 28, 1, 7, 14, 21 and 28. The treatment was applied once topically on Day 0. Count and engorgement determination of dead and live mosquitoes were performed after each exposure to treated and untreated dogs. Compared to control dogs, the spot-on formulation provided a repellent efficacy (anti-feeding effect) against mosquitoes of 98.9%, 98.8%, 98.6%, 96.7% and 97.9% on Days 1, 7, 14, 21 and 28 respectively. There was a significant difference (p ≤ 0.05) between the treated and controlled groups on every assessment day. The insecticidal efficacy on treated dogs at 90 min was 34.7%, 50.3%, 39.7%, 22.8% and 11.4% on Days 1, 7, 14, 21 and 28 respectively. There was a significant difference between the treated and controlled groups for live mosquitoes for all assessment days (p < 0.05). A single topical application of a combination of dinotefuran, permethrin and pyriproxyfen showed a significant repellent effect (i.e. > 96%) against Culex pipiens which lasted for 28 days. The results suggest that the Vectra® 3D spot-on solution could be used as an effective mosquito control strategy in dogs and is therefore recommended for use in a dirofilariosis prevention programme.

Ashworthius sidemi Schulz, 1933 and Haemonchus contortus (Rudolphi, 1803) in cervids in France: integrative approach for species identification

Among gastro-intestinal nematodes, the blood-sucking worms belonging to the subfamily of Haemonchinae are considered to be of pathogenic and economic great importance, particularly in small ruminants. Haemonchus contortus, primary found in domestic ruminants and wild bovines (Mouflon, Chamois), is probably the most studied, but occurrence of Ashworthius sidemi has gradually increased over recent years, especially in Cervids and free roaming wild bovid as the European bison in eastern Europe, and some cases of co-infestation were recently observed on five Roe deer (Capreolus capreolus) and one Red deer (Cervus elaphus) in France. If the diagnosis is possible on the morphological features for adult worms for helminthologists, the identification on some stages (female, subadult, eggs and larvae) is difficult or impossible. Sequencing ND4 domain from the mitochondrial DNA of H. contortus and A. sidemi worms, we observed clearly two distinct clades, with an inter-specific divergence of 28.1%. Basing on this specific domain, a multiplex PCR-based method was developed: new primers were designed and used pooled in one mix PCR, producing amplicons of 454bp for H. contortus and 330bp for A. sidemi, allowing a trivial and an inexpensive taxonomic affiliation after migration. This multiplex PCR-based method was developed here to distinguish H. contortus and A. sidemi regardless their developmental stage, easy to use for highlighting co-infestation cases in both wild and domestic ruminants. It is a non-invasive approach appearing as a good diagnostic tool relevant to coprological cultures.