Ettore Napoli

On a Cercopithifilaria sp. transmitted by Rhipicephalus sanguineus: a neglected, but widespread filarioid of dogs

BackgroundThis study was aimed at investigating the distribution of a Cercopithifilaria sp. sensu Otranto et al., 2011 with dermal microfilariae recently identified in a dog from Sicily (Italy). A large epidemiological survey was conducted by examining skin samples (n = 917) and ticks (n = 890) collected from dogs at different time points in Italy, central Spain and eastern Greece.ResultsThe overall prevalence of Cercopithifilaria sp. in the sampled animal populations was 13.9% and 10.5% by microscopy of skin sediments and by PCR on skin samples, respectively. Up to 21.6% and 45.5% of dogs in Spain were positive by microscopical examination and by PCR. Cumulative incidence rates ranging from 7.7% to 13.9% were estimated in dogs from two sites in Italy. A low level of agreement between the two diagnostic tests (microscopical examination and PCR) was recorded in sites where samples were processed in parallel. Infestation rate as determined by tick dissection (from 5.2% to 16.7%) was higher than that detected by PCR (from 0% to 3.9%); tick infestation was significantly associated with Cercopithifilaria sp. infestation in dogs from two out of four sites. Developing larvae found in ticks were morphometrically studied and as many as 1469 larvae were found in a single tick.ConclusionsOur data suggest that, in addition to the most common species of filarioids known to infest dogs (i.e., Dirofilaria immitis, Dirofilaria repens and Acanthocheilonema reconditum), Cercopithifilaria sp. with dermal microfilariae should be considered due to its widespread distribution in southern Europe and high frequency in tick-exposed dogs.

Evidence for direct transmission of the cat lungworm Troglostrongylus brevior (Strongylida: Crenosomatidae).

Metastrongyloids of cats are emerging pathogens that may cause fatal broncho-pulmonary disease. Infestation of definitive hosts occurs after ingestion of intermediate or paratenic hosts. Among metastrongyloids of cats, Troglostrongylus brevior and Troglostrongylus subcrenatus (Strongylida: Crenosomatidae) have recently been described as agents of severe broncho-pulmonary disease. Here, we provide, for the first time, observational evidence suggesting the direct transmission of T. brevior from queen cat to suckling kittens. This new knowledge will have a significant impact on current scientific information of this parasite and shed new light into the biology and epidemiology of metastrongyloid nematodes.

Rhipicephalus sanguineus (Ixodida, Ixodidae) as intermediate host of a canine neglected filarial species with dermal microfilariae

The life cycles of filarioids of dogs presenting dermal microfilariae have been little studied. Following the recent retrieval of dermal microfilariae identified as Cercopithifilaria sp. in a dog from Sicily (Italy), this study was designed to assess the role of the brown dog tick Rhipicephalus sanguineus as an intermediate host of this filarial species. An experimental tick infestation was performed on an infected dog using 300 nymphs of R. sanguineus. Engorged nymphs were collected and examined by both microscopic dissection and molecular analysis at five time points (i.e., the same day of tick detachment and 10, 20, 30 and 50 days post-detachment) to detect the presence and developmental stage of filariae in the ticks. A total of 270 engorged nymphs were collected from the dog and developing filarioid larvae detected in 10 (5%) out of 200 ticks dissected. Infective third-stage larvae were observed in 4 (2%) of the all dissected ticks, 30 days post-detachment. Twelve (6.6%) out of 181 samples molecularly tested were positive for Cercopithifilaria sp. This study demonstrates that nymphs of R. sanguineus feeding on a dog naturally infected by Cercopithifilaria sp. can ingest microfilariae, which develop up to the third infective stage thus suggesting that this tick species might act as an intermediate host of this little known canine filarioid.

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

BackgroundThe 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).MethodsA 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).ResultsThree 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%.ConclusionsThe 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.

New insights into the ecology and biology of Acanthocheilonema reconditum (Grassi, 1889) causing canine subcutaneous filariosis.

In spite of its wide distribution among dogs and the evidence of its implication as a zoonotic agent, scant information is available on the biology of Acanthocheilonema reconditum (Spirurida, Onchocercidae). In this study, blood samples from 152 Sicilian dogs were examined for A. reconditum microfilariae at the beginning of the study and 1 year later. The periodicity of microfilaraemia was investigated by bleeding 2 highly microfilaraemic dogs twice a day for 10 days and, later on, every 2 weeks for 1 year and a third animal every 3 h for 96 h. Fleas and ticks infesting dogs were collected and dissected for the detection of A. reconditum larvae. The prevalence of infestation was 11·2% (17/152) and 13·3% (16/120) at the beginning and at the end of the study, with a 1 year cumulative incidence of 5·9%. Although dogs bled twice a day showed a higher number of microfilariae in most of the morning samples, the absence of any circadian rhythm was suggested by data of the third experiment conducted by bleeding a dog every 3 h for 4 days. A. reconditum developing forms were detected in 5·1% (4/78) of dissected fleas, but not in any of the 272 ticks. The study provides new insights into the biology and ecology of this dog filarioid in its definitive and intermediate hosts.

Cutaneous distribution and localization of Cercopithifilaria sp. microfilariae in dogs.

The aim of this study was to investigate the anatomical distribution of microfilariae of a recently described Cercopithifilaria sp. and the relationship with the preferred attachment sites of its vector, the brown dog tick Rhipicephalus sanguineus. Skin samples from 20 dogs were collected from eight anatomical sites and soaked twice in saline solution at 37°C. All samples were also molecularly processed for the specific amplification of partial cytochrome c oxidase 1 gene. Microfilariae were unevenly distributed on the body, with higher frequencies on interscapular region (n=13; 68.4%) and on the head (n=9; 47.4%). Larval abundance in dogs was positively correlated with the number of positive anatomical sites with a higher percentage of skin samples scoring positive at the microscopic examination of the first sediment (n=47; 30.9%) than of the second (n=8; 5.3%). Histological examination revealed that microfilariae were scattered in the dermis, in association with inflammatory cells. Molecular analysis of skin samples showed a lower frequency of positive sites (n=37; 24.3%) when compared to the microscopic examination (n=53; 34.9%) with five haplotypes sequenced. The results here presented suggested a close co-evolution of this filarioid with its vector.

Feline and canine leishmaniosis and other vector-borne diseases in the Aeolian Islands: Pathogen and vector circulation in a confined environment

Vector-borne diseases (VBDs) are prevalently investigated in dogs. Studies on feline VBDs are scant, though feline leishmaniosis (FeL) is increasingly recognised as a disease of cats in endemic areas. Comprehensive investigations on the distribution of VBDs in populations of cats and dogs living in relatively small geographical areas, such as islands, are currently lacking. In this study the prevalence of Leishmania infantum and other VBD pathogens was assessed in cohorts of cats and dogs living in the Aeolian Islands. Autochthonous animals (330 cats and 263 dogs) of different age and sex were sampled. Blood and conjunctival samples were collected from cats and dogs for serological and molecular testing. Eighty-five (25.8%) cats were positive for L. infantum, 13 (3.9%) for Bartonella spp. and 1 (0.3%) for Hepatozoon felis. One-hundred and ten dogs (41.8%) were positive for L. infantum and three (1.1%) for Hepatozoon canis. The incidence of L. infantum infection in cats positive after one season of exposure to sand fly was 14.7%. Leishmania infantum prevalence and year incidence were higher in dogs than in cats (p=0.0001 and p=0.0003, respectively). Thirty-four cats (10.3%) scored positive for ticks (mean intensity rate of infestation, 2.03±1.4), which were identified to the species level as Ixodes ventalloi and Rhipicephalus pusillus. Conversely, Rhipicephalus sanguineus sensu lato (s.l.) was the only species identified in dogs (10.6%). A larger prevalence of infestation by Ctenocephalides felis was recorded in cats (n=91; 27.6%) than in dogs (n=33; 12.5%) (p=0.0001). In addition, one female Nosopsyllus fasciatus (syn. Ceratophyllus fasciatus) and one male Spilopsyllus cuniculi were also identified in flea-infected cats. VBDs are endemic in the Aeolian Islands being L. infantum the most prevalent vector-borne pathogen circulating between cats and dogs. The overall seroprevalence of FeL herein recorded is higher than that assessed, only by IFAT, in populations of cats in Greece and in Spain. Because L. infantum and VBDs are more commonly associated with dogs, the recognition of cats as hosts of different vector-borne pathogens is of paramount importance towards a better management of these diseases in both animals and humans.

Lungworms and gastrointestinal parasites of domestic cats: a European perspective

With the exception of Aelurostrongylus abstrusus, feline lungworms have been poorly studied. Information on their distribution is patchy and mostly limited to case reports. In this study, the occurrence of feline lungworms and co-infecting gastrointestinal parasites has been investigated in 12 European countries (i.e. Austria, Belgium, Bulgaria, France, Greece, Hungary, Italy, Portugal, Romania, Spain, Switzerland and the United Kingdom). An average of 10 domestic cats, with regular outdoor access, was sampled each month for 12months, and freshly passed faeces were collected. Stools were processed using a McMaster assay and a quantitative Baermann-Wetzel method. Animals positive for lungworms and/or gastrointestinal parasites were treated with a formulation containing fipronil, (S)-methoprene, eprinomectin, and praziquantel (Broadline®, Merial), and re-sampled 28days post-treatment. The association between lungworm infection and risk factors was analysed using statistical medians/means and the efficacy of the treatment against each lungworm species was assessed. Of 1990 cats sampled, 613 (30.8%) were positive for at least one parasite, while 210 (10.6%) were infected by lungworms. The prevalence of lungworm infection varied between the sampled sites, with the highest recorded in Bulgaria (35.8%) and the lowest in Switzerland (0.8%). None of the cats from Austria or the United Kingdom were infected by lungworms. Aelurostrongylus abstrusus was the species most frequently detected (78.1%), followed by Troglostrongylus brevior (19.5%), Eucoleus aerophilus (14.8%) and Oslerus rostratus (3.8%). The overall efficacy of the treatment was 99% for A. abstrusus and 100% for T. brevior, O. rostratus and E. aerophilus. Data presented provide a comprehensive account of the diagnosis, epidemiology and treatment of feline lungworms in Europe, as well as of the occurrence of co-infections by gastrointestinal parasites.

Efficacy of a combination of 10% imidacloprid and 4.5% flumethrin (Seresto®) in slow release collars to control ticks and fleas in highly infested dog communities

BackgroundDog communities living in kennels are at high risk of being infected by ticks and fleas. In spite of the indubitable efficacy of several topical ectoparasiticides registered for the control of ectoparasites in dogs, the short period of action and the price of these products limit their use in dog communities. This paper reports on the efficacy of imidacloprid/flumethrin slow release collars to cure dogs highly infested with ectoparasites and to prevent infestations for 8 months in a refuge with a history of unsuccessful environmental treatments.MethodsA total of 82 dogs were collared with slow release collars containing a formulation of imidacloprid 10% / flumethrin 4.5%. Dogs were followed-up for ectoparasite presence after 2, 7 and 14 days and thereafter biweekly up to 90 days. Furthermore, dogs were examined for ectoparasites whilst replacing collars 8 months after their application.ResultsAt the time of treatment 79 (96.3%) out of 82 included dogs were heavily infested by ticks and 53 (68.8%) out of the 77 combed dogs were infested by fleas. Tick infested dogs had an estimated mean intensity of 46.9 (± 65.7), while flea infested animals had a load between 20 and 50 fleas. In addition, some of the flea infested dogs (18.9%) were presenting signs of flea allergic dermatitis (FAD). Two days after treatment, 49 (60.5%) and 9 (11.7%) dogs were still infested by live ticks and fleas, respectively. However, the mean intensity of ticks decreased to 3.5 (± 4.3) with a reduction of 92.5%. Except for sporadic cases, no attached ectoparasites were found on dogs from the day 14 visit until the end of the investigation. Cases of FAD resolved without any other treatment within 30 days.ConclusionsTicks and fleas represent a constant hazard for dog populations. Therefore, in particular settings, such as dog refuges, sustainable and long-term strategies to control ectoparasite infestations are needed. Based on the observed evidence of efficacy, long-term duration and safety, the imidacloprid/flumethrin slow release collars can be regarded as an efficacious and sustainable means for ectoparasite control and for treatment of FAD in high-risk dog communities.

Field Evaluation of Two Different Treatment Approaches and Their Ability to Control Fleas and Prevent Canine Leishmaniosis in a Highly Endemic Area

This study investigated the efficacy of two collars for the treatment and prevention of flea infestations. Additionally the effect of these collars on the incidence of Leishmania infantum infection as compared with a group of vaccinated dogs was evaluated. A total of 224 young dogs from private animal shelters were enrolled in April/May into four groups: G1, 55 dogs treated with 10% imidacloprid + 4.5% flumethrin collar (Seresto, Bayer Animal Health); G2, 60 dogs treated with 4% deltamethrin collar (Scalibor protector band, MSD Animal Health); G3, 54 dogs vaccinated with CaniLeish (Virbac Animal Health); and G4, 55 dogs left non-treated as controls. Dogs were followed up at days 120 (September), 210 (December), and 360 (April-May). At those time points, clinical assessments, ectoparasite counts and blood, bone marrow and skin samples, to detect the presence of L. infantum, were performed. The efficacy of Seresto in protecting dogs from flea infestation was 100% (P < 0.01) on day 120 and 210, while animals treated with Scalibor showed a prevalence of the infestation ranging from 23.3% to 33.3% on day 120 and 210, respectively. At the end of the study, the incidence of L. infantum infection in collared dogs—based on animals being positive in any of the tests—was 5.5% in Seresto-treated dogs and 20% in Scalibor-treated dogs, resulting in overall efficacy of prevention of 88.3% for Seresto and 61.8% for Scalibor. No statistical difference was detected in L. infantum positive dogs for bone marrow PCR and/or cytology at day 360 between the CaniLeish (15.4%) and non-treated control dogs (10.0%). Both collars proved to be effective (P < 0.01) in preventing L. infantum infection throughout one transmission season, whereas no significant difference was recorded in the frequency of active infections between dogs vaccinated with CaniLeish and control dogs, emphasizing the importance of using repellent/insecticide actives as a priority measure for protection against canine leishmaniosis.