Rhipicephalus Sanguineus Sensu Lato Research Articles

Babesia canis vogeli infection in dogs and ticks in the semiarid region of Pernambuco, Brazil

Abstract:This study aimed to report the prevalence of Babesia canis vogeli in dogs and ticks in the urban and rural areas of Petrolina, Pernambuco. Serum and peripheral blood samples of 404 dogs were tested by indirect immunofluorescence assay (IFA) and by blood smears, respectively. The presence of tick infestation was evaluated, and some specimens were submitted to DNA amplification by polymerase chain reaction (PCR). The presence of antibodies anti-B. canis vogeli was determinate in 57.9% (234/404) of dogs. The direct detection of Babesia spp was obtained in 0.5% (2/404) dogs by visualization of intraerythrocytic forms. Infestation by Rhipicephalus sanguineus sensu lato was observed in 54.5% (220/404) of dogs in both urban and rural areas. DNA of Babesia canis vogeli were obtained by PCR in 6% individual (3/50) and 8.7% of pool of ticks (7/80). The risk factors for the presence of anti-B. canis vogeli antibodies, as determined through the application of logistic regression models (P<0.05), were the following: medium breed size variables (P<0.001); contact with areas of forest (P=0.021); and access on the street (P=0.046). This study describes, for the first time, the confirmation of infection of B. canis vogeli in dogs and ticks in the semiarid region of Pernambuco, Brazil.

Comparative efficacy of two oral treatments for dogs containing either afoxolaner or fluralaner against Rhipicephalus sanguineus sensu lato and Dermacentor reticulatus

The present study compares the efficacy of two recent oral ectoparasiticides containing isoxazolines (NexGard®, containing afoxolaner and administered at a monthly regimen, and Bravecto™ containing fluralaner and administered at a tri-monthly regimen) against Rhipicephalus sanguineus sensu lato and Dermacentor reticulatus ticks on dogs.24 dogs were randomly allocated to untreated control, NexGard® treated, and Bravecto™ treated groups. The treatments were administered on Days 0, 28 and 56 for afoxolaner and on Day 0 for fluralaner. Tick infestations were performed weekly with 50 unfed adult ticks per each species on each dog from Days 30 to 84 (with the exception of R. sanguineus on Day 63). Ticks were counted at 24h post-infestation.The dogs from both treated groups had statistically significantly (p<0.05) less R. sanguineus and D. reticulatus ticks compared to the untreated dogs on all assessment days. Percent efficacy against R. sanguineus ranged from 86.4% to 99.5% at 24h post-infestation for NexGard® and from 65.7% to 100% for Bravecto™. Statistically significantly (p<0.05) less R. sanguineus ticks were recorded for NexGard® treated dogs compared to Bravecto™ treated dogs on Day 78. Percent efficacy against D. reticulatus ranged from 85.2% to 99.6% at 24h post-infestation for NexGard® and from 63.4% to 99.1% for Bravecto™. Statistically significantly (p<0.05) less D. reticulatus ticks were recorded for NexGard® treated dogs compared to Bravecto™ treated dogs on Days 71, 78 and 85.

One-month comparative efficacy of three topical ectoparasiticides against adult brown dog ticks (Rhipicephalus sanguineus sensu lato) on mixed-bred dogs in controlled environment

This study was designed to compare the therapeutic and residual efficacy for 1 month of three topical ectoparasiticides on mixed-bred dogs against the brown dog tick, Rhipicephalus sanguineus. Adult dogs (n = 32, 10.8–18.4 kg BW) were allocated to 4 groups (n = 8) and infested with 50 adult ticks on days −8, −2, 7, 14, 21, and 28. Within each group, dogs were treated topically on day 0 with a control solution (CS), Vectra® 3D (DPP), Frontline® Plus (FM), or K9 Advantix® (IP). Ticks were enumerated on dogs 24 h after treatment and each subsequent tick infestation by in situ thumb count assessment without removal and at 48 h by combing and removal. Acaricidal efficacy was calculated using arithmetic means for all 24 and 48 h tick count assessments. From 42 to 56 % of the total, infested ticks were found on dogs 48 h post-challenge in the CS group. Therapeutic efficacy for all treatments ranged from 45.5 to 64.6 % after 48 h of infestation. Residual efficacy after FM treatment was consistently lower compared to DPP or IP treatments at the 24 h assessments on days 8, 22, 23, and 29. Residual efficacy measured at this last time point was 94.8 % for DPP, 83.1 % for IP, and 46.9 % for FM. This study demonstrates that permethrin-based formulations (DPP and IP) provided a quicker onset of residual protection against brown dog ticks compared to FM. Although DPP and IP are both permethrin-based formulations, DPP exhibited consistently higher residual acaricidal efficacies and was the only treatment that provided >90 % protection for 1 month at 24 h post challenge.

Potential role of ATP-binding cassette transporters against acaricides in the brown dog tick Rhipicephalus sanguineus sensu lato.

ATP-binding cassette (ABC) transporters have been shown to be involved in pesticide detoxification in arthropod vectors and are thought to contribute to the development of drug resistance. Little is currently known about the role they play in ticks, which are among the more important vectors of human and animal pathogens. Here, the role of ABC transporters in the transport of fipronil and ivermectin acaricides in the tick Rhipicephalus sanguineus (Ixodida: Ixodidae) was investigated. Larvae were treated with acaricide alone and acaricide in combination with a sub-lethal dose of the ABC transporter inhibitor cyclosporine A. The LC50 doses and 95% confidence intervals (CIs) estimated by mortality data using probit analysis were 67.930 p.p.m. (95% CI 53.780-90.861) for fipronil and 3741 p.p.m. (95% CI 2857-4647) for ivermectin. The pre-exposure of larvae to a sub-lethal dose of cyclosporine A reduced the LC50 dose of fipronil to 4.808 p.p.m. (95% CI 0.715-9.527) and that of ivermectin to 167 p.p.m. (95% CI 15-449), which increased toxicity by about 14- and 22-fold, respectively. The comparison of mortality data for each separate acaricide concentration showed the synergic effect of cyclosporine A to be reduced at higher concentrations of acaricide. These results show for the first time a strong association between ABC transporters and acaricide detoxification in R.sanguineus s.l.

Community-based control of the brown dog tick in a region with high rates of Rocky Mountain spotted fever, 2012-2013.

Rocky Mountain spotted fever (RMSF) transmitted by the brown dog tick (Rhipicephalus sanguineus sensu lato) has emerged as a significant public health risk on American Indian reservations in eastern Arizona. During 2003–2012, more than 250 RMSF cases and 19 deaths were documented among Arizona's American Indian population. The high case fatality rate makes community-level interventions aimed at rapid and sustained reduction of ticks urgent. Beginning in 2012, a two year pilot integrated tick prevention campaign called the RMSF Rodeo was launched in a ∼600-home tribal community with high rates of RMSF. During year one, long-acting tick collars were placed on all dogs in the community, environmental acaricides were applied to yards monthly, and animal care practices such as spay and neuter and proper tethering procedures were encouraged. Tick levels, indicated by visible inspection of dogs, tick traps and homeowner reports were used to monitor tick presence and evaluate the efficacy of interventions throughout the project. By the end of year one, <1% of dogs in the RMSF Rodeo community had visible tick infestations five months after the project was started, compared to 64% of dogs in Non-Rodeo communities, and environmental tick levels were reduced below detectable levels. The second year of the project focused on use of the long-acting collar alone and achieved sustained tick control with fewer than 3% of dogs in the RMSF Rodeo community with visible tick infestations by the end of the second year. Homeowner reports of tick activity in the domestic and peridomestic setting showed similar decreases in tick activity compared to the non-project communities. Expansion of this successful project to other areas with Rhipicephalus-transmitted RMSF has the potential to reduce brown dog tick infestations and save human lives.

A nationwide survey of ixodid tick species recovered from domestic dogs and cats in Japan in 2011

A nationwide survey of ixodid ticks was performed in 2011, during which a total of 4237 and 298 ticks were recovered from 1162 dogs and 136 cats, respectively. Haemaphysalis longicornis was the most frequently found tick species on canine hosts (739 dogs), followed by H. flava (166), Ixodes ovatus (139), and Rhipicephalus sanguineus sensu lato (70). H. hystricis, H. japonica, H. megaspinosa, H. formosensis, H. campanulata, H. ias, I. nipponensis, I. persulcatus, and Amblyomma testudinarium were also recovered. H. longicornis was also the most frequently found species on feline hosts (52 cats), followed by I. ovatus (34), A. testudinarium (19), and H. flava (12). H. hystricis, H. japonica, H. megaspinosa, I. nipponensis, I. persulcatus, I. granulatus and R. sanguineus sensu lato were also recovered from cats. The three major species of ticks found on dogs and cats, H. longicornis, H. flava, and I. ovatus, displayed a wide geographical distribution, with specimens found throughout northern and southern Japan. R. sanguineus sensu lato was primarily recovered in Okinawa, but was also found in Kanagawa, Wakayama, Hiroshima, and Yamaguchi Prefectures. A. testudinarium was mainly distributed throughout western Japan, but small numbers were also recovered from Gumma and Shizuoka Prefectures. H. longicornis was more frequently found on dogs in rural areas than those in urban or suburban areas. Exposure to woodland environments was significantly associated with H. flava and I. ovatus in dogs. Dogs in urban or suburban areas encountered R. sanguineus sensu lato more often than other tick species. Most of the cats surveyed in the present study were from rural areas. In the present study, H. hystricis and R. sanguineus sensu lato were found on cats for the first time in Japan.

Molecular detection of tick-borne pathogens in Rhipicephalus sanguineus group ticks

The Rhipicephalus sanguineus group includes some of the most widespread dog ticks, whose identification currently represents a difficult task due to the morphological similarities of these ixodid species. Recently, following the morphological and molecular characterization of tick specimens collected from dogs in all continents, Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus turanicus and three different operational taxonomic units (namely Rhipicephalus sp. I–III) have been identified. Therefore, a comprehensive molecular study has been herein carried out to detect selected canine vector-borne pathogens (i.e., Anaplasma platys, Cercopithifilaria spp., Ehrlichia canis and Hepatozoon canis) in ticks belonging to the R. sanguineus group. A total of 204 tick specimens from dogs were examined and identified as R. sanguineus s.l. (n=81), R. turanicus (n=17), Rhipicephalus sp. I (n=66), Rhipicephalus sp. II (n=37), and Rhipicephalus sp. III (n=3). PCR assays were performed to detect mitochondrial and ribosomal target genes of Cercopithifilaria spp., A. platys, E. canis and H. canis. Out of 204 specimens examined, 2.5%, 7.4% and 21.6% scored positive to A. platys, H. canis and Cercopithifilaria spp., respectively. In addition, co-infections with two pathogens (i.e., Cercopithifilaria bainae and A. platys or H. canis) were detected in four tick specimens. This study suggests a relationship between ticks belonging to the R. sanguineus group and the geographical distribution of A. platys, H. canis and Cercopithifilaria spp. However, the role of each representative tick species within the R. sanguineus group in the transmission of these canine pathogens needs to be further investigated.

Characterisation of ecto- and endoparasites in domestic cats from Tirana, Albania.

During 2008 to 2011, faecal samples, ear swabs, and ectoparasites obtained by full body search and total body comb were collected from 252 cats originating from the greater Tirana area. Faecal samples were examined using the McMaster and Baermann techniques, and a subset of 58 samples was tested for Giardia-specific antigen using a coproantigen enzyme-linked immunosorbent assay (ELISA). The ear swabs were examined for the presence of parasitic mites. Overall, almost 93% of the cats were identified harbouring one or more parasites: 59.1% (95% confidence interval (CI), 53.0-65.0) and 86.9% (95% CI, 82.7-91.1) of the cats tested positive for ecto- or endoparasites, respectively; 53.2% of the cats had evidence for concomitant ectoparasite infestation and endoparasite infection. For ectoparasite infestation, prevalence was 52.0% for total fleas (Ctenocephalides felis, 51.2%; Ctenocephalides canis, 2.0%; and Leptopsylla segnis, 0.4%), 8.3% each for Felicola subrostratus and Otodectes cynotis and 4.0 % for Rhipicephalus sanguineus sensu lato. The most prevalent endoparasites were Toxocara ascarids (48.0%), followed by Aelurostrongylus lungworms (39.7%), Capillaria spp. (31.7%), hookworms (32.9%), dipylidiid cestodes (27.8 %), Cystoisospora spp. (23.4%) and taeniid cestodes (2.0%). One animal was found shedding Pseudamphistomum truncatum eggs. Giardia-specific antigen was detected in 29.3% of the 58 cats tested. Mixed infections with up to six endoparasites concurrently (excluding Giardia) and mixed infestations with two or three species of ectoparasites were recorded in 73.1 and 22.8% of the parasite-positive cats, respectively. Cats ≤9 months of age were more frequently tested (p < 0.05) positive for Toxocara and Cystoisospora infections than cats >9 months while these cats tested more often (p < 0.05) Aelurostrongylus-positive compared with the younger cats. The prevalence of infestation with ectoparasites did not differ between the cats of these two age groups. Given the impact that some of the parasites may have upon animal health as well as the zoonotic potential of some of them, measures should be taken to minimise the transmission of these parasites.

New insights into the biology and ecology of Acanthocheilonema reconditum (spirurida: onchocercidae)

Among filarioids infesting dogs, Acanthocheilonema reconditum has a global distribution and epidemiological data indicate that it is the most prevalent or even the sole filarioid species-infecting dogs in some regions of the Mediterranean basin. For instance, in southern regions of Italy the prevalence is as high as 13.3%, and an annual incidence of 5.9% was estimated in naturally exposed dogs. In spite of its wide distribution and its suspected zoonotic potential, scant information is available on the biology of this filarioid. Nonetheless, recent studies have enhanced current scientific knowledge on the biology and ecology of this nematode in naturally infected dogs. Recent data indicate the absence of any defined periodicity of blood circulating microfilariae with peaks recorded either diurnal or nocturnal. With regard to the life cycle, fleas were confirmed to be vectors of A. reconditum, whereas the role of ixodid ticks (i.e., Rhipicephalus sanguineus sensu lato) as vectors of this filarioid species has been definitively rejected. The full development of microfilariae to infective forms occurs in the experimental infected cat flea Ctenocephalides felis felis in about 15 days. In addition, localization and size of developing larvae inside infected flea suggest that this arthropod might act as an intermediate host throughout the ingestion of infected fleas rather than the inoculation during the blood meal on dogs. If confirmed, this route of A. reconditum transmission is unique, differing from that of other filarioids affecting dogs such as Dirofilaria immitis and Dirofilaria repens, which are actively transmitted through the bites of mosquito vectors.

The intravenous and oral pharmacokinetics of afoxolaner used as a monthly chewable antiparasitic for dogs

The pharmacokinetics of afoxolaner in dogs was evaluated following either intravenous or after oral administration of NEXGARD®, a soft chewable formulation. Afoxolaner is a member of one of the newest classes of antiparasitic agents, known as antiparasitic isoxazolines. The soft chewable formulation underwent rapid dissolution, and afoxolaner was absorbed quickly following oral administration of the minimum effective dose of 2.5mg/kg, with maximum plasma concentrations (Cmax) of 1655±332ng/mL observed 2–6h (Tmax) after treatment. The terminal plasma half-life was 15.5±7.8 days, and oral bioavailability was 73.9%. Plasma concentration-versus-time curves fit a 2-compartment model and increased proportionally with dose over the oral dose range of 1.0–4.0mg/kg, and over the oral dose range from 1.0 to 40mg/kg. Following an intravenous dose of 1mg/kg, the volume of distribution (Vd) was 2.68±0.55L/kg, and the systemic clearance was 4.95±1.20mL/h/kg. Afoxolaner plasma protein binding was >99.9% in dogs. One major metabolite, formed following hydroxylation of afoxolaner, was identified in dog plasma, urine and bile. When afoxolaner is administered orally, there is a strong correlation between afoxolaner plasma concentration and efficacy with EC90 values of 23ng/mL for Ctenocephalides felis and ≥100ng/mL for Rhipicephalus sanguineus sensu lato and Dermacentor variabilis. The pharmacokinetic properties of afoxolaner are suited for a monthly administration product because the fast absorption and long terminal half-life support a rapid onset of action while ensuring month-long efficacy.

Assessment of the efficacy of orally administered afoxolaner against Rhipicephalus sanguineus sensu lato

Two studies were conducted to confirm that a single oral dose of the novel insecticide/acaricide afoxolaner is efficacious against existing infestations of Rhipicephalus sanguineus sensu lato in dogs and can control re-infestation for up to 35 days. Each study utilized 16 purpose bred adult dogs using a controlled randomized block design. One or two days prior to treatment, all dogs were infested with 50 unfed adult ticks. On Day 0 one group was treated with an oral chewable formulation of afoxolaner at a dose as close as possible to the minimum dose of 2.5mg/kg. Weekly re-infestations with 50 adult unfed ticks were repeated for five weeks. Forty-eight hours after treatment and after each re-infestation, the number of remaining live ticks on each dog was counted. Treatment with afoxolaner resulted in efficacies of 98.8–100% within 48h on existing tick infestations, while the efficacy against new tick infestations was >95.7% over five weeks.

Seasonal dynamics of Rhipicephalus rossicus attacking domestic dogs from the steppic region of southeastern Romania

BackgroundDanube Delta Biosphere Reserve is one of the most interesting regions in Europe from an epidemiological point of view due to its great biodiversity, local climatic conditions and various types of habitats. Moreover, there is no data regarding the ectoparasite communities of dogs from this area. In this frame, the aims of our study were to establish the tick communities parasitizing dogs and to provide new data regarding seasonal dynamics of a neglected tick species, Rhipicephalus rossicus.MethodsA survey was carried out in order to gather information regarding tick species attaching to domestic dogs from a steppic region of southeastern Romania and to establish their seasonal dynamics. The research was conducted from 1 December 2012 to 30 November 2013, on 8 dogs from Iazurile, a locality from the west-central part of the Danube Delta Biosphere Reserve. In total, 384 examinations were made, each dog being checked for tick infestation 4 times per month, for one year.ResultsThe 893 ticks found belonged to six species: R. rossicus (95.6%), Dermacentor reticulatus (3.2%), Ixodes ricinus (0.5%), Hyalomma marginatum (0.3%), Rhipicephalus sanguineus sensu lato (s.l.) (0.2%) and Ixodes crenulatus (0.1%). From the 91 positive examinations, R. rossicus was found in 80 (87.9%). Single species infestation occurred in 84 examinations. In 7 out of 91 positive examinations mixed infestation were found. No ticks were found in December, January and September.ConclusionsFor R. rossicus, high frequency and intensity were observed in May, June and July. The activity peaks for D. reticulatus were in spring and autumn. Our results highlight that within the range of R. sanguineus s.l., the most common dog tick worldwide, selected dog populations may be predominantly infested by closely related species, like in our case, R. rossicus.

Occurrence of Hepatozoon canis and Cercopithifilaria bainae in an off-host population of Rhipicephalus sanguineus sensu lato ticks

Hepatozoon canis (Eucoccidiorida, Hepatozoidae) and the filarioid Cercopithifilaria bainae (Spirurida, Onchocercidae) are tick-transmitted infectious agents of dogs, highly prevalent in the Mediterranean basin in association with Rhipicephalus sanguineus sensu lato. Ticks were collected from the environment every 25±2 days in a confined location in southern Italy where a community of dogs lives, from August 2012 to July 2013. In order to study the occurrence of H. canis and C. bainae, 1091 tick specimens (770 adults; 271 nymphs, and 50 larvae) were dissected, and oocysts of H. canis and larvae of C. bainae were morphologically identified. Out of 1091 dissected ticks, 13.47% (n=147) were positive for H. canis, with the highest prevalence recorded in unfed adults (16.4%; 126/770), followed by nymphs collected as larvae and allowed to moult (14%; 7/50), unfed nymphs dissected immediately after collection (3%; 8/271), and adults collected as nymphs and allowed to moult (2%; 6/271). The highest number of H. canis-positive ticks (35.5%; 43/121; P<0.05) was recorded during the summer months (i.e., June–July). In addition, 6% of adult ticks (n=66) were positive for third-stage larvae of C. bainae, with the highest number in June (17%; 14/84; P<0.05). Based on the results reported herein, H. canis and C. bainae infections in the study area seem to be dependent on the seasonality of vector tick populations. Hence, dogs living in these areas are more exposed to both pathogens during the warmer months. These findings provide new insights into the ecology of both H. canis and C. bainae.

Ticks infesting humans in Italy and associated pathogens.

BackgroundTicks may transmit a large variety of pathogens, which cause illnesses in animals and humans, commonly referred to as to tick-borne diseases (TBDs). The incidence of human TBDs in Italy is underestimated because of poor surveillance and the scant amount of studies available.MethodsSamples (n = 561) were collected from humans in four main geographical areas of Italy (i.e., northwestern, northeastern, southern Italy, and Sicily), which represent a variety of environments. After being morphologically identified, ticks were molecularly tested with selected protocols for the presence of pathogens of the genera Rickettsia, Babesia, Theileria, Candidatus Neoehrlichia mikurensis, Borrelia and Anaplasma.ResultsTicks belonged to 16 species of the genera Argas, Dermacentor, Haemaphysalis, Hyalomma, Ixodes and Rhipicephalus, with Ixodes ricinus (59.5%) being the species most frequently retrieved, followed by Rhipicephalus sanguineus sensu lato (21.4%). Nymphs were the life stage most frequently retrieved (41%), followed by adult females (34.6%). The overall positivity to any pathogen detected was 18%. Detected microorganisms were Rickettsia spp. (17.0%), Anaplasma phagocytophilum (0.8%), Borrelia afzelii (0.5%), Borrelia valaisiana (0.3%), C. N. mikurensis (0.5%) and Babesia venatorum (0.6%).ConclusionsResults indicate that people living in the Italian peninsula are at risk of being bitten by different tick species, which may transmit a plethora of TBD causing pathogens and that co-infections may also occur.

First molecular evidence of Hepatozoon canis infection in red foxes and golden jackals from Hungary.

BackgroundRecently, Hepatozoon canis infection has been detected among shepherd, hunting and stray dogs in the southern part of Hungary, which is considered to be free of Rhipicephalus sanguineus sensu lato and close to the border with Croatia. The aim of this study was to acquire information on the possibility that red foxes and/or golden jackals could play a role in the appearance and spread of H. canis in Hungary.MethodsA conventional PCR was used to amplify a 666 bp long fragment of the Hepatozoon 18S rRNA gene from blood samples collected from 334 foxes shot in 231 locations in 16 counties and 15 golden jackals shot in 9 locations in two southwestern counties close to Croatia. A second PCR assay was performed in some of the samples positive by the first PCR to amplify a larger segment (approximately 1500 bp) of the 18S rRNA gene of Hepatozoon spp. for further phylogenetic analysis.ResultsHepatozoon infection was detected in canids shot in 30 locations and 9 counties. Altogether 26 foxes (8.0%, 95% CI: 5-11%) and 9 jackals (60%, 95% CI: 33-81%) were PCR positive. Hepatozoon canis sequences were obtained from 12 foxes and 7 jackals. DNA sequences from 16 animals were 99-100% similar to H. canis from Croatian foxes or dogs while two of the sequences were 99% similar to an Italian fox. Half (13/26) of the infected red foxes and all golden jackals were shot in the two southwestern counties.ConclusionsThis is the first report on molecular evidence of H. canis in red foxes (Vulpes vulpes) and golden jackals (Canis aureus) from Hungary, which is considered free from the tick vector of H. canis, R. sanguineus. Although no R. sanguineus sensu lato had been found on infected or non-infected wild canids, the detection of authochnous canine hepatozoonosis in Hungary might imply that the range of R. sanguineus sensu lato has reached this country.

Vector-borne pathogens in dogs from Costa Rica: First molecular description of Babesia vogeli and Hepatozoon canis infections with a high prevalence of monocytic ehrlichiosis and the manifestations of co-infection

Infection with canine vector-borne pathogens was evaluated in dogs from four different regions of Costa Rica by PCR. Demographic data, clinical signs, packed cell volume values, and the presence of tick infestation were recorded for each dog. Forty seven percent (69/146) of the dogs were infected with at least one pathogen and 12% were co-infected with two pathogens. Ehrlichia canis was detected in 34%, Anaplasma platys in 10%, Babesia vogeli in 8%, and Hepatozoon canis in 7.5% of the blood samples. No infection was detected with Leishmania spp. in blood, skin scrapings or conjunctival swabs. Thirty percent of the dogs presented at least one clinical sign compatible with vector-borne disease, and of those, 66% were infected with a pathogen. Subclinical infections were determined in 58% of the infected dogs including 82% (9/11), 58% (29/50), 42% (5/12) and 36% (5/14) of the dogs with H. canis, E. canis, B. vogeli and A. platys infections, respectively. A distinct relationship was found between infection and anemia. The mean PCV values were 34.4% in dogs with no infection, 31.5% in those who had a single infection and 23% in those with co-infection. Co-infected dogs had significantly lower PCV values compared to non-infected and single-infected dogs (p<0.0001). Thirty five percent (51/146) of the dogs were infested with ticks, 82% of them were infested with Rhipicephalus sanguineus sensu lato and 18% with Amblyomma ovale. Dogs infected with A. platys, B. vogeli, or E. canis were significantly associated with R. sanguineus s.l. infestation (p<0.029).This is the first description of infections with B. vogeli and H. canis in Costa Rica as well as in Central America. The results of this study indicate that multiple vector-borne pathogens responsible for severe diseases infect dogs in Costa Rica and therefore, increased owner and veterinarian awareness are needed. Moreover, prevention of tick infestation is recommended to decrease the threat of these diseases to the canine population.

Comparative analyses of mitochondrial and nuclear genetic markers for the molecular identification of Rhipicephalus spp.

The genus Rhipicephalus (Acari: Ixodidae) comprises a large number of vectors of pathogens of substantial medical and veterinary concern; however, species identification based solely on morphological features is often challenging. In the present study, genetic distance within selected Rhipicephalus species (i.e., Rhipicephalus bursa, Rhipicephalus guilhoni, Rhipicephalus muhsamae, Rhipicephalus sanguineus sensu lato and Rhipicephalus turanicus), were investigated based on molecular and phylogenetic analyses of fragments of the mitochondrial 16S, 12S and cytochrome c oxidase subunit 1 (cox1) genes, as well as of the whole sequences of the ribosomal internal transcribed spacer-2 (ITS-2) region. Mean values of inter-specific genetic distance (e.g., up to 12.6%, 11.1% and 15.2%), as well as of intra-specific genetic distance (e.g., 0.9%, 0.9% and 1%), calculated using the Kimura-2 parameter substitution model with uniform rates among sites for 16S, 12S and cox1 genes, respectively, confirmed the differentiation of the rhipicephaline species herein examined. The molecular identification was also supported by the distinct separation of species-specific clades inferred from the phylogenetic analyses of all mitochondrial sequences. Conversely, little interspecific divergence was detected amongst ribosomal ITS-2 sequences (i.e., up to 2.8%) for species belonging to the R. sanguineus complex, which resulted in the ambiguous placement of selected R. sanguineus s.l. and R. turanicus sequences in the corresponding phylogenetic tree. Results from this study confirm the suitability of mtDNA markers for the reliable identification of ticks within the Rhipicephalus genus and provide a framework for future studies of taxonomy, speciation history and evolution of this group of ticks.

Tick vectors of Cercopithifilaria bainae in dogs: Rhipicephalus sanguineus sensu lato versus Ixodes ricinus

Recently, dermal microfilariae of a Cercopithifilaria species (Spirurida, Onchocercidae), namely Cercopithifilaria bainae , were detected in dogs from several geographical areas of the Mediterranean basin. Evidence from both laboratory and field studies support the role of the brown dog tick, Rhipicephalus sanguineus sensu lato, as an intermediate host of this nematode. In the present study, we investigated the competence of Ixodes ricinus nymphs as vectors of C. bainae. On November 2012, fully engorged nymphs of I. ricinus (n = 174) and R. sanguineus s.l. (n = 10) were collected from a dog infected by C. bainae. The presence of C. bainae in I. ricinus was assessed by both microscopic dissection of specimens and detection of nematode DNA (PCR), at days 3, 10, 20 and 30 (T1-T4) post-collection; due to the small number of specimens available, R. sanguineus s.l. were examined using the same methods at T4 only. No developing larva of C. bainae was detected in I. ricinus specimens at different time points (T1-T4), even if four of these specimens were PCR-positive at T1. Seven out of ten R. sanguineus s.l. were positive for C. bainae third-stage larvae (L3) at both microscopical and molecular analysis at T4. This study indicates that C. bainae does not develop in I. ricinus nymphs, which preclude the role of this tick as an intermediate host of this parasite. Data presented herein provide new insights into the biology of this filarioid species and will lead to a better understanding of the role of different tick species as vectors of nematodes.

Closing remarks

Studies have shown that the brown dog tick, Rhipicephalus sanguineus sensu lato, when fed on the beagle breed of dog, Canis lupus familiaris, development negatively affected in comparison with tick development after feeding on the English cocker spaniel breed. Thus leading to the suggestion that beagle dogs are be tick-resistant dogs. Behavioural studies have demonstrated that more ticks are attracted by extracts from cocker spaniels than from beagles and that the odour of beagles is a repellent. To test the hypothesis that resistant hosts produce repellent compounds, we undertook comparative chemical analysis on beagle odour and cocker spaniel extracts using coupled high-resolution gas chromatography–mass spectrometry (GC–MS) and also used Petri-dish and olfactometer behavioural assays to assess the response of ticks to identified non-host compounds. The beagle odour extracts contained almost three times as many chemical compounds as cocker spaniel samples. Several non-host compounds were identified, i.e. 2-hexanone, benzaldehyde, nonane, decane and undecane. In Petri-dish assays, 2-hexanone was repellent at 30 min at concentrations of 0.200 and 0.050 mg cm−2, whilst at 10 min, the 0.100 mg cm−2 concentration was repellent. Benzaldehyde repelled ticks at 30 min (0.200 mg cm−2) and at 5 min (0.050 mg cm−2). Undecane was repellent for R. sanguineus s.l. ticks for the first 5 min at the highest concentration tested. Nonane and decane did not show any significant repellency at any concentration or time evaluated. When 2-hexanone and benzaldehyde were combined, an increase in the repellency rate was observed, with activity comparable or better than N,N-diethyl-3-methylbenzamide (DEET). In olfactometer bioassays, a 1:1 mixture of 2-hexanone:benzaldehyde and DEET were repellent for R. sanguineus s.l. adults at the concentration of 0.200 mg cm−2. This study identified non-host semiochemicals that mediate avoidance of the beagle dog breed by R. sanguineus s.l. This finding may enable development of new approaches to control this tick.

On the helminth fauna of the frogs(rana ridibunda) inhabiting uzbekistanand southern Kazakhstan

Ticks collected from goats in northern Greece were tested for the presence of tick-borne bacteria. Among adult ticks, 37 (57.8%) were Rhipicephalus bursa, 11 (17.2%) Dermacentor marginatus, 10 (15.6%) Ixodes ricinus, 3 (4.7%) Rhipicephalus sanguineus sensu lato and 2 (3.1%) Haemaphysalis parva; one (1.6%) Rhipicephalus spp. tick was nymph. Rickettsia monacensis, Rickettsia massilae, Anaplasma phagocytophilum and Anaplasma platys were detected in I. ricinus and Rh. bursa ticks. A variety of Coxiella-like endosymbionts were detected in all tick genera tested, forming distinct clades from Coxiella burnetii in the phylogenetic tree based on the 16S rRNA gene. An additional endosymbiont, Candidatus Midichloria mitochondrii, was detected in most of the I. ricinus ticks. Surveillance for human pathogens in ticks provides knowledge helpful for the public health, while further studies are needed to determine the role of endosymbionts in tick physiology, vector competence and probably in public health.