Rhipicephalus Sanguineus Sensu Lato Research Articles

Assessing the cellular and humoral immune response in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) infected with Leishmania infantum (Nicolle, 1908)

The aim of this study was to evaluate aspects of the innate cellular and humoral immune response by evaluating hemocyte dynamics, phagocytosis, phenoloxidase (PO) activity and nitric oxide (NO) production in Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) infected with Leishmania infantum and to assess the persistence of parasites at time 0 and 1, 2, 5, and 7 days post-infection (dpi). The total and differential count of the five types of hemocytes circulating in the hemolymph of R. sanguineus s.l. females showed the average total number of hemocytes in the group infected with L. infantum to be significantly higher (p < 0.05) on the 1st and 2nd dpi compared to the control group. The hemocyte differential count showed that the average number of plasmatocytes and granulocytes increased significantly on the 1st, 2nd, and 5th dpi with L. infantum compared to the control group (p < 0.001). Phagocytosis assays revealed that plasmatocytes and granulocytes were able to perform phagocytosis of latex beads and L. infantum on the 1st and 2nd dpi, respectively. NO production was significantly increased (p < 0.001) on the 1st, 2nd, and 5th dpi with L. infantum and PO activity increased significantly (p < 0.05) only on the 5th dpi. L. infantum DNA was significantly increased (p < 0.001) on the 5th and 7th dpi compared to time 0. Although there are no studies describing the response of R. sanguineus s.l. to an infection with L. infantum, these results suggest that R. sanguineus s.l. activates the cellular and humoral immune response after infection with L. infantum. Further studies are however, needed to assess the impact of such a response on fighting infection.

A molecular survey of hemoplasmas in domestic dogs from Turkey

Mycoplasma haemocanis (Mhc) and Candidatus Mycoplasma haematoparvum (CMhp) are cell-wall-deficient bacterial pathogens that localize on the vertebrate erythrocyte surface. Prevalence of infection with these hemoplasmas and associated risks factors were ascertained from archived DNA samples collected from 621 domestic dogs (201 strays, 262 from shelters, 158 domestic pets) by species-specific PCR assay. The overall prevalence of infection was 15.3% (CI 12.5–18.4), with Mhc and CMhp single infection prevalence of 4.5% (CI 3.0–6.4) and 4.3% (CI 2.9–6.3), respectively. Dual infection with Mhc and CMhp was found in 6.4% (I 4.6–8.715). Infection rates for male (15.8%, CI 12.5–18.4) and female (14.5%, CI 10.5–19.4) dogs were not significantly different (P > 0.05), and the frequency of hemoplasmas was higher in adult dogs (18.9%, CI 15.1–23.2) than in young (9.5%, CI 6.1–14.0) (P < 0.05). Shelter and free-roaming stray dogs had higher prevalence of infection compared to domestic pet dogs (P < 0.05), but there was no significant difference in prevalence between free-roaming and shelter dogs (P> 0.05). A significant association between hemoplasma infection and the presence of Rhipicephalus sanguineus sensu lato was observed (P < 0.05). Presence of tick-borne pathogens (Babesia, Hepatozoon, Anaplasma, Ehrlichia) was also significantly associated with canine hemoplasmas (P < 0.05).

Records of ticks on humans in Rio Grande do Sul state, Brazil

More than seventy tick species have been reported in Brazil. Despite the emergence of tick-borne diseases in Neotropical region, there are still limited data available on tick species parasitizing humans in Brazil. Rio Grande do Sul is the southernmost state of Brazil, comprising the only part of Brazilian territory inside the Pampa biome, as well as the transition between subtropical and temperate zones. Here, we report on human parasitism by ticks in Rio Grande do Sul state between 2004 and 2017. Seventy cases of human parasitism by ticks were recorded, with a total of 81 tick specimens collected. These included 11 tick species belonging to three genera of Ixodidae (hard-ticks), Amblyomma, Haemaphysalis and Rhipicephalus; and one genus of Argasidae, Ornithodoros. The most prevalent tick species associated to cases of human parasitism were Amblyomma parkeri (24%), Rhipicephalus sanguineus sensu lato (22%), Amblyomma aureolatum (15%) and Amblyomma ovale (12%). A spatial analysis showed two major hot spots of human parasitism by ticks in Rio Grande do Sul state. The findings of this study highlight the need for permanent monitoring of human parasitism by ticks in order to provide a better understanding of tick and tick-borne disease eco-epidemiology, and the early identification of potential cases of tick-borne diseases, particularly in spotted fever endemic regions.

Detection of Babesia spp. in Dogs and Their Ticks From Peninsular Malaysia: Emphasis on Babesia gibsoni and Babesia vogeli Infections in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

Canine babesiosis is an emerging tick-borne disease with a worldwide distribution, including Malaysia. While the prevalence of Babesia has been documented from dogs in Malaysia, occurrence of Babesia has been relatively little studied in their tick vectors. Accordingly, a total of 240 dogs and 140 Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) ticks from Malaysia were molecularly screened for the presence of Babesia protozoa in the present study. Babesia gibsoni was only detected in ticks (1.4%), whereas Babesia vogeli was detected in both ticks (1.4%) and dogs (2.1%). This study highlights the detection of B. gibsoni and B. vogeli for the first time, in both adult and nymphal stages of R. sanguineus s.l. in Malaysia, suggesting the potential role of this tick species in transmitting canine babesiosis.

Evaluation of the vector competence of six ixodid tick species for Rangelia vitalii (Apicomplexa, Piroplasmorida), the agent of canine rangeliosis

Rangelia vitalii is the etiologic agent of canine rangeliosis, a severe piroplasmosis that affects domestic dogs in Brazil, Uruguay and Argentina. While R. vitalii is one of the most pathogenic tick-borne pathogens for dogs in the world, its tick vector has remained unknown. The present study evaluated the vector competence of Rhipicephalus sanguineus sensu lato (both tropical and temperate species), Amblyomma aureolatum, Amblyomma ovale, Amblyomma tigrinum, and Amblyomma sculptum for R. vitalii. These six tick species were selected for the study because they comprise the main tick species infesting dogs within the distribution area of canine rangeliosis in South America. Acquisition feeding of the above six tick species was performed on domestic dogs showing clinical signs of canine rangeliosis, after being experimentally infected through intravenous inoculation or infestation with R. vitalii-infected ticks. Thereafter, engorged ticks were evaluated for transstadial and transovarial passages of R. vitalii through molecular analysis after molting or oviposition and egg hatching. The resultant ticks were evaluated for their competence to transmit R. vitalii to susceptible dogs. Among the six tick species, only A. aureolatum was able to acquire and perpetuate R. vitalii by transstadial and transovarial passages, as demonstrated by >5% infection rates of ticks after hatching or molting. When exposed to transmission feeding, only A. aureolatum ticks were competent to transmit R. vitalii to dogs, which became severely ill, and the results confirmed by molecular methods and blood smear examination to have acquired rangeliosis. Results of the present study, coupled with epidemiological data, indicate that A. aureolatum is a natural vector of R. vitalii. Our results also indicate that R. vitalii is the first Piroplasmorida agent to be transovarially transmitted in Amblyomma ticks.

Molecular Evidence for a Novel Species of Babesia in Unfed Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

This study reports a novel species of Babesia in unfed Rhipicephalus sanguineus sensu lato and its phylogenetic relationship to other species. One-hundred and forty DNA samples extracted from tick pools comprising 5,403 unfed R. sanguineus s.l. ticks were screened for Babesia. Overall Babesia infection was detected in female, male, and nymph pools with an infection rate maximum likelihood estimate (MLE) of 1.98 (CI 0.65-4.74), 0.50 (CI 0.03-2.40), and 0.07 (CI 0.01-0.21), respectively. Three adult female tick pools (MLE 1.44, CI 0.38-3.88) and one adult male pool (MLE 0.50, CI 0.03-2.40) hybridized to the catchall and Babesia genus probes but did not hybridize to any species-specific probe tested, suggesting the presence of an unidentified Babesia species. Phylogenetic analysis and sequencing revealed the newly detected Babesia isolate to form a clade distinct from fully identified canine, bovine, equine, and ovine Babesia species, with a range of 88.6-92.9% nucleotide identity.

Infestation of Rhipicephalus sanguineus sensu lato on cats in Malta

Studies on cats as hosts of Rhipicephalus sanguineus sensu lato (s.l.) are scarce. Cats are regarded as infrequent hosts of this species complex, and usually only when dogs are also present. In order to compare the occurrence of developmental stages and mitochondrial DNA haplotypes of R. sanguineus s.l. on cats and other domestic or synanthropic mammalian species, 540 ticks were collected from cats, dogs, hedgehogs and one goat. Collections were made from April to September in 2016 and 2017, from 20 locations in Malta in southern Europe. The sampling sites included six cat colonies, where no dogs were present. Compared to adults, significantly more immatures of R. sanguineus s.l. were found on cats (123 larvae and nymphs versus 10 adults) than on dogs (190 larvae and nymphs versus 173 adults). Furthermore, compared to nymphs, significantly more larvae of R. sanguineus s.l. were found on cats (50 larvae versus 73 nymphs) than on dogs (11 larvae versus 179 nymphs). Adult ticks predominated on male dogs (42 adults versus 28 larvae or nymphs), whereas immatures were significantly more abundant compared to adult ticks on female dogs (142 larvae or nymphs versus 80 adults). Similarly, immature as compared with adult ticks were significantly more likely to occur on female cats (72 immature ticks versus 1 adult) in comparison with male cats (46 immature ticks versus 8 adults). Moreover, R. sanguineus s.l. larvae were found significantly more frequently as compared with nymphs on female cats (38 larvae versus 34 nymphs) than on male cats (12 larvae versus 34 nymphs). To confirm morphological identification and to compare mitochondrial markers (cytochrome c oxidase subunit 1 [cox1] and 16S rRNA genes) of ticks across hosts, 57 ticks were analysed. The amplified parts of the cox1 and 16S rRNA genes of R. sanguineus s.l. collected from various hosts showed 100% sequence identity with each other and with those in GenBank from the middle to western Mediterranean Basin. In conclusion, the present study highlights that cats can be important hosts of the immature life stages of R. sanguineus s.l., even in the absence of dogs. This finding has veterinary-medical significance, because stray cats and free-roaming cats may transport immature stages of R. sanguineus s.l. into gardens, i.e. near dogs and humans.

Differences in tick infestation of Tunisian sheep breeds.

Different infestation patterns by ixodid ticks were studied in three sheep breeds in Tunisia: Barbarine, Queue Fine de l'Ouest and their cross-bred animals. During one year, 700 sheep were monitored and examined for tick infestation. A total of 722 ticks were collected from sheep ears. The most frequent tick species was by far Rhipicephalus sanguineus sensu lato (99%) and there were few specimens of Rhipicephalus bursa (1%) (p < 0.001). Overall infestation prevalence was estimated at 10.4%. The lowest infestation prevalence was in Barbarine sheep (7.3%), followed by Queue Fine de l'Ouest (16.7%) and the highest prevalence was in cross-bred sheep (19.1%) (p < 0.001). Mean overall infestation intensity was 1.6 ticks/sheep: lowest in Barbarine (1.4), followed by Queue Fine de l'Ouest (1.7) and cross-bred sheep (1.8). Similarly, abundance was lowest in Barbarine sheep (0.1), and was 0.3 in Queue Fine de l'Ouest and cross-bred animals. The results demonstrated a reduced infestation, possibly due to reduced attractiveness and/or increased resistance to tick infestation, of the Barbarine breed compared with the other two breeds. Further behavioural, genetic and molecular studies are needed to explain the mechanisms for the lower infestation indicators.

Rickettsia amblyommatis infecting Amblyomma pseudoconcolor in area of new focus of spotted fever in northeast Brazil

In Brazil, active infections of Rickettsia spp. is confirmed in all regions, involving various species of ticks. During investigation of a new focus of Spotted Fever (SF) incidence in the state of Pernambuco, northeastern Brazil, tick species Rhipicephalus sanguineus sensu lato (Latreille), and Amblyomma pseudoconcolor were collected from one Canis familiaris and four Euphractus sexcinctus, respectively, and analized for the presence of rickettsial genes. Ten A. pseudoconcolor ticks (90.9%) were found to be infected with Rickettsia, whereas no evidence of Rickettsia spp. was found in R. sanguineus s. l. Genetic analysis based of five rickettsial genes showed that the detected strain is most closely related to Rickettsia amblyommatis (formerly Candidatus Rickettsia amblyommii). R. amblyommatis was, for the first time, detected in Amblyomma pseudoconcolor and the results pointed to this tick like a potential vector in the enzootic cycle of R. amblyommatis in a typical semiarid Brazilian savannah region. In conclusion, despite the need for further studies to confirm if R. amblyommatis was responsible for the observed case in the state of Pernambuco, the presence of this bacterium during an SF focussed investigation should be a major concern in terms of public health due the capacity of SF for rapid and extensive dispersion within Brazilian territory.

Occurrence of ticks in dogs in a hospital population in the state of Espírito Santo, Brazil

ABSTRACT: Ticks, along with fleas, are considered the main ectoparasites affecting dogs in Brazil. The literature is rich in reports on the occurrence of ticks, which are vectors of diseases in both dogs and humans. The study of the epidemiology of these arthropods provides important data that can help control the infestation in residential areas where dogs are present. Thus, the study of their occurrence in urban areas and veterinary services is very important. The aim of the present study was to determine the occurrence of ticks in dogs in a veterinary hospital population in the state of Espírito Santo, Brazil. Over a one-year period (July 2012 to July 2013), 1483 dogs brought to veterinary services in south-eastern Brazil were examined. Among the dogs examined, 8.97% presented tick infestation, of which 100% were identified as Rhipicephalus sanguineus sensu lato. Given that this species of tick acts as a vector for diseases, it is important that the official health services monitor the occurrence of infestation in dogs and humans, in order to identify diseases transmitted by these ticks in this region.

Babesia microti-like piroplasm (syn. Babesia vulpes) infection in red foxes (Vulpes vulpes) in NW Spain (Galicia) and its relationship with Ixodes hexagonus

Piroplasmosis is caused by several species of protozoa such as the Babesia microti-like piroplasm (Bml), an emerging blood protozoan also known as Theileria annae or Babesia vulpes. Infection by Bml was first reported in dogs in Spain where it is endemic today. Recently, a high prevalence of Bml has been increasingly detected in red foxes (Vulpes vulpes) in European countries. The objective of this study was to determine infection levels of this parasite in foxes from Galicia, NW Spain, and ticks species infestation in these carnivores, where they are so far unknown. Samples of blood, spleen and ticks (if present) were taken from 237 hunted red foxes in the Galicia region. Blood smears were prepared for direct parasite observation, and spleen and tick samples were examined by nested PCR. Prevalences of Bml infection in Galician red foxes were estimated at 72% (171/237) by PCR and 38.23% (26/68) by direct observation. Among 837 ticks collected, the main tick identified was Ixodes hexagonus (present in 82.4% of the foxes) followed by Ixodes ricinus (12.3%), Dermacentor reticulatus (12.3%) and Rhipicephalus sanguineus sensu lato (3.5%). From 34 foxes testing positive for Bml, 616 ticks were collected: positive Bml PCR results were obtained in 55.6% (227/408) of ticks collected from 9 foxes, while the 208 ticks from the remaining 25 infected foxes returned negative PCR results. Given that canine piroplasmosis is endemic in this area, our observations point to the red fox as the main reservoir for Bml infection and the high proportion of I. hexagonus among ticks collected from red foxes suggests its likely role as vectors of B. microti-like piroplasm in this region. Further studies are needed for a better understanding of the link between the wild and domestic life cycles of this piroplasm.

Ticks (Acari: Ixodidae) of the state of Amazonas, Brazil.

The tick fauna of Brazil is currently composed by 72 species. The state of Amazonas is the largest of Brazil, with an area of≈19% of the Brazilian land. Besides its vast geographic area, only 19 tick species have been reported for Amazonas. Herein, lots containing ticks from the state of Amazonas were examined in three major tick collections from Brazil. A total of 5933 tick specimens were examined and recorded, comprising 2693 males, 1247 females, 1509 nymphs, and 484 larvae. These ticks were identified into the following 22 species: Amblyomma cajennense sensu lato, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma dissimile, Amblyomma dubitatum, Amblyomma geayi, Amblyomma goeldii, Amblyomma humerale, Amblyomma latepunctatun, Amblyomma longirostre, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma rotundatum, Amblyomma scalpturatum, Amblyomma varium, Dermacentor nitens, Haemaphysalis juxtakochi, Ixodes cf. Ixodes fuscipes, Ixodes luciae, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato. Ticks were collected from 17 (27.4%) out of the 62 municipalities that currently compose the state of Amazonas. The following four species are reported for the first time in the state of Amazonas: A. coelebs, A. dubitatum, H. juxtakochi, and Ixodes cf. I. fuscipes. The only tick species previously reported for Amazonas and not found in the present study is Amblyomma parvum. This study provides a great expansion of geographical and host records of ticks for the state of Amazonas, which is now considered to have a tick fauna composed by 23 species. It is noteworthy that we report 1391 Amblyomma nymphs that were identified to 13 different species.

&lt;i&gt;Ehrlichia canis &lt;/i&gt; DNA in domestic cats parasitized by &lt;i&gt;Rhipicephalus sanguineus&lt;/i&gt; sensu lato (s.l.) ticks in Brazil - case report

Ectoparasites can transmit pathogens, including bacteria such as Ehrlichia sp., which trigger infectious diseases in domestic animals. Little is known about the epidemiology of feline ehrlichiosis, although several studies have focused on elucidating the pathogenesis and transmission of this disease. This paper presents the first mutual infection by Ehrlichia sp. between a domestic cat and a Rhipicephalus sanguineus sensu lato (s.l.) tick removed from the animal. The cat and tick were tested by Polymerase Chain Reaction (PCR) to detect the dsb gene, and the analyzed sequences revealed samples 100% identical to E. canis. Based on this report, we discussed the importance of cats as E. canis reservoirs s and their position in the cycle of transmission between dogs and cats in Brazil.

Detección de Borrelia burgdorferi sensu lato en perros y sus garrapatas en comunidades rurales de Yucatán, México

In Mexico, the distribution and the presence of pathogenic genospecies of B. burgdorferi in dogs and their ticks has not been extensively investigated. The study of canine borreliosis is acquiring greater relevance, since the dog is considered to be an important sentinel for pathogens pertaining to the complex Borrelia burgdorferi sensu lato; in addition, dogs could be playing a key role in the spread of ticks from forested areas into the domestic environment. This study aimed to detect and estimate the prevalence of B. burgdorferi s.l. in dogs and their ticks in two rural communities of Yucatán, Mexico. In each community, 50 houses were visited, where 144 blood samples from dogs were studied by puncture of the saphenous vein, as well as the collection of their ticks. To detect the presence of B. burgdorferi s.l. in these samples, the conserved gene flaB, p66 and ospC were PCR amplified. A total of 144 dog blood samples, and 846 of ticks were obtained from the examined animals. Considering tick species, Rhipicephalus sanguineus sensu lato (786 / 846) was common, while Ixodes affinis (33 / 846), and Amblyomma mixtum (27 / 846) resulted less frequent. As per gene conservation, the prevalence of B. burgdorferi in canine blood was 17.3 % (25 / 144) to flaB, 12.50 % (18 / 144) for p66 and 1.38 % (2 / 144) for the ospC gene. Within the analyzed ticks, R. sanguineus s.l. had a prevalence of 0.89 %, A. mixtum 5.88 % and I. affinis 15.15 %, being this last species the one that presented higher prevalence. Two dogs and their ticks I. affinis were positive to the flaB gene. Only a tick R. sanguineus s.l. was positive to the gene p66 and no tick species was positive the ospC gene. This study confirmed the existence of B. burgdorferi s.l. in dogs and their ticks in rural communities of Yucatán, Mexico. The detection of Borrelia in dogs may be an important criterion for the evaluation of the risk of borreliosis in humans, since the dog can be used as an epidemiological indicator for the identification of new outbreaks of this disease.

Effect of Ozone as Acaricide: Action of the Ozone on the Cuticle and Respiratory Spiracle of Tick Rhipicephalus sanguineus sensu lato

ABSTRACTParasitoses that affect domestic animals, the Rhipicephalus sanguineus sensu lato deserves attention for being cosmopolitan. Ozone gas has been used as an agent for insect control. The objective of this study was to verify the acaricidic effect of the ozone gas on the R. sanguineus s. l. Ticks were distributed in three groups: two controls and one submitted to ozone action. Images were obtained using a scanning electron microscope. All specimens from the group treated with ozone died after the gas application and presented other lesions on cuticle and respiratory spiracles. Ozone acted as an acaricide to the ticks.

A randomized, controlled study to assess the efficacy and safety of lotilaner (Credelio\u2122) in controlling ticks in client-owned dogs in Europe

BackgroundOral administration of lotilaner flavoured chewable tablets (Credelio™, Elanco) to dogs has been shown to provide a rapid onset of killing activity of infesting ticks, with sustained efficacy for at least 35 days. A study was undertaken in Europe to confirm lotilaner’s safety and anti-tick efficacy in client-owned dogs.MethodsIn this assessor-blinded study, dogs were enrolled at 19 clinics in Germany, Hungary and Portugal. Qualifying households with no more than three dogs were randomized in an approximate 2:1 ratio to a lotilaner or fipronil/(S)-methoprene (FSM) (Frontline® Combo Spot-on, Merial) treatment group. One household dog with at least three live attached ticks was the primary dog. Treatments were dispensed Days 0, 28 (± 2) and 56 (± 2) for owner administration to all household dogs. Tick counts were performed on primary dogs Days 7 (± 1), and ±2 days on Days 14, 21, 28, 42, 56, 70 and 84; supplementary dogs were assessed for safety ± 2 days on Days 28, 56 and 84. Efficacy was assessed by comparing mean Day 0 live attached tick counts with subsequent counts.ResultsThe most frequently retrieved ticks were Ixodes ricinus, Dermacentor reticulatus and Rhipicephalus sanguineus (sensu lato), with Ixodes hexagonus also present. In the lotilaner group (n = 127) geometric mean tick count reductions were at least 98% from the first post-treatment visit (Day 7) through Day 56, when efficacy was 100%. For FSM (n = 68), efficacy remained at least 96% through Day 84, but at no point were all dogs free of live attached ticks. Mean counts in lotilaner-treated dogs were significantly lower than FSM-treated dogs on Days 7, 42, 70 and 84 (P < 0.05). Percent efficacy over all post-enrolment visits was 99.3 and 98.3% for lotilaner and FSM groups, respectively (t(190) = 2.23, P = 0.0268). Owners successfully administered all treatments, and both products were well-tolerated.ConclusionUnder European field conditions, lotilaner flavoured chewable tablets administered monthly, were > 98% effective in eliminating live ticks from the first post-treatment assessment (Day 7) through Day 56 and maintained 100% of dogs tick-free on Days 70 and 84. Lotilaner was safe, providing superior tick control to FSM administered according to the same schedule.

Rickettsia spp. among wild mammals and their respective ectoparasites in Pantanal wetland, Brazil

The genus Rickettsia comprises obligatory intracellular bacteria, well known to cause zoonotic diseases around the world. The present work aimed to investigate the occurrence of Rickettsia spp. in wild animals, domestic dogs and their respective ectoparasites in southern Pantanal region, central-western Brazil, by molecular and serological techniques. Between August 2013 and March 2015, serum, whole blood and/or spleen samples were collected from 31 coatis, 78 crab-eating foxes, seven ocelots, 42 dogs, 110 wild rodents, and 30 marsupials. Serum samples from canids, felids, rodents and marsupials were individually tested by indirect fluorescent antibody test (IFAT) in order to detect IgG antibodies to Rickettsia rickettsii, Rickettsia parkeri and Rickettsia amblyommatis. DNA samples from mammals and ectoparasites were submitted to a multiplex qPCR assay in order to detect and quantify spotted fever group (SFG) and typhus group (TG) rickettsiae and Orientia tsutsugamushi. Positive samples in qPCR assays were submitted to conventional PCR assays targeting gltA, ompA, ompB and htrA genes, followed by sequencing and phylogenetic analyses. The ticks collected (1582) from animals belonged to the species Amblyomma sculptum, Amblyomma parvum, Amblyomma ovale, Amblyomma tigrinum, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus sensu lato and Amblyomma auricularium. Overall, 27 (64.2%) dogs, 59 (75.6%) crab-eating foxes and six (85.7%) ocelots were seroreactive (titer≥64) to at least one Rickettsia species. For 17 (40.4%) dogs, 33 (42.3%) crab-eating foxes, and two (33.3%) ocelots, homologous reactions to R. amblyommatis or a closely related organism were suggested. One hundred and sixteen (23.5%) tick samples and one (1.2%) crab-eating fox blood sample showed positivity in qPCR assays for SFG Rickettsia spp. Among SFG Rickettsia-positive ticks samples, 93 (80.2%) belonged to A. parvum, 14 (12%) belonged to A. sculptum species, three (2.5%) belonged to A. auricularim, and six (5.2%) were Amblyomma larval pools. Thirty samples out of 117 qPCR positive samples for SFG Rickettsia spp. also showed positivity in cPCR assays based on gltA, htrA and/or ompB genes. The Blast analyses showed 100% identity with ‘Candidatus Rickettsia andeanae’ in all 30 sequences obtained from gltA, htrA and/or ompB genes. The concatenated phylogenetic analysis based on gltA and 17-kDa htrA genes grouped the Rickettsia sequences obtained from tick samples in the same clade of ‘Candidatus Rickettsia andeanae’. The present study revealed that wild and domestic animals in southern Pantanal region, Brazil, are exposed to SFG rickettsiae agents. Future studies regarding the pathogenicity of these agents are necessary in order to prevent human cases of rickettsiosis in Brazilian southern Pantanal.

Contributions to the knowledge of hard ticks (Acari: Ixodidae) in Colombia

The known tick fauna of Colombia includes 58 species (15 Argasidae and 43 Ixodidae). To add to the knowledge of the biology of ticks in Colombia, hard ticks (Ixodidae) were collected from domestic animals or vegetation during 2014–2016 in 10 of Colombia’s Departments. Ticks were identified to species through morphological examinations. Taxonomic identification was confirmed for some specimens by molecular methods, including phylogenetic analyses inferred from three tick genes (cytochrome c oxidase, 16S rDNA, second internal transcribed spacer). A total of 1745 tick specimens encompassing 8 species were collected. Overall, 5 tick species were recorded on cattle [Amblyomma dissimile, Amblyomma mixtum, Dermacentor nitens, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato (s.l.)], 5 on dogs (Amblyomma maculatum, Amblyomma ovale, Amblyomma varium, R. microplus, R. sanguineus s.l.), 3 on horses (A. mixtum, D. nitens, R. sanguineus s.l.), 3 on donkeys (A. mixtum, D. nitens, R. microplus), 1 on pig (D. nitens), and 2 from vegetation (A. mixtum, A. dissimile). This included the first records of A. mixtum from two Colombian Departments, indicating that the distribution of this tick in Colombia may be broader than currently known. Phylogenetic analyses confirmed that R. sanguineus s.l. specimens from 8 Departments belong to the “tropical species”. Moreover, Colombian specimens of A. maculatum formed a large clade with GenBank sequences of A. maculatum and A. triste, although some Colombian specimens grouped with A. maculatum from the United States while others grouped with A. triste from Brazil. Significant polymorphisms were observed between specimens of A. ovale or D. nitens; for the former species, it is noteworthy that two distinct clades were observed. Our study provides new records for 8 tick species parasitizing domestic animals in Colombia, including species with veterinary and medical importance in the Neotropical region, such as R. microplus, R. sanguineus, D. nitens, A. mixtum, and A. maculatum. Noteworthy, we provide the first record of A. varium infesting a domestic mammal.

Water immersion of dogs close to the time of topical fluralaner treatment does not reduce efficacy against a subsequent experimental challenge with Rhipicephalus sanguineus (sensu lato)

BackgroundFluralaner is a novel systemic ectoparasiticide for dogs and cats providing immediate and persistent flea- and tick-control after a single topical dose. Prescribing directions recommend waiting 72 h following topical administration before immersing dogs in water. The objective of this study was to determine whether water immersion immediately prior to treatment or earlier than 72 h post-treatment reduced subsequent treatment efficacy.MethodsForty (n = 40) dogs were blocked on tick carrying capacity into 5 experimental groups and all but one of the groups (untreated control) were treated topically with fluralaner (Bravecto® Spot-On Solution, Merck Animal Health, Madison, NJ, USA) at the commercial dose. Three of the four remaining groups were immersed in 38–40 °C water for a 5 min bath - either 1 h before treatment; 12 h after treatment; or 24 h after treatment. Seven days after treatment all dogs were challenged with 50 Rhipicephalus sanguineus (sensu lato) ticks and after 24 h attached ticks were counted and removed.ResultsEfficacies (compared to the untreated control group) were: 99.3% for no water immersion; 99.6% for immersion 1 h before treatment; 99.3% for immersion 12 h after treatment; and, 100% for immersion 24 h after treatment.ConclusionsWater immersion of dogs around the time of topical fluralaner administration did not reduce subsequent systemic acaricidal efficacy.

Molecular detection and phylogenetic analysis of Ehrlichia canis in a Philippine dog

Canine monocytic ehrlichiosis (CME), caused by a rickettsial bacterium, Ehrlichia canis, is distributed worldwide, particularly in tropical and subtropical regions. Transmission of E. canis is primarily mediated by the vector tick, Rhipicephalus sanguineus sensu lato and the bacteria then infect and replicate in monocytes and macrophages. Many cases are seen in veterinary hospitals and treated routinely; however, the genetic variation of E. canis strains found in the Philippines has been poorly investigated to date. In this study, the 16S rRNA gene and the gp200 gene of E. canis were detected by polymerase chain reaction from an infected dog in the Philippines, and the deduced amino acid sequence of the gp200 gene was subjected to a phylogenetic analysis. The Philippine genotype formed a cluster with the Taiwan genotype, and was somewhat divergent from the USA and Brazil strains. This suggested that E. canis underwent evolution in East and Southeast Asia, confirming the utility of the gp200 gene for the assessment of genetic relationships among strains.