Rhipicephalus sanguineus

To ascertain whether brown dog tick Rhipicephalus sp. infests resistant (beagle) and susceptible (English cocker spaniel) dogs differently, five animals of each breed were maintained in a kennel whose walls were infested with 7,000 larvae, 320 nymphs, 80 males and 80 ...

Rhipicephalus sanguineus, commonly known as “brown dog tick” or “kennel tick”, is a three-host tick that parasitizes mainly dogs and occasionally humans. This arthropod is worldwide distributed and is a vector of some zoonosis, as Rickettsia conorii (pathogen of Mediterranean spotted fever).
In Portugal, R. turanicus present high morphological resemblances to R. sanguineus, and as both populations are sympatric and very genetically similar, are easily misidentified. However, through a careful morphological analysis, it is possible to distinguish them, especially by the use of electronic microscopy.
Although some prior molecular and morphological studies have already been performed on these Portuguese populations, the results differ, which means there is still much speculation and disagreement around this taxonomic classification. 
In this context, this study was conducted using morphological (stereoscopic microscopy), ultramorfological (scanning electron microscopy - SEM) and molecular analysis (COI was the molecular marker of choice) in order to clarify the taxonomic status of these populations. For that purpose, three R. sanguineus s.l. populations collected from the districts of Óbidos, Santarém and Caldas da Rainha were used.
The species identification was performed based on morphology characteristics, using standard taxonomic keys (Dias, 1994; Papadopoulos et al., 1992; Walker et al., 2003). Ticks that could not be morphological identified as R. sanguineus or R. turanicus were defined as intermediate species. Some R. pusillus specimens were included in the analysis as an out-group.
The results obtained with the mentioned methods (except for the molecular analysis), allowed to conclude that there is a great morphological diversity within R. sanguineus s.l. Portuguese populations, and that the presence of R. turanicus in Portugal is grounded. Thus, it is suggested a new taxonomic classification based in observed variability within the group. It also suggested the future use of the statistical methodology employed as a technique for morphological variability evaluation within a representative population.

Background and Aim: Tick-borne pathogens (TBPs) are of great concern having the potential to threaten canine health. Dogs infected with Ehrlichia canis, Anaplasma platys, Babesia canis, and Hepatozoon canis are commonly found in Thailand; Rhipicephalus sanguineus tick is the most common vector of diseases. This study aimed to determine the prevalence of common TBPs in dogs and their ticks in Thailand using polymerase chain reaction (PCR) and DNA sequencing methods.

Materials and Methods: Forty-four blood samples were positively diagnosed with TBPs infection by microscopy. Samples were from animal hospitals in Maha Sarakham, Amnat Charoen, Nakhon Ratchasima, and Bangkok, Thailand, during January-June 2020. Five to six ticks were also taken from infected dogs, and then, both blood and tick were analyzed using PCR and DNA sequencing.

Results: PCR results showed that R. sanguineus was the only tick species detected in this study. The appearance of single infection with E. canis was the most common infection found in dogs and ticks (64% and 82%, respectively). Correlation of pathogen infection in hosts and their vector was performed by similarity detection of pathogens between blood and tick samples based on PCR analysis in 29 samples (66%) but there was no significant differentiation.

Conclusion: E. canis appears as the most common canine tick-borne pathogen in Thailand, which was detected in both healthy and sick dogs as well as in R. sanguineus. The findings show the relationships among host dogs, pathogens, and ticks. Veterinarians should be proactive in educating pet owners about the risks associated with ticks and their important pathogens and plan effective control strategies.

The aims of this work were to identify the compounds and to investigate the acaricidal activity of the essential oil of Lippia sidoides for unengorged larvae and nymphs of Rhipicephalus sanguineus and Amblyomma cajennense. The oil was analyzed by gas chromatography and gas chromatography/mass spectrometry. In total, 22 compounds comprising 98.5% of the total peak area were identified. The major constituent of the essential oil was thymol (69.9%). The acaricidal activity against larvae and nymphs was assessed using a modified larval packet test. In all experiments, oils were tested at concentrations of 2.35, 4.70, 9.40 14.10 and 18.80 mg/mL. The mortalities of larvae and nymphs of R. sanguineus were 20.6, 47.8, 73.6, 99.5 and 99.0% and 12.0, 50.0, 76.3, 96.0 and 96.1%, respectively. For larvae and nymphs of A. cajennense the rates of mortality were 41.9, 63.3, 77.8, 82.5 and 100.0% and 0.0, 32.8, 64.8, 71.1 and 94.0%, respectively. The LC 90 values of the L. sidoides oil were 11.56 a...

SUMMARYDogs serve as hosts for a great number of parasites, which may affect their health and wellbeing. This study aimed to observe tick borne pathogens in dogs from Palestine including Hepatozoon canis and Babesia species. The prevalence of both H. canis and Babesia species infections in apparently healthy dogs, from ten districts of the West Bank was surveyed. DNA was extracted from blood samples obtained from dogs (n = 362) and ticks (n = 213) collected from dogs (n = 77). A primer set that amplifies a partial sequence of the Babesia and Hepatozoon 18S rRNA gene was used for PCR and the DNA sequences of the PCR products of all samples were determined. Twenty-nine (8·0%) of the dogs were found infected including 20 with H. canis (5·5%), seven with Babesia vogeli (1·9%) and two with undefined Babesia spp. (0·6%). Twelve Rhipicephalus sanguineus s.l ticks were pathogen-positive, including ten with H. canis (4·7%), one with B. vogeli (0·5%), and one with Hepatozoon felis (0·5%). The...

Doxycycline generally alleviates clinical monocytic ehrlichiosis, but its efficacy in the control of monocytotropic ehrlichial pathogens requires further investigation. In this study, Ehrlichia canis was detected in dogs treated with doxycycline for 14 days and in ticks fed on these dogs, suggesting that treated dogs can remain reservoirs for E. canis.

Effective control of tick infestations on dogs is important to reduce the risk of transmission of bacterial, viral, and protozoal pathogens. Laboratory studies were initiated to determine the efficacy of lotilaner against common ticks infesting dogs in the United States. Eight studies investigated the efficacy of lotilaner against ticks. In two studies dogs were infested with both Dermacentor variabilis and Rhipicephalus sanguineus: one additional study was completed for each of these species. Two studies assessed infestations with Amblyomma americanum and two with Ixodes scapularis. In all studies, dogs were ranked and blocked by counts from pre-treatment infestations and randomly allocated, at least eight per group, to be treated orally with lotilaner (minimum dose rate 20 mg/kg), or to be untreated controls. Treatments were administered on Day 0, within 30 min after dogs were fed. In all studies, infestations were performed with 50 adult ticks on Days -2, 7, 14, 21 and 28, and al...

This study evaluated the seasonal dynamics of Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) on naturally infested dogs in a private shelter in southern Italy. From March to May 2008, 39 autochthonous mixed-breed young dogs and 10 beagles were enrolled in the study. From March 2008 until March 2009, every 21 ± 2 days, 11 body sites of each dog were checked for ticks. At each follow-up, the number of ticks, their developmental stage, sex and location on the dog's body were recorded. Adult ticks were found throughout the year, but immatures were absent in January and February. The adult tick population increased from July to August, whereas the load of immatures increased in early July and peaked in September, which suggests that R. sanguineus develops one generation per year in this area. The mean number of immature ticks per infested dog was higher than that of adults from March to October 2008. Ears, interdigital areas and armpits were the most frequent attachment sites of adult ticks. At the last follow-up, a total of 2266 ticks were collected and identified as R. sanguineus. The results suggest that R. sanguineus develops one generation per year in the study area, but that it infests dogs in all seasons. This information should be taken into account when planning control programmes against this tick species and the pathogens it transmits.