Tick infestation of dogs in Thessaloniki, northern Greece

The epidemiology of tick infestation in dog breeds in the UK

OBJECTIVES

The purpose of this study is to report the prevalence and risk factors for tick infestation in dogs in the UK based on anonymised electronic patient records.

MATERIALS AND METHODS

Clinical records of dogs under veterinary care in 2016 at clinics participating in the VetCompass Programme were followed over a 5-year period to identify cases of tick infestation. Risk factor analysis used multivariable logistic regression modelling.

RESULTS

The study included 905,553 dogs. From a random sample, 1903 tick infestation cases were identified. The estimated 5-year (2014 to 2018) period prevalence was 2.03% (95% confidence interval: 2.00 to 2.06). Sixteen breeds showed increased odds compared with non-designer-crossbreed dogs. Breeds with the highest odds included Cairn terrier (odds ratio 2.86, 95% confidence interval 1.64 to 4.98), standard poodle (odds ratio 2.80, 95% confidence interval 1.25 to 6.29) and Goldendoodle (odds ratio 2.63, 95% confidence interval 1.17 to 5.91). Six breeds showed reduced odds, with lowest odds shown by Staffordshire bull terrier (odds ratio 0.35, 95% confidence interval 0.25 to 0.50), Rottweiler (odds ratio 0.35, 95% confidence interval 0.15 to 0.85) and Chihuahua (odds ratio 0.38, 95% confidence interval 0.26 to 0.55). Males had 1.24 (95% confidence interval 1.13 to 1.36) times the odds of females. Compared with non-designer-crossbred dogs, designer-crossbreed dogs had increased odds (odds ratio 1.81, 95% confidence interval 1.52 to 2.15). Compared with breeds with short coats, breeds with medium length coats (odds ratio 2.20, 95% confidence interval 1.96 to 2.48) showed increased odds. Breeds with V-shaped drop and pendulous ear carriage had higher odds compared with breeds with erect ear carriage.

CLINICAL SIGNIFICANCE

These findings provide an evidence base for veterinary professionals to raise awareness of tick infestation as a preventable disorder in dogs in the UK and to support more effective prevention and therapeutic protocols based on targeted approaches.

The Scenario of Ticks and Tick-Borne Pathogens of Sheep on a Mediterranean Island

Ticks and transmitted pathogens constitute a major concern for livestock health/welfare and productivity for the Mediterranean region, often posing an important zoonotic threat. The aim of this study was to investigate the presence, infection intensity, and seasonality of ticks and tick-borne pathogens on the island of Lesvos in Greece, which was selected as a potential hotspot for their circulation. To this end, 101 sheep farms were visited over a tick activity season, and ticks, blood samples, and questionnaire data were collected. Ticks were identified by species, and DNA from both ticks and blood samples was further investigated using the polymerase chain reaction–reverse line blot (PCR–RLB) technique. In 72.3% of the farms, sheep were found to be infected by 9 ixodid species, with Rhipicephalus turanicus being the most common during the spring/early summer period. As regards tick-borne pathogens (TBPs), 84.9% of the animals were found to be infected with at least one pathogen, the most common being genera of Anaplasma and Theileria, alone or in co-infections. To further characterize the Anaplasma species found, selected samples were sequenced, revealing isolates of A. ovis, A. capra, A. marginale, and A. phagocytophilum. Of the 169 female R. turanicus ticks analyzed by PCR–RLB, 89.9% were harboring at least one TBP belonging to the genera Anaplasma, Ehrlichia, Babesia, Theileria, or Rickettsia. Overall, the data presented in this study revealed a high burden of ticks and TBPs in sheep, including zoonotic species, stressing the need for applying effective monitoring and control programs using a more holistic One Health approach.

Tick-Borne Pathogens and Diseases in Greece

Tick-borne diseases (TBDs) are recognized as a serious and growing public health epidemic in Europe, and are a cause of major losses in livestock production worldwide. This review is an attempt to present a summary of results from studies conducted over the last century until the end of the year 2020 regarding ticks, tick-borne pathogens, and tick-borne diseases in Greece. We provide an overview of the tick species found in Greece, as well as the most important tick-borne pathogens (viruses, bacteria, protozoa) and corresponding diseases in circulation. We also consider prevalence data, as well as geographic and climatic conditions. Knowledge of past and current situations of TBDs, as well as an awareness of (risk) factors affecting future developments will help to find approaches to integrated tick management as part of the ‘One Health Concept’; it will assist in avoiding the possibility of hotspot disease emergencies and intra- and intercontinental transmission. Increased surveillance in Greece is required to ensure clear and effective policies for TBD control.

Importation of Ticks on Companion Animals and the Risk of Spread of Tick-Borne Diseases to Non-Endemic Regions in Europe

Increased human mobility elevates the risk of exposure of companion animals travelling with their owners or imported from other regions to tick attacks. In this study, we highlight the potential role of dogs and cats taken for tourist trips or imported animals in the spread of ticks and tick-borne pathogens. The Rhipicephalus sanguineus tick, which is a vector of numerous pathogens causing diseases in animals and humans, is imported most frequently from endemic areas to many European countries. Additionally, alien tick species with high epizootic and epidemiological importance can be imported on dogs from other continents. Companion animals play an even greater role in the spread of autochthonous tick species and transmission of tick pathogens to other animals and humans. Although the veterinary and medical effects of the parasitism of ticks carried by companion animals travelling with owners or imported animals are poorly assessed, these animals seem to play a role in the rapid spread of tick-borne diseases. Development of strategies for protection of the health of companion animals in different geographic regions should take into account the potential emergence of unknown animal tick-borne diseases that can be transmitted by imported ticks.

First Report of Chlamydia Seroprevalence and Risk Factors in Domestic Black-Boned Sheep and Goats in China

The Gram-negative bacteria of the genus Chlamydia cause a wide range of diseases in humans and animals. The seroprevalence of Chlamydia in domestic black-boned sheep and goats in China is unknown. In this survey, a total of 481 serum samples were collected randomly from domestic black-boned sheep and goats from three counties in Yunnan province, southwest China, from July to August 2017. The sera were examined by an indirect hemagglutination assay (IHA). Antibodies to Chlamydia were detected in 100/481 [20.79%, 95% confidence interval (CI), 17.16–24.42] serum samples (IHA titer ≥1:64). The Chlamydia seroprevalence ranged from 12.21% (95% CI, 7.81–16.61) to 30.89% (95% CI, 22.72–39.06) across different regions in Yunnan province, and the differences were statistically significant (P < 0.01). The seroprevalence in male domestic black-boned sheep and goats (28.64%; 95% CI, 22.36–34.92) was significantly higher than that in the females (15.25%; 95% CI, 11.05–19.45) (P < 0.01). However, there was no statistically significant difference in Chlamydia seroprevalence in domestic black-boned sheep and goats between ages and species (P > 0.05). To our knowledge, this is the first report of Chlamydia seroprevalence in domestic black-boned sheep and goats in Yunnan Province, southwest China. These data provide baseline information for future implementation of measures to control Chlamydia infection in these animals.

Cross-Sectional Serosurvey and Factors Associated with Exposure of Dogs to Vector-Borne Pathogens in Greece

Blood samples from 2620 dogs living in 7 different areas were used for the detection of antibodies against Ehrlichia canis and Borrelia burgdorferi and Dirofilaria immitis antigen. Previously published seropositivity data against Leishmania infantum from the same samples were also used to identify multiple-pathogen seropositivity. The associations between seropositivity against each pathogen and gender, age, utility, hair length, and region of residence were evaluated by multivariate logistic regression analyses. The prevalence of seropositivity against E. canis, B. burgdorferi, and D. immitis was 12.25%, 2.23%, and 5.96%, respectively. Double- and triple-pathogen seropositivity was detected in seven different combinations. Age and region of residence were strongly associated with seropositivity against all pathogens. The association between seropositivity and the area of residence highlights the need for regular testing of dogs for vector-borne pathogens in areas with similar conditions to define control measures.

Parasites and vector-borne diseases in client-owned dogs in Albania: infestation with arthropod ectoparasites

To establish the diversity and seasonality of ectoparasite infestation in client-owned dogs in Albania, 602 dogs visiting four small animal clinics in Tirana from March 2010 to April 2011 inclusive were examined for ectoparasites by full body search and total body comb. In addition, ear swab specimens collected from all dogs and scrapings taken from skin lesions suspicious of mite infestation were examined for parasitic mites. Overall, 93 dogs (15.4 %, 95%CI 12.6-18.6) were demonstrated to be infested, and nine species of ectoparasites were identified: Ixodes ricinus, 0.8 %; Rhipicephalus sanguineus s. l., 8.1 %; Demodex canis, 0.2 %; Sarcoptes scabiei, 0.7 %; Otodectes cynotis, 2.8 %; Ctenocephalides canis, 4.8 %; Ctenocephalides felis, 3.0 %; Pulex irritans, 0.2 %; and Trichodectes canis, 0.2 %. Single and multiple infestations with up to four species of ectoparasites concurrently were recorded in 67 (11.1 %, 95%CI 8.7-13.9) and 26 dogs (4.3 %, 95%CI 2.8-6.3), respectively. On univariate analysis, the category of breed (pure breed dogs vs. mixed-breed dogs), the dog's purpose (pet, hunting dog, working dog), the housing environment (mainly indoors/indoors with regular outside walking vs. yard plus kennel/run), the history of ectoparasiticide treatment and the season of examination were identified as significant (p < 0.05) factors predisposing dogs to various ectoparasites, while the variables dog's age, gender, the dog's habitat (city, suburban, rural) and the presence/absence of other pets were not significant predictors. Multivariate logistic regression analysis for factors associated with overall ectoparasitism revealed that dogs treated with ectoparasiticides at least once per year (odds ratio [OR] = 0.24; p < 0.001) had a significantly lower risk of infestation compared with dogs not treated against ectoparasite infestation. Dogs examined during spring, summer and autumn (OR = 7.08, 7.43 and 2.48, respectively; all p < 0.001) had a significantly higher risk of infestation than dogs examined during winter. By providing basic data on the infestation with ectoparasites in client-owned, veterinary-cared-for dogs from Albania for the first time, the results of this survey should emphasize the need of an increase of attention to ectoparasites in dogs by both veterinarians and dog owners.

Species diversity and spatial distribution of ixodid ticks on small ruminants in Greece

A cross sectional field study on the distribution of Ixodidae ticks was carried out over two consecutive tick seasons (2012 and 2013) in small ruminants (309 farms) located in mainland and five islands of Greece. A total of 2108 ticks (1199 females, 908 males, and 1 nymph) were collected from sheep and goats. Two species of Rhipicephalus, two of Ixodes, five of Hyalomma, three of Haemaphysalis, and one of Dermacentor were detected. The species with the widest distribution were Rhipicephalus sanguineus s.l. (64.8 %), R. bursa (25.9 %), and Dermacentor marginatus (4.1 %), whereas the least frequently collected species were Ixodes ricinus, I. gibbosus, Haemaphysalis parva, H. sulcata, H. punctata, Hyalomma marginatum, H. excavatum, H. dromedarii, H. rufipes, and H. impeltatum representing together less than 5.3 % of the collections. R. sanguineus s.l. was the predominant species, while D. marginatus and I. gibbosus were restricted to the northeastern Aegean Sea islands. This is the first survey on tick fauna from mainland and islands in Greece.

Human otoacariasis: Demographic and clinical outcomes in patients with ear-canal ticks and a review of literature

INTRODUCTION

Otoacariasis is a rare infestation of the ear canal, which affects the quality of life especially in rural areas. Different types of ticks and mites may cause otoacariasis. Although treatment of otoacariasis is simple, diseases transmitted through ticks and mites should be considered during diagnosis and treatment. Both local and systemic signs and symptoms of such diseases should be followed up.A literature review was conducted in PubMed using the following terms: "otoacariasis," "ticks," "mites," and "outer ear canal infestations." Demographic, radiologic, and treatment options were discussed. Treatment hints and pitfalls were also discussed with the literature review.

CONCLUSION

In this paper, we describe otoacariasis in humans and discuss the appropriate interventions.

Efficacy of oral afoxolaner plus milbemycin oxime chewables against induced infestations with Dermacentor reticulatus in dogs

The efficacy of afoxolaner plus milbemycin oxime (AFX + MO) combination chewables (NexGard Spectra®, Merial) and AFX single-entity chewables (NexGard®, Merial) against induced infestations with Dermacentor reticulatus ticks was evaluated in dogs. Thirty dogs were assigned to blocks of three animals each based on pre-allocation tick counts and were randomly allocated to one of three groups: untreated (control), treated with a combination of AFX + MO chewables to be as close as possible to the minimum effective dose of AFX + MO (2.5 + 0.5 mg per kg body weight), and treated with a combination of NexGard® chewables to be as close as possible to the minimum effective dose of AFX (2.5 mg per kg body weight). Treatments were administered orally once on day 0. Starting 2 days before treatment administration, each dog was infested with approximately 50 ticks weekly for six consecutive weeks. Live ticks were counted at ∼48 h post-treatment (removal count) and at ∼48 h (in situ counts) and ∼72 h (removal counts) following each post-treatment infestation. Treatment with both AFX + MO and NexGard® chewables rapidly eliminated the existing tick infestations (100 % efficacy) within 2 days following treatment administration. Weekly re-infestations were controlled for a minimum of 5 weeks with the efficacy ranging from 92.2 to 99.7 % based on ∼48 h post-treatment in situ counts and between 99.0 and 100 % based on ∼72 h post-treatment removal counts (p < 0.0001 at each occasion). This study demonstrated a high efficacy of both AFX + MO chewable and NexGard® chewable treatments against infestations of dogs with D. reticulatus ticks for at least 5 weeks. In addition, this study indicated no interference between the two compounds with respect to the acaricidal activity provided by AFX.

Abundance and seasonal activity of Haemaphysalis concinna (Acari: Ixodidae) at the border between China and Russia in Northern Inner Mongolia, China

Background

Haemaphysalis concinna, a three-host tick vector of several pathogens, poses a high risk to the health of humans and livestock. However, knowledge of the seasonal activities, relative density and other ecological characteristics of this tick is quite limited and fragmentary. This knowledge gap represents a bottleneck in our understanding of the health risks associated with tick-borne pathogens.

Methods

We conducted a two-year study from April 2012 to March 2014 in Northern Inner Mongolia situated on the China-Russia border, China, to investigate the seasonal activities and relative density of the three developmental stages of H. concinna. During the study period, feeding ticks were removed weekly from domestic sheep and their attachment sites were recorded. Questing ticks were collected weekly from five habitats (broadleaf forest, coniferous forest, shrubs, grassland and mixed coniferous forest) using the flagging-dragging method of capture. Rodents were captured and examined on two consecutive nights each week from June to September in 2012.

Results

H. concinna ticks were found mainly in shrubs and grasslands habitats. Adults were encountered from February to October with the major peak occurring in June. Larvae, which were observed mainly from late April to late September, reached peak numbers in late July. Nymphs were observed mainly from March to October, and their numbers peaked in early July. H. concinna adults and nymphs were found attached to sheep and their most favored sites of attachment were the face and ears. H. concinna larvae were found on two rodent species, Apodemus peninsulae and Eutamias sibiricus.

Conclusion

The relative density and seasonal activities of H. concinna have been systematically reported for Northern Inner Mongolia, China. The information about the hosts infested by H. concinna and its preferred attachment sites on sheep will help efforts to control this tick and the tick-borne diseases carried by it.

Prevalence, distribution and risk associated with tick infestation of dogs in Great Britain

Current concerns over the potential impacts of climate change and the increased movement between countries of people and companion animals on the distribution of ectoparasites, highlight the need for accurate understanding of existing prevalence patterns. Without these future changes will not be detected. Here, the distribution and prevalence of tick infestations of domestic dogs in Great Britain were examined. A total of 173 veterinary practices were recruited to monitor tick attachment to dogs in their local areas between March and October 2009. Practices selected five dogs at random each week from those brought to the surgery and undertook a thorough, standardized examination for ticks. Each veterinary practice participated for 3 months before being replaced. Any ticks identified were collected and a sample sent to the investigators for identification, along with a clinical history of the dog. A total of 3534 dogs were examined; 810 dogs were found to be carrying at least one tick. Ixodes ricinus (Linnaeus) (Acari: Ixodidae) was identified in 72.1% of cases, Ixodes hexagonus Leach in 21.7% and Ixodes canisuga Johnston in 5.6% of cases. Five samples of Dermacentor reticulatus (Fabricius) (Acari: Ixodidae) were also found, adding to the growing evidence that an established population of D. reticulatus now exists in south-eastern England. Almost all the ticks found were adults. Overall, 19.2% of the veterinary practices reported no tick detections, 50% reported that ≥14.9% of the dogs seen were infested and 14.6% reported that >50% of the dogs inspected carried ticks. The estimated incidence of tick attachment was 0.013 per day in March (lowest) and 0.096 per day in June (highest). A number of risk factors affected the likelihood of tick attachment on dogs. Gundog, terrier and pastoral breed groups were more likely to carry ticks, as were non-neutered dogs. Dogs with shorter hair were less likely to have ticks, and dogs were most likely to carry a tick in June. This study is of value because, unusually, it presents the results of a randomized sample of dogs and gives a prevalence which is higher than those previously recorded in Great Britain.

Real-time quantitative polymerase chain reaction detection of haemoplasmas in healthy and unhealthy dogs from Central Macedonia, Greece

OBJECTIVES

The aims of this study were to determine the prevalence of canine haemoplasmas, Mycoplasma haemocanis and "Candidatus Mycoplasma haematoparvum" infection in Central Macedonia, Greece, and to evaluate any associations between canine haemoplasma infection and clinical presentation, selected laboratory data or the presence of ticks.

METHODS

Genomic DNA was purified from excess blood (n=151) submitted for haematological examination. Purified DNA was subjected to species-specific quantitative polymerase chain reaction assays duplexed with a canine DNA control quantitative polymerase chain reaction. Clinical records were retrospectively examined and selected clinical parameters were compared to haemoplasma infection status.

RESULTS

Nine samples were excluded due to inadequate canine DNA polymerase chain reaction results. Of the remaining 142 samples: eight (5·6%) were positive for M. haemocanis alone, six (4·2%) were positive for "Ca. M. haematoparvum" alone and one (0·7%) was dual positive. No association was found between haemoplasma status and age, sex, breed, health status, presence of anaemia, selected biochemistry parameters, presence of ectoparasites, routine ectoparasiticide treatment or the presence of selected tick-borne diseases.

Biology and ecology of the brown dog tick, Rhipicephalus sanguineus

The brown dog tick (Rhipicephalus sanguineus) is the most widespread tick in the world and a well-recognized vector of many pathogens affecting dogs and occasionally humans. This tick can be found on dogs living in both urban and rural areas, being highly adapted to live within human dwellings and being active throughout the year not only in tropical and subtropical regions, but also in some temperate areas. Depending on factors such as climate and host availability, Rh. sanguineus can complete up to four generations per year. Recent studies have demonstrated that ticks exposed to high temperatures attach and feed on humans and rabbits more rapidly. This observation suggests that the risk of human parasitism by Rh. sanguineus could increase in areas experiencing warmer and/or longer summers, consequently increasing the risk of transmission of zoonotic agents (e.g., Rickettsia conorii and Rickettsia rickettsii). In the present article, some aspects of the biology and ecology of Rh. sanguineus ticks are discussed including the possible impact of current climate changes on populations of this tick around the world.

Determination of prevalence and risk factors of infection with Babesia in small ruminants from Greece by polymerase chain reaction amplification

A total of 124 blood samples were collected from 92 sheep and 32 goats from 21 randomly selected herds located in two regions of Greece. Data on the characteristics of the animals (species, gender, age, tick burden, presence of haemoglobinuria, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. Nineteen animals (15%) produced the DNA fragment specific for Babesia of which 16 were sheep and three were goats. Nucleotide sequence of PCR products revealed 100% homology with Babesia ovis 18S rRNA gene. Nine farms (43%) were found positive for B. ovis. The percentage of positive animals in each farm varied between 10 and 61%. The relative risk of the presence of ticks in sheep and goats (p<0.01) and farm dogs (p<0.01) for PCR-positive results for B. ovis in sheep and goats was found 6.63 and 4.14, respectively.

Ixodid tick species attaching to dogs in Hungary

A survey was carried out to investigate the occurrence of hard tick species (Acari: Ixodidae) infesting domestic dogs in Hungary. Forty veterinary clinics from a wide geographical area were asked to collect hard ticks from dogs and to complete a questionnaire. In total, 25 veterinary clinics submitted 900 ticks from 310 dogs. Intensity of infestation ranged from one to 78 per dog. The most preferred sites of tick attachment in decreasing order were head, neck and legs. The majority of ticks (91.7%) were adults, which were identified to species level, the others were nymphs. Six species were found: Dermacentor reticulatus (48.9%), Ixodes ricinus (43.2%), Ixodes canisuga (5.6%), Haemaphysalis concinna (2%) and there was one specimen of both Dermacentor marginatus and Ixodes hexagonus. Single species infestation with I. ricinus or D. reticulatus was found on 145 (46.8%) and 120 animals (38.7%), respectively. Mixed infestation caused by these two species was detected on 24 dogs (7.7%). I. canisuga and H. concinna were found on seven and five dogs, respectively. D. reticulatus and I. ricinus were collected almost throughout the year, except for a single month. The activity peaks were in spring and in autumn for both species. Based on clinical signs, canine babesiosis was diagnosed by the veterinarians in 66 (21.3%) tick infested dogs. These dogs were more frequently infested with D. reticulatus than the others. Our data contribute to the understanding of geographical and seasonal distribution of ixodid tick species infesting dogs in Hungary. The implication of these data, for the risk of canine tick borne diseases is discussed.

Anti-Hepatozoon canis serum antibodies and gamonts in naturally-occurring canine monocytic ehrlichiosis

The prevalence of IgG antibodies to Hepatozoon canis and the presence of gamonts in the blood and hemolymphatic tissues were studied in dogs with canine monocytic ehrlichiosis (CME) caused by Ehrlichia canis. Both pathogens are transmitted by the tick Rhipicephalus sanguineus. Forty-five out of 69 (65.2%) dogs with CME were seropositive to H. canis by an enzyme-linked immunosorbent assay (ELISA). Intra-neutrophilic gamonts of H. canis were found in 2 out of 69 dogs (2.9%) comprising 4.5% of the seropositive dogs. The present study indicated that the prevalence of antibodies to H. canis was high among dogs with CME in an area where both infections are endemic. However, previous exposure to H. canis was not found as an important contributor to clinical or clinicopathologic abnormalities found in dogs with CME.

Human otoacariasis: a retrospective study from an area of Sri Lanka

Intra-aural ticks were present in 870 (15.2%) of 5714 patients who reported with ear-related complaints to the ear, nose and throat ward at Ratnapura Hospital, Sabaragamuwa Province, Sri Lanka, from January 2000 to December 2001. A retrospective study of 383 of these otoacariasis cases showed that the majority (70.8%) of surgically-removed ticks were nymphal Amblyomma integrum, together with nymphal and adult Rhipicephalus haemaphysaloides, R. sanguineus, Hyalomma brevipunctata, H. marginatum, and unidentified (damaged) ticks (collectively, 29.2%). Tick infestations peaked during the period November-February. More female than male patients reported with otoacariasis, and more children (aged 0-10 years) and adults (aged >/=21 years) than adolescents. There was no evidence of age-dependent differences in infestation among male and female patients. The tick-infested cases were widespread, spanning 75 km on a north-south axis and 55 km on an east-west axis within Sabaragamuwa Province. The present report represents the largest episode of human otoacariasis recorded in the literature, and may be indicative of a wider, but little-reported, human tick problem in Sri Lanka.