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Anaplasma phagocytophilum, Anaplasma platys and Ehrlichia canis, responsible of diseases in dogs, are tick-borne pathogens with a proven or potential zoonotic role that have shown increasing prevalence worldwide. The aims of this retrospective study were to assess the frequency of Anaplasma spp. and Ehrlichia spp. exposure in dogs tested in a veterinary teaching hospital in Italy over a 9-year period, to compare the performance of the diagnostic tests used, to evaluate correlations with clinical data, and to genetically analyse the identified bacteria. During the study period, 1322 dogs tested by at least one of the rapid immunoenzymatic test, indirect immunofluorescent antibody test or end-point PCR assay for Anaplasmataceae detection were included. Dogs were tested if they had clinical signs or clinicopathological alteration or risk factors related to infection, and if they were potential blood-donor animals. Ninety-four of 1322 (7.1%) dogs tested positive for at least one pathogen: 53 (4.3%) for A. phagocytophilum, one (0.1%) for A. platys and 63 (4.6%) for E. canis. The number of dogs tested increased and the positivity rate progressively declined over the years. Comparison of tests showed a near-perfect agreement between serological tests and a poor agreement between PCR and indirect assays. A breed predisposition has been highlighted for A. phagocytophilum infection in hunting breed dogs and for E. canis infection in mixed breed dogs. Phylogeny confirmed potential zoonotic implications for A. phagocytophilum and showed no correlation of the identified bacteria with the geographical origin. Our study provides new insights into possible risk factors in dogs and evidenced discordant results between different tests, suggesting that a combination of serological and molecular assays is preferable for a correct diagnosis., (© 2024. The Author(s).)

Background: Cercopithifilaria bainae is a filarioid parasite that infects dogs, being transmitted by Rhipicephalus sanguineus group ticks in many countries of the Mediterranean basin. This study assessed the incidence density rate (IDR) of infection by C. bainae in dogs and the probability of co-infection with other tick-borne pathogens (i.e., Anaplasma platys, Babesia vogeli and Hepatozoon canis), in an area of high endemicity in southern Italy., Methodology/principal Findings: From March 2011 to October 2012, a field study involving 58 young dogs naturally exposed to tick infestation was conducted. Skin and blood samples obtained from each dog six times during an 18-month period were tested for C. bainae by parasite detection within skin snip sediments, with subsequent confirmation through PCR and DNA sequencing. Dogs examined monthly for ticks and A. platys, B. vogeli and H. canis were microscopically and/or molecularly diagnosed and after the first and the second summer seasons, the IDR for positive animal-month at risk was 3.8% and 1.7% in November 2011 and October 2012, respectively. All 58 C. bainae-infected dogs were simultaneously infected with at least one other tick-borne pathogen. After the first summer season (assessment in November 2011), a C. bainae-infected dog had a 33% probability of being infected with H. canis or A. platys, whereas after the second tick season (assessment in October 2012) the probability of co-infection was 78%, 22% and 11% for H. canis, A. platys and B. vogeli, respectively., Conclusions: Our data indicate that tick-infested dogs are at risk of acquiring infection by C. bainae. In addition, the detection of C. bainae microfilariae indicates a prior tick exposure and, should stimulate testing for other tick-borne disease causing pathogens.

Canine monocytic ehrlichiosis is a common and widespread disease. This disease is present in Sardinia year-round because the temperate weather on the island permits the survival of many types of tick vectors. A total of 35 ticks was collected from goats in south-eastern Sardinia, Italy, and tested for Ehrlichia DNA using polymerase chain reaction and DNA sequencing. This study provides the first evidence of the presence of Ehrlichia canis in Rhipicephalus bursa ticks. The data presented here increase our knowledge of tick-borne diseases in Sardinia and provide a useful contribution toward understanding their epidemiology. The role of R. bursa in the life cycle and transmission of E. canis needs however further investigation., (Copyright © 2012 Elsevier GmbH. All rights reserved.)

Canine vector-borne diseases (CVBDs) pose a diagnostic challenge, particularly when a dog is coinfected with more than one pathogen. The purpose of this study was to generate information about the diagnosis of CVBDs in young dogs following their first exposure to flea, tick, sand fly, louse, and mosquito vectors. From March 2008 to May 2009, 10 purpose-bred young naive beagle dogs and a cohort of 48 mixed-breed dogs living in an area to which CVBD is endemic in southern Italy were monitored using different diagnostic tests (cytology, serology, and PCR). Overall, PCR detected the highest number of dogs infected with Anaplasma platys, Babesia vogeli, and Ehrlichia canis, whereas seroconversion was a more sensitive indicator of exposure to Leishmania infantum. For A. platys infection, combining blood and buffy coat cytology in parallel enhanced the relative sensitivity (SE(rel)) (87.3%). For B. vogeli, the best diagnostic combination was buffy coat cytology and serology used in parallel (SE(rel), 67.5%), whereas serology and PCR used in parallel (SE(rel), 100%) was the best combination for L. infantum. Overall, 12 (20.7%) dogs were coinfected; however, the percentage of new coinfections decreased from baseline (50%) to the first (33.3%) and second (16.6%) follow-up time points. Numbers of coinfections with A. platys and B. vogeli were significantly higher (P < 0.05) than coinfections with other pathogen combinations. The data generated in this study provide insights on the incidence of certain pathogens infecting young dogs in southern Italy, highlight important diagnostic testing limitations, and support the use of multiple diagnostic modalities when attempting to confirm a tick-borne infection in an individual dog or in a canine population.

We investigated the prevalence of Ehrlichia canis (E. canis) (n = 601) and Anaplasma phagocytophilum (A. phagocytophilum) (n = 460) infection by means of real-time PCR from blood of Italian dogs. The prevalence of E. canis in northern, central, and southern Italy was 2.9%, 8%, and 9.7%, respectively. The prevalence of A. phagocytophilum was 0%.

Fourteen blood samples collected from dogs that were seropositive for Ehrlichia canis were examined for the presence of the citrate synthase gene using a highly specific and sensitive novel polymerase chain reaction assay. The assay detected E. canis DNA in 3 dogs. The complete nucleotide sequence of the citrate synthase gene was determined in 2 of the test-positive samples, and represents the first sequence of the gene to be derived from Italian isolates. The sequence data displayed high identity (99.2%) between the geographically separated Italian samples and the Oklahoma strain of E. canis. The high-sequence conservation revealed by molecular analysis confirmed the usefulness of the citrate synthase gene as a target for detection of E. canis.