Molecular Survey of Ehrlichia canis and Anaplasma phagocytophilum from Blood of Dogs in Italy

Detection of Anaplasma spp. and Ehrlichia spp. in dogs from a veterinary teaching hospital in Italy: a retrospective study 2012-2020

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.

Looking for Dog Blood Donors in an Endemic Area for Vector-Borne Infections of Central Italy

Simple Summary

Dogs have proved to be competent reservoir hosts for several vector-borne pathogens, whose prevalence varies according to the area and over time due to the increased movement of people and their pets, climate changes, and vector adaptation strategies. The purpose of this study was to determine the prevalence of some vector-borne pathogens in dog blood donors, living in central Italy. Blood samples of 126 donors included were tested for a broad screening panel for infectious pathogens. The differences in pathogens prevalence according to age, sex, and breeds were tested. Overall, 50 animals tested positive for at least one pathogen. A tendency of hemoplasmas to be more prevalent in older dogs (41.2%) was noted. We highlight the difficulties of selecting healthy blood donor dogs in an endemic area for vector-borne infections. Close collaboration between specialists is important in the interpretation of positive test results. Finally, we underline the important role of blood donors as an epidemiological tool for active surveillance against canine infectious diseases.

Abstract

Dogs are proved to be competent reservoir hosts for several vector-borne pathogens. Their prevalence varies according to the geographical area. Many vector-borne pathogens may be transmitted by blood transfusion. The purpose of this study was to determine the serological and molecular prevalence of some vector-borne pathogens in dog blood donors, living in central Italy. Blood samples of 126 donors (19 breeds) included were tested for a broad serological and DNA-base tests panel. The differences in pathogen prevalence according to age, sex, and breeds were tested (chi-square test, Fisher’s exact test). Overall, 50 animals (39.7%) tested positive at PCR (polymerase chain reaction) and/or serology (IFAT, indirect fluorescent antibody test) for at least one pathogen. Three dogs were positive at both serology and PCR. A tendency of hemoplasmas to be more prevalent in older dogs (41.2%) compared to the younger ones (25.7%) was noted. We highlight the difficulties of selecting healthy blood donor dogs in an endemic area for vector-borne infections. It is important to choose the serological and biomolecular investigations panel that is most suited to the donor’s environment. Close collaboration between clinician and parasitologists is important in the interpretation of IFAT and PCR results. Finally, we underline the important role of blood donors as an epidemiological tool for active surveillance against canine vector-borne diseases.

Prevalence of Dirofilaria repens in dogs living in deltaic coastal plain of the Volturno River (Italy): a geographical risk model of infection

The prevalence of vector-associated parasitic infections is high in central-southern Italy. The deltaic coastal plain of the Volturno River has been suspected, by veterinary practitioners, to have a high accidental incidence of Dirofilaria repens. Thus, the goal of this study was to evaluate the prevalence of dirofilariasis and other coinfections frequently described in dogs living in the Volturno area. Blood samples of 100 clinical asymptomatic dogs were examined using a Knott's technique and polymerase chain reaction in order to identify microfilariae. Other vector-borne coinfections were also investigated using ELISA kits. The results were analysed using statistical and Geographic Information System (GIS) software. Microfilariae of D. repens were detected in 10% of the dogs surveyed, with a presence of antibodies against Ehrlichia canis (4/10) and Dirofilaria immitis (1/10). Such high incidence should be considered in light of the zoonotic potential for D. repens and the support for more regular use of repellents to prevent the spread of this disease. The GIS analyses indicated that the study area provides suitable conditions to sustain populations of mosquito vectors and D. repens parasites throughout much of the year.

Rickettsiales in Italy

There is no updated information on the spread of Rickettsiales in Italy. The purpose of our study is to take stock of the situation on Rickettsiales in Italy by focusing attention on the species identified by molecular methods in humans, in bloodsucking arthropods that could potentially attack humans, and in animals, possible hosts of these Rickettsiales. A computerized search without language restriction was conducted using PubMed updated as of December 31, 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was followed. Overall, 36 species of microorganisms belonging to Rickettsiales were found. The only species identified in human tissues were Anaplasma phagocytophilum,Rickettsia conorii, R. conorii subsp. israelensis, R. monacensis, R. massiliae, and R. slovaca. Microorganisms transmissible by bloodsucking arthropods could cause humans pathologies not yet well characterized. It should become routine to study the pathogens present in ticks that have bitten a man and at the same time that molecular studies for the search for Rickettsiales can be performed routinely in people who have suffered bites from bloodsucking arthropods.

Tick-borne pathogens in Ixodidae ticks collected from privately-owned dogs in Italy: a country-wide molecular survey

Background

Ticks and tick-borne diseases are increasingly recognized as a cause of disease in dogs worldwide. The epidemiology of ticks and tick-transmitted protozoa and bacteria has changed due to the spread of ticks to urban and peri-urban areas and the movement of infected animals, posing new risks for animals and humans. This countrywide study reports information on distribution and prevalence of pathogens in ticks collected from privately-owned dogs in Italy.

We analyzed 2681 Ixodidae ticks, collected from 1454 pet dogs from Italy. Specific PCR protocols were used to detect i) Piroplasms of the genera Babesia and Theileria, ii) Gram-negative cocci of the family Anaplasmataceae and iii) Borrelia burgdorferi sensu lato. Sequencing of positive amplicons allowed for species identification.

Results

Babesia/Theileria spp. DNA was detected in 435 homogeneous tick-pools (Minimum Infection Rate (MIR) = 27.6%; 95% confidence interval (CI) = 25.4–29.8%) with higher prevalence in Ixodes ricinus and Rhipicephalus sanguneus group. The zoonotic B. venatorum was the most prevalent species (MIR = 7.5%; 95% CI = 6.3–9.0%). Anaplasma and Ehrlichia species were detected in 165 tick-pools (MIR = 10.5%; 95% CI = 9.3–11.8%) and specifically, A. phagocytophilum was identified with MIR = 5.1% (95% CI = 4.1–6.3%). Borrelia burgdorferi s.l. and B. afzelii were detected with MIR = 0.4% (95% CI = 0.2–0.8%) and MIR = 0.3% (95% CI 0.1–0.7%) respectively.

Conclusions

Zoonotic pathogens B. venatorum and A. phagocytophilum were the most frequently detected in ticks collected from privately-owned dogs which might be used as markers of pathogens presence and distribution.

Serological Survey of Ehrlichia canis and Anaplasma phagocytophilum in Dogs from Central Italy: An Update (2013⁻2017)

Ehrlichia canis and Anaplasma phagocytophilum are tick-borne bacteria of veterinary concern. Indirect immunofluorescent assay was carried out to detect antibodies against E. canis and A. phagocytophilum in 1026 owned dogs living in Central Italy during the period 2013–2017. One hundred and eighty-six (18.12%) dogs were positive for at least one pathogen and 14 (1.36%) for both agents. More in detail, 166 (16.18%) samples were positive for E. canis and 34 (3.31%) for A. phagocytophilum. No statistically significant differences in the seroprevalence values related to gender were detected, whereas the highest rate to E. canis occurred in animals aged more than 10 years. Mean seroprevalence values for both E. canis and A. phagocytophilum detected in 2014 and 2015 were statistically higher with respect to other years. Even though dogs’ owners are informed about the risk of pet infections by tick-borne pathogens and prophylaxis against ticks is often executed, E. canis and A. phagocytophilum are still present and infect the canine population in Central Italy.

Exposure to vector-borne pathogens in candidate blood donor and free-roaming dogs of northeast Italy

Background

Many vector-borne pathogens including viruses, bacteria, protozoa and nematodes occur in northeast Italy, representing a potential threat to animal and human populations. Little information is available on the circulation of the above vector-borne pathogens in dogs. This work aims to (i) assess exposure to and circulation of pathogens transmitted to dogs in northeast Italy by ticks, sandflies, and mosquitoes, and (ii) drive blood donor screening at the newly established canine blood bank of the Istituto Zooprofilattico Sperimentale delle Venezie.

Methods

Blood samples from 150 privately-owned canine candidate blood donors and 338 free-roaming dogs were screened by serology (IFA for Leishmania infantum, Ehrlichia canis, Anaplasma phagocythophilum, Babesia canis, Rickettsia conorii, R. rickettsii), microscopic blood smear examination, and blood filtration for Dirofilaria spp. All candidate donors and seropositive free-roaming dogs were tested by PCR for L. infantum, E. canis, A. phagocythophilum, Babesia/Theileria and Rickettsia spp. The dogs had no clinical signs at the time of sampling.

Results

Overall, 40 candidate donors (26.7 %) and 108 free-roaming dogs (32 %) were seroreactive to at least one vector-borne pathogen. Seroprevalence in candidate donors vs free-roaming dogs was: Leishmania infantum 6.7 vs 7.1 %; Anaplasma phagocytophilum 4.7 vs 3.3 %; Babesia canis 1.3 vs 2.7 %; Ehrlichia canis none vs 0.9 %; Rickettsia conorii 16 vs 21.3 % and R. rickettsii 11 vs 14.3 %. Seroreactivity to R. rickettsii, which is not reported in Italy, is likely a cross-reaction with other rickettsiae. Filariae, as Dirofilaria immitis (n = 19) and D. repens (n = 2), were identified in free-roaming dogs only. No significant differences were observed between candidate donors and free-roaming dogs either in the overall seroprevalence of vector-borne pathogens or for each individual pathogen. All PCRs and smears performed on blood were negative.

Conclusions

This study demonstrated that dogs are considerably exposed to vector-borne pathogens in northeast Italy. Although the dog owners reported regularly using ectoparasiticides against fleas and ticks, their dogs had similar exposure to vector-borne pathogens as free-roaming dogs. This prompts the need to improve owner education on the use of insecticidal and repellent compounds in order to reduce the risk of arthropod bites and exposure to vector-borne pathogens. Based on the absence of pathogens circulating in the blood of healthy dogs, the risk of transmission of these pathogens by blood transfusion seems to be low, depending also on the sensitivity of the tests used for screening.

Alpha proteobacteria of genusAnaplasma(Rickettsiales: Anaplasmataceae): Epidemiology and characteristics ofAnaplasmaspecies related to veterinary and public health importance

TheAnaplasmaspecies are important globally distributed tick-transmitted bacteria of veterinary and public health importance. These pathogens, cause anaplasmosis in domestic and wild animal species including humans.Rhipicephalus, Ixodes, DermacentorandAmblyommagenera of ticks are the important vectors ofAnaplasma.Acute anaplasmosis is usually diagnosed upon blood smear examination followed by antibodies and nucleic acid detection. All age groups are susceptible but prevalence increases with age. Serological cross-reactivity is one of the important issues amongAnaplasmaspecies. They co-exist and concurrent infections occur in animals and ticks in same geographic area. These are closely related bacteria and share various common attributes which should be considered while developing vaccines and diagnostic assays. Movement of susceptible animals from non-endemic to endemic regions is the major risk factor of bovine/ovine anaplasmosis and tick-borne fever. Tetracyclines are currently available drugs for clearance of infection and treatment in humans and animals. Worldwide vaccine is not yet available. Identification, elimination of reservoirs, vector control (chemical and biological), endemic stability, habitat modification, rearing of tick resistant breeds, chemotherapy and tick vaccination are major control measures of animal anaplasmosis. Identification of reservoirs and minimizing the high-risk tick exposure activities are important control strategies for human granulocytic anaplasmosis.

Molecular and serological detection of Ehrlichia canis in naturally exposed dogs in Iran: an analysis on associated risk factors

The general aim of this study, which was conducted for the first time in Iran, was to evaluate the seroprevalence and geographical distribution of Ehrlichia canis in a dog population in Iran, followed by molecular confirmation using PCR and sequencing. Blood samples were collected from 240 dogs in different areas of Alborz and Tehran Provinces and initially analyzed using the immunofluorescent antibody (IFA) test to detect anti-Ehrlichia canis IgG antibodies. Subsequently, nested PCR was performed based on a fragment of the 16S rRNA gene of E. canis on serologically positive samples. The results showed that 40/240 dogs (16.6%) presented anti-Ehrlichia canis IgG antibodies and that nine of the blood samples from the 40 seropositive dogs (22.5%) contained E. canis DNA, which was confirmed by sequencing. The seroprevalence of E. canis tended to be higher in purebred, one to three-year-old male dogs living in the Plain zone, in rural areas; however, this difference was not statistically significant.

The role of wild canids and felids in spreading parasites to dogs and cats in Europe. Part I: Protozoa and tick-borne agents

Over the last few decades, the world has witnessed radical changes in climate, landscape, and ecosystems. These events, together with other factors such as increasing illegal wildlife trade and changing human behaviour towards wildlife, are resulting into thinning boundaries between wild canids and felids and their domestic counterparts. As a consequence, the epidemiology of diseases caused by a number of infectious agents is undergoing profound readjustements, as pathogens adapt to new hosts and environments. Therefore, there is a risk for diseases of wildlife to spread to domestic carnivores and vice versa, and for zoonotic agents to emerge or re-emerge in human populations. Hence, the identification of the hazards arising from the co-habitation of these species is critical in order to plan and develop adequate control strategies against these pathogens. In the first of this two-part article, we review the role that wild canids and felids may play in the transmission of protozoa and arthropod-borne agents to dogs and cats in Europe, and provide an account of how current and future progress in our understanding of the ecology and epidemiology of parasites, as well as of host-parasite interactions, can assist efforts aimed at controlling parasite transmission.

First record of autochthonous canine ehrlichiosis caused by Ehrlichia canis in Romania

This case study describes the first genetically confirmed and clinically manifested autochthonous Ehrlichia canis infection in a 9-year-old female mixed-breed dog from Romania. Health screening of the dog included clinical examination, evaluation of stained peripheral blood smear and hematologic variables, as well as serologic testing and molecular analysis. Clinical signs included fever, apathy, dehydration, pale mucous membranes, and weakness. The microscopic examination of the blood smear and immunologic assays for Borrelia burgdorferi, Anaplasma phagocytophilum, and E canis antibodies, and for Dirofilaria immitis antigen yielded negative results. Hematologic abnormalities included moderate nonregenerative anemia, leucopenia with neutropenia, and moderate thrombocytopenia. The biochemical abnormalities identified were hypoalbuminemia, and mildly increased serum enzyme activities of AST and ALT. In addition, increased urea and creatinine levels associated with low urine specific gravity and proteinuria were also present. Nested PCR amplification of the partial E canis 16S rRNA gene demonstrated the presence of this rickettsial pathogen in the dog's blood, which subsequently was confirmed through sequencing based on the 100% homology with GenBank deposited E canis isolates. After specific treatment with doxycycline (10 mg/kg, orally, SID) for one month, the proteinuria, and hematologic and serum biochemical abnormalities with the exception of mild azotemia resolved. This report supports the geographical expansion of canine ehrlichiosis caused by E canis in nonendemic regions of Europe.

Acute febrile illness is associated with Rickettsia spp infection in dogs

BACKGROUND

Rickettsia conorii is transmitted by Rhipicephalus sanguineus ticks and causes Mediterranean Spotted Fever (MSF) in humans. Although dogs are considered the natural host of the vector, the clinical and epidemiological significance of R. conorii infection in dogs remains unclear. The aim of this prospective study was to investigate whether Rickettsia infection causes febrile illness in dogs living in areas endemic for human MSF.

METHODS

Dogs from southern Italy with acute fever (n = 99) were compared with case-control dogs with normal body temperatures (n = 72). Serology and real-time PCR were performed for Rickettsia spp., Ehrlichia canis, Anaplasma phagocytophilum/A. platys and Leishmania infantum. Conventional PCR was performed for Babesia spp. and Hepatozoon spp. Acute and convalescent antibodies to R. conorii, E. canis and A. phagocytophilum were determined.

RESULTS

The seroprevalence rates at first visit for R. conorii, E. canis, A. phagocytophilum and L. infantum were 44.8%, 48.5%, 37.8% and 17.6%, respectively. The seroconversion rates for R. conorii, E. canis and A. phagocytophilum were 20.7%, 14.3% and 8.8%, respectively. The molecular positive rates at first visit for Rickettsia spp., E. canis, A. phagocytophilum, A. platys, L. infantum, Babesia spp. and Hepatozoon spp. were 1.8%, 4.1%, 0%, 2.3%, 11.1%, 2.3% and 0.6%, respectively. Positive PCR for E. canis (7%), Rickettsia spp. (3%), Babesia spp. (4.0%) and Hepatozoon spp. (1.0%) were found only in febrile dogs. The DNA sequences obtained from Rickettsia and Babesia PCRs positive samples were 100% identical to the R. conorii and Babesia vogeli sequences in GenBank®, respectively. Febrile illness was statistically associated with acute and convalescent positive R. conorii antibodies, seroconversion to R. conorii, E. canis positive PCR, and positivity to any tick pathogen PCRs. Fourteen febrile dogs (31.8%) were diagnosed with Rickettsia spp. infection based on seroconversion and/or PCR while only six afebrile dogs (12.5%) seroconverted (P = 0.0248). The most common clinical findings of dogs with Rickettsia infection diagnosed by seroconversion and/or PCR were fever, myalgia, lameness, elevation of C-reactive protein, thrombocytopenia and hypoalbuminemia.

CONCLUSIONS

This study demonstrates acute febrile illness associated with Rickettsia infection in dogs living in endemic areas of human MSF based on seroconversion alone or in combination with PCR.

Guideline for veterinary practitioners on canine ehrlichiosis and anaplasmosis in Europe

Canine ehrlichiosis and anaplasmosis are important tick-borne diseases with a worldwide distribution. Information has been continuously collected on these infections in Europe, and publications have increased in recent years. Prevalence rates are high for Ehrlichia and Anaplasma spp. infections in dogs from different European countries. The goal of this article was to provide a practical guideline for veterinary practitioners on the diagnosis, treatment, and prevention of ehrlichiosis and anaplasmosis in dogs from Europe. This guideline is intended to answer the most common questions on these diseases from a practical point of view.

The risk of vector-borne infections in sled dogs associated with existing and new endemic areas in Poland: Part 1: A population study on sled dogs during the racing season

The achievements of sled dogs in competitions depend both on their training and on their health. Vector-borne infections may lead to anaemia, affect joints or heart muscle or even cause death. Between December 2009 and October 2010, one hundred and twenty six individual blood samples were collected from 26 sled dog kennels situated in different regions of Poland. The majority of samples were taken during the racing season (winter 2009/10). The prevalences of 3 vector-borne infections- including 2 'old pathogens' Anaplasma phagocytophilum and Babesia canis, and 'new pathogen' Hepatozoon canis-were estimated in sled dogs using PCR and nested PCR. Additionally, 25 serum samples originating from a subset of 3 kennels situated in a tick-borne encephalitis (TBE) endemic area (Mazowiecki region), were tested for antibodies against the tick-borne encephalitis virus (TBEV). Because of the recently reported occurrence of Dirofilaria repens in Central Poland and that of fatal cases of unknown aetiology in two of the kennels, blood samples collected from dogs at these kennels in 2010 and in February-May 2013 and from two unaffected kennels were checked for evidence of presence of this parasite. Babesia canis DNA was detected in 11 sled dogs (4 with clinical babesiosis, 7 asymptomatic; 8.7%) inhabiting mainly endemic regions of Poland (9/11 cases). Three serum samples originating from one location tested positive for TBEV antibodies (total seroprevalence: 3/25=12%, local seroprevalence: 3/12=25%). The risk of TBEV infection was associated with previous B. canis infections. Dirofilaria repens DNA was detected in 15 dogs (44%). Prevalence was especially high in two sled dog kennels situated near Grodzisk Mazowiecki (50-57%). No blood samples tested positive for A. phagocytophilum or H. canis DNA. The present study has established that the prevalence of vector-borne pathogens in working sled dogs is significant in the endemic regions and has justified the important role of surveillance of reservoir hosts in the epidemiology of TBE. Our results emphasize the need for regular monitoring for the presence of D. repens.

Tick-borne infections in dogs-an emerging infectious threat

Many viral, bacterial and parasitic pathogens have been associated with tick transmission, including several recently identified pathogens in both humans and domestic animals, especially dogs. The emergence in dogs of these tick-borne infections has a multi factorial origin. Better animal care, better diagnostic tools, and a broader distribution of the vectors in favorable habitats through population migrations including travel with owned pets, translocation or commercial trade of pet dogs, are some of the factors contributing to the emergence and recognition of these new pathogens. The present review focuses on the recent epidemiological studies which support the emergence or re-emergence of tick-borne pathogens in dogs around the world, as well as give some insight on newly recognized potentially tick-borne pathogens, such as Bartonella infections.

Anaplasmosis in two dogs in France and molecular and phylogenetic characterization of Anaplasma phagocytophilum

Two dogs in France were diagnosed with Anaplasma phagocytophilum infection by real-time PCR. The most remarkable hematologic and biochemical findings were severe thrombocytopenia, mild neutrophilia, morulae in neutrophils, and increased serum concentration of the α2-globulin fraction detected by agarose gel electrophoresis of serum proteins. Using sequencing of the partial 16S rRNA and ankA genes, molecular characterization of the A. phagocytophilum strains showed that the organisms from both dogs were identical to the European strains isolated from horses and people. Based on phylogenetic analysis, the ankA gene was more discriminating than the 16S rRNA gene in distinguishing the majority of European and American strains of A. phagocytophilum infecting people and animals. Three isolates of A. phagocytophilum, 1 from Spain (cow) and 2 from Norway (sheep and deer), were external to the European and American clades.

Infections with Anaplasma phagocytophilum in dogs in Germany

The main objectives of this prospective study were to establish prevalence of Anaplasma phagocytophilum infections in dogs from Northeast Germany; and to evaluate the hematological parameters of sero- or real-time PCR-positive clinically healthy dogs. The mean prevalence of A. phagocytophilum seropositivity of 522 dogs (258 suspected to have anaplasmosis, 264 healthy) was 43%. There was no difference between sick (46.9%) and healthy dogs (39.8%) (p=0.100). The PCR test was positive in 30 dogs (20 sick, 10 healthy); morulae were found in 12 of them. Twenty-six of 30 dogs tested PCR-positive between May and September (p<0.05). There was no difference with regard to abnormal CBC parameters between seropositive and seronegative clinically healthy dogs. The CBC was within reference range in 10 PCR-positive clinically healthy dogs suggesting a routine examination of blood donors for A. phagocytophilum in endemic areas to minimize the risk of transmission.

Canine and feline vector-borne diseases in Italy: current situation and perspectives

In Italy, dogs and cats are at risk of becoming infected by different vector-borne pathogens, including protozoa, bacteria, and helminths. Ticks, fleas, phlebotomine sand flies, and mosquitoes are recognized vectors of pathogens affecting cats and dogs, some of which (e.g., Anaplasma phagocytophilum, Borrelia burgdorferi, Dipylidium caninum, Leishmania infantum, Dirofilaria immitis, and Dirofilaria repens) are of zoonotic concern. Recent studies have highlighted the potential of fleas as vectors of pathogens of zoonotic relevance (e.g., Rickettsia felis) in this country. While some arthropod vectors (e.g., ticks and fleas) are present in certain Italian regions throughout the year, others (e.g., phlebotomine sand flies) are most active during the summer season. Accordingly, control strategies, such as those relying on the systematic use of acaricides and insecticides, should be planned on the basis of the ecology of both vectors and pathogens in different geographical areas in order to improve their effectiveness in reducing the risk of infection by vector-borne pathogens. This article reviews the current situation and perspectives of canine and feline vector-borne diseases in Italy.

PCR survey of vectorborne pathogens in dogs living in and around Barcelona, an area endemic for leishmaniasis

Blood samples from 153 dogs living in and around Barcelona were assayed for Leishmania infantum and Ehrlichia, Anaplasma, Rickettsia, Bartonella, Hepatozoon, Babesia and Theileria species by PCR amplification of DNA, and the amplicons obtained were sequenced. The prevalence of the infectious agents was L infantum (29.4 per cent), Ehrlichia and Anaplasma species (4.0 per cent), Hepatozoon canis (3.3 per cent), Babesia canis vogeli (2.0 per cent), Babesia gibsoni (2.0 per cent), Babesia canis canis (1.3 per cent) and Theileria annae (0.7 per cent). Coinfections were present in seven of the dogs and they were significantly associated with L infantum infection (P=0.024). There was a significant correlation between clinical signs of illness and the load of L infantum.

Detection of erythrocyte binding IgM and IgG by flow cytometry in sick dogs with Babesia canis canis or Babesia canis vogeli infection

The aim of this study was to examine by means of flow cytometry immunophenotyping (FCI) if sick dogs infected with Babesia canis canis (B. c. canis) or Babesia canis vogeli (B. c. vogeli) had anti-erythrocyte membrane binding IgG and/or IgM at the time of diagnosis. Diagnosis of Babesia infection was assessed by blood smear and by PCR-restriction fragment length polymorphism analysis in 30 sick dogs. Signalment, clinical history, physical examination and laboratory tests of B. c. canis (n=24) and of B. c. vogeli (n=6) infected dogs were studied. The majority of B. c. canis infected dogs showed anemia (92%) predominantly non-regenerative (94%), while the B. c. vogeli infected dogs had a regenerative anemia (67%). Eccentrocytosis was present in 33% of the B. c. canis infections. Four of six B. c. vogeli infected dogs had erythrocytes membrane antibodies. One dog resulted uncertain and one resulted negative to FCI. In contrast, all the B. c. canis infected dogs were negative for erythrocytes membrane binding immunoglobulins detection. In addition, the mean percentages of erythrocytes binding IgG and IgM were statistically much lower in B. c. canis than in B. c. vogeli infected dogs. At the time of the diagnosis, the formation of erythrocyte membrane binding IgG and IgM by immune mechanisms appears not to be involved in B. c. canis infections while it is present in the majority of B. c. vogeli infections.

Host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, Ehrlichia canis

The ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. Ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. Historically, advances in tick-borne disease control strategies have typically followed explication of tick-pathogen-vertebrate interactions, thus it is reasonable to expect novel, more sustainable approaches to control of these diseases as the transmission of their associated infections are investigated at the molecular through ecological levels. Better understanding of the interactions between E. canis and its canine and tick hosts would also elucidate similar interactions for other Ehrlichia species as well as the potential roles of canine sentinels, reservoirs and models of tick-borne zoonoses. This article summarizes natural exposure studies and experimental investigations of E. canis in the context of what is understood about biological vectors of tick-borne Anaplasmataceae.

Genetic and antigenic diversities of major immunoreactive proteins in globally distributed Ehrlichia canis strains

The extent of knowledge regarding the diversity of globally distributed Ehrlichia canis strains has been limited to information gained from a few evolutionarily conserved genes. In this study, E. canis strains from the United States (strain Jake [US]), Brazil (strain São Paulo [BR]), and Israel (strain 611 [IS] and Ranana [IS-R]) were used to examine the antigenic and genetic diversities of four well-characterized major immunoreactive protein genes/proteins. gp36 and gp200 were the most divergent genes, and nucleotide substitutions in the gp36 tandem repeat region of the IS strain, but not the IS-R strain, resulted in two amino acid differences (S-->P and P-->T) in each nine-amino-acid repeat (epitope-containing region). DNA sequences of gp19 and gp140 were completely conserved in the US and BR strains, but differences were found in the Israeli strains, including two fewer tandem repeats in gp140 and a single amino acid substitution in gp19 from the IS strain. E. canis whole-cell lysates from each isolate were examined by Western immunoblotting using sera from naturally infected dogs from each country, and four major immunoreactive proteins (gp19, gp36, gp140, and gp200) were identified in each strain using protein-specific antisera. The US and BR strains exhibited highly conserved immunoreactive protein profiles, while some differences were identified in the IS strain. Sera from naturally infected Israeli dogs confirmed gene sequencing information, which demonstrated two distinct E. canis strains, defined by the gp36 gene. Conversely, gp19 was strongly reactive and present in all E. canis isolates. gp140 and gp200 were also present in all strains, although gp140 in the IS strain had two fewer tandem repeats and exhibited a smaller mass.