Prevalence of Vector-Borne Pathogens in Southern California Dogs With Clinical and Laboratory Abnormalities Consistent With Immune-Mediated Disease

ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

A retrospective study of vector borne disease prevalence among anemic dogs in North Carolina

BACKGROUND

Anemia is an important cause of morbidity and mortality in dogs. Further understanding of the prevalence of vector borne diseases (VBD) in anemic dogs is needed.

OBJECTIVES

The objective of this retrospective study was to describe the rate of exposure to or infection with VBD among anemic dogs presented to a teaching hospital in North Carolina and to further characterize the anemia in dogs with VBD exposure.

ANIMALS

A total of 597 anemic dogs that were concurrently tested for VBD were examined at a referral veterinary hospital between January 2012 and December 2018.

METHODS

Retrospective descriptive study. Demographic, clinicopathologic, and VBD testing data were obtained from medical records.

RESULTS

Of the 597 anemic dogs examined, 180 (30.15%; 95% CI: 26.49-34.01%) tested positive for one or more VBD. There was no difference in the severity of anemia or the proportion of dogs displaying a regenerative anemia between dogs testing positive and negative for VBD.

CONCLUSIONS

A large proportion of anemic dogs from this region test positive for exposure to or infection with VBD. Our study supported the use of PCR and serology run in parallel to maximize the chance of detecting exposure to or infection with VBD compared to either serology or PCR alone. At this time, it is unknown whether infection with VBD contributed to the development of anemia in these patients. However, given the prevalence of VBD exposure in anemic dogs, testing for VBD in anemic patients from this region of the United States is warranted.

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Tick-borne pathogens detected in sheltered dogs during an epidemic of Rocky Mountain spotted fever, a One Health challenge

OBJECTIVE

To assess exposure to and infection with 3 pathogens (Rickettsia rickettsii, Anaplasma platys, and Ehrlichia canis) vectored by brown dog ticks (Rhipicephalus sanguineus) in sheltered dogs at the western US-Mexico border.

ANIMALS

239 dogs in shelters in San Diego and Imperial counties, US, and Mexicali and Tijuana, Mexico.

PROCEDURES

Each dog had blood drawn and basic demographic data collected. PCR was performed to determine active infection with Rickettsia spp, E canis, and A platys. Serology was performed to determine exposure to Rickettsia, Anaplasma, and Ehrlichia species.

RESULTS

2 of 78 (2.6%) dogs sampled in Tijuana were actively infected with R rickettsii. A single brown dog tick collected from a dog in Tijuana was PCR-positive for R rickettsii. Infection with E canis and A platys ranged across shelters from 0% to 27% and 0% to 33%, respectively. Dogs in all 4 locations demonstrated exposure to all 3 pathogens, though Rickettsia and Ehrlichia seropositivity was highest in Mexicali (81% and 49%, respectively) and Anaplasma seropositivity was highest in Tijuana (45%).

CLINICAL RELEVANCE

While infection and exposure were highest in sheltered dogs in the southern locations, dogs in all locations demonstrated exposure to all pathogens, demonstrating the potential for emergence and spread of zoonotic pathogens with significant public health consequences in southern California and northern Baja California. In addition, veterinarians and shelter staff should be aware that Ehrlichia or Anaplasma infection may co-occur with Rocky Mountain spotted fever, which is a human health risk.

A Review of Bartonella Infections in California-Implications for Public and Veterinary Health

Bartonella are vector-transmitted, intracellular bacteria that infect a wide variety of blood-feeding arthropods and their vertebrate hosts. In California, more than 13 species of Bartonella have been described from companion animals, livestock, and wildlife, of which four have been associated with human disease. Infections in humans cause a range of symptoms from relatively mild to severe, especially in immunocompromised individuals. Exposure to infected domestic animals and wildlife, and their ectoparasites, may increase the risk of cross-species transmission. The objective of this review was to compile and summarize published materials on human and animal Bartonella infections in California. Medical and veterinary case reports of bartonellosis were highlighted in an effort to increase the awareness of this poorly understood and potentially under-recognized disease among healthcare professionals and veterinarians.

Vector-borne disease and its relationship to hematologic abnormalities and microalbuminuria in retired racing and show-bred greyhounds

Background

Reference intervals for platelets and white blood cell (WBCs) counts are lower in greyhounds than other breeds. Proteinuria is common. Vector‐borne diseases (VBD) cause thrombocytopenia, leukopenia, and proteinuria. Racing greyhounds are commonly exposed to vectors that carry multiple organisms capable of chronically infecting clinically healthy dogs.

Hypothesis/Objectives

Vector‐borne disease prevalence is higher in retired racing greyhounds than in show‐bred greyhounds. Occult infection contributes to breed‐related laboratory abnormalities.

Animals

Thirty National Greyhound Association (NGA) retired racing and 28 American Kennel Club (AKC) show‐bred greyhounds.

Methods

Peripheral blood was tested for Anaplasma, Babesia, Bartonella, Ehrlichia, hemotropic Mycoplasma, and Rickettsia species using PCR. Antibodies to Anaplasma, Babesia, Bartonella, Ehrlichia, and Rickettsia species and Borrelia burgdorferi were detected using immunofluorescence and ELISA assays. Complete blood counts, semiquantitative platelet estimates, and microalbuminuria concentration were determined.

Results

Seven of 30 NGA and 1/28 AKC greyhounds tested positive for ≥1 VBD (P = .05). More positive tests were documented in NGA (10/630) than in AKC dogs (1/588; P = .02). Exposure to Bartonella species (3/30), Babesia vogeli (2/30), Ehrlichia canis (1/30), and infection with Mycoplasma hemocanis (3/30) occurred in NGA dogs. Platelet counts or estimates were >170 000/μL. White blood cell counts <4000/μL (4/28 AKC; 5/30 NGA, P > .99; 1/8 VBD positive; 8/51 VBD negative, P = .99) and microalbuminuria (10/21 AKC; 5/26 NGA, P = .06; 1/8 VBD positive; 14/25 VBD negative, P = .41) were not associated with VBD.

Conclusions and Clinical Importance

The prevalence of thrombocytopenia and B. vogeli exposure was lower than previously documented. Larger studies investigating the health impact of multiple VBD organisms are warranted.

Benefits, companion animal zoonotic disease prevalence and public perceptions of pet ownership among people experiencing homelessness in northern California

California has the highest proportion of unhoused individuals in the country, and up to 25% of unhoused individuals own pets, providing substantial benefits but unique challenges including access to housing, transportation and unfounded grounds for social stigmatization. Unhoused individuals and pets may also be at risk for diseases due to impaired access to sanitation facilities. The purpose of this cross-sectional survey was to evaluate differences in perceived benefits, challenges and public perceptions among pet owners of varying housing security and the prevalence of diseases among their pets. Questionnaires were administered to housed and unhoused pet owners and pet blood screened for rickettsiosis, bartonellosis, ehrlichiosis, anaplasmosis, borreliosis, West Nile fever and heartworm. Among 147 canine and 16 feline blood samples, seropositivity of ectoparasitic diseases did not vary by housing status. Among 45 housed and 56 unhoused owners, unhoused owners were significantly more likely to report protective benefits, challenges obtaining housing, finding a flea on their pet, using bottled water for their pet and their pet sleeping in their bed. Housed owners were significantly more likely to report companionship and entertainment benefits, challenges with pet sitting and consistently administering parasite preventatives. Similar (96-98%) percentages stated they would not give up their pet for better housing and 31% of housed pet owners believed that people should not own pets if they do not have secure housing. Social stigma against unhoused pet owners is present within the community, requiring education to change public perception and guide policy regarding housing for pet owners experiencing homelessness.

Evaluation of the role of Babesia species and Cytauxzoon felis in feline anemia cases in Colorado, USA

Objectives

The aim of this study was to evaluate the blood of cats in Colorado, USA, with suspected infectious causes of anemia for the presence of Babesia species and Cytauxzoon felis DNA. Results of PCR testing for other common vector-borne diseases potentially associated with anemia are also reported.

Methods

Samples from 101 cats were tested using a PCR assay that coamplified the DNA of C felis and Babesia species mitochondrial DNA. PCR testing for DNA of hemoplasmas, Bartonella species, Ehrlichia species, Anaplasma species, Neorickettsia risticii and Wolbachia genera was also performed if not carried out previously.

Results

Twenty-two cats (21.8%) were positive for DNA of an infectious agent. DNA from hemoplasma species were amplified from 14 cats (13.9%). Bartonella species DNA was amplified from four cats (4%) and Ehrlichia canis, Anaplasma platys, Anaplasma phagocytophilum and Wolbachia genera DNA were amplified from one cat each. Babesia species and C felis mitochondrial DNA were not amplified from any sample.

Conclusions and relevance

Based on the results of this study, it does not appear that Babesia species or C felis are clinically relevant in anemic cats in Colorado, USA. For C felis, this suggests that the vector Amblyomma americanum is still uncommon in this geographic area.

Dal-induced red blood cell incompatibilities in a Doberman Pinscher with von Willebrand factor deficiency and ehrlichiosis

OBJECTIVE

To describe a complex case involving the management of a dog with von Willebrand disease (vWD), active ehrlichiosis infection, nonregenerative anemia, and blood type incompatibility related to the Dal antigen.

CASE SUMMARY

A 13-week-oldintact male Doberman Pinscher weighing 7.2 kg was presented to the emergency service for a previous hemorrhaging event and progressive nonregenerative anemia. The dog had received a fresh whole blood transfusion 8 days prior to presentation due to severe anemia. Upon presentation, the puppy was tachycardic, and his mucous membranes were pale. A CBC revealed a nonregenerative anemia with a PCV of 0.11 L/L (11%). von Willebrand factor deficiency was suspected and later confirmed. The dog's blood type was dog erythrocyte antigen (DEA) 1 positive, but cross-matching to 4 RBC units, both DEA 1 positive and negative, failed to yield any compatible units. Antibody against a possible Dal RBC antigen was suspected, and 11 blood donors (Dalmatians and Dobermans) were cross-matched to find 2 compatible donors. After an uneventful fresh whole blood transfusion, a bone marrow biopsy revealed a hypocellular bone marrow and erythroid hypoplasia. A SNAP4DxPlus test and subsequent polymerase chain reaction (PCR) testing were positive for Ehrlichia ewingii and E. canis. Treatment with doxycycline was started, and the PCV was 0.17 L/L (17%) at discharge. At the 1-week follow-up, the PCV was 0.24 L/L (24%), and the puppy was doing well.

NEW OR UNIQUE INFORMATION PROVIDED

This is a unique case of a dog presenting with several challenging disorders, including vWD resulting in hemorrhage, ehrlichiosis potentially contributing to a nonregenerative anemia, and a blood type incompatibility due to the Dal antigen. Doberman Pinschers have a high prevalence of vWD- and Dal-negative phenotype, which emphasizes the value of cross-matching and the recognition of antigen prevalence in specific breeds.

A retrospective study of vector-borne disease prevalence in dogs with proteinuria: Southeastern United States

Background

Proteinuria is a risk factor for progressive kidney injury in dogs. Enhanced understanding of potential associations between canine vector‐borne diseases (CVBD) and proteinuria is needed.

Objectives

To determine the proportion of evaluated proteinuric dogs exposed to ≥1 CVBD, including Babesia spp., Ehrlichia spp., spotted‐fever group Rickettsia, Bartonella spp., Anaplasma spp., hemotropic Mycoplasma spp., Borrelia burgdorferi, and Dirofilaria immitis, and to determine if demographic or clinicopathologic differences exist between proteinuric dogs exposed to CVBD versus proteinuric dogs with no evidence of CVBD exposure.

Animals

Two‐hundred nine proteinuric dogs, concurrently tested for CVBD, which were examined at a single academic veterinary hospital between January 2008 and December 2015.

Methods

Retrospective cross‐sectional study. Demographic, clinicopathologic, and CVBD test results were extracted from medical records. A multivariable logistic regression model was used to assess associations between CVBD and selected variables.

Results

Based on serology and polymerase chain reaction testing, 34% of proteinuric dogs (72/209) were exposed to ≥1 CVBD. Exposure to Rickettsia spp. (19%), Ehrlichia spp. (12%), and B. burgdorferi (9%) were most common. The CVBD exposure was lower in dogs tested in autumn or spring, higher in intact dogs, and higher in dogs with lower serum albumin and higher serum creatinine concentrations.

Conclusions and Clinical Importance

Exposure to CVBD, particularly exposure to Rickettsia spp., Ehrlichia spp., and B. burgdorferi was found in proteinuric dogs from the southeast United States. Additional controlled prospective studies examining a potential causal relationship between CVBD and proteinuria are warranted.

Detection of Bartonella spp. in dogs after infection with Rickettsia rickettsii

Background

Dynamics of infection by Bartonella and Rickettsia species, which are epidemiologically associated in dogs, have not been explored in a controlled setting.

Objectives

Describe an outbreak investigation of occult Bartonella spp. infection among a group of dogs, discovered after experimentally induced Rickettsia rickettsii (Rr) infection.

Animals

Six apparently healthy purpose‐bred Beagles obtained from a commercial vendor.

Methods

Retrospective and prospective study. Dogs were serially tested for Bartonella spp. and Rr using serology, culture, and PCR, over 3 study phases: 3 months before inoculation with Rr (retrospective), 6 weeks after inoculation with Rr (retrospective), and 8 months of follow‐up (prospective).

Results

Before Rr infection, 1 dog was Bartonella henselae (Bh) immunofluorescent antibody assay (IFA) seroreactive and 1 was Rickettsia spp. IFA seroreactive. After inoculation with Rr, all dogs developed mild Rocky Mountain spotted fever compatible with low‐dose Rr infection, seroconverted to Rickettsia spp. within 4‐11 days, and recovered within 1 week. When 1 dog developed ear tip vasculitis with intra‐lesional Bh, an investigation of Bartonella spp. infection was undertaken. All dogs had seroconverted to 1‐3 Bartonella spp. between 7 and 18 days after Rr inoculation. Between 4 and 8 months after Rr inoculation, Bh DNA was amplified from multiple tissues from 2 dogs, and Bartonella vinsonii subsp. berkhoffii (Bvb) DNA was amplified from 4 of 5 dogs' oral swabs.

Conclusions and Clinical Importance

Vector‐borne disease exposure was demonstrated in research dogs from a commercial vendor. Despite limitations, our results support the possibilities of recrudescence of chronic subclinical Bartonella spp. infection after Rr infection and horizontal direct‐contact transmission between dogs.

Molecular identification of vector-borne organisms in Ehrlichia seropositive Nicaraguan horses and first report of Rickettsia felis infection in the horse

Certain vector-borne organisms serve as etiological agents of equine disease. After previously identifying a new Ehrlichia species in horses from Mérida, we aimed to determine the infection frequency and screen for a wide range of vector-borne organisms from 93 tick-exposed, Ehrlichia seropositive horses in this region. PCR assays were performed to identify infection by organisms within the following genera: Anaplasma, Babesia, Bartonella, Ehrlichia, Leishmania, Mycoplasma, Neorickettsia, Rickettsia and Theileria. Overall, 90/93 horses (96.8%) were infected with one or more vector-borne organisms. Ninety (96.8%) horses were infected with Theileria equi and 21 (26.8%) with Babesia caballi. Nine (9.7%) horses were infected with the novel Ehrlichia species previously designated H7, reported in horses from Nicaragua and Brazil. Two horses (2.2%) were infected with Rickettsia felis. Anaplasma, Bartonella, Leishmania, Mycoplasma, or Neorickettsia species DNA was not amplified from any horse. Ticks collected from horses infected with vector-borne organisms were identified as Amblyomma cajennense sensu lato and Dermacentor nitens. Horses in Mérida are infected by a range of vector-borne organisms, including B. caballi, T. equi, Ehrlichia species H7, and R. felis. To the authors' knowledge, this constitutes the first report of molecular detection of R. felis in horses.

Prevalence of Babesia spp. and clinical characteristics of Babesia vulpes infections in North American dogs

Background

Babesiosis is an important cause of thrombocytopenia and hemolytic anemia in dogs. Babesia vulpes, reported in European dogs and North American foxes, rarely has been reported in domestic North American dogs. Newly optimized polymerase chain reaction (PCR) primers facilitate more sensitive amplification of B. vulpes DNA.

Objectives

To determine the prevalence of Babesia sp. infections in dogs being tested for Babesia infection, and to describe co‐infections and clinicopathologic abnormalities in B. vulpes positive dogs.

Animals

Dog blood or tissue samples (n = 9367) submitted to a diagnostic laboratory between June 2015 and June 2018 were tested using an optimized Babesia PCR assay.

Methods

Comprehensive canine vector‐borne disease diagnostic testing was performed on convenience samples.

Results

Babesia sp. DNA was amplified from 269/9367 (2.9%) North American dogs. Babesia sp. infections included B. gibsoni monoinfection (157; 1.7%), B. vulpes monoinfection (19; 0.20%), and B. gibsoni and B. vulpes coinfection (29; 0.31%). Forty‐three of the 48 total B. vulpes‐infected dogs were American Pit Bull Terrier‐type breeds, of which 36 historically were involved with dog fights. Coinfections with Mycoplasma, Dirofilaria immitis, or Wolbachia and coexposures to Bartonella, Ehrlichia, and Rickettsia spp. were documented in B. vulpes‐infected dogs. Clinicopathologic data in B. vulpes‐infected dogs both with and without coinfections included anemia, thrombocytopenia, hyperglobulinemia, hypoalbuminemia, and proteinuria.

Conclusions and Clinical Importance

Babesia vulpes infection in domestic North American dogs is commonly found in conjunction with other coinfections, including B. gibsoni and hemotropic Mycoplasma. Similar to B. gibsoni, dog‐to‐dog transmission of B. vulpes may be a frequent mode of transmission.

Evidence for vertical transmission of Mycoplasma haemocanis, but not Ehrlichia ewingii, in a dog

A 2-year-old female intact pregnant Beagle was evaluated after the owner surrendered her to a shelter. Prepartum and 2 months postpartum at the time of routine spay, the dam was whole-blood polymerase chain reaction (PCR) positive for Ehrlichia ewingii. She was also whole-blood PCR positive for Mycoplasma haemocanis prepartum and continuously for 5 months thereafter. The dam delivered 5 healthy puppies, 1 of which was whole-blood PCR positive for M. haemocanis. All 5 puppies had antibodies against Ehrlichia spp. at 1 month of age but not thereafter, and all puppies were Ehrlichia spp. PCR negative for 5 months of follow-up. Therefore, this study supports a potential role for vertical transmission in the maintenance of M. haemocanis in dogs as reservoir hosts. In contrast, in this case there was no evidence that E. ewingii was transmitted transplacentally or during the perinatal period.

Optimal Vector-borne Disease Screening in Dogs Using Both Serology-based and Polymerase Chain Reaction-based Diagnostic Panels

Vector-borne disease and idiopathic immune-mediated disease present similarly. Diagnostic panels that include multiple organisms help detect infection and identify coinfections. Comprehensive diagnostic panels that combine polymerase chain reaction (PCR) and serology should be used in initial screening to maximize sensitivity and identify infection. Repeat testing using PCR is warranted in dogs at high risk of infection with organisms that circulate in blood in low numbers or intermittently. Convalescent serologic testing can help diagnose acute infection. This article discusses the pathophysiology and epidemiology of the organisms, panel selection, and how to recognize when more aggressive testing for an organism is warranted.

ACVIM consensus statement on the diagnosis of immune-mediated hemolytic anemia in dogs and cats

Immune-mediated hemolytic anemia (IMHA) is an important cause of morbidity and mortality in dogs. IMHA also occurs in cats, although less commonly. IMHA is considered secondary when it can be attributed to an underlying disease, and as primary (idiopathic) if no cause is found. Eliminating diseases that cause IMHA may attenuate or stop immune-mediated erythrocyte destruction, and adverse consequences of long-term immunosuppressive treatment can be avoided. Infections, cancer, drugs, vaccines, and inflammatory processes may be underlying causes of IMHA. Evidence for these comorbidities has not been systematically evaluated, rendering evidence-based decisions difficult. We identified and extracted data from studies published in the veterinary literature and developed a novel tool for evaluation of evidence quality, using it to assess study design, diagnostic criteria for IMHA, comorbidities, and causality. Succinct evidence summary statements were written, along with screening recommendations. Statements were refined by conducting 3 iterations of Delphi review with panel and task force members. Commentary was solicited from several professional bodies to maximize clinical applicability before the recommendations were submitted. The resulting document is intended to provide clinical guidelines for diagnosis of, and underlying disease screening for, IMHA in dogs and cats. These should be implemented with consideration of animal, owner, and geographical factors.

Clinicopathological findings in 41 dogs (2008-2018) naturally infected with Ehrlichia ewingii

Background

Ehrlichia ewingii is the most seroprevalent Ehrlichia‐infecting dogs in the southern and mid‐western United States. Fever, lameness, and polyarthritis are commonly reported findings in dogs naturally infected with E. ewingii.

Objectives

To evaluate clinicopathologic findings in a population of dogs naturally infected with E. ewingii.

Animals

Forty‐one dogs PCR positive for E. ewingii and PCR negative for other targeted vector‐borne organisms.

Methods

Retrospective study. Clinical and clinicopathologic data including physical examination findings, CBC, serum biochemistry, urinalysis (UA), symmetric dimethylarginine (SDMA), and vector‐borne disease diagnostic results were reviewed.

Results

Frequent clinical diagnoses other than ehrlichiosis (28/41; 68.3%) were renal disease (7/41; 17.1%) and immune‐mediated hemolytic anemia (IMHA) (6/41; 14.6%). The most frequent physical examination finding was joint pain (14/41; 34.1%). Prominent hematologic and biochemical abnormalities included abnormal lymphocyte counts (22/36; 61.1%); neutrophilia (21/37; 56.8%); increased alkaline phosphatase (20/35; 57.1%) and alanine transaminase (14/35; 40%) activities; and increased SDMA concentration (11/34; 32.4%). Urinalysis abnormalities included proteinuria (20/27; 74%), most with inactive sediments (16/20; 80%). Dogs were seroreactive by Ehrlichia canis immunofluorescence assay (IFA; 17/39; 43.6%) and Ehrlichia ELISA (34/41; 82.9%). Seroreactivity by IFA for other vector‐borne pathogens included Bartonella (1/39; 2.6%), Rickettsia rickettsii (spotted‐fever group rickettsiae) (12/39; 30.8%), and Borrelia burgdorferi by ELISA (1/41; 2.4%).

Conclusions and Clinical Importance

Renal disease, IMHA, proteinuria, neutrophilia, abnormal lymphocytes, and increased liver enzyme activities were common in this group of E. ewingii‐infected dogs. Studies are needed to determine if E. ewingii contributes to comorbidities or is a precipitating factor in clinical syndromes in persistently infected dogs.

Bartonella henselae in a dog with ear tip vasculitis

BACKGROUND

Bartonella henselae, a Gram-negative, zoonotic, alpha-proteobacteria has been previously implicated in association with cutaneous vasoproliferative lesions (bacillary angiomatosis), nodular panniculitis and multifocal erythema (erythema multiforme) in dogs.

OBJECTIVE

Describe clinical, microbiological and histological lesions in a dog with ear margin vasculitis and B. henselae infection.

ANIMALS

A 12-month-old, specific pathogen-free intact female beagle dog maintained in a vector-free laboratory animal resource facility.

METHODS AND MATERIALS

Bartonella and Rickettsia serological evaluation, Bartonella and Rickettsia PCR, Bartonella alpha-proteobacteria growth medium (BAPGM) enrichment blood culture/PCR, histopathological investigation and confocal immunohistochemical evaluation.

RESULTS

Serological investigation (seroreversion) and PCR testing of aural tissue biopsies failed to support Rickettsia rickettsii as a cause of the aural vasculitis; however, B. henselae, genotype San Antonio 2 DNA was amplified and sequenced from both ear tip margins and from normal-appearing abdominal skin. Seroconversion to B. henselae was documented retrospectively by IFA testing. Bartonella henselae organisms were visualized by confocal immunostaining within all three biopsies. Histopathology revealed small vessel necrotizing vasculitis and dermal necrosis. Bartonella henselae seroreversion and complete resolution of skin lesions occurred in conjunction with administration of oral doxycycline and enrofloxacin for six weeks.

CONCLUSIONS AND CLINICAL IMPORTANCE

Bartonella henselae is an emerging zoonotic pathogen that has been associated with leucocytoclastic vasculitis in humans and may have had a contributing or causative role in the development of the cutaneous aural margin vasculitis in this beagle.

Does co-infection with vector-borne pathogens play a role in clinical canine leishmaniosis?

BACKGROUND

The severity of canine leishmaniosis (CanL) due to Leishmania infantum might be affected by other vector-borne organisms that mimic its clinical signs and clinicopathological abnormalities. The aim of this study was to determine co-infections with other vector-borne pathogens based on serological and molecular techniques in dogs with clinical leishmaniosis living in Spain and to associate them with clinical signs and clinicopathological abnormalities as well as disease severity.

METHODS

Sixty-one dogs with clinical leishmaniosis and 16 apparently healthy dogs were tested for Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum and Bartonella henselae antigens by the immunofluorescence antibody test (IFAT) and for E. canis, Anaplasma spp., Hepatozoon spp., Babesia spp. and filarioid DNA by polymerase chain reaction (PCR).

RESULTS

Among the dogs examined by IFAT, the seroprevalences were: 69% for R. conorii, 57% for E. canis, 44% for A. phagocytophilum and 37% for B. henselae; while the prevalences found by PCR were: 8% for Ehrlichia/Anaplasma, 3% for Anaplasma platys and 1% for H. canis. No other pathogen DNA was detected. Statistical association was found between dogs with clinical leishmaniosis and seroreactivity to R. conorii antigen (Fisher's exact test: P = 0.025, OR = 4.1, 95% CI = 1-17) and A. phagocytophilum antigen (Fisher's exact test: P = 0.002, OR = 14.3, 95% CI = 2-626) and being positive to more than one serological or molecular tests (co-infections) (Mann-Whitney test: U = 243, Z = -2.6, n ₁  = 14, n ₂  = 61, P = 0.01) when compared with healthy dogs. Interestingly, a statistical association was found between the presence of R. conorii, E. canis, A. phagocytophilum and B. henselae antibodies in sick dogs and some clinicopathological abnormalities such as albumin and albumin/globulin ratio decrease and increase in serum globulins. Furthermore, seroreactivity with A. phagocytophilum antigens was statistically associated with CanL clinical stages III and IV.

CONCLUSIONS

This study demonstrates that dogs with clinical leishmaniosis from Catalonia (Spain) have a higher rate of co-infections with other vector-borne pathogens when compared with healthy controls. Furthermore, positivity to some vector-borne pathogens was associated with more marked clinicopathological abnormalities as well as disease severity with CanL.