Complex formation with nucleic acids and aptamers alters the antigenic properties of platelet factor 4

Comparison of Serological and Molecular Assays for Bartonella Species in Dogs with Hemangiosarcoma

Currently, a gold standard diagnostic test for Bartonella infection in dogs is lacking. This represents a critical limitation for the development and evaluation of new diagnostic tests, as well as for the diagnosis of, and research on, bartonellosis in dogs. This retrospective observational study aims to compare the results of commonly performed and newly-reported Bartonella spp. diagnostic tests in banked clinical specimens from 90 dogs with hemangiosarcoma (HSA) using composite reference standard (CRS) and random effects latent class analysis (RE-LCA) techniques. Samples from each dog were tested using six serological or molecular diagnostic assays, including indirect fluorescent antibody (IFA) and Western blot (WB) for the detection of antibodies in serum, and qPCR and droplet digital PCR (ddPCR) in blood and fresh frozen tissue biopsy samples (mainly splenic HSA tumors and histopathologically normal spleen or skin/adipose tissue). Bartonella infection prevalence was estimated to be 78% based on the CRS (parallel testing with all six assays), and 64% based on the RE-LCA model. The assay with the highest diagnostic accuracy was qPCR performed on fresh frozen tissue biopsy samples (sensitivity: 94% by RE-LCA and 80% by CRS; specificity: 100%). When comparing newly-reported to traditional Bartonella diagnostic assays, ddPCR was more sensitive for the detection of Bartonella DNA than qPCR when testing blood samples (36% vs. 0%, p < 0.0001). Dogs that were positive on serological assays alone with negative molecular assays were highly unlikely (<3%) to be classified as infected by the RE-LCA model. These data indicate that Bartonella spp. DNA can be PCR amplified from fresh frozen tissues from a majority of dogs with HSA using both qPCR and ddPCR, supporting the use of these methods for future controlled studies comparing the prevalence of Bartonella spp. DNA in the tissue of dogs with HSA to that of unaffected controls.

Bartonella rochalimae, a newly recognized pathogen in dogs

Background

Bartonella spp. comprise a genus of bacteria that frequently cause persistent, often subclinical infection. Although many Bartonella spp. have been implicated in a variety of clinical presentations, Bartonella rochalimae has yet to be documented in association with a clinical presentation other than infectious endocarditis (IE) in dogs.

Objectives

To document a spectrum of clinical presentations accompanied by mild hematological abnormalities in B rochalimae‐infected dogs from the United States.

Animals

Eight dogs with documented B rochalimae infection.

Methods

Retrospective 10‐year study of B rochalimae naturally infected dogs. Clinical and clinicopathologic data, including medical history, CBC, serum biochemistry panel, urinalysis, echocardiogram, and comprehensive vector‐borne disease diagnostic panel results, were reviewed.

Results

Eight dogs were diagnosed with B rochalimae via polymerase chain reaction (PCR) amplification. Five dogs were diagnosed with IE. Three dogs, PCR positive for B rochalimae, were diagnosed with seizures or antibiotic responsive lameness or during routine screening of a military working dog.

Conclusions

This case series provides support for an association between B rochalimae and IE and provides documentation of dogs infected with B rochalimae with other clinical diagnoses.

Molecular prevalence of Bartonella, Babesia, and hemotropic Mycoplasma species in dogs with hemangiosarcoma from across the United States

Hemangiosarcoma (HSA), a locally invasive and highly metastatic endothelial cell neoplasm, accounts for two-thirds of all cardiac and splenic neoplasms in dogs. Bartonella spp. infection has been reported in association with neoplastic and non-neoplastic vasoproliferative lesions in animals and humans. The objective of this study was to determine the prevalence of Bartonella spp. in conjunction with two other hemotropic pathogens, Babesia spp. and hemotropic Mycoplasma spp., in tissues and blood samples from 110 dogs with histopathologically diagnosed HSA from throughout the United States. This was a retrospective, observational study using clinical specimens from 110 dogs with HSA banked by the biospecimen repository of the Canine Comparative Oncology and Genomics Consortium. Samples provided for this study from each dog included: fresh frozen HSA tumor tissue (available from n = 100 of the 110 dogs), fresh frozen non-tumor tissue (n = 104), and whole blood and serum samples (n = 108 and 107 respectively). Blood and tissues were tested by qPCR for Bartonella, hemotropic Mycoplasma, and Babesia spp. DNA; serum was tested for Bartonella spp. antibodies. Bartonella spp. DNA was amplified and sequenced from 73% of dogs with HSA (80/110). In contrast, hemotropic Mycoplasma spp. DNA was amplified from a significantly smaller proportion (5%, p<0.0001) and Babesia spp. DNA was not amplified from any dog. Of the 100 HSA tumor samples submitted, 34% were Bartonella PCR positive (32% of splenic tumors, 57% of cardiac tumors, and 17% of other tumor locations). Of 104 non-tumor tissues, 63% were Bartonella PCR positive (56% of spleen samples, 93% of cardiac samples, and 63% of skin/subcutaneous samples). Of dogs with Bartonella positive HSA tumor, 76% were also positive in non-tumor tissue. Bartonella spp. DNA was not PCR amplified from whole blood. This study documented a high prevalence of Bartonella spp. DNA in dogs with HSA from geographically diverse regions of the United States. While 73% of all tissue samples from these dogs were PCR positive for Bartonella DNA, none of the blood samples were, indicating that whole blood samples do not reflect tissue presence of this pathogen. Future studies are needed to further investigate the role of Bartonella spp. in the development of HSA.

A review on the occurrence of companion vector-borne diseases in pet animals in Latin America

Companion vector-borne diseases (CVBDs) are an important threat for pet life, but may also have an impact on human health, due to their often zoonotic character. The importance and awareness of CVBDs continuously increased during the last years. However, information on their occurrence is often limited in several parts of the world, which are often especially affected. Latin America (LATAM), a region with large biodiversity, is one of these regions, where information on CVBDs for pet owners, veterinarians, medical doctors and health workers is often obsolete, limited or non-existent. In the present review, a comprehensive literature search for CVBDs in companion animals (dogs and cats) was performed for several countries in Central America (Belize, Caribbean Islands, Costa Rica, Cuba, Dominican Republic, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Puerto Rico) as well as in South America (Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, French Guiana, Guyana (British Guyana), Paraguay, Peru, Suriname, Uruguay, Venezuela) regarding the occurrence of the following parasitic and bacterial diseases: babesiosis, heartworm disease, subcutaneous dirofilariosis, hepatozoonosis, leishmaniosis, trypanosomosis, anaplasmosis, bartonellosis, borreliosis, ehrlichiosis, mycoplasmosis and rickettsiosis. An overview on the specific diseases, followed by a short summary on their occurrence per country is given. Additionally, a tabular listing on positive or non-reported occurrence is presented. None of the countries is completely free from CVBDs. The data presented in the review confirm a wide distribution of the CVBDs in focus in LATAM. This wide occurrence and the fact that most of the CVBDs can have a quite severe clinical outcome and their diagnostic as well as therapeutic options in the region are often difficult to access and to afford, demands a strong call for the prevention of pathogen transmission by the use of ectoparasiticidal and anti-feeding products as well as by performing behavioural changes.

Bartonella infections in cats and dogs including zoonotic aspects

Bartonellosis is a vector-borne zoonotic disease with worldwide distribution that can infect humans and a large number of mammals including small companion animals (cats and dogs). In recent years, an increasing number of studies from around the world have reported Bartonella infections, although publications have predominantly focused on the North American perspective. Currently, clinico-pathological data from Europe are more limited, suggesting that bartonellosis may be an infrequent or underdiagnosed infectious disease in cats and dogs. Research is needed to confirm or exclude Bartonella infection as a cause of a spectrum of feline and canine diseases. Bartonella spp. can cause acute or chronic infections in cats, dogs and humans. On a comparative medical basis, different clinical manifestations, such as periods of intermittent fever, granulomatous inflammation involving the heart, liver, lymph nodes and other tissues, endocarditis, bacillary angiomatosis, peliosis hepatis, uveitis and vasoproliferative tumors have been reported in cats, dogs and humans. The purpose of this review is to provide an update and European perspective on Bartonella infections in cats and dogs, including clinical, diagnostic, epidemiological, pathological, treatment and zoonotic aspects.

Vector-borne and zoonotic diseases of dogs in North-west New South Wales and the Northern Territory, Australia

Background

Vector-borne diseases of dogs in Australian Aboriginal communities are relatively unexplored. These dogs represent a unique group with variable ecto- and endo-parasitic burdens, nutritional stresses and a general lack of veterinary intervention. We investigated haemoprotozoal and bacterial pathogen prevalences in relation to erythrocyte and platelet numbers in dogs from North-West New South Wales (N-W NSW) and the Northern Territory (NT; Central Australia).

Methods

Real-time PCR (qPCR) amplification of Anaplasma platys, Babesia vogeli, Mycoplasma haemocanis, Candidatus Mycoplasma haematoparvum and Bartonella spp., serological screening for Coxiella burnetii, and Bartonella spp. and haematological analyses were performed on dogs from the two cohorts (96 dogs in total). Brucella suis serology was determined additionally for the N-W NSW cohort.

Results

Anaplasma platys (n = 26 dogs), Babesia vogeli (n = 7), Candidatus Mycoplasma haematoparvum (n = 10 dogs), and Mycoplasma haemocanis (n = 14) were detected in the sample population (n = 96) using qPCR. There were significant associations between (i) A. platys and anaemia (OR 8.7, CI 2.4–31.7; P < 0.001), thrombocytopenia (OR 12.1, CI 3.4–43.2; P < 0.001) and breed (OR 16.1, CI 2.1–121.5; P = 0.007), and (ii) between B. vogeli and anaemia (OR 11.8, CI 2.3–61.6; P = 0.003). Neither protozoal nor bacterial DNA loads, estimated using qPCR, were positively correlated with anaemia or thrombocytopenia. Haemotropic mycoplasmas were not associated with any haematologic abnormality. Four dogs from the NT were seropositive for Coxiella burnetii, while no dogs were seropositive for Brucella suis or to a panel of Bartonella spp. antigens. Despite directed efforts, Bartonella DNA was not detected in blood from any of the cohorts studied. A sample of dogs from the NT recruited specifically for Bartonella α-proteobacteria growth medium enrichment blood culture were also Bartonella PCR negative.

Conclusions

Vector-borne pathogens occur in dogs free ranging near Aboriginal communities, with higher detection rates in NT than N-W NSW. The preponderant haematologic abnormalities were anaemia and thrombocytopenia, likely attributable to A. platys and B. vogeli infections, but also probably affected by nutritional, parasitic, lactational and environmental stressors. The absence of Bartonella spp. is of importance to the Australian setting, and work needs to be extended to tropical coastal communities where fleas are present as well as ticks. Dogs living in and around Aboriginal communities may provide valuable sentinel information on disease infection status of human public health significance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1169-2) contains supplementary material, which is available to authorized users.

Bartonellosis, One Health and all creatures great and small

BACKGROUND

Bartonellosis is a zoonotic infectious disease of worldwide distribution, caused by an expanding number of recently discovered Bartonella spp.

OBJECTIVES

This review serves as an update on comparative medical aspects of this disease, including the epidemiology, pathogenesis, clinical diagnosis, treatment and challenges.

RESULTS

Of comparative medical importance, Bartonella spp. are transmitted by several arthropod vectors, including fleas, keds, lice, sand flies, ticks and, potentially, mites and spiders. Prior to 1990, there was only one named Bartonella species (B. bacilliformis), whereas there are now over 36, of which 17 have been associated with an expanding spectrum of animal and human diseases. Recent advances in diagnostic techniques have facilitated documentation of chronic bloodstream and dermatological infections with Bartonella spp. in healthy and sick animals, in human blood donors, and in immunocompetent and immunocompromised human patients. The field of Bartonella research remains in its infancy and is rich in questions, for which patient relevant answers are badly needed. Directed Bartonella research could substantially reduce a spectrum of chronic and debilitating animal and human diseases, and thereby reduce suffering throughout the world.

CONCLUSION

A One Health approach to this emerging infectious disease is clearly needed to define disease manifestations, to establish the comparative infectious disease pathogenesis of this stealth pathogen, to validate effective treatment regimens and to prevent zoonotic disease transmission.

Bartonella henselae, Bartonella koehlerae and Rickettsia rickettsii seroconversion and seroreversion in a dog with acute-onset fever, lameness, and lymphadenopathy followed by a protracted disease course

Following recent tick exposure in Arkansas, a 2-year-old, female spayed Labradoodle was examined because of a one-week history of lethargy and shifting-leg lameness. The dog was febrile, had prominent lymph nodes, dull mentation, a stiff gait, and left forelimb lameness. Thrombocytopenia was the only initial hematological or biochemical abnormality. Despite treatment with doxycycline for suspected Rocky Mountain spotted fever, the dog continued to have waxing and waning clinical signs including inappetence, fever, shifting-leg lameness, lymphadenopathy, splenomegaly, and weight loss in association with moderate to severe hematological abnormalities, including anemia, thrombocytopenia, neutrophilia, and monocytosis. Sequential serological testing confirmed Bartonella henselae, Bartonella koehlerae and R. rickettsii seroconversion. Doxycycline, enrofloxacin and clarithromycin were administered in sequential combination for treatment of rickettsioses, B. henselae and B. koehlerae. Prednisone, thyroid supplementation and other drugs were administered to elicit symptomatic improvement. Based upon seroreversion, and the eventual resolution of all clinical and hematological abnormalities, therapeutic elimination of all three pathogens was seemingly achieved. Whether cortisol insufficiency due to adrenal exhaustion syndrome or post-infectious immune-mediated sequelae contributed to the symptoms and pathophysiological abnormalities reported in this dog was not determined, but are considerations for future cases.

Heparin induced thrombocytopenia in critically ill: Diagnostic dilemmas and management conundrums

Thrombocytopenia is often noted in critically ill patients. While there are many reasons for thrombocytopenia, the use of heparin and its derivatives is increasingly noted to be associated with thrombocytopenia. Heparin induced thrombocytopenia syndrome (HITS) is a distinct entity that is characterised by the occurrence of thrombocytopenia in conjunction with thrombotic manifestations after exposure to unfractionated heparin or low molecular weight heparin. HITS is an immunologic disorder mediated by antibodies to heparin-platelet factor 4 (PF4) complex. HITS is an uncommon cause of thrombocytopenia. Reported incidence of HITS in patients exposed to heparin varies from 0.2% to up to 5%. HITS is rare in ICU populations, with estimates varying from 0.39%-0.48%. It is a complex problem which may cause diagnostic dilemmas and management conundrum. The diagnosis of HITS centers around detection of antibodies against PF4-heparin complexes. Immunoassays performed by most pathology laboratories detect the presence of antibodies, but do not reveal whether the antibodies are pathological. Platelet activation assays demonstrate the presence of clinically relevant antibodies, but only a minority of laboratories conduct them. Several anticoagulants are used in management of HITS. In this review we discuss the incidence, pathogenesis, diagnosis and management of HITS.

Bartonella spp. bacteremia in blood donors from Campinas, Brazil

Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%). Sixteen donors (3.2%) were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.

Bartonella is a genus of small bacteria with worldwide distribution, transmitted by blood-sucking insects, and is capable of causing disease in humans and animals. Some of the clinical presentations of Bartonella spp., such as cat scratch disease, trench fever, and bacillary angiomatosis are well documented; however, novel presentations have been described in the last two decades, ranging from cyclic flu-like syndrome to neurologic disease and life-threatening endocarditis. Asymptomatic human infection is possible and accidental blood transmission has been reported. Bacterium isolation is very difficult because they grow slowly and require special culture media and procedures. Serology testing poorly predicts active Bartonella infection, except in infection of cardiac valves. Therefore, diagnosis is generally challenging. However, when molecular detection techniques are coupled with special culture protocols, enhanced sensitivity and specificity can be achieved. We investigated Bartonella spp. infection prevalence in a large blood donor population and confirmed bacteremia in 1.2% of the subjects. Bloodstream infection was detected with at least three different molecular methods in 3.2% of donors. These results indicate that Bartonella is a genus of importance for transfusion medicine.

Vector-borne pathogens in arctic foxes, Vulpes lagopus, from Canada

Because of the relatively low biodiversity within arctic ecosystems, arctic foxes, Vulpes lagopus, could serve as sentinels for the study of changes in the ecology of vector-borne zoonotic pathogens. The objective of this study was to determine the molecular prevalence of 5 different genera of vector borne pathogens (Anaplasma, Babesia, Bartonella, Ehrlichia, and Hemotropic Mycoplasma spp.) using blood collected from 28 live-trapped arctic foxes from the region of Karrak Lake, Nunavut, Canada. Bartonella henselae (n = 3), Mycoplasma haemocanis (n = 1), Ehrlichia canis (n = 1), and an Anaplasma sp. (n = 1) DNA were PCR amplified and subsequently identified by sequencing. This study provides preliminary evidence that vector borne pathogens, not typically associated with the arctic ecosystem, exist at low levels in this arctic fox population, and that vector exposure, pathogen transmission dynamics, and changes in the geographic distribution of pathogens over time should be investigated in future studies.

Concurrent Bartonella henselae infection in a dog with panniculitis and owner with ulcerated nodular skin lesions

BACKGROUND

Bartonella henselae, a Gram-negative, zoonotic Alphaproteobacteria that infects erythrocytes, endothelial cells and dendritic cells, has previously been implicated as a cause of panniculitis in dogs and a human.

ANIMAL AND OWNER

An 8-year-old, spayed female Labrador retriever and its 78-year-old male owner living in the same household.

METHODS AND RESULTS

When preliminary and advanced testing failed to identify the cause of near-simultaneous-onset dermatological lesions, Bartonella serology, Bartonella Alphaproteobacteria growth medium (BAPGM) enrichment blood culture/PCR and immunohistochemistry were used to test specimens from the dog and owner. Bartonella henselae, genotype San Antonio 2 DNA was amplified and sequenced from the man's BAPGM enrichment blood culture and the dog's panniculitis lesion. The bacterium was visualized by immunohistochemistry in the dog's panniculitis lesion; however, neither the dog nor the owner was B. henselae seroreactive. Antibiotic therapy elicited dermatological improvement in both dog and owner.

CONCLUSIONS AND CLINICAL IMPORTANCE

Bartonella henselae is an emerging zoonotic pathogen that induces granulomatous inflammatory lesions in various tissues of animals, including humans. We conclude that this bacterium had a contributory or causative role in the development of the dermatological lesions in the dog and owner.

Prostatitis, steatitis, and diarrhea in a dog following presumptive flea-borne transmission of Bartonella henselae

Bartonella henselae is increasingly associated with a variety of pathological entities, which are often similar in dogs and human patients. Following an acute flea infestation, a dog developed an unusual clinical presentation for canine bartonellosis. Comprehensive medical, microbiological, and surgical interventions were required for diagnosis and to achieve a full recovery.