Seroprevalence of antibodies against Borrelia burgdorferi and Anaplasma phagocytophilum in cats

Exposure to Tick-Borne Pathogens in Cats and Dogs Infested With Ixodes scapularis in Quebec: An 8-Year Surveillance Study

Cats that spend time outdoors and dogs are particularly at risk of exposure to ticks and the pathogens they transmit. A retrospective study on data collected through passive tick surveillance was conducted to estimate the risk of exposure to tick-borne pathogens in cats and dogs bitten by blacklegged ticks (Ixodes scapularis) in the province of Quebec, Canada, from 2010 to 2017. Blacklegged ticks collected from these host animals were tested by PCR for Borrelia burgdorferi sensu stricto, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia microti. A total of 13,733 blacklegged ticks were collected from 12,547 animals. Most ticks were adult females and partially engorged. In total, 1,774 cats were infested with ticks and 22.6 and 2.7% of these animals were bitten by at least one tick infected with B. burgdorferi and A. phagocytophilum, respectively. For the 10,773 tick infested dogs, 18.4% were exposed to B. burgdorferi positive ticks while 1.9% of infested dogs were exposed to ticks infected with A. phagocytophilum. The risk of exposure of both cats and dogs to B. miyamotoi and B. microti was lower since only 1.2 and 0.1% of ticks removed were infected with these pathogens, respectively. Traveling outside of the province of Quebec prior to tick collection was significantly associated with exposure to at least one positive tick for B. burgdorferi, A. phagocytophilum and B. microti. Animals exposed to B. burgdorferi or B. miyamotoi positive tick(s) were at higher risk of being concurrently exposed to A. phagocytophilum; higher risk of exposure to B. microti was also observed in animals concurrently exposed to B. burgdorferi. The odds of dogs having B. burgdorferi antibodies were higher when multiple ticks were collected on an animal. The testing and treatment strategies used on dogs bitten by infected ticks were diverse, and misconceptions among veterinarians regarding the treatment of asymptomatic but B. burgdorferi-seropositive dogs were noted. In conclusion, our study demonstrates that cats and dogs throughout Quebec are exposed to blacklegged ticks infected with B. burgdorferi and A. phagocytophilum, and veterinarians across the province need to be aware of this potential threat to the health of pets and their owners.

Analysis of gaps in feline ectoparasiticide purchases from veterinary clinics in the United States

Background

The study objective was to examine cat owner ectoparasiticide purchases in the United States and estimate the impact of purchase gaps on timely ectoparasite protection administration. These purchase gaps lead to periods of time when cats are unprotected from ectoparasites.

Methods

Ectoparasiticide purchase transactions for individual cats from 671 U.S. veterinary clinics from January 1, 2017 through June 30, 2019 were evaluated to determine time “gaps” between doses of ectoparasiticides purchased in a defined 12-month period. Ectoparasiticides examined were topically applied products that contained fluralaner, fipronil/(S)-methoprene/pyriproxyfen, imidacloprid/pyriproxyfen or selamectin as active ingredients. The duration of protection following administration of one dose was 8–12 weeks for the fluralaner-containing product and one month for the other products.

Results

Ectoparasiticide purchase records were obtained from 114,853 cat owners and analysis found that most owners bought ≤ 6 months of protection during the year, with 61–75% (depending on the product) purchasing just 1–3 months of protection. The size of the average purchase gap was determined for all dose combinations out to 12 months of protection (5–7 doses for fluralaner and 12 doses for the other three products dosed monthly. The largest gaps occurred between the first and second doses and the second and third doses. Average purchase gaps for the four different products between doses 1 and 2 ranged from 11.2 to 13.9 weeks and between doses 2 and 3 ranged from 7.7 to 12.2 weeks. The fraction of purchases separated by gaps and the average length of the gap tended to decrease with increasing number of doses purchased. Owners purchasing the 8 to 12-week duration product containing fluralaner provided ectoparasite protection (“doses plus gap period”) for a larger proportion of each 2-dose period compared with owners purchasing products administered monthly.

Conclusions

When cat owners purchase flea and tick medication, gaps between subsequent purchases reduces the proportion of time ectoparasite protection can be provided. The duration of the gap between doses has an impact on the effectiveness of flea/tick medication because it inserts a period without flea and tick protection between doses of flea and tick medication. The gaps between purchases were shorter and the period of ectoparasite protection was larger for owners purchasing a 12-week product than for owners purchasing a monthly product.

Ticks infesting dogs and cats in North America: Biology, geographic distribution, and pathogen transmission

A diverse array of ixodid and argasid ticks infest dogs and cats in North America, resulting in skin lesions, blood loss, and disease. The ticks most commonly found on pets in this region are hard ticks of the genera Amblyomma, Dermacentor, Ixodes, and Rhipicephalus, as well as the more recently established Haemaphysalis longicornis. Soft tick genera, especially Otobius and Ornithodoros, are also reported from pets in some regions. In this review, we provide a summary of the complex and diverse life histories, distinct morphologies, and questing and feeding behaviors of the more common ticks of dogs and cats in North America with a focus on recent changes in geographic distribution. We also review pathogens of dogs and cats associated with the different tick species, some of which can cause serious, potentially fatal disease, and describe the zoonotic risk posed by ticks of pets. Understanding the natural history of ticks and the maintenance cycles responsible for providing an ongoing source of tick-borne infections is critical to effectively combatting the challenges ticks pose to the health of pets and people.

Seroprevalence Rates of Tick-Borne Pathogens in Cats from Southern Bulgaria

The aim of the present study was to investigate the prevalence rates of the feline tick-borne pathogens (FTBPs)-Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum in stray cats from Southern Bulgaria. Serum antibodies were used to estimate the prevalence of exposure to FTBPs from blood swabs. Of the 100 cat samples tested with in-clinic assay SNAP 4Dx Plus, the overall FTBP seroprevalence was 3% (3/100); with B. burgdorferi-1% (1/100) and E. canis-2% (2/100). This study provides the first evidence of exposure to B. burgdorferi and E. canis in cats from Bulgaria.

Anaplasma phagocytophilum infection in cats: A literature review to raise clinical awareness

PRACTICAL RELEVANCE

Granulocytic anaplasmosis is a disease in humans and animals caused by the Gram-negative bacterium Anaplasma phagocytophilum within the family Anaplasmataceae. The pathogen is transmitted by ticks of the Ixodes species. Infections with A phagocytophilum have often been described in dogs but reports on natural infections in cats are rare. An infection with A phagocytophilum should be considered as a differential diagnosis in cats if the history reveals tick infestation and/or outdoor access in combination with the relevant clinical signs.

GLOBAL IMPORTANCE

A phagocytophilum is also important in human medicine because of its zoonotic potential. Due to the risk of vector-borne infections for both feline and public health, cats should be protected with ectoparasiticides, especially in endemic areas.

AIM

The aim of this review is to give an overview of the published data and summarise the epidemiology, pathogenesis, diagnosis, clinical signs and therapy of feline granulocytic anaplasmosis. As clinical signs are vague and non-specific, this review aims to raise awareness of A phagocytophilum infection, both among clinicians, so that they consider testing potentially exposed cats, and scientists, in order to prompt further research.

EVIDENCE BASE

Sixteen publications describing 55 cats have been reviewed. Thirty-four cats were well diagnosed based on guidelines of the European Advisory Board on Cat Diseases and blood analyses were performed to varying extents for these cats. Because of the limited number of studies and a lack of knowledge in cats, clinical signs and blood analyses are compared with available data in dogs.

First report of Lyme borreliosis leading to cardiac bradydysrhythmia in two cats

Case series summary

Two cats were presented for investigation of bradyarrhythmia detected by their referring veterinarians during routine examination. Both cats had extensive investigations, including haematology, serum biochemistry with electrolytes and thyroxine concentrations, systolic blood pressure measurement, echocardiography, electrocardiography and infectious disease testing. Infectious disease testing included serology for Toxoplasma gondii, Ehrlichia canis, Anaplasma phagocytophilum and Borrelia burgdorferi, and PCR for B burgdorferi antigen in both cats. Case 1 was also assessed by PCR for Bartonella henselae antigen and case 2 was assessed for Dirofilaria immitis by serology. All infectious disease tests, other than for B burgdorferi, were negative. Case 1 was diagnosed with Lyme carditis based on marked bradydysrhythmia, positive B burgdorferi serology, a structurally normal heart and clinical resolution with appropriate treatment with a 4-year follow-up. Case 2 was diagnosed with Lyme carditis based on marked bradydysrhythmia and positive B burgdorferi PCR; however, this cat had structural heart disease that did not resolve with treatment.

Relevance and novel information

This small case series describes two B burgdorferi positive cats presenting with newly diagnosed cardiac abnormalities consistent with those found in humans and dogs with Lyme carditis. Both cats were asymptomatic as perceived by their owners; the arrhythmia was detected by their veterinarians.

Feline Vector-Borne Diseases in North America

"In North America, with the exceptions of Bartonella henselae and Cytauxzoon felis, feline vector-borne diseases (FVBDs) have been minimally studied in domestic cats. Cats can be infected with many of the same vector-borne pathogens that infect dogs. Nonspecific clinical signs linked to FVBDs and low prevalence of certain vector-borne pathogens contribute to a limited awareness of FVBDs in sick cats. As clinicians become informed about FVBDs and as vector-borne disease diagnostics are routinely applied to evaluate sick cats, we will gain a stronger understanding of vector-borne pathogens in cats. This article focuses on recent findings related to FVBDs."

Evidence for Clinical Anaplasmosis and Borreliosis in Cats in Maine

The objectives of this study were to use data from client-owned cats in an Ixodes scapularis endemic area to evaluate for clinical associations with diagnostic test results for Anaplasma phagocytophilum and Borrelia burgdorferi and to provide information from a group of cats with possible borreliosis as the cause of clinical manifestations of disease. All cases were evaluated at one clinic, medical records were evaluated, and sera from all cats were tested using one of two commercially available assays labeled for the use with dog sera (SNAP 4Dx or SNAP 4Dx Plus; IDEXX Laboratories, Westbrook, ME). Of the 159 cats evaluated, 42 cats (26.4%) had clinical signs consistent with A. phagocytophilum or B. burgdorferi infection and 117 cats (73.6%) were apparently healthy. Antibodies against B. burgdorferi or A. phagocytophilum were detected in sera of 18.2% and 6.3% of the 159 cats, respectively. Cats with clinical signs of disease were 4 times more likely to have antibodies against one or both agents than healthy cats (95% confidence interval [CI] 1.7928-8.9246; P = .0007), cats allowed outdoors were 5 times more likely to have antibodies against one or both agents than cats housed exclusively indoors (95% CI 2.0196-12.4497; P = .0005), and cats of owners who purchased acaricides were more likely (odds ratio = .3977) to have antibodies against one or both agents than cats of owners who did not purchase acaricides (95% CI .1659-.9534; P = .0387). The cats in the case series were believed to have B. burgdorferi infection as the most likely cause of illness based on serological testing, select clinical information, and apparent response to administration of doxycycline. The results suggest that both A. phagocytophilum and B. burgdorferi are associated with clinical illness in cats. Owners of cats allowed outdoors should be diligent in the use of acaricides.

ACVIM consensus update on Lyme borreliosis in dogs and cats

An update of the 2006 American College of Veterinary Internal Medicine (ACVIM) Small Animal Consensus Statement on Lyme Disease in Dogs: Diagnosis, Treatment, and Prevention was presented at the 2016 ACVIM Forum in Denver, CO, followed by panel and audience discussion and a drafted consensus statement distributed online to diplomates for comment. The updated consensus statement is presented below. The consensus statement aims to provide guidance on the diagnosis, treatment, and prevention of Lyme borreliosis in dogs and cats.

Vector-borne diseases in cats in Germany

Vector-borne diseases (VBDs) are caused by a wide range of pathogens, which are transmitted by a variety of vectors, such as ticks and fleas. As a result of climate changes, more vector-borne diseases are becoming endemic in Germany, not only in dogs, but also in cats. For some of the pathogens prevalence data still need to be investigated in Germany. However, natural infections with Bartonella, Anaplasma, haemotropic Mycoplasma and Borrelia species have already been described in German cats. Clinical relevance of these pathogens is not fully understood, and it is still unknown, why most infected cats stay asymptomatic and which predisposing factors contribute to the development of clinical signs in cats. Moreover, there is a risk of zoonotic transmission for some of the pathogens, e.  g., for some Bartonella spp. infections that are associated with cat scratch disease in humans. Due to the increasing number of VBDs in cats in Germany, preventive measures, such as the use of acaricides and insecticides, should be performed on a regular base in order to reduce the risk of these infections.

Anaplasma, Ehrlichia and Rickettsia species infections in cats: European guidelines from the ABCD on prevention and management

OVERVIEW

Anaplasma species, Ehrlichia species and Rickettsia species are vector-borne pathogens infecting a wide variety of mammals, but causing disease in very few of them. Infection in cats: Anaplasma phagocytophilum is the most important feline pathogen among these rickettsial organisms, and coinfections are possible. Little information is available on the pathogenesis of these agents in cats. Clinical signs are usually reported soon after tick infestation. They are mostly non-specific, consisting of fever, anorexia and lethargy. Joint pain may occur. Infection in humans: Some rickettsial species ( A phagocytophilum, Ehrlichia chaffeensis, Ehrlichia ewingii, Rickettsia conorii, Rickettsia rickettsii, Rickettsia felis, Rickettsia typhi and Candidatus Neoehrlichia mikurensis) are of zoonotic concern. Direct contact with cat saliva should be avoided because of potential contamination by R felis. Infected cats are 'sentinels' of the presence of rickettsial pathogens in ticks and fleas in a given geographical area, and they signal a risk for people exposed to vectors.

Anaplasma phagocytophilum infection of domestic cats: 16 cases from the northeastern USA

OBJECTIVES

Anaplasma phagocytophilum is an Ixodes species-transmitted rickettsial organism that is occasionally associated with clinical abnormalities in humans, ruminants, horses, dogs and cats. While serological evidence of A phagocytophilum exposure is common in cats in Ixodes species endemic areas, reports of clinical feline anaplasmosis are few. The objective of this study was to describe the clinical and laboratory abnormalities and treatment responses in 16 cats with A phagocytophilum DNA amplified from blood.

METHODS

Commercial laboratory electronic records were searched to find cats that had A phagocytophilum DNA amplified from their blood. Once cases were identified, the primary care veterinarian was interviewed and the medical records were reviewed.

RESULTS

The cats ranged in age from 4 months to 13 years (mean 4.1 years, median 2 years). All cats lived in Ixodes scapularis endemic areas and had potential for exposure. All cats were lethargic, 15 (94%) had elevated body temperature (>39.4°C) and 14 were anorexic on initial physical examination. Other less common clinical findings included hepatosplenomegaly, ataxia, conjunctivitis and elevation of the nictitating membranes. Blood from 11 cats was evaluated by complete blood cell count; abnormalities included lymphopenia in seven (64%) cats, thrombocytopenia in seven (64%), morulae in neutrophils of three (27%), neutropenia in three (27%) and leukopenia in two (18%). Treatment responses were reported for 14 cats, and the clinical abnormalities in these cats resolved when doxycycline was administered.

CONCLUSIONS AND RELEVANCE

This is the first published report describing A phagocytophilum morulae in neutrophils of naturally infected North American cats with infection confirmed by PCR. A phagocytophilum infection should be considered in cats evaluated for lethargy, anorexia and fever living in Ixodes species endemic areas.

Evidence of Anaplasma phagocytophilum and Borrelia burgdorferi infection in cats after exposure to wild-caught adult Ixodes scapularis

Cats are infected by Anaplasma phagocytophilum and Borrelia burgdorferi when exposed to infected Ixodes scapularis (black-legged ticks). The purpose of our study was to allow wild-caught I. scapularis to feed on healthy research cats (n = 4) and temporally evaluate for A. phagocytophilum DNA in blood by a polymerase chain reaction (PCR) assay as well as for antibody responses to the B. burgdorferi C6 peptide, to the A. phagocytophilum P44 peptide, and to a novel A. phagocytophilum peptide (P44-4). Prior to I. scapularis infestation, all cats were negative for antibodies against both organisms based on a kit optimized for dog serum, and negative for A. phagocytophilum DNA in blood using a conventional PCR assay. Using the pre-infestation samples, an enzyme-linked immunosorbent assay for detecting antibodies against the P44-4 peptide was optimized. Cats were infested with wild-caught I. scapularis for 7 days. Genomic DNA of A. phagocytophilum was amplified from the blood before antibodies were detected in all 4 cats. Antibodies against the C6 peptide, P44 peptide, and P44-4 peptide were detected in the sera of all 4 cats. Antibodies against P44-4 were detected prior to those against P44 in 3 out of 4 cats. The results suggest that a PCR assay should be considered in acutely ill cats with suspected anaplasmosis that are seronegative.

Serological and molecular analysis of feline vector-borne anaplasmosis and ehrlichiosis using species-specific peptides and PCR

Background

With the exception of Bartonella spp. or Cytauxzoon felis, feline vector-borne pathogens (FVBP) have been less frequently studied in North America and are generally under-appreciated as a clinical entity in cats, as compared to dogs or people. This study investigated selected FVBP seroreactivity and PCR prevalence in cats using archived samples.

Methods

Feline blood samples submitted to the Vector Borne Diseases Diagnostic Laboratory (VBDDL) at North Carolina State University College of Veterinary Medicine (NCSU-CVM) between 2008 and 2013 were tested using serological assays and PCR. An experimental SNAP® Multi-Analyte Assay (SNAP® M-A) (IDEXX Laboratories, Inc. Westbrook, Maine, USA) was used to screen all sera for antibodies to Anaplasma and Ehrlichia genus peptides and A.phagocytophilum, A.platys, B.burgdorferi, E.canis, E.chaffeensis, and E.ewingii species-specific peptides. PCR assays were used to amplify Anaplasma or Ehrlichia DNA from extracted ethylenediaminetetraacetic acid (EDTA)-anti-coagulated blood samples. Amplicons were sequenced to identify species.

Results

Overall, 7.8 % (56/715) of cats were FVBP seroreactive and 3.2 % (13/406) contained Anaplasma or Ehrlichia DNA. Serologically, B.burgdorferi (5.5 %) was the most prevalent FVBP followed by A.phagocytophilum (1.8 %). Ehrlichia spp. antibodies were found in 0.14 % (12/715) of cats with species-specific seroreactivity to E.canis (n = 5), E.ewingii (n = 2) and E.chaffeensis (n = 1). Of seropositive cats, 16 % (9/56) were exposed to more than one FVBP, all of which were exposed to B.burgdorferi and either A.phagocytophilum (n = 7) or E.ewingii (n = 2). Based upon PCR and DNA sequencing, 4, 3, 3, 2, and 1 cat were infected with A.phagocytophilum, A.platys, E. ewingii, E. chaffeensis and E.canis, respectively.

Conclusions

Cats are exposed to and can be infected with vector-borne pathogens that commonly infect dogs and humans. To our knowledge, this study provides the first evidence for E.chaffeensis and E.ewingii infection in naturally-exposed cats in North America. Results from this study support the need for regional, serological and molecular FVBP prevalence studies, the need to further optimize serodiagnostic and PCR testing for cats, and the need for prospective studies to better characterize clinicopathological disease manifestations in cats infected with FVBP.

Vector-borne diseases in client-owned and stray cats from Madrid, Spain

The role of various vector-borne pathogens as a cause of disease in cats has not been clearly determined. The current study evaluated risk factors, clinical and laboratory abnormalities associated with Ehrlichia spp., Anaplasma spp., Neorickettsia spp., Leishmania spp., and Bartonella spp. infection or exposure in 680 client-owned and stray cats from Madrid, Spain. Our results indicate that a large portion (35.1%) of the cat population of Madrid, Spain, is exposed to at least one of the five vector-borne pathogens tested. We found seroreactivity to Bartonella henselae in 23.8%, to Ehrlichia canis in 9.9%, to Anaplasma phagocytophilum in 8.4%, to Leishmania infantum in 3.7%, and to Neorickettsia risticii in 1% of the feline study population. About 9.9% of cats had antibody reactivity to more than one agent. L. infantum DNA was amplified from four cats (0.6%), B. henselae DNA from one cat (0.15%), and B. clarridgeiae DNA from another cat (0.15%).

Lyme borreliosis in dogs and cats: background, diagnosis, treatment and prevention of infections with Borrelia burgdorferi sensu stricto

Lyme borreliosis (LB), synonymous with the often-used term Lyme disease, is an infectious disease caused by the spirochetal bacterium Borrelia burgdorferi. LB is the most frequent vector-borne disease in humans in the Northern Hemisphere. In animals, clinically apparent disease is found primarily in dogs. Severe polyarthritis, fever and lameness in dogs are reported from the main endemic areas of North America: the New England States, and eastern parts of the United States; several cases of LB are also seen in California and the Midwest. Because of the difficulties in finding sufficient indicative clinical signs, additional information (detailed case history, laboratory testing for antibodies) is especially important to make the clinical diagnosis of Lyme borreliosis. This article reviews the etiology, diagnosis, therapy, and prevention of LB.

Ehrlichiosis and anaplasmosis in dogs and cats

In the time since canine ehrlichiosis due to Ehrlichia canis was first described in 1935 and first recognized in the United States in 1962, many key advances have been made in our understanding of the diversity of the rickettsial organisms responsible for ehrlichiosis and anaplasmosis in dogs and, occasionally, cats, the vectors capable of transmitting these agents, and the role these organisms play as both important veterinary pathogens and zoonotic disease agents. Despite considerable progress in the field, much remains to be learned regarding mechanisms contributing to pathogenesis, effective treatment modalities, and prevention strategies that best protect pet health. This article highlights current understanding of the transmission, diagnosis, and management of ehrlichiosis and anaplasmosis in dogs and cats.

Anaplasma phagocytophilum infection in a domestic cat in Finland: Case report

Background

Anaplasmosis is a vectorborne disease caused by the gram-negative bacterium Anaplasma phagocytophilum. This species displays positive tropism to granulocytes and can cause illness in several mammalian species, including cats, dogs, and humans. It is considered as an emerging disease in Europe. The clinical signs are nonspecific and include fever, lethargy, and inappetence. The most typical hematologic abnormality is thrombocytopenia. A tentative diagnosis can be made by detecting intracytoplasmic morulae inside neutrophils. The diagnosis is confirmed by PCR and serology in paired serum samples. A sample for PCR analysis should be taken before treatment. Anaplasmosis is treated with doxycycline.

Case presentation

A feline case of anaplasmosis is presented. The history, clinical presentation, diagnostics, treatment, and follow-up are discussed.

Conclusions

This case indicates that Anaplasma phagocytophilum infects cats in Finland. To provide accurate treatment, anaplasmosis should be listed as a differential diagnosis in cats suffering from acute febrile illness with previous tick exposure.

Burden of tick-borne infections on American companion animals

This review examines the biology of ticks and tick-borne infections in the United States. The most common tick-borne diseases in dogs and cats are discussed. We demonstrate that there is much interest in tick-borne infections at the level of the lay public (pet owners), describe trends in the distribution and prevalence of tick-borne infections in the United States, summarize some issues in understanding the degree of ill health due to tick-borne infections, and suggest some avenues for research that would clarify these issues.

Feline uveitis. An 'intraocular lymphadenopathy'

Practical relevance

Feline uveitis can be a subtle, insidious, painful, vision-threatening disease with causes that can sometimes be fatal. It is essential that clinicians remain alert to its various clinical presentations, thoroughly diagnose cases once detected, and treat the primary cause whenever possible.

Clinical challenges

In the majority of patients, a cause is not found and aggressive immunomodulating therapy of what may become a chronic or recurrent immune-mediated disease must be instigated. As with immune-mediated disease elsewhere, this involves local or systemic immunosuppression with slow tapering and frequent monitoring. The aim of this review is to aid diagnosis and therapy of uveitis by likening it to inflammation elsewhere (because it is more similar than it is different) while highlighting differences (because these are helpful).

Global importance

Feline uveitis is similar in its presentation throughout the world. Although the list of infectious causes may vary in composition or order of likelihood, idopathic, immune-mediated and neoplastic causes of feline uveitis are univerasal.

Patient group

Patients of either gender and all ages and breeds are affected by uveitis.

Evidence base

Despite the fact that feline uveitis is a serious and common disorder, the peer-reviewed literature regarding this disease is somewhat limited. Approximately half the publications are review articles, case reports or case series. The majority of prospective and retrospective research describes epidemiologic surveys of antibodies, antigens and organism DNA in serum and aqueous humor.

Meta-analysis of coinfection and coexposure with Borrelia burgdorferi and Anaplasma phagocytophilum in humans, domestic animals, wildlife, and Ixodes ricinus-complex ticks

Anaplasma phagocytophilum, which causes granulocytic anaplasmosis, and Borrelia burgdorferi, the agent of Lyme borreliosis, are transmitted in multiple Holarctic regions by the same Ixodes sp. tick vectors and maintained in sylvatic cycles with the same rodent reservoirs. Coinfection of humans, domestic animals, wildlife, and ticks with both B. burgdorferi and A. phagocytophilum appears to be common, yet the pathologic mechanisms and ecology remain poorly understood compared with single-agent infection. We compiled available literature describing experimental and naturally occurring coinfection with B. burgdorferi and A. phagocytophilum in I. ricinus-complex ticks and host species, including wildlife, humans, livestock, and pets; calculated odds ratios for coinfection risks; evaluated the hypotheses that odds ratios for coinfection differ significantly between different tick life stages, ticks and vertebrate hosts, and reservoir and nonreservoir hosts; and finally, calculated the predicted coinfection prevalence based on the probability of each pathogen alone and compared this to the reported coinfection prevalence. Sixty-one manuscripts referenced coinfection or coexposure between these pathogens, with prevalence estimates for coinfection up to 67% in vertebrates and 28% in ticks. Of 61 different reports of coinfection or coexposure, 18 had odds ratios for coinfection significantly higher than 1. The combined odds ratios for coinfection in vertebrates and ticks were 1.9 and 1.28, respectively, with statistically significant variability among host and tick species in odds ratios. The overall predicted coexposure prevalence for vertebrates was 3.1% compared with an observed 8.9% prevalence. Odds ratios were not significantly different among classes of vertebrate hosts, species of ticks, stages of ticks, or ticks compared with hosts. We confirm a considerable level of coinfection and coexposure with these pathogens, although not predictably across host or tick species or geographical region.

Prevalence of Anaplasma phagocytophilum in domestic felines in the United States

Anaplasma phagocytophilum is among the more common tick-borne disease agents in the United States. It is of veterinary and public health significance as dogs, cats, and human beings are known to be susceptible. A. phagocytophilum is transmitted trans-stadially by either nymphs or adults of either the black-legged tick (Ixodes scapularis) or the western black-legged tick (Ixodes pacificus). Little information is available regarding either the prevalence of this agent in cats or the dynamics of vector transmission. Four hundred and sixty feline blood samples from sites throughout the United States were assayed for antibodies to A. phagocytophilum using an indirect immunofluorescence assay (IFA). Results of the prevalence study showed that 20 samples (4.3%) were positive for A. phagocytophilum antibodies by IFA at a 1:50 dilution, however these results could not be confirmed by PCR analysis. PCR analysis for other cross-reacting Ehrlichia/Anaplasma spp. was also negative. These results demonstrate that natural infection of A. phagocytophilum in cats is uncommon.

Detection of antibodies to Francisella tularensis in cats

Blood samples were obtained from privately owned cats in Connecticut and New York State, USA in 1985-1990, and analyzed for evidence of Francisella tularensis, the etiologic agent of tularemia. Of the 91 sera tested by microagglutination (MA) methods, 11 (12%) contained antibodies to F. tularensis. Analyses of the same sera by indirect fluorescent antibody (IFA) staining methods revealed 22 (24%) positives. There was good agreement in results of both tests (73% concordance). However, we measured higher titers (1:80 to 1:640) with IFA analysis than by MA methods (1:80 to 1:160). Both tests were suitable for general screening purposes. The DNA of F.tularensis was not detected in the 24 antibody-positive sera tested. Cats living in Connecticut and New York State were naturally exposed to F.tularensis or a closely related organism. With exposure to ticks, other biting arthropods, mice, and rabbits, cats are at risk for acquiring F.tularensis infections and can be an important source of information on the presence of this agent in nature.