Does coinfection of Bartonella henselae and FIV induce clinical disorders in cats?

Prevalence and genetic diversity of Bartonella spp. in wild small mammals from South Africa

Bartonella spp. are intracellular bacteria associated with several re-emerging human diseases. Small mammals play a significant role in the maintenance and spread of Bartonella spp. Despite the high small mammal biodiversity in South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals. The main aim of this study was to determine the prevalence and genetic diversity of Bartonella spp. from wild small mammals from 15 localities in 8 provinces of South Africa. Small mammals (n = 183) were trapped in the Eastern Cape, Free State, Gauteng, Limpopo, Mpumalanga, Northern Cape, North West, and Western Cape provinces of South Africa between 2010 and 2018. Heart, kidney, liver, lung, and spleen were harvested for Bartonella DNA screening, and prevalence was determined based on the PCR amplification of partial fragments of the 16S-23S rRNA intergenic spacer (ITS) region, gltA, and rpoB genes. Bartonella DNA was detected in Aethomys chrysophilus, Aethomys ineptus, Gerbillurus spp., Lemniscomys rosalia, Mastomys coucha, Micaelamys namaquensis, Rhabdomys pumilio, and Thallomys paedulcus. An overall prevalence of 16.9% (31/183, 95% CI: 12.2%-23%) was observed. Bartonella elizabethae, Bartonella grahamii, and Bartonella tribocorum were the zoonotic species identified, while the remaining sequences were aligned to uncultured Bartonella spp. with unknown zoonotic potential. Phylogenetic analyses confirmed five distinct Bartonella lineages (I-V), with lineage IV displaying strong M. coucha host specificity. Our results confirm that South African wild small mammals are natural reservoirs of a diverse assemblage of Bartonella spp., including some zoonotic species with high genetic diversity, although prevalence was relatively low.IMPORTANCESmall mammals play a significant role in the maintenance and spread of zoonotic pathogens such as Bartonella spp. Despite the high small mammal biodiversity in southern Africa including South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals across the country. Results from our study showed the liver and spleen had the highest positive cases for Bartonella spp. DNA among the tested organs. Bartonella elizabethae, B. grahamii, and B. tribocorum were the three zoonotic species identified and five distinct Bartonella lineages (I-V) were confirmed through phylogenetic analyses. To the best of our knowledge, this study presents the first extensive nuclear diversity investigation of Bartonella spp. in South African small mammals in South Africa.

Risk factors of Bartonella spp. infection and the association between Bartonella spp. and T-lymphocyte subset alteration in asymptomatic retrovirus-infected cats in Bangkok Metropolitan, Thailand

Background and Aim: Cats are a reservoir for Bartonella spp. infection in humans. Human bartonellosis causes disseminated inflammation to develop in immunocompromised patients, such as those infected with human immunodeficiency virus. However, the associated risks of Bartonella spp. infection in immunocompromised retroviral-infected cats have been inconclusive. This study aimed to evaluate the associated risks of Bartonella spp. infection with the alteration of T-lymphocyte subsets of retroviral-infected cats. Materials and Methods: We collected blood samples from 161 client-owned cats at veterinary clinics and hospitals throughout the Bangkok Metropolitan area from 2017 to 2020. The samples underwent hematological biochemical tests, feline retroviral status evaluation, Bartonella spp. polymerase chain reaction assay, immunofluorescence assay, and CD4+ and CD8+ lymphocyte counts. Risk factors associated with Bartonella spp. infection were determined by odds ratio (OR). Hematological and biochemical parameters were compared using independent t-tests. CD4+ and CD8+ lymphocyte counts and the CD4+/CD8+ ratio were compared among groups classified according to their retroviral and Bartonella spp. infection status. Results: The prevalence of Bartonella spp. in our study cohort was 16.1%, and the seroprevalence was 94.9%. Cats aged >1 year were at a higher risk of seropositivity than cats aged <1 year (OR: 4.296, 95% confidence interval: 1.010–18.275). The CD8+ percentage was significantly higher in seropositive cats (p = 0.026). There was a significant reduction in the CD4+/CD8+ ratio between cats negative for both retrovirus and Bartonella spp. infection and cats with concurrent retrovirus and Bartonella spp. infection (p = 0.041). Conclusion: In endemic countries or areas, cat owners must be made aware of the risk of exposure to Bartonella spp. due to the high rate of bacteremia and seroprevalence. Retrovirus-infected cats with concurrent Bartonella spp. infection also showed a significant, inverted CD4+/CD8+ ratio, which may be used as a novel marker in bartonellosis. Similar studies focusing on the different stages of retrovirus infection should be undertaken further to elucidate the effect of retrovirus infection on Bartonella spp. infection.

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.

Molecular survey of Bartonella henselae and Bartonella clarridgeiae in pet cats across Japan by species-specific nested-PCR

Cats are known to be the main reservoir for Bartonella henselae and Bartonella clarridgeiae, which are the agents of 'cat-scratch disease' in humans. In the present study, we investigated the prevalence of the two Bartonella species on 1754 cat bloods collected from all prefectures in Japan during 2007-2008 by a nested-polymerase chain reaction (PCR) targeting the 16S-23S rRNA internal transcribed spacer region. Overall, Bartonella DNA was detected in 4·6% (80/1754) of the cats examined. The nested-PCR showed that 48·8% (39/80) of the positive cats were infected with B. henselae mono-infection, 33·8% (27/80) with B. clarridgeiae mono-infection and 17·5% (14/80) were infected with both species. The prevalence (5·9%; 65/1103) of Bartonella infection in the western part of Japan was significantly higher than that (2·3%; 15/651) of eastern Japan (P < 0·001). Statistical analysis of the cats examined suggested a significant association between Bartonella infection and FeLV infection (OR = 1·9; 95% CI = 1·1-3·4), but not with FIV infection (OR = 1·6; 95% CI = 1·0-2·6).

Bartonella spp. - a chance to establish One Health concepts in veterinary and human medicine

Infectious diseases remain a remarkable health threat for humans and animals. In the past, the epidemiology, etiology and pathology of infectious agents affecting humans and animals have mostly been investigated in separate studies. However, it is evident, that combined approaches are needed to understand geographical distribution, transmission and infection biology of “zoonotic agents”. The genus Bartonella represents a congenial example of the synergistic benefits that can arise from such combined approaches: Bartonella spp. infect a broad variety of animals, are linked with a constantly increasing number of human diseases and are transmitted via arthropod vectors. As a result, the genus Bartonella is predestined to play a pivotal role in establishing a One Health concept combining veterinary and human medicine.

Bartonella species infection in cats: ABCD guidelines on prevention and management

OVERVIEW

Over 22 Bartonella species have been described in mammals, and Bartonella henselae is most common worldwide. Cats are the main reservoir for this bacterium. B henselae is the causative agent of cat scratch disease in man, a self-limiting regional lymphadenopathy, but also of other potentially fatal disorders in immunocompromised people.

INFECTION

B henselae is naturally transmitted among cats by the flea Ctenocephalides felis felis, or by flea faeces. A cat scratch is the common mode of transmission of the organism to other animals, including humans. Blood transfusion also represents a risk.

DISEASE SIGNS

Most cats naturally infected by B henselae do not show clinical signs but cardiac (endocarditis, myocarditis) or ocular (uveitis) signs may be found in sporadic cases. B vinsonii subspecies berkhoffii infection has reportedly caused lameness in a cat affected by recurrent osteomyelitis and polyarthritis.

DIAGNOSIS

Isolation of the bacterium is the gold standard, but because of the high prevalence of infection in healthy cats in endemic areas, a positive culture (or polymerase chain reaction) is not confirmatory. Other compatible diagnoses must be ruled out and response to therapy gives a definitive diagnosis. Serology (IFAT or ELISA) is more useful for exclusion of the infection because of the low positive predictive value (39-46%) compared with the good negative predictive value (87-97%). Laboratory testing is required for blood donors.

DISEASE MANAGEMENT

Treatment is recommended in the rare cases where Bartonella actually causes disease.

Chronic Bartonellosis in cats: what are the potential implications?

PRACTICAL RELEVANCE

Bartonellae are small, vector-transmitted Gram-negative intracellular bacteria that are well adapted to one or more mammalian reservoir hosts. Cats are the natural reservoir for Bartonella henselae, which is a (re-)emerging bacterial pathogen. It can cause cat scratch disease in humans and, in immunocompromised people, may lead to severe systemic diseases, such as bacillary angiomatosis. Cats bacteraemic with B henselae constitute the main reservoir from which humans become infected. Most cats naturally infected with B henselae show no clinical signs themselves, but other Bartonella species for which cats are accidental hosts appear to have more pathogenicity.

GLOBAL IMPORTANCE

Several studies have reported a prevalence of previous or current Bartonella species infection in cats of up to 36%. B henselae is common in cats worldwide, and bacteraemia can be documented by blood culture in about a quarter of healthy cats. The distribution of B henselae to various parts of the world has largely occurred through humans migrating with their pet cats. The pathogen is mainly transmitted from cat to cat by fleas, and the majority of infected cats derive from areas with high flea exposure. No significant difference in B henselae prevalence has been determined between male and female cats. In studies on both naturally and experimentally infected cats, chronic bacteraemia has mainly been found in cats under the age of 2 years, while those over 2 years of age are rarely chronically bacteraemic.

EVIDENCE BASE

This article reviews published studies and case reports on bartonellosis to explore the clinical significance of the infection in cats and its impact on humans. The article also discusses possible treatment options for cats and means of minimising the zoonotic potential.

Detection of hemoplasma and Bartonella species and co-infection with retroviruses in cats subjected to a spaying/neutering program in Jaboticabal, SP, Brazil

Hemotrophic mycoplasmas and Bartonella species are important pathogens that circulate between cats and invertebrate hosts, occasionally causing diseases in humans. Nevertheless, there are few reports on occurrences of these agents in cats in Brazil. The present study aimed to detect the presence of hemoplasma and Bartonella DNA by means of PCR and sequencing. FIV antigens and anti-FeLV antibodies, were studied by using a commercial kit on blood and serum samples, respectively, among 46 cats that were sampled during a spaying/neutering campaign conducted in Jaboticabal, SP. Three (6.5%) cats were positive for hemoplasmas: two (4.3%) for 'Candidatus M. haemominutum' and one (2.2%) for both M. haemofelis and 'Candidatus M. turicensis'. One of the two 'Candidatus M. haemominutum'-infected cats was also positive for FeLV antigens and showed antibodies for FIV. Two cats (4.3%) were positive for B. henselae. One of them was also positive for FeLV antigens. Eight cats (17.4%) were positive for FeLV, and just one (2.2%) showed anti-FIV antibodies. Bartonella species and hemoplasmas associated with infection due to retroviruses can circulate among apparently healthy cats.

Detection of Bartonella henselae IgM in serum of experimentally infected and naturally exposed cats

BACKGROUND

Results of Bartonella henselae blood culture, polymerase chain reaction (PCR) assay on blood, or IgG antibody assays do not always correlate with the presence or absence of clinical disease in cats, and B. henselae IgG antibodies in serum do not always correlate with bacteremia. However, little is known concerning Bartonella spp. IgM antibodies in naturally exposed cats.

HYPOTHESIS

Bartonella spp. IgM antibodies in serum are associated with fever, stomatitis, and bacteremia based on PCR assay results in experimentally infected or client-owned cats.

ANIMALS

Stored sera from cats experimentally infected with B. henselae by exposure to Ctenocephalides felis, client-owned cats with and without fever, and client-owned cats with and without stomatitis were studied.

METHODS

A Bartonella spp. IgM ELISA was titrated with samples from experimentally infected cats and then test sera from client-owned cats were assayed. Associations among IgM ELISA results, clinical findings, and bacteremia as defined by Bartonella spp. PCR assay were assessed.

RESULTS

All experimentally infected cats developed Bartonella spp. IgM antibodies. Bartonella spp. IgM antibody assay results were not always in agreement with PCR assay results in client-owned cats (60%). Bartonella spp. DNA in blood, IgM antibodies, and IgG antibodies were not associated with the presence of fever or stomatitis.

CONCLUSIONS AND CLINICAL IMPORTANCE

Because Bartonella spp. IgM antibodies as measured by this assay were not associated with fever or stomatitis and were not always in agreement with PCR assay results, there appears to be little need for assessing individual client-owned cats for this antibody class alone.

Feline bartonellosis

Bartonella infection is common among domestic cats, but the role of Bartonella species as feline pathogens requires further study. Most Bartonella species that infect cats are zoonotic. Cats are the mammalian reservoir and vector for Bartonella henselae, an important zoonotic agent. Cat fleas transmit Bartonella among cats, and cats with fleas are an important source of human B henselae infections. New information about Bartonella as feline pathogens has recently been published, and this article summarizes much of that information. Issues surrounding diagnosis and treatment of feline Bartonella infections are described, and prevention of zoonotic transmission of Bartonella is discussed.

Association between Bartonella species infection and disease in pet cats as determined using serology and culture

This study's objective was to determine whether a relationship exists between infection or seropositivity to Bartonella species and clinical illness in cats. Blood samples were obtained for Bartonella species isolation and immunofluorescent antibody serology from 298 cats presenting to a tertiary referral hospital. Medical records were searched and the history, physical examination findings and the results of diagnostic testing relating to the visit at which Bartonella species testing was performed were recorded. Fifty-two (17%) samples were seropositive for Bartonella henselae, four (1%) for Bartonella clarridgeiae, and 57 (19%) for both organisms. Nineteen (6.4%) samples were culture positive, 17 for B henselae and two for B clarridgeiae. Gingivostomatitis was associated with Bartonella species isolation (P=0.001), but not seropositivity. There was no association with uveitis, neurologic signs, or chronic kidney disease, and a weak association between seropositivity and idiopathic lower urinary tract disease (feline interstitial cystitis) (P=0.05).

Does a feline leukemia virus infection pave the way for Bartonella henselae infection in cats?

Domestic cats serve as the reservoir hosts of Bartonella henselae and may develop mild clinical symptoms or none after experimental infection. In humans, B. henselae infection can result in self-limiting cat scratch disease. However, immunocompromised patients may suffer from more-severe courses of infection or may even develop the potentially lethal disease bacillary angiomatosis. It was reasoned that cats with immunocompromising viral infections may react similarly to B. henselae infection. The aim of our study was to investigate the influence of the most important viruses known to cause immunosuppression in cats-Feline leukemia virus (FeLV), Feline immunodeficiency virus (FIV), and Feline panleukopenia virus (FPV)-on natural B. henselae infection in cats. Accordingly, 142 cats from animal shelters were necropsied and tested for B. henselae and concurrent infections with FeLV, FIV, or FPV by PCR and immunohistochemistry. A significant association was found between B. henselae and FeLV infections (P = 0.00028), but not between B. henselae and FIV (P = 1.0) or FPV (P = 0.756) infection, age (P = 0.392), or gender (P = 0.126). The results suggest that susceptibility to B. henselae infection is higher in cats with concurrent FeLV infections, regardless of whether the infection is latent or progressive. Histopathology and immunohistochemistry for B. henselae failed to identify lesions that could be attributed specifically to B. henselae infection. We conclude that the course of natural B. henselae infection in cats does not seem to be influenced by immunosuppressive viral infections in general but that latent FeLV infection may predispose cats to B. henselae infection or persistence.

Oral shedding of Bartonella in cats: correlation with bacteremia and seropositivity

Cats are the main reservoirs of zoonotic Bartonella henselae, B. clarridgeiae and B. koehlerae, transmitted among cats by cat fleas. No study has investigated the presence of Bartonella in the saliva of bacteremic and non-bacteremic cats to correlate it to the level of bacteremia and the presence or absence of oral lesions. Shelter cats from northern California (n=130) and Michigan (n=50) were tested for Bartonella bacteremia by blood culture, presence of Bartonella antibodies and Bartonella DNA in oral swabs. Bacteremia was detected in 45 (25%) cats, mainly from northern California (n=40), which were highly flea infested and were 4 times more likely to be bacteremic than the non-flea-infested cats from Michigan. Overall, 69 (38.3%) cats had Bartonella PCR positive oral swabs. Bacteremic cats were almost 3 times (P=0.003) more likely to have PCR positive oral swabs (59%, 26/44) than non-bacteremic cats (32.5%, 44/135). However, there was no correlation between cats being bacteremic and having oral lesions. Antibody prevalences for B. henselae and B. clarridgeiae were 30% and 42.8%. B. henselae and B. clarridgeiae seropositive cats were almost 4 times (P=0.0001) and 3 times (P=0.003) more likely to have oral lesions than seronegative cats. Despite a higher prevalence (odds ratio=1.73; 95% confidence interval=0.88-3.38) of oral lesions in cats with oral swabs testing PCR positive, no statistical association could be demonstrated in this cat population.

Emergent opportunities in humans: playful kittens, an arthropod vector, and a zoonotic agent

Bartonella henselae is implicated as the main etiologic agent of Cat scratch disease (CSD, Cat-scratch fever). A majority of domestic cats may harbor the intra-erythrocytic agent for extended periods without apparent disease. In humans, B. henselae most commonly results in a subacute, bacterial infection that presents with one or more reddish papules which may progress to pustules and regional lymph node enlargement. Usual features include fever, malaise, and a granulomatous lymphadenitis on biopsy. However, atypical clinical presentations occur, albeit with infrequence, and may result in a difficult and protracted diagnostic process. The infection in susceptible hosts such as immunocompromised or elderly patients may result in endocarditis, encephalitis, fever of unknown origin, and general malaise. It is not transmitted from person to person and quarantine is not necessary. The arthropod vector, Ctenocephalides felis, or the cat flea, plays a major role in transmission among cats and to humans. The transmission risk to humans can be substantially reduced through elimination of flea infestations in companion animals. There are numerous recent reviews and case reports in the veterinary and medical literature reflecting increased recognition of this zoonotic agent. All this notwithstanding, many physicians and other providers may not be familiar with this agent and the potential spectrum of human disease; this may lead to delays in diagnosis and unnecessary diagnostic procedures. This article emphasizes the aspects of B. henselae infection, including a typical case report and a table with selected human case reports of unusual clinical manifestations from the published literature.

Association of Bartonella species, feline calicivirus, and feline herpesvirus 1 infection with gingivostomatitis in cats

Feline gingivostomatitis (FGS) is a common syndrome in cats; feline calicivirus (FCV), feline herpesvirus 1 (FHV-1), and Bartonella species are common differential diagnoses. In this study, blood from 70 cats with FGS and 61 healthy control cats was tested for Bartonella species antibodies in serum by enzyme-linked immunosorbent assay and Western blot immunoassay and DNA in blood using a conventional polymerase chain reaction assay. Additionally, fresh oral biopsies from cats with FGS (n=42) and 19 healthy controls were tested for FCV RNA, FHV-1 DNA and Bartonella species DNA. The prevalence rates for Bartonella species antibodies and DNA in the blood and the tissues did not differ between the two groups. FHV-1 DNA was also not significantly different between groups. Only FCV RNA was present in significantly more cats with FGS (40.5%) than control cats (0%). The results suggest that FCV was associated with FGS in some of the cats.

Molecular detection of Bartonella henselae and Bartonella clarridgeiae in clinical samples of pet cats from Southern Italy

Bartonella henselae is considered an emerging pathogen of veterinary and medical interest that can be occasionally transmitted to humans. Cats are considered to be the only reservoir host for B. henselae. In this study, we used a nested-PCR assay to investigate the prevalence of B.henselae and Bartonella clarridgeiae DNA in peripheral blood samples, fine needle lymph node aspirate specimens and oral swabs from 85 cats in order to develop an easy diagnostic strategy for the selection of infection-free cats that are being considered as pets, especially for immunocompromised patients. Overall, molecular analysis showed that 71 cats (83.5%) tested PCR positive for the presence of B. henselae DNA. PCR amplification of DNA B. henselae produced positive products from lymph node aspirate specimens (62/85; 72.9%) similar to those obtained from blood samples (60/85; 70.6%) and higher than those from oral swabs (51/85; 60%) of cats. No PCR product was obtained for B. clarridgeiae. The simultaneous analysis of three different clinical samples in our study increased the diagnostic possibilities for B. henselae infection in the examined cats from 60-72.9% to 83.5%. Lymph node aspirates were found to be the most effective clinical samples for the detection of B. henselae and blood samples were the next best. Oral swab samples were used in this study with good results when considered in combination with blood and/or lymph node aspiration. The use of nested-PCR assay on these three clinical samples may enhance the diagnostic sensitivity for bartonellosis in cats irrespective of the clinical status of animals.

Prevalence of Bartonella species antibodies and Bartonella species DNA in the blood of cats with and without fever

The purpose of this study was to determine whether there are associations between Bartonella species antibody (enzyme-linked immunosorbent assay (ELISA) and Western blot (WB)) and polymerase chain reaction assay results in cats with and without fever. Afebrile control cats (39/93; 42.0%) were more likely to have Bartonella species antibodies than cats with fever (29/93; 31.2%). The difference in prevalence of Bartonella species deoxyribonucleic acid (DNA) in blood of cats with fever (14/81; 17.3%) as compared to afebrile control cats (6/81; 7.4%) approached statistical significance (P=0.0571). Bartonella species ELISA or WB results frequently did not correlate to the presence or absence of Bartonella species DNA in blood. The results of this study indicate that in cats, Bartonella species antibody tests cannot predict whether fever is due to Bartonella species infection and should not be used to determine the Bartonella species infection status.

Molecular evidence for Bartonella spp. in cat and dog fleas from Germany and France

Nine hundred and fifty-two fleas were collected from 148 cats and 133 dogs at 18 widely distributed geographic locations in Germany and France and examined for the presence of six different Bartonella spp. (Bartonella bacilliformis, Bartonella clarridgeiae, Bartonella elizabethae, Bartonella henselae, Bartonella quintana, Bartonella vinsonii subsp. berkhoffii) by PCR. Thirty-five specimens (3.7%) tested positive for either B. henselae (14 positive fleas) or B. clarridgeiae (21 positive fleas). DNA of other Bartonella spp. were not detected. Bartonella clarridgeiae was the dominating species in samples from France (19 out of 22 positive fleas), whereas B. henselae was more frequent in Germany (11 out of 13 positive fleas). With 3.5% (22 out of 632 fleas) in France and 4.1% (13 out of 320 fleas) in Germany, the overall prevalences of pathogen did not vary significantly between the flea populations of both countries. 5.4% of cats in France versus 16.1% of cats from Germany were infested by fleas carrying Bartonella, whereas 9.5% of dogs in France but none of the examined dogs from Germany were infested by Bartonella positive fleas. The molecular evidence of Bartonella infections reveals that agents of zoonotic potential are established in flea populations in Germany and France and that the spectrum of species can vary significantly from country to country.

Evaluation of the association of Bartonella species, feline herpesvirus 1, feline calicivirus, feline leukemia virus and feline immunodeficiency virus with chronic feline gingivostomatitis

Gingivostomatitis (GS) is a significant condition in cats because of oral discomfort and associated periodontal disease. Several infectious agents have been associated with the presence of GS, but a causal relationship is unclear. The cats in this study were housed together, had a history of flea exposure, and were vaccinated with a modified live FVRCP product. There were nine cats with active GS and 36 unaffected cats at the time of sample collection. Serum was tested for feline leukemia virus (FeLV) antigen and antibodies against feline immunodeficiency virus, feline calicivirus (FCV), feline herpesvirus 1 (FHV-1), and Bartonella species (enzyme-linked immunosorbent assay and Western blot immunoassay). PCR assays for Bartonella species and FHV-1 and a reverse transcriptase PCR assay for FCV were performed on blood and throat swabs. All cats were negative for FeLV. Assay results failed to correlate to the presence of GS in the group of cats studied.

Prevalence of DNA of Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum,' Anaplasma phagocytophilum, and species of Bartonella, Neorickettsia, and Ehrlichia in cats used as blood donors in the United States

OBJECTIVE

To identify the prevalence of DNA of Mycoplasma haemofelis; 'Candidatus Mycoplasma haemominutum'; Anaplasma phagocytophilum; and species of Bartonella, Neorickettsia, and Ehrlichia in blood of cats used as blood donors in the United States.

DESIGN

Prospective study.

ANIMALS

146 cats that were active blood donors.

PROCEDURES

Environmental history was requested for each blood-donor cat from which a blood sample (mixed with EDTA) was available. Polymerase chain reaction assays capable of amplifying the DNA of the microorganisms of interest following DNA extraction from blood were performed.

RESULTS

Overall, DNA of one or more of the infectious agents was detected in blood samples from 16 of 146 (11%) feline blood donors. Twenty-eight laboratory-reared cats housed in a teaching hospital had negative results for DNA of all organisms investigated. The DNA of at least 1 infectious agent was amplified from blood samples collected from 16 of 118 (13.6%) community-source cats; assay results were positive for 'Candidatus M haemominutum,' M haemofelis, or Bartonella henselae alone or in various combinations. Of the community-source cats allowed outdoors (n = 61) or with known flea exposure (44), DNA for a hemoplasma or B henselae was detected in 21.3% and 22.7%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

When community-source cats, cats allowed outdoors, or cats exposed to fleas are to be used as blood donors, they should be regularly assessed for infection with M haemofelis, 'Candidatus M haemominutum,' and Bartonella spp, and flea-control treatment should be regularly provided.

Prevalence of Bartonella henselae antibodies in serum of cats with and without clinical signs of central nervous system disease

Bartonella henselae is occasionally associated with neurological dysfunction in people and some experimentally infected cats. The purpose of this study was to determine whether B henselae seroprevalence or titer magnitude varies among cats with neurological disease, cats with non-neurological diseases, and healthy cats while controlling for age and flea exposure. There was no difference in B henselae seroprevalence rates between cats with seizures and cats with other neurological diseases. Cats with non-neurological disease and healthy cats were more likely than cats with neurological disease to be seropositive. While the median B henselae antibody titer was greater in cats with seizures than in cats with other neurological disease, the median B henselae antibody titer was also greater in healthy cats than cats with seizures. The results suggest that titer magnitude cannot be used alone to document clinical disease associated with B henselae infection and that presence of B henselae antibodies in serum of cats with neurological disease does not prove the clinical signs are related to B henselae.

Gingivostomatitis

Gingivostomatitis (GS) with various patterns of disease may require antiviral therapy, steroids, laser fulguration, immunomodulation drugs, or nonsteroidal anti-inflammatory drugs. The use of cyclosporine as an immunomodulation drug has long-term benefits in reduction of the immunologic events that contribute to GS. Whole-mouth extraction or partial extraction (premolars and molars), with radiographic conformation that all root remnants have been removed, may be the most viable option in nonresponsive and or intractably painful stomatitis in noncompliant cats or dogs. Oral inflammation subsided after extraction without the need for further medication in approximately 70% of the cats from two studies with previous chronic unrelenting oral disease. The combination of immunomodulation with cyclosporine together with laser resection of proliferative tissue should be recommended if extraction of teeth is not desired. Removal of proliferative oral tissues by lasing (carbon dioxide laser) removes the tissue that maybe producing tissue antigens and the area where bacteria are sequestered. The use of anti-inflammatory medications is recommended in the management of GS. Therapeutic success is achieved when there is elimination of proliferative tissue and inflammation.

Bartonellosis

The role of Bartonella species as pathogens in dogs and cats is being defined. Diagnosis and treatment of Bartonella infections of dogs and cats remain challenging. As new information regarding Bartonella infections of companion animals becomes available, the understanding of the pathogenesis of these infections will improve. Most Bartonella species infecting dogs and cats are zoonotic, with B henselae the most important zoonotic species. B henselae bacteremia is common in domestic cats, and cats transmit B henselae to people. Transmission of Bartonella infections among cats and dogs is believed to occur primarily by way of arthropod vectors. Control of arthropod vectors and avoiding interactions with pets that result in scratches or bites are the most effective means to prevent transmission between animals and people.

Clinical impact of persistent Bartonella bacteremia in humans and animals

Bartonella spp. are emerging vector-borne pathogens that cause persistent, often asymptomatic bacteremia in their natural hosts. As our knowledge progresses, it appears that chronic infection may actually predispose the host to mild, insidious nonspecific manifestations or induce, in selected instances, severe diseases. Persistent asymptomatic bacteremia is most common in animals that serve as the main reservoir for the specific Bartonella. In humans, these organisms are B. bacilliformis and B. quintana. Other Bartonella species, for which humans are not the natural reservoir, tend to cause persistent bacteremia only in immunodeficient individuals. In some of these individuals, endothelial cell proliferation may create lesions such as bacillary angiomatosis or bacillary peliosis. In cats, bacteremia of variable level and continuity may last for years. Some strains of B. henselae may induce clinical manifestations, including fever, mild neurological signs, reproductive disorders, whereas others do not induce clinically obvious disease. Reproductive disorders have also been reported in mice experimentally infected with B. birtlesii. Finally, canids constitute the most interesting naturally occurring animal model for the human disease. Like immunocompetent people, healthy dogs only occasionally demonstrate long-term bacteremia when infected with Bartonella spp. However, some dogs develop severe clinical manifestations, such as endocarditis, and the pathologic spectrum associated with Bartonella spp. infection in domestic dogs is rapidly expanding and resembles the infrequently reported clinical entities observed in humans. In coyotes, persistent bacteremia is more common than in domestic dogs. It will be of interest to determine if coyotes develop clinical or pathological indications of infection.

Bartonella infection in animals: carriership, reservoir potential, pathogenicity, and zoonotic potential for human infection

Recent observations have begun to support a role for Bartonella spp. as animal as well as human pathogens. Bartonella spp. are vector-transmitted, blood-borne, intracellular, gram-negative bacteria that can induce prolonged infection in the host. Persistent infections in domestic and wild animals result in a substantial reservoir of Bartonella organisms in nature that can serve as a source for inadvertent human infection. The prevalence of bacteremia can range from 50 to 95% in selected rodent, cat, deer, and cattle populations. Dogs infected with Bartonella spp. can develop lameness, endocarditis, granulomatous lymphadenitis, and peliosis hepatis, lesions that have also been reported in association with human infection. Understanding the role of Bartonella spp. as pathogens in cats and other wild or domestic animals awaits the results of additional studies. Considering the extensive animal reservoirs and the large number of insects that have been implicated in the transmission of Bartonella spp., both animal and human exposure to these organisms may be more substantial than is currently believed.

Bartonella infection in animals: carriership, reservoir potential, pathogenicity, and zoonotic potential for human infection

Recent observations have begun to support a role for Bartonella spp. as animal as well as human pathogens. Bartonella spp. are vector-transmitted, blood-borne, intracellular, gram-negative bacteria that can induce prolonged infection in the host. Persistent infections in domestic and wild animals result in a substantial reservoir of Bartonella organisms in nature that can serve as a source for inadvertent human infection. The prevalence of bacteremia can range from 50 to 95% in selected rodent, cat, deer, and cattle populations. Dogs infected with Bartonella spp. can develop lameness, endocarditis, granulomatous lymphadenitis, and peliosis hepatis, lesions that have also been reported in association with human infection. Understanding the role of Bartonella spp. as pathogens in cats and other wild or domestic animals awaits the results of additional studies. Considering the extensive animal reservoirs and the large number of insects that have been implicated in the transmission of Bartonella spp., both animal and human exposure to these organisms may be more substantial than is currently believed.

Bartonella spp antibodies and DNA in aqueous humour of cats

Bartonella spp antibodies were measured in the serum and aqueous humour of cats with and without uveitis and polymerase chain reaction (PCR) for Bartonella spp DNA was performed on aqueous humour from most of the cats. Serum and aqueous humour were assayed from 49 client-owned cats with uveitis, 49 healthy shelter cats, and nine cats experimentally inoculated with either B henselae or B clarridgeiae, 454 days after inoculation. An aqueous antibody coefficient (C value) was calculated for cats positive for Bartonella spp antibodies in the aqueous humour. Ocular production of Bartonella spp IgG (C value >1) was detected in seven of 49 cats with uveitis, none of 49 healthy shelter cats, and four of nine experimentally inoculated cats. The organism was detected by PCR in the aqueous humour of three of 24 cats with uveitis, one of 49 healthy shelter cats, and four of nine experimentally inoculated cats. Bartonella spp infect the eyes of some cats following natural exposure or experimental inoculation and may cause uveitis in some cats.

Bartonella vinsonii subsp. berkhoffii and related members of the alpha subdivision of the Proteobacteria in dogs with cardiac arrhythmias, endocarditis, or myocarditis

Cardiac arrhythmias, endocarditis, or myocarditis was identified in 12 dogs, of which 11 were seroreactive to Bartonella vinsonii subspecies berkhoffii antigens. Historical abnormalities were highly variable but frequently included substantial weight loss, syncope, collapse, or sudden death. Fever was an infrequently detected abnormality. Cardiac disease was diagnosed following an illness of short duration in most dogs, but a protracted illness of at least 6 months' duration was reported for four dogs. Valvular endocarditis was diagnosed echocardiographically or histologically in eight dogs, two of which also had moderate to severe multifocal myocarditis. Four dogs lacking definitive evidence of endocarditis were included because of seroreactivity to B. vinsonii antigens and uncharacterized heart murmurs and/or arrhythmias. Alpha proteobacteria were not isolated from the blood by either conventional or lysis centrifugation blood culture techniques. Using PCR amplification and DNA sequencing of a portion of the 16S rRNA gene, B. vinsonii was identified in the blood or heart valves of three dogs. DNA sequence alignment of PCR amplicons derived from blood or tissue samples from seven dogs clustered among members of the alpha subdivision of the Proteobacteria and suggested the possibility of involvement of one or more alpha proteobacteria; however, because of the limited quantity of sequence, the genus could not be identified. Serologic or molecular evidence of coinfection with tick-transmitted pathogens, including Ehrlichia canis, Babesia canis, Babesia gibsonii, or spotted fever group rickettsiae, was obtained for seven dogs. We conclude that B. vinsonii subsp. berkhoffii and closely related species of alpha proteobacteria are an important, previously unrecognized cause of arrhythmias, endocarditis, myocarditis, syncope, and sudden death in dogs.

Clinical and pathologic evaluation of chronic Bartonella henselae or Bartonella clarridgeiae infection in cats

Human Bartonella infections result in diverse medical presentations, whereas many cats appear to tolerate chronic bacteremia without obvious clinical abnormalities. Eighteen specific-pathogen-free cats were inoculated with Bartonella henselae- and/or Bartonella clarridgeiae-infected cat blood and monitored for 454 days. Relapsing bacteremia did not correlate with changes in protein profiles or differences in antigenic protein recognition. Intradermal skin testing did not induce a delayed type hypersensitivity reaction to cat scratch disease skin test antigen. Thirteen cats were euthanatized at the end of the study. Despite persistent infection, clinical signs were minimal and gross necropsy results were unremarkable. Histopathology revealed peripheral lymph node hyperplasia (in all of the 13 cats), splenic follicular hyperplasia (in 9 cats), lymphocytic cholangitis/pericholangitis (in 9 cats), lymphocytic hepatitis (in 6 cats), lymphoplasmacytic myocarditis (in 8 cats), and interstitial lymphocytic nephritis (in 4 cats). Structures suggestive of Bartonella were visualized in some Warthin-Starry stained sections, and Bartonella DNA was amplified from the lymph node (from 6 of the 13 cats), liver (from 11 cats) heart (from 8 cats), kidney (from 9 cats), lung (from 2 cats), and brain (from 9 cats). This study indicates that B. henselae or B. clarridgeiae can induce chronic infection following blood transfusion in specific-pathogen-free cats and that Bartonella DNA can be detected in blood, brain, lymph node, myocardium, liver, and kidney tissues of both blood culture-positive cats and blood culture-negative cats. Detection of histologic changes in these cats supports a potential etiologic role for Bartonella species in several idiopathic disease processes in cats.

Seroprevalence of Bartonella henselae and Toxoplasma gondii infections among pet cats in Kanagawa and Saitama Prefectures

Seroprevalence of Bartonella henselae and Toxoplasma gondii was investigated among 471 pet cats obtained from seven private animal hospitals in Kanagawa and Saitama Prefectures during the period from May 1994 to June 1995. 'Furthermore, 67 randomly selected from the 471 serum samples were examined for the feline immunodeficiency virus (FIV) antibody and feline leukemia virus (FeLV) antigen. The antibody to B. henselae was examined by an indirect immunofluorescent antibody test. T. gondii, FIV and FeLV infections in cats were detected with respective commercial kits. Of the cat serum samples tested, 43 (9.1%) were found to be seropositive for B. henselae and 41 (8.7%) for T. gondii. The B. henselae-positive rate (12.9%) of male cats was significantly higher than that (5.2%) of female cats. On the other hand, T. gondii-positive rate was 9.1% in male and 8.7% in female cats and there was no significant difference in the positivity between sexes. The positive rate in each hospital varied from 0 to 19.5% for B. henselae and 4.9 to 18.8% for T. gondii. The ages of B. henselae- and T. gondii-positive cats were distributed from < 1-year-old to 14-year-old and the seropositivity increased with age of cats. Of the 67 cat serum samples, 16 and 6 cases were positive for FIV and FeLV, respectively. There was no relationship between these viral and B. henselae infections in cats.

Seroprevalence of Bartonella henselae infection and correlation with disease status in cats in Switzerland

The prevalence of infection with Bartonella henselae was investigated in cats from different areas of Switzerland. Serum samples of 728 cats were examined for antibodies to B. henselae by immunofluorescent antibody testing, and the results were analyzed with a view to a possible correlation between a positive titer and signalment, clinical signs, infection with feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline coronavirus (FCoV), or feline spumavirus (FeSFV), and the living environments of the cats. The seroprevalence in all cats was 8.3%. No significantly different prevalence was found in sick versus healthy cats (9.2 versus 7.2%); however, in sick cats seropositive for B. henselae, there was an increased frequency of stomatitis and a variety of diseases of the kidneys and the urinary tract. There was an increased prevalence of B. henselae in cats positive for FCoV (P = 0.0185) or FeSFV (P = 0.0235) and no statistically significant increased prevalence in cats infected with FeLV or FIV. There was no correlation between a positive titer and sex or breed. The same prevalence of B. henselae antibodies was found in cats with and without access to the outdoors and in cats from single- and multicat households. The seroprevalence was increased in cats living south of the Alps (12.1%); however, this difference was not significant (P = 0.0616).