Cat-scratch disease in Northern Italy: atypical clinical manifestations in humans and prevalence of Bartonella infection in cats

Canine and Feline Parasitology: Analogies, Differences, and Relevance for Human Health

Cats and dogs are treated as family members by most pet owners. Therefore, a high quality of veterinary care and preventive medicine is imperative for animal health and welfare and for the protection of humans from zoonotic pathogens. There is a general perception of cats being treated as "small dogs," especially in the field of clinical parasitology. As a result, several important differences between the two animal species are not taken into proper consideration and are often overlooked. Dogs and cats are profoundly different under evolutionary, biological, ethological, behavioral, and immunological standpoints. These differences impact clinical features, diagnosis, and control of canine and feline parasites and transmission risk for humans. This review outlines the most common parasitoses and vector-borne diseases of dogs and cats, with a focus on major convergences and divergences, and discusses parasites that have (i) evolved based on different preys for dogs and cats, (ii) adapted due to different immunological or behavioral animal profiles, and (iii) developed more similarities than differences in canine and feline infections and associated diseases. Differences, similarities, and peculiarities of canine and feline parasitology are herein reviewed in three macrosections: (i) carnivorism, vegetarianism, anatomy, genetics, and parasites, (ii) evolutionary adaptation of nematodes, including veterinary reconsideration and zoonotic importance, and (iii) behavior and immune system driving ectoparasites and transmitted diseases. Emphasis is given to provide further steps toward a more accurate evaluation of canine and feline parasitology in a changing world in terms of public health relevance and One Health approach.

Serological Survey on the Occurrence of Rickettsia spp., Neospora caninum, Bartonella henselae and Toxoplasma gondii in Cats from Tuscany (Central Italy)

Simple Summary

Domestic and stray cats are frequently infected by pathogens, some of which are zoonotic. The occurrence of microorganisms such as Bartonella henselae and Toxoplasma gondii, even though they are well known, could be underestimated because they are not regularly investigated in cats. Other pathogens, such as Neospora caninum and Rickettsia spp., have not been largely studied in feline populations and data about their spreading in Italian cats are very scanty. Monitoring of domestic and stray cats for these pathogens is important to evaluate the health status of the animals, but also, regarding B. henselae, Rickettsia spp. and T. gondii, from a One Health perspective.

Abstract

Asymptomatic cats often harbor pathogens, some of which have not been largely investigated in feline populations. The aim of this study was to evaluate the occurrence of antibodies against Rickettsia conorii, Rickettsia felis, Rickettsia typhi, Neospora caninum, Bartonella henselae and Toxoplasma gondii in cats from Tuscany. Ninety-five blood serum samples, previously collected, were analyzed by indirect immunofluorescence assay. Fifty-six (58.94%) cats had antibodies to at least one investigated pathogen: 28 (29.47%) cats were positive for B. henselae, 17 (17.89%) for R. felis, 14 (14.73%) for R. conorii, 14 (14.73%) for T. gondii, 2 (2.1%) for N. caninum. No cats were positive for R. typhi. Positive reactions to two or more pathogens were detected in 18 (18.94%) cats. The occurrence of antibodies against these microorganisms suggests that cats, even though asymptomatic, may be infected by pathogens, often zoonotic, and thus may be a source of infections for other animals and humans.

Bartonella henselae IgM seropositivity in both adult and pediatric patients with diverse clinical conditions in Turkey

Bartonella henselae is the causative agent of cat scratch disease (CSD). In this study, we aimed to investigate the clinical data of patients with suspicion of CSD and delineate current epidemiological features.A total of 785 patients with suspected CSD were included in the study. B. henselae IgM antibody was determined by indirect fluorescent antibody (IFA) test using a commercial kit (Euroimmun, Germany). Sex, age, clinical pre-diagnosis and animal contact information of the patients were obtained from hospital electronic database records.Seventy-eight (9.9%) of 785 samples were seropositive. Out of 78 patients, 46 with animal contact data were further analyzed. Of these patients, 56% were male, and 41% were under 18 years of age. Seropositivity was more commonly observed in fall and winter. The most common finding was lymphadenitis (63%). Thirty-five patients (76%) had a previous history of animal contact (cat/dog). Of the 46 seropositive patients, 78.3, 15.2, 4.4, and 2.1% had titers of 1:80, 1:160, 1:320, and 1:640, respectively.Our study confirms that CSD is not rare in Turkey. Thus, it should always be considered in the differential diagnosis of patients presenting with lymphadenopathy in all age groups, particularly children. Questioning of cat exposure should never be neglected, especially in areas with intense population of stray cats, such as Istanbul.

Serological and molecular detection of Bartonella henselae in specimens from patients with suspected cat scratch disease in Italy: A comparative study

Cat scratch disease (CSD) is an infectious disease caused by Bartonella henselae, usually characterized by self-limiting regional lymphadenopathy and fever. Given the low clinical diagnostic sensitivity and specificity of conventional anti-B. henselae indirect immunofluorescence assays (IFAs), real-time polymerase chain reaction (PCR)-based detection of B. henselae is now being proposed as a more sensitive tool to diagnose CSD. Thus, here we have assessed the efficacy of real-time PCR in detecting B. henselae in different specimens from patients with suspected CSD and compared it to that of IFA. From March 2011 to May 2016, at the Microbiology and Virology Unit, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, Turin, Italy, 115 clinical specimens (56 aspirated pus, 39 fresh lymph node biopsies, and 20 whole blood samples) and 99 sera from 115 patients with suspected CSD (62 females and 53 males between the ages of 3 months and 68 years) were analyzed by both real-time PCR, used in a qualitative way, and IFA (IgM and IgG) for the presence of B. henselae. For 16 patients, serological results were not available due to a clinical decision not to request the test. B. henselae DNA positivity was detected by real-time PCR in 37.39% of patients, while 62.61% of them were negative. Thus, patients were divided into two groups: real-time PCR+ (n = 43) and real-time PCR- (n = 72). Real-time PCR screening of whole blood, biopsies, and aspirated pus revealed B. henselae positivity in 40%, 38.46%, and 35.71% of patients, respectively. When we analyzed samples by IFA, we found the presence of B. henselae in 28 out of 99 (28.28%) patients, of which 11 (11.11%) belonged to the real-time PCR+ group and 17 (17.17%) to the real-time PCR- group. Among the 71 seronegative subjects, 16 (16.16%) were found positive for B. henselae by real-time PCR. Thus, by combining the results of both assays, we were able to increase the percentage of B. henselae positive specimens from 27.27% (real-time PCR) or 28.28% (IFA) to 44.44% (real-time PCR+IFA). Altogether, these findings indicate that the early detection of B. henselae in patients with suspicious CSD through combined real-time PCR and serological analyses can lead to a more accurate diagnosis of CSD, thereby allowing prompt and appropriate disease management.

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.

Bartonella henselae infection presenting as cervical spine osteomyelitis: case report

Bartonella henselae is a gram-negative bacillus implicated in cat-scratch disease. Cat-scratch disease is usually self-limiting and results in local lymphadenopathy. In rare circumstances, patients may develop endocarditis, neuroretinitis, or osteomyelitis. Osteomyelitis of the cervical spine is exceedingly rare, especially in the pediatric population, and to date there have been only 4 previously reported cases of cervical spine osteomyelitis caused by B. henselae, all of which were treated surgically. In this article, the authors report the case of a 7-year-old boy who presented with neck swelling and was found to have a C2-4 paravertebral B. henselae abscess with osteomyelitis of C-3 and epidural extension. To the authors' knowledge, this represents the first case in the literature of a cervical spine B. henselae infection managed conservatively.

The cat did it: erythema nodosum and additional atypical presentations of Bartonella henselae infection in immunocompetent hosts

A healthy patient presented with painful skin lesions on the anterior surface of her legs. Erythema nodosum was diagnosed but all the usual causes were ruled out. The finding of bilateral enlarged axillary lymph nodes with necrosis and granulomas led to the diagnosis of Bartonella infection, an unusual cause of erythema nodosum. Imaging also revealed splenomegaly and small para-aortic lymph nodes. Up to one quarter of the patients with cat-scratch disease present atypically, a considerably higher prevalence than previously reported. A comprehensive review of the literature (PubMed, since inception, all languages) revealed a remarkable array of unusual presentations which are summarised and briefly discussed.

Seroprevalence of Bartonella henselae in patients awaiting heart transplant in Southern Italy

BACKGROUND

Bartonella henselae is the etiologic agent of cat-scratch disease. B. henselae infections are responsible for a widening spectrum of human diseases, although often symptomless, ranging from self-limited to life-threatening and show different courses and organ involvement due to the balance between host and pathogen. The role of the host immune response to B. henselae is critical in preventing progression to systemic disease. Indeed in immunocompromised patients, such as solid organ transplant patients, B. henselae results in severe disseminated disease and pathologic vasoproliferation. The purpose of this study was to determine the seroprevalence of B. henselae in patients awaiting heart transplant compared to healthy individuals enrolled in the Regional Reference Laboratory of Transplant Immunology of Second University of Naples.

METHODS

Serum samples of 38 patients awaiting heart transplant in comparison to 50 healthy donors were examined using immunfluorescence assay.

RESULTS

We found a B. henselae significant antibody positivity rate of 21% in patients awaiting heart transplant (p = 0.002). There was a positive rate of 8% (p > 0.05) for immunoglobulin (Ig)M and a significant value of 13% (p = 0.02) for IgG, whereas controls were negative both for IgM and IgG antibodies against B. henselae. The differences in comorbidity between cases and controls were statistically different (1.41 ± 0.96 vs 0.42 ± 0.32; p = 0.001).

CONCLUSIONS

Although this study was conducted in a small number of patients, we suggest that the identification of these bacteria should be included as a routine screening analysis in pretransplant patients.

Clinical Profile and Visual Outcome of Ocular Bartonellosis in Malaysia

Background. Ocular bartonellosis can present in various ways, with variable visual outcome. There is limited data on ocular bartonellosis in Malaysia. Objective. We aim to describe the clinical presentation and visual outcome of ocular bartonellosis in Malaysia. Materials and Methods. This was a retrospective review of patients treated for ocular bartonellosis in two ophthalmology centers in Malaysia between January 2013 and December 2015. The diagnosis was based on clinical features, supported by a positive Bartonella spp. serology. Results. Of the 19 patients in our series, females were predominant (63.2%). The mean age was 29.3 years. The majority (63.2%) had unilateral involvement. Five patients (26.3%) had a history of contact with cats. Neuroretinitis was the most common presentation (62.5%). Azithromycin was the antibiotic of choice (42.1%). Concurrent systemic corticosteroids were used in approximately 60% of cases. The presenting visual acuity was worse than 6/18 in approximately 60% of eyes; on final review, 76.9% of eyes had a visual acuity better than 6/18. Conclusion. Ocular bartonellosis tends to present with neuroretinitis. Azithromycin is a viable option for treatment. Systemic corticosteroids may be considered in those with poor visual acuity on presentation.

Bartonella henselae in Italy: a rare seasonal infection

BACKGROUND

Symptomatic Bartonella henselae infection is considered rare in Europe. Cat fleas transmit the microorganism between cats, but their role in transmission of B. henselae to humans has not been defined. The aim of our study was to perform a retrospective study of detected cases at our Hospital.

METHODS

We retrospectively analyzed data of all children showing lymphadenopathy and a 4-fold increase in specific IgM for B. henselae over the period from June 2010 to May 2015. We therefore examined clinical data, laboratory exams in order to achieve a description of the expression of Bartonella infection in our series: age, geographical area of origin, symptoms, laboratory exams, the seat of the swelling lymph nodes with ultrasound description, and data on biopsy of lymph node when performed.

RESULTS

We could identify a total of 7 patients (4 females, range of age: mean age 8.75±2.87 SD): three cases in 2011 and 1 case per year in 2010, 2012, 2013 and 2014 with an average distance between one case and the sequent of 246.16±214.54 days. All patients came from small towns with no preference between the inland and coastal areas. The infection was characterized only by lymphadenopathy with nonspecific alterations at blood tests and with no history of cat scratch.

CONCLUSIONS

By our experience, Bartonella infection presents as a seasonal disease with increased incidence in autumn, with peaks in October, and a decrease after spring. In conclusion, infection with B. henselae is an issue to keep in consideration in all cases of lymphadenopathy, especially in children coming from small towns even without a declared cat scratch.

Visceral cat scratch disease with endocarditis in an immunocompetent adult: a case report and review of the literature

Infective endocarditis and hepatosplenic abscesses are rare manifestations of cat scratch disease (CSD), especially among immunocompetent adults. An otherwise healthy woman who presented with fever and abdominal pain was diagnosed with multiple abscesses in the spleen and the liver, as well as a mitral valve vegetation. PCR on spleen tissue was positive for Bartonella henselae. Prolonged treatment with doxycycline and gentamicin led to complete recovery. Review of the literature revealed 18 cases of hepatosplenic CSD in immunocompetent adults; the majority presented with fever of unknown origin and abdominal pain. In most cases the causative organism was B. henselae and the pathological findings were necrotizing granulomas, similar to the pathological features in classic CSD. Concomitant endocarditis was diagnosed in one case. Because Bartonella is one of the leading pathogens of culture-negative endocarditis, we raise the question of whether a comprehensive evaluation for endocarditis is needed in cases of systemic CSD.

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.