First report of Cytauxzoon sp. infection in Germany: organism description and molecular confirmation in a domestic cat

Sylvatic vector-borne pathogens including Cytauxzoon europaeus in the European wildcat (Felis silvestris) from southwestern Germany

BACKGROUND

European wildcats (Felis silvestris) are widely distributed in Europe and a strictly protected species in Germany. Lately, anthropogenic protective efforts lead to increasing numbers of wildcats in southwestern Germany. Moreover, in recent years the numbers of domestic cats are increasing. Thus, the contact between domestic and wildcats may lead to the spread of zoonotic pathogens in both animal species. As data on vector-borne pathogens (VBPs) in wildcats from Germany are limited to date, the objective of this study was to investigate the presence and current distribution of VBPs in wildcats from southwestern Germany.

METHODS

Skin and spleen samples from 117 European wildcats, originating from a regional carcass-monitoring program in southwestern Germany, were examined by real-time and conventional polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum, Neoehrlichia mikurensis, Rickettsia spp., Bartonella spp., and Piroplasmida.

RESULTS

In total, 6.8% (n = 8) of the wildcats were Rickettsia-positive, specified as R. helvetica. Three wildcats were positive for A. phagocytophilum (2.6%), one for Bartonella spp., namely B. taylorii (0.8%), and 84 for Cytauxzoon spp. (71.8%). Out of these 84 samples, 23 were further sequenced revealing very high identity levels (99.84-100%) to C. europaeus, which is considered to be pathogenic for domestic cats. All wildcats were negative for the presence of N. mikurensis DNA.

CONCLUSIONS

European wildcats in southwestern Germany are hosting several VBPs. With the exception of Cytauxzoon spp., low prevalence rates of most examined pathogens suggest that wildcats are primarily incidental hosts for sylvatic pathogens associated with rodents, in contrast to domestic cats. However, the high prevalence of the cat-associated pathogen C. europaeus suggests that wildcats in southwestern Germany may serve as reservoirs for this pathogen.

Vector-Borne Pathogens in Stray Cats in Eastern Germany (Thuringia)

Bacterial, protozoal, and viral vector-borne pathogens (VBPs) can cause infections in cats. There is little information on feline VBP prevalence in Germany. Stray cats are frequently exposed to vectors but receive no veterinary care. The aim of this study was to determine the prevalence of selected VBPs in stray cats. EDTA blood and serum samples were taken from apparently healthy stray cats during a spay/neuter campaign in the federal state of Thuringia. Overall, 11/50 (22%) and 32/50 (64%) cats tested positive for at least one VBP by direct and indirect detection methods, respectively. PCR testing of EDTA blood detected hemotropic Mycoplasma spp. in 12% of cats, Hepatozoon spp. in 10%, and Anaplasma phagocytophilum in 4%. PCR testing for Rickettsia spp. and piroplasms was negative. IFAT on serum samples showed 46% of cats had detectable antibodies for Bartonella spp., 30% for Rickettsia spp., and 16% for A. phagocytophilum. The cats were additionally tested for feline coronavirus, FIV, and FeLV to identify potential risk factors for pathogen contact and/or infections. No correlation between FIV and FeLV status and VBP positivity was detected. Anaplasma phagocytophilum, Rickettsia spp., and Bartonella spp. have zoonotic potential, and surveillance is recommended in the context of the One Health approach.

Molecular survey of Cytauxzoon spp. and Hepatozoon spp. in felids using a novel real-time PCR approach

Tick-transmitted apicomplexans of the genera Cytauxzoon and Hepatozoon affect a wide range of felids worldwide, but little is known about them. Recently, several studies addressed the species circulating in Europe, their distribution, and their hosts. Molecular assays are the method of choice for their detection. Unfortunately, conventional PCRs already described are time- and cost-consuming and specific for either Hepatozoon or Cytauxzoon detection. This study was developed to evaluate (i) the occurrence of Cytauxzoon and Hepatozoon in felids using a fast and cost-saving real-time PCR capable of detecting both protozoa simultaneously, (ii) the distribution of Cytauxzoon and Hepatozoon species in north-eastern Italy, and (iii) the involvement of other susceptible felid hosts in the same area. An SYBR^® Green-based real-time PCR with primers targeting the 18S-rRNA was validated and applied to 237 felid samples, i.e., whole blood from 206 domestic cats and 12 captive exotic felids, and tissues from 19 wildcats. Positive results were obtained by melting temperature curve analysis due to the specific melting peak (i.e., 81°C Cytauxzoon spp.; 78-78.5°C Hepatozoon spp.). Positive samples were subjected to conventional PCR, followed by sequencing for species identification. Phylogenetic analyses were performed to assess relatedness among European isolates. Data on domestic cats (age class, sex, origin, management, and lifestyle) were recorded, and statistical analyses were performed to identify potential risk factors. A total of 31 (15%) domestic cats were positive for Hepatozoon spp. (i.e., 12 for H. felis, 19 for H. silvestris), while six (2.9%) for C. europaeus. The prevalence of Hepatozoon felis was significantly (p < 0.05) higher in domestic cats, while H. silvestris was higher in strays and animals from the Eastern region (i.e., Friuli-Venezia Giulia). Cytauxzoon europaeus was detected only in stray cats from Friuli-Venezia Giulia (province of Trieste). Among captive felids, one tiger was infected with H. felis and another with H. silvestris; eight out of 19 (42%) wildcats were positive for Hepatozoon spp. (i.e., six with H. felis, two with H. silvestris) and four out of 19 (21%) for Cytauxzoon europaeus. Outdoor lifestyle and origin (i.e., Friuli-Venezia Giulia region) were the most relevant risk factors for H. silvestris and C. europeus infections. Conversely, H. felis was most frequently isolated from domestic cats, suggesting different modes of transmission.

Screening of Domestic Cats from North-Eastern Hungary for Hepatozoon felis and Cytauxzoon europaeus That Cause Infections in Local Wildcat Populations

Among vector-borne protozoa Hepatozoon felis and Cytauxzoon europaeus are considered emerging species in felids in Europe. To investigate the presence of these two protozoa 127 domestic cats and 4 wildcats were screened by PCRs targeting the 18S rRNA gene of Hepatozoon spp. and piroplasms, as well as the cytb gene of Cytauxzoon spp. The samples were collected inside and outside a region of Hungary, where both protozoan groups are endemic in wildcats. Among domestic cats, one proved to be infected with H. felis. Furthermore, spleen samples of four wildcats were also examined, among which three tested positive for H. felis, and one had co-infection with C. europaeus. Importantly, H. felis from the co-infected wildcat belonged to genogroup II, similarly to H. felis from the positive domestic cat. Based on phylogenetic evidence, this genogroup probably represents a separate species from genogroup I of H. felis, which was hitherto reported from Mediterranean countries in Europe. The two other wildcats also harbored H. felis from genogroup I. Neither Hepatozoon nor Cytauxzoon infections were detected outside the recently discovered endemic region. In conclusion, this study demonstrates for the first time in Europe that H. felis from genogroup II may emerge in free-roaming domestic cats in regions where this protozoan parasite is endemic in wildcats.

Apicomplexan haemoparasites in domestic cats in Romania

BACKGROUND

Apicomplexan haemoparasites are protozoans that infect a variety of domestic and wild animal species, as well as humans. Data regarding haemoprotozoans in domestic cats are limited; therefore, the aim of this study was to assess the occurrence of Babesia spp., Cytauxzoon spp., and Hepatozoon spp. in domestic cats in Romania using molecular tools.

METHODS

Blood samples from 371 domestic cats were screened for the presence of piroplasmids. All samples that yielded a visible band in agarose gels were subsequently tested by specific assays targeting the 18S rDNA of Babesia spp., Cytauxzoon spp., and Hepatozoon spp. Moreover, nested PCR assays targeting mitochondrial genes of Babesia spp. were used for screening of all Babesia spp. 18S rDNA-positive samples.

RESULTS

From the total number of sampled cats, 19.4% were positive in the PCR assay targeting piroplasmids. Babesia spp. were identified in 15.1% of cats, while 0.5% were positive for Hepatozoon spp. Molecular analyses confirmed the presence of Babesia canis. No samples were positive for Cytauxzoon spp.

CONCLUSIONS

The high infection rates of domestic cats with Babesia spp. and the need for species differentiation highlight the importance of mitochondrial genes as targets for molecular protocols.

Clinicopathological findings and risk factors associated with Cytauxzoon spp. infection in cats: A case-control study (2008–2021)

In Europe, Cytauxzoon spp. infection was documented in domestic and wild felids. Cats often develop a subclinical infection, while fatal disease is rare. Currently, information on the epidemiology, risk factors and clinicopathological findings of Cytauxzoon spp. infection remains limited and obtained by a single subject or small groups of cats. The objective of this case-control study was to evaluate clinicopathological findings and to describe risk factors associated with Cytauxzoon spp. infection in domestic cats. Infected cats (n = 39) and non-infected (n = 190) cats were selected from the database of the referral San Marco Veterinary Laboratory between 2008 and 2021. Demographic information, a preset questionnaire considering lifestyle, environment, and clinical status, and a CBC performed contextually with the PCR analysis were recorded for all cats. Data on the biochemical profile and serum protein electrophoresis were also evaluated when available. Compared to the control group, infection was more likely to occur in stray cats (24/39, 61.5%, P &lt; 0.001), living totally/partially outdoors (36/39, 92.3%, P &lt; 0.001), in an urban context (37/39, 94.9%, P = 0.002), taken or recently adopted from colonies (34/35, 97.1, P &lt; 0.001), with irregular or absent parasite preventive treatments (39/39, 100%, p = 0.005), without fleas (28/35, 80%, P = 0.047) and without clinical signs (22/39, 56.4%, p = 0.026) at the time of medical evaluation. Anemia was not associated with infection, but in cats without clinical signs, the percentage of anemic-infected cats (7/22, 31.8%, P = 0.009) was higher compared to non-infected cats (5/65, 7.7%). Furthermore, a decrease in total iron serum concentration approximating the lowest reference interval [median values (IQR): 79 μg/dL (52.25) vs. 50.5 μg/dL (34), P = 0.007] was likely in infected cats. No other laboratory findings were associated with infection. Interestingly, a partial/total outdoor lifestyle was a risk factor for infection (OR: 8.58, 95% CI: 2.90–37.0, P &lt; 0.001). In conclusion, the present study revealed that Cytauxzoon spp. infection manifests itself prevalently as a subclinical infection, based on physical examination and laboratory findings, in domestic European cats. However, subclinical infected cats were more likely to be anemic compared to non-infected.

Cytauxzoon sp. Infection and Coinfections in Three Domestic Cats in Central Italy

Cytauxzoonosis is an emerging disease caused by a tick-transmitted haemoprotozoan affecting domestic and wild felids. The clinical and biomolecular findings of the infection due to Cytauxzoon sp. and concomitant coinfections are described in three cats in central Italy. Three domestic cats were referred for different clinical conditions (impact trauma, lameness, and weight loss and lethargy). They presented different hematobiochemical profiles. Only two cats were anemic, but in all three cats, endo erythrocyte inclusions suggestive of piroplasmids were found at blood smear evaluation. EDTA blood samples were submitted to rapid ELISA test for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), and to biomolecular investigations for Piroplasmida (Babesia spp., Theileria spp., Cytauxzoon spp.) and Mycoplasma spp. All three cats were positive for Cytauxzoon sp. (European Cytauxzoon species) and two cases were also coinfected by Candidatus Mycoplasma turicensis and FIV. This report suggests that cytauxzoonosis should be included among differential diagnoses in subjects with possibility of contact with ticks and with presence of coinfections by tick-borne parasites, including in non-endemic areas.

Cytauxzoon europaeus infections in domestic cats in Switzerland and in European wildcats in France: a tale that started more than two decades ago

BACKGROUND

Cytauxzoon spp. infection is believed to be a newly emerging tick-borne disease in felids in Europe, with three species of the haemoparasite having recently been differentiated in wild felids. In Switzerland, rare infections have been documented in domestic cats in the west and northwest of the country, the first of which was in 2014. The aims of the present study were: (i) to characterize a Cytauxzoon spp. hotspot in domestic cats in central Switzerland; (ii) to elucidate the geographic distribution of Cytauxzoon spp. in domestic cats in Switzerland; (iii) to assess suspected high-risk populations, such as stray and anaemic cats; and (iv) to investigate the newly emerging nature of the infection. Cytauxzoon spp. were further differentiated using mitochondrial gene sequencing.

METHODS

The overall study included samples from 13 cats from two households in central Switzerland (study A), 881 cats from all regions of Switzerland (study B), 91 stray cats from a hotspot region in the northwest of Switzerland and 501 anaemic cats from across Switzerland (study C), and 65 Swiss domestic cats sampled in 2003 and 34 European wildcats from eastern France sampled in the period 1995-1996 (study D). The samples were analysed for Cytauxzoon spp. using real-time TaqMan quantitative PCR, and positive samples were subjected to 18S rRNA, cytochrome b (CytB) and cytochrome c oxidase subunit I (COI) gene sequencing.

RESULTS

In study A, six of 13 cats from two neighbouring households in central Switzerland tested postive for Cytauxzoon spp.; two of the six infected cats died from bacterial infections. In studies B and C, only one of the 881 cats (0.1%; 95% confidence interval [CI]: 0-0.3%) in the countrywide survey and one of the 501 anaemic cats (0.2%; 95% CI: 0-0.6%) tested postive for Cytauxzoon spp. while eight of the 91 stray cats in the northwest of Switzerland tested positive (8.8%; 95% CI: 3.0-14.6%). In study D, Cytauxzoon spp. was detected in one of the 65 domestic cat samples from 2003 (1.5%; 95% CI: 0-4.5%) and in ten of the 34 European wildcat samples from 1995 to 1996 (29%; 95% CI: 14.2-44.7%). The isolates showed ≥ 98.6% sequence identities among the 18S rRNA, CytB and COI genes, respectively, and fell in the subclade Cytauxzoon europaeus based on CytB and COI gene phylogenetic analyses.

CONCLUSIONS

The study challenges the newly emerging nature of Cytauxzoon spp. in central Europe and confirms that isolates from domestic cats in Switzerland and European wild felids belong to the same species.

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.

Cytauxzoon sp. and Hepatozoon spp. in Domestic Cats: A Preliminary Study in North-Eastern Italy

Knowledge on the presence of Cytauxzoon sp. and Hepatozoon spp. in Italy is scant and mostly limited to a few areas of Northern and Southern regions, respectively. The present study updated the current epidemiological scenario by investigating the occurrence of these protozoa in domestic cats from three broad regions of North-Eastern Italy. Blood samples from cats at risk of vector-borne diseases were processed by PCR to detect Cytauxzoon and Hepatozoon DNA. Blood smears were observed for haemoparasite inclusions. The influence of cat individual data (e.g., provenance, management, indoor/outdoor lifestyle) on the prevalence of haemoprotozoan infections was statistically evaluated. Among 158 cats, Cytauxzoon and Hepatozoon DNA were detected in 6 (3.8%) and 26 (16.5%) animals, respectively. No Hepatozoon gamonts were detected in blood smears, whereas all Cytauxzoon PCR-positive samples were microscopically positive, though with low levels of parasitaemia. Two species of Hepatozoon were identified, Hepatozoon felis (n = 10) and Hepatozoon silvestris (n = 16). Hepatozoon silvestris prevalence values were significantly (p < 0.05) higher in the region Friuli Venezia Giulia and in stray cats. Cytauxzoon sp. was detected in 6/39 (15.4%) stray cats from Friuli Venezia Giulia (Trieste province). These data add new information on the occurrence of these neglected protozoa in domestic cats' populations.

Role of Zoo-Housed Animals in the Ecology of Ticks and Tick-Borne Pathogens-A Review

Ticks are ubiquitous ectoparasites, feeding on representatives of all classes of terrestrial vertebrates and transmitting numerous pathogens of high human and veterinary medical importance. Exotic animals kept in zoological gardens, ranches, wildlife parks or farms may play an important role in the ecology of ticks and tick-borne pathogens (TBPs), as they may serve as hosts for local tick species. Moreover, they can develop diseases of varying severity after being infected by TBPs, and theoretically, can thus serve as reservoirs, thereby further propagating TBPs in local ecosystems. The definite role of these animals in the tick-host-pathogen network remains poorly investigated. This review provides a summary of the information currently available regarding ticks and TBPs in connection to captive local and exotic wildlife, with an emphasis on zoo-housed species.

Three new species of Cytauxzoon in European wild felids

Protists of the genus Cytauxzoon infect a wide variety of wild and domestic felids worldwide. While the American Cytauxzoon felis has been well described, data on the European isolates of Cytauxzoon are still scant. The aim of the current study was to determine the genetic diversity of European Cytauxzoon spp. in wild felids across Europe by analyzing one nuclear and two mitochondrial genes, along with representative complete mitochondrial genomes. Overall, 106 biological samples from wild felids (92 from Felis silvestris and 14 from Lynx lynx) from Germany, Romania, Czech Republic, and Luxembourg were collected and screened for the presence of Cytauxzoon spp. using nested PCR protocols, targeting the highly conserved 18S rDNA, mitochondrial cytochrome b (CytB) and cytochrome c oxidase subunit I (COI) genes. Furthermore, 18 previously confirmed wild felid biological samples from Europe, and comparative material from USA positive for C. felis, were included in the study. In 18S rDNA sequences analyses, Cytauxzoon spp. from felids formed two separate clades of New World and Old World isolates, with a low inner diversity of the European clade. In contrast to 18S rDNA, the phylogenetic analyses of CytB and COI genes affirmatively revealed three highly supported clades, resulting in three defined genotypes. Similar intra- and interspecific variability of CytB and COI genes was observed in the case of different Babesia spp. Considering geography, host species and analyses of three genes, we conclude that the three detected genotypes of Cytauxzoon in European wild felids represent three new species, which we herein describe.