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Introduction
Feline vector-borne diseases (FVBDs) are caused by a wide range of pathogens, including viruses, bacteria, protozoa, and helminths that are transmitted by blood-sucking arthropods, such as fleas, ticks, and flies (HARTMANN & BERGMANN, 2017). The vector-borne diseases (VBDs) are becoming more common not only in humans, but also in dogs and cats (BANETH et al., 2012; MAIA et al., 2014; ANDRÉ et al., 2017) in Brazil (ANDRÉ et al., 2017) and worldwide (MAIA et al., 2014) as a result of changing climate. Some fvbds can be life-threatening for cats while others represent a major zoonotic concern (MAIA et al., 2014; ANDRÉ et al., 2015). Although the occurrence of Bartonella spp., Leishmania spp. and hemoplasmas has been extensively investigated among cats, further studies are necessary regarding the dispersion of Anaplasmataceae agents, piroplasmids and Hepatozoon spp. in domestic and stray cats (OTRANTO & DANTAS-TORRES, 2010; ANDRÉ et al., 2017; GUIMARÃES et al., 2019).
Nowadays, the extensive contact between domestic cats and humans has favored the transmission of zoonotic agents. Therefore, it is crucial to increase the FVBP surveillance aiming at determining the real impact of these agents on Public Health (UDELL & SHREVE, 2017). Currently, no data on vector-borne agents in cats is available in the municipality of Canoinhas, SC, southern Brazil, so molecular and serological methods were used to investigate the DNA presence and/or serological exposure to FVBP, namely Anaplasma, Ehrlichia, Babesia/Theileria, Bartonella, Mycoplasma, Cytauxzoon and Hepatozoon in domestic cats in this region.
Material and Methods
Population and studied area
Blood and ectoparasite samples were collected from 30 apparently healthy domestic cats neutered at the Veterinary Hospital of the University of Contestado (UnC) in Canoinhas (latitude 26° 10’ 38” S and longitude 50º 23' 24” W), SC, Brazil, between November and December 2017. The cats aged from 8 months to 7 years: 15 males (46.7% were less than 2 years old, 40% between 2 and 5 years old and 13.3% with more than 5 years old) and 15 females (80% were less than 2 years old and 20% between 2 and 5 years old). All performed procedures followed the ethical guidelines of the Ethics Committee of the UnC (number 11/17). The owners answered a questionnaire regarding animal gender, breed, living conditions, age and use of acaricides/insecticides.
Blood and ectoparasites sampling
Blood samples were collected from the cephalic or jugular vein. A fraction of the sample was stored in DNAse and RNAse free sterile microtubes containing anticoagulant (EDTA) while another fraction was centrifuged to separate the serum. Both whole blood and serum samples were stored at -20°.
Ectoparasite specimens were collected and preserved in 70% ethanol (Êxodo Científica®). Ticks and fleas were identified using previously described taxonomic keys (BICHO & RIBEIRO, 1998; BARROS-BATTESTI et al., 2006).
Hemogram and Giemsa-stained blood smears
The hemogram was performed according to the routine technique. The leukocyte differential count and the search for the FVBP were performed manually in May-Grünwald-Giemsa - stained blood smears.
FVBP molecular screening and characterization
For the FVBP molecular screening and characterization, a 200 μL whole blood aliquot from each cat was used to extract the DNA using the QIAamp DNA Blood Mini kit (QIAGEN®, Valencia, CA, USA), following the manufacturer’s instructions. The DNA concentration and quality were measured using the 260/280nm absorbance ratio (Nanodrop®, Thermo Fisher Scientific, Waltham, MA, USA). The amplifiable DNA was detected by a PCR assay targeting a fragment of mammalian glyceraldehyde-3-phosphate dehydrogenase (gapdh), according to Birkenheuer et al. (2003).
The performed conventional PCR (cPCR) assays targeted the 16S rRNA gene of Ehrlichia (MURPHY et al., 1998), Anaplasma (MASSUNG et al., 1998), and Mycoplasma (MAGGI et al., 2013), and the 18S rRNA of Cytauxzoon sp. (BIRKENHEUER et al., 2006), Hepatozoon spp. (INOKUMA et al., 2002), Babesia spp. (JEFFERIES et al., 2007) and kinetoplast DNA Leishmania spp. (RODGERS et al., 1990; LOPES et al., 2016). Additionally, the cPCR also targeted gltA (BILLETER et al., 2011), rpoB (DINIZ et al., 2007), ftsZ (PAZIEWSKA et al., 2011), and nuoG gene fragments (ANDRÉ et al., 2015) of Bartonella spp. and the msp2 gene fragment (DRAZENOVICH et al., 2006) of A. phagocytophilum.
The DNA positive controls for Leishmania infantum (JUSI et al., 2015), Bartonella henselae (André et al., 2015), Mycoplasma sp. (GONÇALVES et al., 2015), Hepatozoon caimani (BOUER et al., 2017), Babesia vogeli (Jaboticabal strain), Cytauxzoon sp. (ANDRÉ et al., 2009), Ehrlichia canis (Jaboticabal strain), and Anaplasma sp. (BENEVENUTE et al., 2017) were obtained from naturally infected animals. Ultra-pure water (Nuclease-Free Water Promega®, Wisconsin, USA) was used as a negative control in all PCR assays. The gels were imaged under ultraviolet light using the Image Lab Software, version 4.1 (Bio-Rad®).
The reaction products of PCR-positive samples were purified using the Silica Bead DNA gel extraction kit (Thermo Fisher Scientific®, USA). Purified amplified DNA fragments were submitted to phylogenetic analysis and sequence confirmation using an automatic sequencer (ABI PRISM 3700 DNA Analyser/ Applied Biosystem®) in the Center for Biological Resources and Genomic Biology (CREBIO, Jaboticabal, São Paulo, Brazil). The sequences were aligned with GenBank data using the MAFFT software, version 7 (KATOH & STANDLEY, 2013). Phylogenetic inference was based on Bayesian Inference (BI) analysis, using the MrBayes X-SEDE (3.2.6) (RONQUIST & HUELSENBECK, 2003). All phylogenetic analyses used the CIPRES Science Gateway (MILLER, 2010). The trees were examined in Treegraph 2.0.56-381 beta (STOVER & MULLER, 2010).
Serological screening for selected FVBP
The serological screening for FVBP was performed by the indirect fluorescence antibody test (IFAT) using slides sensitized with E. canis (ANDRÉ et al., 2010), A. phagocytophilum (SOUSA et al., 2017) and L. infantum (OLIVEIRA et al., 2008) antigens as previously described. Briefly, antigen slides were removed from storage and allowed to thaw at room temperature for 30 min. Ten microliters of twofold serum dilutions (starting at 1:64, the cut-off for E. canis and A. phagocytophilum, and 1:80 for Leishmania infantum) were placed in the wells of antigen-sensitized slides. On each slide, serum samples from dogs naturally infected with E. canis (NAKAGHI et al., 2008) and L. infantum (OLIVEIRA et al., 2008) as well as from horses experimentally infected with A. phagocytophilum (SOUSA et al., 2017) were used as positive controls. Dog and horse serum samples negative to the studied VBP were kindly supplied by IMUNODOT Diagnostics Ltda. (Jaboticabal, SP, Brazil). Slides were incubated at 37 °C in a moist chamber for 30 min, washed three times in PBS (pH 7.2) for 5 min, and air dried at room temperature. Then, the slides were incubated with fluorescein isothiocyanate, labeled anti-cat IgG (Sigma®, St. Louis, USA) in tested serum samples and anti-dog IgG and anti-horse IgG (Sigma®, St. Louis, USA) in positive and negative control serum samples, which were diluted following the manufacturer instructions. These slides were incubated again at 37 °C, washed three times in PBS, once more in distilled water, and air dried at room temperature. Finally, slides were overlaid with buffered glycerin (pH 8.7), covered with glass coverslips, and examined in a fluorescence microscope (Olympus®, Tokyo, Japan).
Results
The May-Grünwald-Giemsa–stained blood smears (n=30) showed no inclusions suggestive of FVBP. However, the PCR and IFAT techniques detected FVBP and the results are shown in Table 1. Of the 30 domestic cats, 17 (56.6%) were positive to at least one FVBP by either serological or molecular techniques. Among cats positive for only one agent, Ehrlichia spp. was the most common pathogen (36.6%), followed by Anaplasma spp. and Bartonella spp. (13.3% each), and Mycoplasma spp. and Leishmania spp. (6.6% each) (Table 1). Five cats were positive to at least two pathogens from different genera (Table 2). Despite this, all cats were considered healthy based on history, physical examination and body condition scores.
Table 1 FVBP positive cats according to the results of the serological and molecular techniques used in this study.
| Pathogen | Number of positive cats (%) | ||
|---|---|---|---|
| PCR | IFAT | Total | |
| Ehrlichia spp. | 6 (20.0) | 7 (23.3) | 11 (36.6) |
| Anaplasma spp. | 1 (3.3) | 3 (10.0) | 4 (13.3) |
| Bartonella spp. | 4 (13.3) | - | 4 (13.3) |
| Mycoplasma spp. | 2 (6.6) | - | 2 (6.6) |
| Leishmania spp. | 0 (0.0) | 2 (6.6) | 2 (6.6) |
| Cytauxzoon spp. | 1 (3.3) | - | 1 (3.3) |
| Hepatozoon spp. | 0 (0.0) | - | 0 (0.0) |
| Babesia spp. | 0 (0.0) | - | 0 (0.0) |
Table 2 FVBP co-positivity assessed by molecular and serological techniques in blood samples of cats in Canoinhas, SC, Brazil.
| Pathogens detected (Diagnostic technique) | Total of positive cats (%) |
|---|---|
| Ehrlichia spp. (IFAT) + Bartonella spp. (PCR) | 2 (6.6) |
| Ehrlichia spp. (PCR) + Bartonella spp. (PCR) | |
| Ehrlichia spp. (PCR) + Cytauxzoon spp. (PCR) | 1 (3.3) |
| Ehrlichia spp. (PCR/ IFAT) + Bartonella spp. (PCR) + Leishmania spp. (IFAT) | 1 (3.3) |
| Ehrlichia spp. (IFAT) + Mycoplasma spp. (PCR) + Anaplasma spp. (IFAT) | 1 (3.3) |
According to the owners, 76.6% of the cats were not controlled for ectoparasites. A total of 80% (24/30) of the cats had parasites, of which 95.8% (23/24) were parasitized by fleas of the species Ctenocephalides felis Bouché, 1835, and 4.2% (1/24) was parasitized by an adult female tick, Amblyomma aureolatum Pallas, 1772.
The owners reported that most cats did not have a history of recent fights (83.3%), were not aggressive with people (76.7%), had access to the street (80%), and lived with other cats (83.3%).
Furthermore, the hematological results indicated that the monocyte count was significantly lower in FVBP-free cats (Table 3), whereas monocytosis was observed in two cats seropositive for FVBP.
Table 3 Mean ± Std. Error of Mean (SE) for the hematological parameters of domestic felines -positive and negative for FVBP.
| Parameter | Ranges for healthy cats | Positive (n=17) | Negative (n=13) | P-value |
|---|---|---|---|---|
| (Weiss, Wardrop, 2010) | (mean ± SE) | (mean ± SE) | (test) | |
| Hematocrit (%) | 24-45 | 42.71 ± 1.53 | 39.62 ± 1.59 | 0.171 |
| RBC count (x 106/mL) | 5.0-10.0 | 7.8 ± 0.30 | 7.3 ± 0.28 | 0.291 |
| WBC count (x 103/mL) | 5,500-19,500 | 10,065 ± 821.9 | 11,862 ± 1,326 | 0.298 |
| Band neutrophils | 0-300 | 110.6 ± 32.3 | 66.81 ± 34.4 | 0.232 |
| Segmented neutrophils | 2,500-12,500 | 5,486 ± 688.4 | 7,154 ± 1211 | 0.298 |
| Lymphocytes | 1,500-7,000 | 3,757 ± 523.6 | 4,294 ± 690.4 | 0.532 |
| Monocytes | 0-850 | 293.3 ± 75.0 | 148.6 ± 63.8 | 0.046 |
| Eosinophils | 0-1,500 | 311 ± 42.6 | 198.3 ± 46.0 | 0.085 |
| PPT | 5.4-7.8 | 7.08 ± 0.22 | 6.71 ± 0.14 | 0.205 |
Note: No significant difference was observed between groups for the Mann-Whitney (U) at p≥0.05.
Out of 30 samples, two (6.6%) were positive for M. haemofelis. The cluster was composed of M. haemofelis 16S rRNA sequences previously detected in domestic cats in Switzerland, Australia, and the United Kingdom (Figure 1).
Figure 1 Phylogenetic relationships based on the sequence of 16S rRNA fragment amplified from Mycoplasma species isolated from domestic cats, compared with known species of the genus Mycoplasma. The phylogenetic tree was constructed from 1.300 bp sequences, inferred using the Bayesian method and GTRGAMMA+I evolutionary model. Numbers at nodes correspond to Bayesian posterior probabilities over 50, using Mycoplasma pneumoniae (NR113659) as outgroup.
Seven cats 23.1% (7/30) were positive for E. canis with the following titers: 64 (six animals) and 128 (one animal). Further, six animals (19.8%) were positive for Ehrlichia spp. in the 16S rRNA PCR assay, of which two cats (6.6%) were also positive in the IFAT. The only tick found was collected from an E. canis seropositive cat. Although apparently healthy, 54.5% of the positive animals for Ehrlichia (PCR and/or IFAT) had hematological disorders such as lymphopenia (27.27%), neutropenia (9.09%) and hyperproteinemia (18.18%). The phylogenetic analysis indicated that the Ehrlichia 16S rRNA sequences (seq. 1, 2 and 3) detected in three different cats were closely related to the E. canis sequences identified in a domestic cat (MH234591) in Brazil and in ticks in the USA (MF059355) and Mexico (MG029082), supported by a high Bayesian posterior probability (100%) (Figure 2).
Figure 2 Phylogenetic relationships based on the sequence of 16S rRNA fragment amplified from Ehrlichia species isolated from domestic cats, compared with known species of the genus Ehrlichia. The phylogenetic tree was constructed from 350 bp sequences, inferred using the Bayesian method and GTRGAMMA+I evolutionary model. Numbers at nodes correspond to Bayesian posterior probabilities over 50, using Anaplasma phagocytophilum (NR044762) and ‘Candidatus Neoehrlichia mikurensis’ (AB074460) as outgroups.
One cat was positive for Anaplasma spp. in the 16S rRNA nPCR but negative to A. phagocytophilum in the msp-2 qPCR assay. Three cats seropositive for A. phagocytophilum had titers ranging from 64 to 512 but none was positive for Anaplasma spp. in both PCR and IFAT.
The phylogenetic analysis indicated that the Anaplasma 16S rRNA sequence is phylogenetically related to A. phagocytophilum. The phylogenetic relationships inferred by Bayesian analysis indicated five main clades, supported by posterior probabilities ranging from 54.2 to 99.8% (Figure 3). The sequence detected in a domestic cat in Santa Catarina, in the present study, was positioned in the main clade comprising the A. phagocytophilum/Anaplasma spp. sequences previously detected in animals and ticks in Brazil and worldwide, corroborating the BLASTn analysis, which indicated 100% identity with a sequence of Anaplasma sp. previously detected in a domestic cat in Brazil.
Figure 3 Phylogenetic relationships based on the sequence of 16S rRNA fragment amplified from Anaplasma species isolated from domestic cats, compared with known species of the genus Anaplasma. The phylogenetic tree was constructed from 932 bp sequences, inferred using the Bayesian method and GTR+G+I evolutionary model. Numbers at nodes correspond to Bayesian posterior probabilities over 50, using Neorickettsia sennetsu (M73219) as outgroup.
Two of the four positive cats for Anaplasma spp. (IFAT or PCR) had anemia, neutropenia, monocytosis, hypoproteinemia, and lymphopenia.
In this study, 13.3% (4/30) of the sampled cats had Bartonella spp. DNA. The four qPCR (nuoG) positive samples for Bartonella spp were also positive for at least one targeted gene in cPCR assays. All four were positive for the gltA gene, three for the ftsZ gene and three for the rpoB gene. The sampled animals, sequencing confirmed B. clarridgeiae (6.6%, 2/30), B. henselae (6.6%, 2/30) and B. koehlerae (3.3%, 1/30) infections. The analysis on the sequenced products showed that they presented 99.8-100% identicalness with B. henselae (access numbers MF314832, KY913627 and KX499336); 100% with B. clarridgeiae (access number KY913636) and 100% with B. koehlerae (access numbers FJ832089 and AF176091) (Table 4). Cases in which gltA and rpoB sequences from a single cat corresponded to different feline Bartonella species were considered coinfections. Therefore, one cat (3.3%, 1/30) was concurrently infected with B. clarridgeiae and B. henselae.
Table 4 Bartonella species identified in cats sampled in Canoinhas, State of Santa Catarina, southern Brazil, according to conventional PCR assays based on three different genes and BLAST analysis.
| Cat ID | % identity according to Blast analysis (GenBank ID) | ||
|---|---|---|---|
| rpoB gene | gltA gene | ftsZ gene | |
| #6 | 100% B. henselae (MF314832) | 100% B. clarridgeiae (KY913636) | 99,81% B. henselae (KX499336) |
| #8 | negative | 100% B. clarridgeiae (KY913636) | negative |
| #15 | 100% B. henselae (MF314832) | 100% B. henselae (KY913627) | 100% B. henselae (KX499336) |
| #29 | 100% B. koehlerae (FJ832089) | 100% B. koehlerae (AF176091) | 100% Bartonella sp. (GU903912) |
The B. clarridgeiae gltA sequences amplified in this study were closely positioned to sequences previously detected in fleas in Chile (KY913636) and in a cat in Thailand (KX001761), supported by a 100% posterior probability. Additionally, the amplified B. koehlerae gltA sequence detected in cat #29 was closely related to a B. koehlerae sequence (AF176091) detected in a cat in the USA, supported by a high Bayesian posterior probability of 100%. The detected B. henselae sequence was closely related to a B. henselae sequence (AF176091) previously detected in fleas in Chile (KY913627), supported by a high Bayesian posterior probability of 100% (Figure 4).
Figure 4 Phylogenetic relationships based on the sequence of a citrate synthase (gltA) gene fragment amplified from Bartonella species isolated from domestic cats, compared with known species of the genus Bartonella. The phylogenetic tree was constructed from 767 bp sequences, inferred using the Bayesian method and GTR+G+I evolutionary model. Numbers at nodes correspond to Bayesian posterior probability over 50, using Brucella abortus and Ochrobactrum anthropi as outgroups.
The Bartonella koehlerae rpoB sequence was positioned near to B. koehlerae sequences detected in a dog in Israel (FJ832089), supported by 100% posterior probability. In addition, the amplified B. henselae rpoB sequences are closely related to B. henselae sequences previously detected in Rattus rattus Linnaeus, 1758 in New Zealand (MF 314832) and a cat in New Caledonia (JN646670), supported by a high Bayesian posterior probability of 100% (Figure 5).
Figure 5 Phylogenetic relationships based on the sequence of a rpoB gene fragment amplified from Bartonella species isolated from domestic cats, compared with known species of the genus Bartonella. The phylogenetic tree was constructed from 720 bp sequences, inferred using the Bayesian method and GTR+G+I evolutionary model. Numbers at the nodes correspond to Bayesian posterior probability over 80, using Brucella abortus and Ochrobactrum anthropi as outgroups.
Finally, the amplified B. henselae ftsZ sequences were closely related to B. henselae sequences previously detected in Acinonyx jubatus Schreber, 1775 in Zimbabwe (KX499336) and in a cat in Guatemala (KP822812), supported by high Bayesian posterior probability of 100% (Figure 6). The amplified ftsZ B. koehlerae sequence detected in the cat #29 presented 100% identity with a Bartonella sp. previously detected in Leopardus wiedii Schinz, 1821 from Brazil (GU903912), and was closely related to B. koehlerae from Panthera leo Linnaeus, 1758 from South Africa (KX499334) and to Bartonella sp. from a margay from Brazil (GU903912), supported by a Bayesian posterior probability of 75% (Figure 6, Table 4).
Figure 6 Phylogenetic relationships based on the sequence of a ftsZ gene fragment amplified from Bartonella species isolated from domestic cats, compared with known species of the genus Bartonella. The phylogenetic tree was constructed from 600 bp sequences, inferred using the Bayesian method and GTR+G+I evolutionary model. Numbers at the nodes correspond to Bayesian posterior probability over 80, using Brucella abortus and Ochrobactrum anthropi as outgroups.
A concatenated phylogenetic tree of the genes was constructed to achieve more robust support to identify Bartonella species in this study. The amplified B. henselae sequences detected in cats #6 and #15 were closely related to B. henselae strain Houston-1 (BX897699), supported by a high Bayesian posterior probability of 99-100%. The amplified B. koehlerae sequence detected in cat #29 was closely related to B. koehlerae C-29 (KL407334) supported by a high Bayesian posterior probability of 100% (Figure 7).
Figure 7 Concatenated phylogenetic analysis of Bartonella sequences: a) rpoB and ftsZ sequences (4902 bp after alignment), b) rpoB, gltA and ftsZ sequences (6294 bp after alignment), based on the topology generate on the Bayesian method. The values of support of posterior probability than 50% are shown in each branch, using Brucella abortus and Ochrobactrum anthropi as outgroups.
Two cats were seropositive for L. infantum, with 80 and 160 titers. However, all 30 cats (including the two positives) were negative for L. infantum based on the PCR assay targeting the kinetoplast DNA. Even though one cat (3.3%) was positive to Cytauxzoon sp. in the 18S rRNA cPCR, the low amount of amplified DNA resulted in weak band intensity in agarose gel electrophoresis, precluding a high-quality sequencing.
None of the sampled cats was positive for either Babesia/Theileria spp. or Hepatozoon spp. in the PCR assays.
Discussion
The FVBP geographical distribution and prevalence are on the rise worldwide (BANETH et al., 2012; ANDRÉ et al., 2017) while an increasing number of FVBP has been detected in humans (SANTOS et al., 2008; EYER-SILVA et al., 2017). No molecular studies investigating FVBP in cats had been previously conducted in the Canoinhas municipality, SC, southern Brazil. The results of the IFAT and PCR assays revealed a wide variety of FVBP species such as Mycoplasma, Ehrlichia, Anaplasma, Bartonella, and Cytauxzoon in household cats of the region. The low number of cats sampled in the present study, an acknowledged limitation of this work, precludes any statistical inference on the real prevalence of FVBP in the studied area.
Ehrlichia canis was the most common FVBP detected in this study and, interestingly, the only cat parasitized by an Amblyomma tick was positive for this pathogen as well. The seropositivity found in the present study suggests the exposure to Ehrlichia spp. in a feline population studied. However, the occurrence of cross-reactivity with other Anaplasmataceae family agents cannot be ruled out (WEN et al., 1997; ORTUÑO et al., 2005). Ehrlichia canis-like DNA was also detected in domestic cats in Mato Grosso (BRAGA et al., 2014b), Mato Grosso do Sul (ANDRÉ et al., 2015), Rio Grande do Norte (ANDRÉ et al., 2017), and Rio de Janeiro (GUIMARÃES et al., 2019), and in wild felids maintained in captivity in the state of São Paulo and in the Federal District (ANDRÉ et al., 2010; 2012).
Of the 11 cats positive for Ehrlichia, two (one positive in PCR and another positive in IFAT) had hyperproteinemia, which has also been found in E. canis seropositive cats in Rio de Janeiro (GUIMARÃES et al., 2019). In fact, this finding may be attributed to the increase of gamma globulins concentration during the febrile stage and persistence during subclinical and chronic stages of monocytic canine ehrlichiosis (RISTIC & HOLLAND, 1993). Lymphopenia was also observed in seropositive cats to Ehrlichia spp. in Mato Grosso (BRAGA et al., 2013) whereas the authors in the present study observed that positive cats to Ehrlichia sp. in PCR tended to be lymphopenic.
The Bartonella species detected in the cats sampled in Canoinhas suggests that these animals may act as a source of infection to humans via scratching contaminated with flea feces or bites contaminated with infected blood (PENNISI et al., 2013).
Herein, B. henselae, B. clarridgeiae and B. koehlerae were detected in cats in the present study. Bartonella spp., an increasingly important Gram-negative intracellular bacteria in veterinary and human medicine (HARTMANN & BERGMANN, 2017), was detected in four C. felis-infested cats. In fact, fleas are the main vector for B. henselae among cats (CHOMEL & KASTEN, 2010). Bartonella henselae, the agent of the cat scratch disease (CSD), has been frequently reported in cats, which are considered the major reservoir for human infection (PENNISI et al., 2013). On the other hand, Bartonella clarridgeiae has been incriminated as a minor causative agent of CSD (CHOMEL & KASTEN, 2010). Indeed, B. henselae and B. clarridgeiae have been already detected in domestic cats in other Brazilian states (BRAGA et al., 2012a, 2015; MICELI et al., 2013; ANDRÉ et al., 2014, 2015). Additionally, B. henselae (PITASSI et al., 2015) and B. clarridgeiae (VIEIRA-DAMIANI et al., 2015) have been detected in blood donors in Brazil, raising suspicions regarding Bartonella transmission among humans via blood transfusion (SILVA et al., 2016).
Previously, a small Bartonella-gltA sequence fragment (96-bp) sharing 99% identity with B. koehlerae was detected in a margay (L. wiedii) maintained in captivity in a Brazilian zoo (FILONI et al., 2012). Recently, B. koehlerae was detected in cats in Rio de Janeiro (RAIMUNDO et al., 2019). Although B. koehlerae has been isolated from cat blood, the routes of transmission among cats have not been fully established yet (PENNISI et al., 2013).
The 16S rRNA-Anaplasma genotypes closely related to A. phagocytophilum have been detected in little-spotted-cats, Leopardus pardalis Linnaeus, 1758 (ANDRÉ et al., 2012), stray cats (ANDRÉ et al., 2014; 2017), coatis (SOUSA et al., 2017), and wild birds (MACHADO et al., 2012; WERTHER et al., 2017) in Brazil. However, in the present study, the sampled animals were negative for A. phagocytophilum in msp-2-qPCR assays, indicating that an Anaplasma genotype closely related to the human granulocytic anaplasmosis agent circulates in South America (ANDRÉ, 2018). Similarly, the cat #18 was negative for A. phagocytophilum in msp-2 qPCR, despite presenting a 16S rRNA Anaplasma genotype closely related to A. phagocytophilum. The Anaplasma-positive cat in this study had no hematological disorders, corroborating the report by Pennisi et al. (2017) that cats seem to remain chronic carriers after infected with A. phagocytophilum.
There are few reports on the occurrence of piroplasmids among cats in Brazil (ANDRÉ et al., 2014, 2015, 2017; MALHEIROS et al., 2016). Regarding the molecular detection of piroplasmids, one cat was positive for Cytauxzoon sp. whereas none was positive for Babesia/Theileria spp. Even though 18S rRNA Cytauxzoon sp. closely related to Cytauxzoon felis has already been detected in cats in Mato Grosso do Sul (ANDRÉ et al., 2015), Rio de Janeiro (MAIA et al., 2013), and Rio Grande do Norte (ANDRÉ et al., 2017), clinical cytauxzoonosis has never been described in domestic cats in Brazil so far. Nonetheless, fatal cytauxzoonosis was reported among lions maintained in captivity in a zoo in Volta Redonda, Rio de Janeiro (PEIXOTO et al., 2007). While neotropical wild felids have been incriminated as potential reservoirs for Cytauxzoon spp. in Brazil (ANDRÉ et al., 2009; FURTADO et al., 2017), the vectors remain unknown in South America (ANDRÉ et al., 2017). Similarly, though there are reports on cats being infected with both Babesia vogeli (ANDRÉ et al., 2014, 2015; MALHEIROS et al., 2016) and Theileria spp. associated with ruminants and equids (ANDRÉ et al., 2014, 2015) in Brazil, the clinical relevance of these findings is unknown.
Likewise, Hepatozoon spp. has been scarcely reported in cats in Brazil. For instance, H. felis (BORTOLI et al., 2011; BRAGA et al., 2016) and Hepatozoon sp. closely related to H. americanum (ANDRÉ et al., 2015) have been reported in cats in Brazil. The real clinical significance of these infections deserves further investigation.
Albeit the absence of Leishmania DNA in whole blood samples from seropositive cats has been previously reported (BRAGA et al., 2014a; COURA et al., 2018), feline leishmaniasis is an emergent feline disease (PENNISI & PERSICHETTI, 2018). And, even though the role of cats in the epidemiological cycles of leishmaniasis remains unclear, they may act as a reservoir for this parasite since sandflies feed on them (COURA et al., 2018). In Santa Catarina state, two autochthonous cases of canine visceral leishmaniasis were first detected in 2010 (FIGUEIREDO et al., 2012) while the first autochthonous case of human visceral leishmaniasis was diagnosed in 2017 (SMS, 2017), both in Florianópolis city. Because Canoinhas is not an endemic area for visceral leishmaniasis, we did not expect to find animals seropositive for Leishmania spp. The positive results in serology may be explained by serological cross-reactions between Leishmania and Trypanosoma species, as previously reported in dogs (LONGONI et al., 2012).
Hemoplasmas are one of the most prevalent flea-borne bacterial pathogens in cats (SHAW et al., 2004). In this study, despite two cats being infected with M. haemofelis, the most pathogenic hemoplasma, the erythrocyte count was within the reference values in both cats, albeit one had lymphopenia. According to Tasker et al. (2018), M. haemofelis chronic infection is usually not associated with significant anemia and carrier cats may show no evidence of anemia. Although ‘Candidatus Mycoplasma haemominutum’ is the most frequent hemoplasma species found in cats (BRAGA et al., 2012b; ANDRÉ et al., 2014; TASKER et al., 2018), often associated with chronic or subclinical infections (HARTMANN & BERGMANN, 2017; TASKER et al., 2018), this agent was not detected in the cats of this study. Since blood-sucking arthropods (ticks and fleas) are suspected to be the vectors of feline hemoplasmas among domestic cats (SHAW et al., 2004; TASKER et al., 2018), and flea infestation was quite common in the sampled cats, including those positive for hemoplasmas, it is most likely that fleas acted as hemoplasma-vectors to these animals.
Furthermore, five cats were simultaneously positive for Ehrlichia and other FVB pathogens, such as Bartonella, Cytauxzoon, and Mycoplasma. Previously, co-positivity to Ehrlichia/ Anaplasma/ Cytauxzoon and Mycoplasma was reported in two cats in Rio Grande do Norte (ANDRÉ et al., 2017); to Cytauxzoon and ‘Candidatus Mycoplasma haemominutum’ in one cat in Rio de Janeiro (MAIA et al., 2013), and to ‘Candidatus Mycoplasma haemominutum’ and Babesia vogeli, Bartonella spp., and to ‘Candidatus Mycoplasma turicensis’ or Mycoplasma haemofelis in stray cats in São Paulo (ANDRÉ et al., 2014). André et al. (2017) concluded that most likely that co-positivity is frequent in cats living in geographic areas where the competent vectors are present. According to these authors, the effect of multiple arthropod-borne hemoparasites in the pathogenesis of feline vector-borne diseases warrants further investigation. Although FBVP-positive cats were apparently healthy in the present study, veterinarians should keep in mind that cats co-positive to multiple FVBP may present a non-specific disease, which may further complicate the diagnosis, treatment and prognosis (BANETH et al., 2012; MAIA et al., 2014; ANDRÉ et al., 2017).
Conclusion
The results allow concluding that apparently healthy cats, with no clinical signs of infection, are exposed to multiple FVBP in the Canoinhas region, southern Brazil. The adoption of effective prophylaxis and control measures against arthropod vectors is much needed to prevent infection of cats, as well as the potential transmission to other animals and humans.
