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.
