Abstract
BackgroundCytauxzoonosis is an emerging tick-borne disease of domestic and wild felids. Cytauxzoon felis induces severe and often fatal disease in domestic cats. In Europe, clinical and subclinical infections caused by Cytauxzoon sp. are described. We report the first cases of Cytauxzoon sp. infection in domestic cats in Switzerland.MethodsClinical and laboratory data and results of PCR analyses were collected from Cytauxzoon sp. PCR-positive cats and the cats followed for up to 851 days.ResultsThe cases were three two-month old kittens from the same litter (Cases 1–3) and two adult domestic shorthair cats (Cases 4 and 5). The cats originated from the north-west and west of Switzerland. Cases 1–3 presented with moderate to severe regenerative anaemia and intraerythrocytic inclusions. Cytauxzoon sp. was confirmed by PCR and sequencing. The kittens made a clinical and haematological recovery after blood transfusion and/or treatment with azithromycin and atovaquone, but erythroparasitaemia persisted. Case 4 presented with severe non-regenerative anaemia. Case 5 was healthy and used as a blood donor for Case 4. Following blood transfusion, Case 4 showed intraerythrocytic inclusions, and Cytauxzoon sp. was confirmed in both Cases 4 and 5 using PCR and sequencing. Case 4 achieved clinical and haematological remission after treatment with azithromycin, atovaquone and immunosuppressive drugs. Eight months later, Case 4 was presented again with anaemia but tested Cytauxzoon sp. PCR-negative. Sequencing of 1637 bp of the 18S rRNA gene of Cytauxzoon sp. revealed 100% nucleotide sequence identity among isolates of Cases 1–3 and between isolates of Cases 4 and 5, and 99% sequence identity between isolates of all cases. Phylogenetic analysis revealed the closest relationship of the Swiss isolates to Cytauxzoon sp. isolates from domestic cats and wild felids from France, Spain and Romania and to Cytauxzoon manul from a Pallas’s cat.ConclusionsThis is the first report of Cytauxzoon sp. infection in domestic cats in Switzerland. It is also the first report of infection in very young kittens and transmission of Cytauxzoon sp. to an adult cat by transfusion of blood from an asymptomatic cat. The cats recovered but some developed chronic asymptomatic erythroparasitaemia for up to 28 months. Domestic cats may act as reservoirs for Cytauxzoon sp. in Europe and blood donor cats should be screened for this agent by PCR.
Highlights
Cytauxzoonosis is an emerging tick-borne disease of domestic and wild felids
Patient characteristics and geographical location Details of patient characteristics and geographical locations of the five cats are shown in Table 1 and Fig. 1
Our results further support the hypothesis that different Cytauxzoon species or strains exist in different geographical locations and that the species might differ in pathogenicity
Summary
Cytauxzoonosis is an emerging tick-borne disease of domestic and wild felids. Cytauxzoon felis induces severe and often fatal disease in domestic cats. Despite high mortality associated with C. felis infection in domestic cats, both survival after clinical infection and subclinical persistent parasitaemia have recently been documented [7,8,9]. This may suggest a shift in parasite vector-host interactions, the reason for this is unclear [8, 9]. The main natural reservoir of C. felis in the USA is thought to be the wild bobcat (Lynx rufus) Infections in this species are most often subclinical [4, 11, 12], fatal cytauxzoonosis has been documented in bobcats, tigers and lions [12,13,14,15,16]. The schizogonous phase in bobcats appears to be short and is rarely associated with clinical signs [12]
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