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

Abstract

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. Graphical Abstract

Molecular epidemiological study on ticks and tick-borne protozoan parasites (Apicomplexa: Cytauxzoon and Hepatozoon spp.) from wild cats (Felis silvestris), Mustelidae and red squirrels (Sciurus vulgaris) in central Europe, Hungary

“…Cytauxzoon europaeus , which was identified in a wild cat in the present study, appears to be the most widespread species of its genus in Europe, reported so far in Germany, the Czech Republic, Luxembourg, Bosnia and Herzegovina, Italy, Switzerland and France [ 14 , 31 ]. While the clinical signs of infection in wild cats, if any, remain to be explored (taking into account that all studies conducted so far used postmortem sampling), domestic cats most often do not show relevant symptoms (e.g.…”

“…While the clinical signs of infection in wild cats, if any, remain to be explored (taking into account that all studies conducted so far used postmortem sampling), domestic cats most often do not show relevant symptoms (e.g. anemia) and remain clinically unaffected [ 31 ]. This is in contrast to what is known of C. felis in North America [ 32 ].…”

Babesiosis in Southeastern, Central and Northeastern Europe: An Emerging and Re-Emerging Tick-Borne Disease of Humans and Animals

“…In cats, infections with another apicomplexan tick-borne hemoprotozoan, Cytauxzoon spp., emerged, with a report in 2018 of five domestic kittens from the northwest and west of Switzerland presenting with severe anemia [ 262 ]. Furthermore, six infected domestic cats were identified in 2019 in the central part of Switzerland, triggering a nationwide epidemiological study, in which one seropositive (1 of 881 randomly selected cats), and one PCR-positive cat (1 of 501 anemic cats), both originating from the region of the Jura mountains, were identified [ 263 ]. In summary, these cases in companion animals indicate a higher risk of hemoprotozoan infections in the western part of Switzerland, where also tick vectors such as D. reticulatus can frequently be encountered [ 25 ].…”

The First Case of Cytauxzoon spp. in Russia: The Parasite Conquers Eurasia

“…However, increasing the intensity of the studies of this pathogen after the first finding in Europe may lend this explanation more credence. The last findings of the pathogen in the samples of European wildcats collected at the end of the 20th century confirm the presence of this parasite in France during that period [ 65 ]. Cytauxzoon spp.…”