Emergence and spread of feline infectious peritonitis due to a highly pathogenic canine/feline recombinant coronavirus

Abstract

Cross-species transmission of coronaviruses (CoVs) poses a serious threat to both animal and human health1-3. Whilst the large RNA genome of CoVs shows relatively low mutation rates, recombination within genera is frequently observed and demonstrated4-7. Companion animals are often overlooked in the transmission cycle of viral diseases; however, the close relationship of feline (FCoV) and canine CoV (CCoV) to human hCoV-229E5,8, as well as their susceptibility to SARS-CoV-29highlight their importance in potential transmission cycles. Whilst recombination between CCoV and FCoV of a large fragment spanning orf1b to M has been previously described5,10, here we report the emergence of a novel, highly pathogenic FCoV-CCoV recombinant responsible for a rapidly spreading outbreak of feline infectious peritonitis (FIP), originating in Cyprus11. The recombination, spanning spike, shows 97% sequence identity to the pantropic canine coronavirus CB/05. Infection is spreading fast and infecting cats of all ages. Development of FIP appears rapid and likely non-reliant on biotype switch12. High sequence identity of isolates from cats in different districts of the island is strongly supportive of direct transmission. A deletion and several amino acid changes in spike, particularly the receptor binding domain, compared to other FCoV-2s, indicate changes to receptor binding and likely cell tropism.

Molecular detection using hybridization capture and next-generation sequencing reveals cross-species transmission of feline coronavirus type-1 between a domestic cat and a captive wild felid

“…An ongoing outbreak of a novel FCoV (FCoV-23) in feral/stray cats and free-roaming owned cats in Cyprus has resulted in at least 91 confirmed cases since 2021, representing a 40-fold increase in reported cases of FCoV-related deaths in the island. (59). This outbreak highlights the negative impact FCoV could have on populations of both domestic and wild felids and the need for rapid genetic characterization of FCoV.…”

An outbreak of canine coronavirus type 2 in captive snow leopards(Panthera uncia)demonstrates a possible role for felids as mixing vessels for alphacoronaviruses

“…The diverse recombinant variants of FCoV-2 reported to date display different recombination breakpoints (25,47,48), indicating multiple recombination events between FCoV-1 and CCoV-2. The recent deadly outbreak in feral/stray cats in Cyprus caused by the novel recombinant FCoV-23 (26) has further emphasized the need to identify new recombinant variants and understand the hosts and ecological conditions that promote recombination. Viruses must co-infect the same host cell to exchange their genetic material (i.e., recombine).…”

“…Recently, a novel FCoV-2-like recombinant variant, FCoV-23, has spread among Cyprus's feral/stray cat population, resulting in a 40-fold increase in reported FCoV-related deaths on the island (26). This outbreak shows that novel recombinant variants of FCoV-1 and CCoV-2 can emerge and rapidly spread in specific populations, posing a serious threat to animal and human health.…”

Identification of key residues in MERS-CoV and SARS-CoV-2 main proteases for resistance against clinically applied inhibitors nirmatrelvir and ensitrelvir

“…Such a recombination event between pandemic SARS-CoV-2 and endemic MERS-CoV could have unpredictable consequences. In fact, a recently described recombinant of feline and canine coronaviruses has shown a strong increase in transmissibility (10).…”