TABLE 1.
Comparison between FCoV/SARS‐CoV‐2 infection and FIP/COVID diseases
| FCoV/FIP | SARS‐CoV‐2/COVID‐19 | ||
|---|---|---|---|
| Virology | Genus | Alphacoronavirus | Betacoronavirus |
| Presence of serotypes/clades/strains | Yes (serotype I and II) | Yes (research ongoing) | |
| Origin | Serotype I: unknown (likely bat origin of alphacoronaviruses) | Suggested spillover from other species (bats, pangolins) | |
| Serotype II: recombination FCoV I/ CCoV | |||
| Cell Receptor | Serotype I: Unknown (possibly fDC‐SIGN) | ACE2 receptor | |
| Serotype II: fAPN (possibly also fDC‐SIGN) | |||
| Frequency of mutation | High (quasispecies) | Mutations reported, research ongoing (suggested groups with different virulence) | |
| Epidemiology | Transmissibility | High | High |
| Epidemiologic pattern | Epidemic ‐> endemic | Epidemic (up to now) | |
| Reinfections | Frequent | Rarely reported (up to now) | |
| Model of infection | SIS (susceptible‐infected‐susceptible) | Unknown (up to now) | |
| Lethality | Epidemic phase: high; Endemic phase: low | Epidemic phase: high | |
| Pathogenesis | Route of infection | Faecal–Oral | Respiratory (oral not excluded) |
| Cellular tropism | Enterocytes, monocytes/macrophages | Alveolar macrophages, enterocytes | |
| Role of mutated viral variants | Probable | Postulated | |
| Main target organs | FECV: intestine, FIPV: multiple organs/tissues | Lung (less frequently GI tract or other organs) | |
| Lesions | Granulomatous lesions, vasculitis and effusions, lymphoplasmocytic infiltrates | Cytopathic effect on lung cells, multinucleated syncytial cells, mononuclear infiltrates | |
| Immunopathogenesis | Type III hypersensitivity | Demonstrated | Postulated |
| T‐cell lymphopenia | Demonstrated | Demonstrated | |
| ADE | Hypothesized | Hypothesized | |
| Cytokine storm/SIRS | Demonstrated | Demonstrated | |
| Prevention | Vaccination | Available but not recommended (risk of ADE) | Not available |
| Quarantine/isolation | May eradicate the disease from catteries | May reduce the prevalence of infection/disease | |
| Treatment | Symptomatic drugs | Effective as a support therapy | Effective, curative in mild forms |
| Anti‐inflammatory drugs | Effective as a support therapy | Possibly curative | |
| Anti‐cytokine drugs | Not tested | Effective, curative in mild forms | |
| Hyper‐immune plasma | Not tested | Possibly curative | |
| Interferon or Th1 modulators | Rarely effective | Studies ongoing | |
| Antiviral drugs | Effective in a few clinical trials (GS‐441524, GS‐5734, Xraphconn) | Possibly effective (GS‐5734) |
Abbreviations: ACE2, angiotensin‐converting enzyme 2; ADE, antibody‐dependent enhancement; CCoV, canine coronavirus; fAPN, feline aminopeptidase N; FCoV, feline coronavirus; fDC‐SIGN, C‐type lectin dendritic cell‐specific intercellular adhesion molecule‐3‐grabbing nonintegrin; SIRS, systemic inflammatory response syndrome.