2.1 History, clinical examination, hematology and serum biochemistry
This study is focused on the clinical and laboratory investigation of 3 European Shorthaired cats, which were residing exclusively indoors with their owner, a veterinary medicine undergraduate student affected by COVID-19. The owner lives by herself, in the city of Thessaloniki (Central Macedonia, Northern Greece) in a 40 m2 flat in an apartment block. Owner’s signs of worsening fatigue and intense sneezing first appeared on November 12th 2020 (day 0; D0), followed by anosmia and loss of taste two days later (D2). On D4 the owner was diagnosed with COVID-19 after being subjected to a rapid SARS-CoV-2 antigen test, followed by real-time RT-PCR. Since the onset of clinical signs, the owner was quarantined at home, according to the guidelines issued by the National Public Health Organization of Greece (EODY). The duration of the owner’s clinical signs was one week, followed by complete recovery. During the entire period (i.e. before the onset of signs and far beyond the time of apparent clinical recovery), the owner remained in close contact with all cats, sharing with them all the apartment’s rooms, including the bedroom. The interaction pattern between the owner and each cat was similar (i.e. petting, giving kisses or licks) and did not change, even after the molecular confirmation of the SARS-CoV-2 infection of the owner.
One day after the confirmation of the diagnosis (D5), one of the cats, an 11-year-old neutered female (Cat #1; C1) showed mild signs of self-limiting diarrhea for 3 days, without exhibiting any other symptoms. Given the COVID-19 infection status of the owner, this cat, as well as the other two (Cat #2; C2: a 10-year-old neutered male and Cat #3; C3: a 10-year-old neutered female) that were living in the same environment and did not experience clinical signs were subjected to clinical examination and laboratory investigations for SARS-CoV-2 infection.
On D16, all cats were clinically evaluated in detail in their household environment, and blood samples were obtained for hematology and serum biochemistry. Complete blood counts (ADVIA® 120 hematology system; Siemens Healthcare Diagnostics, Eschborn, Germany), including 100-cell manual differential leukocyte counts and evaluation for platelet aggregates, along with comprehensive blood serum biochemistry analysis (Vitalab Flexor E, Vital Scientific N.V., Spankeren/Dieren, The Netherlands) were performed for each cat.