Seroprevalence of SARS‐CoV‐2 infection among pet animals in Croatia and potential public health impact

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) emerged in late 2019 and has since caused a global pandemic. Experimental studies and sporadic reports have confirmed susceptibility of dogs and cats to SARS‐CoV‐2 infection. However, the importance of pet animals in the epidemiology of this infection is unclear. This study reports on a first large‐scale serosurvey of SARS‐CoV‐2 infections in dogs and cats in Europe. From 26 February 2020, just one day after the first confirmed human case of SARS‐CoV‐2 infection in Croatia, to 15 June 2020, dog and cat serum samples were collected from animals admitted to three veterinary facilities in Croatia. Additionally, on 25 May 2020, a total of 122 serum samples from employees of the Faculty of Veterinary Medicine University of Zagreb were collected. Total of 656 dogs and 131 cat serum samples were tested using an in‐house microneutralisation test (MNT). Human serum samples, as well as 172 randomly selected, dog sera were tested using enzyme‐linked immunosorbent assay (ELISA). ELISA‐positive human sera were subsequently tested using MNT. Neutralising antibodies were confirmed in 0.76% cats and 0.31% dogs. ELISA reactivity was recorded in 7.56% tested dog sera. On the other hand, 5.19% of administrative, basic and pre‐clinical sciences department personnel and 5.13% of animal health service providers and laboratory personnel tested ELISA positive. Neutralising antibodies were not confirmed in any of the human samples. In conclusion, seropositivity among pet animals in Croatia is low, especially when compared to results from China. A small number of seropositive animals with a low titre of neutralising antibodies suggest infections are rare and are following infections in the human population. Additionally, contact with animals does not seem to be an occupational risk for veterinary practitioners.

Detection and Genome Sequencing of SARS-CoV-2 in a Domestic Cat with Respiratory Signs in Switzerland

“…In serological screenings, the prevalence of anti-SARS-CoV-2 antibodies in cats from Germany, Italy, Croatia, France, and China ranged from 0.69% to 23.5% [ 40 , 41 , 42 , 43 , 44 , 45 ]. A study from China could not detect SARS-CoV-2 specific antibodies in any of the 423 tested cat sera collected after November 2019 during the early stages of the COVID-19 pandemic [ 42 ], and a serological investigation in nine cats living with COVID-19 positive students at a veterinary campus in France could not prove SARS-CoV-2 infection in the tested cats.…”

Emerging and Neglected Viruses of Zoonotic Importance in Croatia

“…A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a respiratory virus that emerged in February 2020 and spread rapidly throughout the country. Acute infections as well as seropositivity have been confirmed in humans and pet animals [ 32 , 33 , 34 ]. The rabies virus (RABV) still presents a major veterinary and public health threat.…”

“…ELISA reactivity was recorded in 5.19% of administrative, basic and preclinical sciences department personnel and 5.13% of animal health service providers and laboratory personnel; however, neutralizing antibodies were not confirmed in any of the human samples. A small number of seropositive animals suggest that infections are rare and are following infections in the human population [ 34 ]. So far, there have been no published data on the genetic characterization of SARS-CoV-2 strains detected in Croatian COVID-19 patients.…”

Third update on possible animal sources for human COVID‐19

“…Often SARS‐CoV‐2 in cats or dogs was only detected by PCR assays, occasionally the pet in question seroconverted, and in only a few cases, mild clinical signs were described 8 . Commonly, field assessments of the general cat and dog population using serology assays resulted in a low prevalence of antibody‐positive animals 36,37 . Overall, this has triggered a number of controlled experimental and observational studies.…”