Serological Screening for Antibodies against SARS-CoV-2 in Dutch Shelter Cats

Abstract

The COVID-19 pandemic raised concerns that companion animals might be infected with, and could become a reservoir of, SARS-CoV-2. As cats are popular pets and susceptible to Coronavirus, we investigated the seroprevalence of SARS-CoV-2 antibodies in shelter cats housed in Dutch animal shelters during the COVID-19 pandemic. In this large-scale cross-sectional study, serum samples of shelter cats were collected during the second wave of human COVID-19 infections in The Netherlands. Seroprevalence was determined by using an indirect protein-based ELISA validated for cats, and a Virus Neutralization Test (VNT) as confirmation. To screen for feline SARS-CoV-2 shedding, oropharyngeal and rectal swabs of cats positive for ELISA and/or VNT were analyzed using PCR tests. In 28 Dutch animal shelters, 240 shelter cats were convenience sampled. Two of these cats (0.8%; CI 95%: 0.1–3.0%) were seropositive, as evidenced by the presence of SARS-CoV-2 neutralizing antibodies. The seropositive animals tested PCR negative for SARS-CoV-2. Based on the results of this study, it is unlikely that shelter cats could be a reservoir of SARS-CoV-2 or pose a (significant) risk to public health.

Frequent Infection of Cats With SARS-CoV-2 Irrespective of Pre-Existing Enzootic Coronavirus Immunity, Brazil 2020

“…The highest seroprevalence rates were described upon testing cats from COVID-19 positive households, e.g., 14.8% of cats in Wuhan, China ( 9 ) and, 58.8% of cats in France ( 39 ). Regardless, the seroprevalence in Brazil was higher than those reported from domestic cats in Europe during early 2020, namely 0.7 to 1.4% in Germany, 0.8% in Croatia and 3.3% in the UK ( 5 , 35 – 38 ) and 0.8% found in cat shelters in the Netherlands ( 40 ), likely consistent with less intense SARS-CoV-2 circulation in humans during those studies. On the other hand, our data is consistent with seroprevalence rates of 4.2 to 5.8% in Italy ( 5 , 38 ), 4.2% Germany and 6.4% in Spain ( 38 ), likely due to relatively higher SARS-CoV-2 incidence during late 2020 and in those countries.…”

Cats and SARS-CoV-2: A Scoping Review

“…Besides domestic, stray, and feral cats, there is also a considerable number of cats that is housed in animal shelters. Only one study by van der Leij et al [ 39 ] focused exclusively on shelter cats and Zhang et al [ 41 ] included 46 shelter cats among a total of 102 cats studied. Both studies aimed at measuring the prevalence of SARS-CoV-2 infection among cats in the Netherlands and Wuhan, China respectively.…”

Susceptibility of Pets to SARS-CoV-2 Infection: Lessons from a Seroepidemiologic Survey of Cats and Dogs in Portugal

“…Hence, it is unlikely that dogs from shelters are more prone to SARS-CoV-2 infection, as this infection was more prevalent within COVID-19-positive households. However, a SARS-CoV-2 seropositivity of 2.1% was reported in Dutch shelter cats [17], evidencing that cats may be more susceptible to SARS-CoV-2 infection in these conditions due to efficient viral transmission between cats. Moreover, reports of stray cats and dogs seropositive for SARS-CoV-2 were also described, evidencing the role of cat-to-cat transmission and/or environmental contamination as a potential source of SARS-CoV-2 infection [15,16,22].…”

“…Cats and dogs have been exposed to SARS-CoV-2, involving the detection of SARS-CoV-2 RNA in respiratory and/or fecal specimens [9][10][11][12][13], as well as specific SARS-CoV-2 antibodies [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. According to experimental studies, dogs have little susceptibility to infection [29,30] in contrast with cats, who exhibited higher viral shedding, respiratory pathology, and efficient transmission of SARS-CoV-2 within cats by respiratory droplets [29][30][31][32].…”