Report of One-Year Prospective Surveillance of SARS-CoV-2 in Dogs and Cats in France with Various Exposure Risks: Confirmation of a Low Prevalence of Shedding, Detection and Complete Sequencing of an Alpha Variant in a Cat

Abstract

Despite the probable zoonotic origin of SARS-CoV-2, only limited research efforts have been made to understand the role of companion animals in SARS-CoV-2 epidemiology. According to recent serological prevalence studies, human-to-companion animal transmission is quite frequent, which led us to consider that the risk of SARS-CoV-2 transmission from animal to human, albeit negligible in the present context, may have been underestimated. In this study, we provide the results of a prospective survey that was conducted to evaluate the SARS-CoV-2 isolation rate by qRT-PCR in dogs and cats with different exposure risks and clinical statuses. From April 2020 to April 2021, we analyzed 367 samples and investigated the presence of SARS-CoV-2 RNA using qRT-PCR. Only four animals tested positive, all of them being cats. Three cats were asymptomatic and one presented a coryza-like syndrome. We describe in detail the infection in two cats and the associated clinical characteristics. Importantly, we obtained SARS-CoV-2 genomes from one infected animal and characterized them as Alpha variants. This represents the first identification of the SARS-CoV-2 Alpha variant in an infected animal in France.

SARS-CoV-2 Serological and Biomolecular Analyses among Companion Animals in Campania Region (2020–2021)

“…In agreement with data reported in other studies conducted among companion animals in the last two years, ranging between 0.2% and 14.7% [12,30,31], with differences related to the area under investigation and the period of the pandemic [32,33], we obtained an exposure rate of 1.3% but no evidence of viral RNA was observed when SARS-CoV-2 molecular analysis was performed, including animals from active surveillance coming from positive householders. Sampling time could justify these findings, since we were not able to rapidly test owned pets belonging to SARS-CoV-2-positive owners, due to the quarantine they were subjected to, according to current regulations, associated with the low viral shedding of the naturally infected asymptomatic pets [12,30]. Consequently, it is likely that the animals came into contact with the virus, seroconverted and eliminated the virus, which was also probably caused by the low viral excretion that these animal species exhibit [12].…”

“…We identified a significant difference between owned and stray cats (p = 0.0067), related to contact with confirmed COVID-19 human cases. In fact, it is reported that one of the main factors clearly influencing SARS-CoV-2 prevalence among companion animals [3,12,13,30] is living in infected households, with an eight-fold higher risk of testing seropositive [13]. Both in humans and in hamsters, gender has been identified as an important risk factor; indeed, male subjects with COVID-19 show more severe symptoms and higher fatality rates [46][47][48][49].…”

“…In fact, although the prevalence in pets could be considered insignificant compared to the scale of human infections [50], a relatively high seroprevalence in cats living in close contact with infected humans has been demonstrated, indicating the high anthropozoonotic potential of the virus. Moreover, it seems that pet ACE2 has increased affinity for variants carrying the 501Y mutation [41], which is currently spreading worldwide [51]; thus, it is fairly probable that the true prevalence in these species may be underestimated, also caused by the lack of investigation and the absence of symptoms that mainly characterize pet infection [30]. Finally, the horizontal transmission of the virus between cats and the evidence that SARS-CoV-2 is likely adapting to feline hosts could help the viral sequence evolution dynamics in this species [33].…”

First Evidence of Natural SARS-CoV-2 Infection in Domestic Rabbits

“…Binding events were displayed as median fluorescence intensities (MFI). These two tests were previously successfully used for dogs and cats [11][12][13].…”

The spike glycoprotein of SARS-CoV-2: A review of how mutations of spike glycoproteins have driven the emergence of variants with high transmissibility and immune escape

“…Interestingly, in September 2021, a French group had already identified the SARS-CoV-2 Alpha variant in cats and dogs in France [134] . Recently, scientists in the UK identified cases of severe myocarditis in cats and dogs associated with the Alpha variant that crossed the inter-species line in the that country, raising questions regarding its potential pathogenicity in these animals [135] .…”