OmniVira

Dogs and Cats Are Less Susceptible to the Omicron Variant of Concern of SARS-CoV-2: A Field Study in Germany, 2021/2022.

Constantin Klein1 Anna Michelitsch1 Valerie Allendorf1 Franz Josef Conraths1 Martin Beer1 Nicolai Denzin1 Kerstin Wernike1
Affiliations 1 institutions
  1. Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany.
PMID40303725 DOI10.1155/2023/1868732 Year2023 Journal Transboundary and emerging diseases Transbound Emerg Dis Languageeng Statusepublish

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a pandemic of unprecedented extent. Besides humans, a number of animal species can be infected; however, in some species, differing susceptibilities were observed depending on the virus variant. Here, we serologically investigated cats and dogs living in households with human COVID-19 patients. The study was conducted during the transition period from delta as the dominating variant of concern (VOC) to omicron (BA.1/BA.2) to investigate the frequency of virus transmission of both VOCs from infected owners to their pets. The animal sera were tested by surrogate virus neutralization tests (sVNT) using either the original receptor-binding domain (RBD), enabling the detection of antibodies against the delta variant, or an omicron-specific RBD. Of the 290 canine samples, 20 tested positive by sVNT, but there were marked differences between the sampling time and, related thereto, the virus variants the dogs had contact to. While in November 2021, infected owners led to 50% seropositive dogs (18/36), only 0.8% (2/254) of animals with household contacts to SARS-CoV-2 between December 2021 and April 2022 tested positive. In all cases, the positive reaction was recorded against the original RBD. For cats, a similar pattern was seen, as in November 2021, 38.1% (16/42) tested positive, and between December 2021 and March 2022, only 5.0% (10/199). The markedly reduced ratio of seropositive animals during the period of omicron circulation suggests a considerably lower susceptibility of dogs and cats to this VOC. To examine the effect of further omicron subvariants, sera taken in the second and third quarter of 2022 from randomly selected cats were investigated. 2.3% (11/372) tested seropositive, and all of them showed a stronger reaction against the original RBD, further supporting the assumption of a lower susceptibility of companion animals to the omicron VOC.

Supporting text Virus Host Location
Cat Diseases 67 COVID-19 425 Dog Diseases 65 SARS-CoV-2 453 Animals 1948 Antibodies, Viral 212 Cats 120 Dogs 176 Female 289 Germany 20 Humans 1440 SARS-CoV-2 variants 86

Evidence records

5 total
Zoonotic Surveillance
5 records · 1 evidence types
Evidence type Serological Evidence
5 records
OVE9199 Serological Evidence
Key finding

Serological testing found 6.9% overall SARS-CoV-2 antibody positivity in dogs, with 50% seropositive in November 2021 during Delta predominance and only 0.8% during Omicron circulation in Germany.

Virus
Severe acute respiratory syndrome coronavirus 2
Host
dog Canis lupus familiaris Natural host
Location
Not specified
Supporting text

Of the 290 canine samples, 20 tested positive by sVNT, but there were marked differences between the sampling time and, related thereto, the virus variants the dogs had contact to. While in November 2021, infected owners led to 50% seropositive dogs (18/36), only 0.8% (2/254) of animals with household contacts to SARS-CoV-2 between December 2021 and April 2022 tested positive.

Method
surrogate virus neutralization test (sVNT)
Sample type
serum samples
OVE9200 Serological Evidence
Key finding

Serological testing of cats showed 38.1% antibody positivity during Delta circulation and 5.0% during Omicron, indicating markedly lower cat susceptibility to Omicron VOC.

Virus
Severe acute respiratory syndrome coronavirus 2
Host
domestic cat Felis catus Natural host
Location
Not specified
Supporting text

For cats, a similar pattern was seen, as in November 2021, 38.1% (16/42) tested positive, and between December 2021 and March 2022, only 5.0% (10/199). The markedly reduced ratio of seropositive animals during the period of omicron circulation suggests a considerably lower susceptibility of dogs and cats to this VOC.

Method
surrogate virus neutralization test (sVNT)
Sample type
sera
OVE9201 Serological Evidence
Key finding

Serological testing of 372 cat sera collected mid-2022 found 2.3% SARS-CoV-2 antibody positivity, all showing stronger reactions to the original RBD compared to Omicron-specific RBD.

Virus
Severe acute respiratory syndrome coronavirus 2 original RBD
Host
domestic cat Felis catus Natural host
Location
Not specified
Supporting text

To examine the effect of further omicron subvariants, sera taken in the second and third quarter of 2022 from randomly selected cats were investigated. 2.3% (11/372) tested seropositive, and all of them showed a stronger reaction against the original RBD, further supporting the assumption of a lower susceptibility of companion animals to the omicron VOC.

Method
surrogate virus neutralization test (sVNT)
Sample type
sera
OVE9202 Serological Evidence
Key finding

Transmission of SARS-CoV-2 variants from infected human owners to companion animals (cats and dogs) was detected, demonstrating human‑to‑animal spillback.

Virus
Severe acute respiratory syndrome coronavirus 2
Host
human Homo sapiens Natural host domestic cat Felis catus Natural host dog Canis lupus familiaris Natural host
Location
Germany
Supporting text

The study was conducted during the transition period from delta as the dominating variant of concern (VOC) to omicron (BA.1/BA.2) to investigate the frequency of virus transmission of both VOCs from infected owners to their pets. Dogs and Cats Are Less Susceptible to the Omicron Variant of Concern of SARS-CoV-2: A Field Study in Germany, 2021/2022.

Method
serological testing | surrogate virus neutralization tests (sVNT) | variant-specific receptor-binding domain assays
OVE9203 Serological Evidence
Key finding

Serological evidence indicated reduced spillover of the Omicron variant from humans to cats and dogs compared with Delta, suggesting lower susceptibility of pets to Omicron.

Virus
Severe acute respiratory syndrome coronavirus 2
Host
human Homo sapiens Natural host domestic cat Felis catus Natural host dog Canis lupus familiaris Natural host
Location
Germany
Supporting text

The markedly reduced ratio of seropositive animals during the period of omicron circulation suggests a considerably lower susceptibility of dogs and cats to this VOC. Dogs and Cats Are Less Susceptible to the Omicron Variant of Concern of SARS-CoV-2: A Field Study in Germany, 2021/2022.

Method
serological testing | surrogate virus neutralization tests (sVNT) | RBD-based antibody assays