A serological and molecular survey of SARS-CoV-2 infection in domestic dogs and cats in Bangkok and vicinity Thailand

Abstract

The COVID-19 pandemic caused by SARS-CoV-2 has significant impact to human health worldwide. As of June 2022, over 500 million human cases with 6 million deaths have been reported. Despite SARS-CoV-2 infection in human, SARS-CoV-2 infections in domestic animals have also been reported due to spillover of the viruses from human-animals interface. The aim of this study was to conduct serological and molecular detection of SARS-CoV-2 in dogs and cats in Bangkok and vicinity in Thailand during the pandemic outbreaks. A large-scale SARS-CoV-2 survey in domestic animals which a total of 4,696 serum samples (2,960 of dogs, 1,736 of cats) and 363 swabs (n=174 of 87 dogs, n=189 of 92 cats) were collected from April 2020 to August 2021. Serum samples were tested for SARS-CoV-2 antibodies using multi-species ELISA and surrogate virus neutralization test (sVNT). Swab samples were tested for SARS-CoV-2 RNA by real-time RT-PCR with four panels of specific primers and probes. The ELISA results showed that 1.79% (53/2,960) of dogs and 0.35% (6/1,736) of cats were seropositive. Most animals with seropositivity showed no clinical signs. Positive and suspected serum samples were subjected to sVNT test and the results showed that neutralizing antibodies was detected in a cat (n=1) suggesting SARS-CoV-2 infection in animals during the pandemic in Thailand. However, all swab samples were negative for SARS-CoV-2 RNA. This thesis showed the benefit of disease surveillance in domestic animals during the pandemic. Thus, routine surveillance and monitoring of SARS-CoV-2 in animals are necessary for planning the prevention and control strategies for COVID-19 in human and animals.