Infection of dogs with SARS-CoV-2

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first detected in Wuhan in December 2019 and caused coronavirus disease 2019 (COVID-19)^1,2. In 2003, the closely related SARS-CoV had been detected in domestic cats and a dog³. However, little is known about the susceptibility of domestic pet mammals to SARS-CoV-2. Here, using PCR with reverse transcription, serology, sequencing the viral genome and virus isolation, we show that 2 out of 15 dogs from households with confirmed human cases of COVID-19 in Hong Kong were found to be infected with SARS-CoV-2. SARS-CoV-2 RNA was detected in five nasal swabs collected over a 13-day period from a 17-year-old neutered male Pomeranian. A 2.5-year-old male German shepherd was positive for SARS-CoV-2 RNA on two occasions and virus was isolated from nasal and oral swabs. Antibody responses were detected in both dogs using plaque-reduction-neutralization assays. Viral genetic sequences of viruses from the two dogs were identical to the virus detected in the respective human cases. The dogs remained asymptomatic during quarantine. The evidence suggests that these are instances of human-to-animal transmission of SARS-CoV-2. It is unclear whether infected dogs can transmit the virus to other animals or back to humans.

Extended data figure:

Sequence alignment of ACE2 proteins from human, dog, macaca, masked palm civet, cat and mouse. Amino acid residues of human ACE2 that are experimentally shown to interact with the receptor binding domain (RBD) of SARS-CoV-2⁸ are denoted by *. Mutations known to disrupt the interaction between human ACE2 and RBD of SARS-CoV are highlighted in red boxes and these amino acid residues are all conserved between human and dog ACE2 proteins.

Figure 1:

Timeline of events.

Figure 2:

A phylogenetic tree of SARS-CoV-2 showing viruses from infected dogs and humans in Hong Kong. Virus sequences from humans and animals from the two affected households are indicated in red font. Other human virus sequences in Hong Kong were indicated in blue. Other selected full and partial (length longer that 23k nucleotides) virus genomes from the GISAID data base were included in this analysis. The tree is unrooted and was constructed by maximum likelihood method using PhyML.