Near-complete genome of SARS-CoV-2 Delta variant of concern identified in a symptomatic dog (Canis lupus familiaris) in Botswana

Abstract

We sought to investigate whether SARS-CoV-2 was present, and to perform full-length genomic sequencing, in a 5-year-old male crossbreed dog from Gaborone, Botswana that presented overt clinical signs (flu-like symptoms, dry hacking cough and mild dyspnoea). It was only sampled a posteriori, because three adult owners were diagnosed with SARS-CoV-2 infection. Next-generation sequencing based on Oxford Nanopore Technology (ONT) was performed on amplicons that were generated using a reverse transcriptase real-time polymerase chain reaction (RT-qPCR) of confirmed positive SARS-CoV-2 nasopharyngeal and buccal swabs, as well as a bronchoalveolar lavage with mean real cycle threshold (qCt) value of 36 based on the Nucleocapsid (N) gene. Descriptive comparisons to known sequences in Botswana and internationally were made using mutation profiling analysis and phylogenetic inferences. Human samples were not available. A near-full length SARS-CoV-2 genome (∼90% coverage) was successfully genotyped and classified under clade 20 O and Pango-Lineage AY.43 (Pango v.4.0.6 PLEARN-v1.3; 2022-04-21), which is a sublineage of the Delta variant of concern (VOC) (formerly called B.1.617.2, first detected in India). We did not identify novel mutations that may be used to distinguish SARS-CoV-2 isolates from the dog and humans. In addition to Spike (S) region mutation profiling, we performed phylogenetic analysis including 30 Delta sequences publicly available reference also isolated from dogs. In addition, we performed another exploratory analysis to investigate the phylogenetic relatedness of sequence isolated from dog with those from humans in Botswana (n = 1303) as of 31 March 2022 and of same sublineage. Expectedly, the sequence formed a cluster with Delta sublineages - AY.43, AY.116 and B.1.617.2 - circulating in same time frame. This is the first documented report of human-associated SARS-CoV-2 infection in a dog in Botswana. Although the direction of transmission remains unknown, this study further affirms the need for monitoring pets during different COVID-19 waves for possible clinically relevant SARS-CoV-2 transmissions between species.

Keywords: Africa; Botswana; COVID-19; SARS-CoV-2; dog; next-generation sequencing (NGS).

FIGURE 1

Full genome representation of a Delta SARS‐CoV‐2 sequence isolated from a dog, defining mutations with those in the Spike (green). Figure generated by covdb.stanford.edu.

FIGURE 2

Phylogenetic tree showing the dog sequence with (top) 30 Delta sequences from dogs and (bottom) human Delta SARS‐CoV‐2 sequences isolated from Botswana circulating during the time the dog sample was swabbed.