bulbul coronavirus hku11 bulbul coronavirus hku11 bulbul coronavirus hku11 (bulbul-cov hku11) is a positive-sense single-stranded rna deltacoronavirus of avian origin found in chinese bulbuls. bulbul coronavirus hku11 virus classification (unranked): virus realm: riboviria kingdom: orthornavirae phylum: pisuviricota class: pisoniviricetes order: nidovirales family: coronaviridae genus: deltacoronavirus subgenus: buldecovirus species: bulbul coronavirus hku11