A septicaemic disease outbreak in one of the enclosures at a zoo in Western Australia (zoo A) resulted in the death of three resident squirrel gliders within a month following the introduction of two new gliders from another zoo (zoo B) into the enclosure. Tissue samples from two of the dead gliders as well as oral swabs from the two introduced gliders and a resident woylie confirmed Pasteurella multocida as the bacterial cause of the outbreak and also the presence of the organism in the remaining animals. Oral swabs were then taken from thirteen marsupials (10 squirrel gliders two rufous bettongs and one woylie) from four different enclosures at zoo B (enclosures B1 to B4). P. multocida was isolated from five of the seven marsupials in enclosure B1, the enclosure where the two introduced gliders came from, as well as residents of enclosures B3 and B4, but not from those cohabiting enclosure B2. The isolates were then analysed via lipopolysaccharide typing, repetitive extragenic palindromic polymerase chain reaction (rep-PCR) typing, multilocus sequence typing (MLST), whole genome sequencing and phylogenomic analysis to investigate isolates relatedness.

The outbreak isolates displayed the same rep-PCR profile, MLST and LPS structure as those obtained from squirrel gliders moved to zoo A, and also those obtained from marsupials at zoo B. Core genome SNP tree demonstrated that the outbreak isolate and those from marsupials at zoo B were clonal, suggesting zoo B as the source of the outbreak. However, the P. multocida isolate obtained from the woylie cohabiting with the dead gliders at zoo A was unrelated to the outbreak isolates. Overall, the use of WGS technique has allowed a comprehensive tracking of this disease outbreak and will guide future quarantine and movement protocols.