Rapid mortality in captive bush dogs (Speothos venaticus) caused by influenza A of avian origin (H5N1) at a wildlife collection in the United Kingdom

Abstract

Europe has suffered unprecedented epizootics of high pathogenicity avian influenza (HPAI) clade 2.3.4.4b H5N1 since Autumn 2021. As well as impacting upon commercial and wild avian species, the virus has also infected mammalian species more than ever observed previously. Mammalian species involved in spill over events have primarily been scavenging terrestrial carnivores and farmed mammalian species although marine mammals have also been affected. Alongside reports of detections in mammalian species found dead through different surveillance schemes, several mass mortality events have been reported in farmed and wild animals. During November 2022, an unusual mortality event was reported in captive bush dogs (Speothos venaticus) with clade 2.3.4.4b H5N1 HPAIV of avian origin being the causative agent. The event involved an enclosure of fifteen bush dogs, ten of which succumbed during a nine-day period with some dogs exhibiting neurological disease. Ingestion of infected meat is proposed as the most likely infection route.

Avian influenza overview March–June 2024

“…The recent detections of A(H5N1) virus in dairy cows in the USA have raised questions about the potential risk of viral transmission through the consumption of milk and meat from infected animals (see Section 2.3). To date, the vast majority of HPAI spillovers from birds to mammals have been reported in scavenging species, where the most likely source of infection was feeding on infected birds (Falchieri et al, 2024). Therefore, carnivorous species, especially those that prey on wild birds, are considered particularly at risk of contracting HPAI.…”

“…These seropositive dogs were reported to have all hunted in areas where waterfowl had tested positive for HPAI virus, and three of them had hunted dead waterfowl (without evidence of having been hunted or shot) or waterfowl that showed neurological signs. In November 2022, A(H5N1) virus was detected by RT-PCR in an enclosure of 15 captive bush dogs in the United Kingdom (Falchieri et al, 2024). Ten of the animals died suddenly or were euthanised on welfare grounds, with some showing neurological signs.…”