Mortalities, amyloidosis and other diseases in free‐living red squirrels (Sciurus vulgaris) on Jersey, Channel Islands

Abstract

Between 2007 and 2014, 337 free-living red squirrels () on Jersey, Channel Islands, were examined post mortem as part of a mortality and disease surveillance scheme. Road traffic accidents (RTAs) were attributable for 50.7 per cent (171/337) of the casualties, 34.4 per cent (116/337) succumbed to diseases including fatal exudative dermatitis (FED), 7.1 per cent (24/337) to predation, 6.5 per cent (22/337) to other trauma and 1.2 per cent (4/337) to suspected poisoning. Cat predation accounted for 5 per cent (17/337) of mortalities. Pathologies were diverse and individual animals were often identified with more than one disease process. Squirrelpox virus (SQPV) particles were not detected in selected cases examined by transmission electron microscopy (TEM). Amyloid was identified in 19.3 per cent (65/337) of squirrels, often in conjunction with inflammatory lesions like hepatic capillariasis. A consistent cause of amyloid accumulation was not identified, although there was a significant association of amyloidosis with hepatic capillariasis and FED. In addition to RTAs, amyloidosis and FED have been identified as important causes of squirrel morbidity and mortality on Jersey, while the underlying aetiology and predisposing factors for these two disease complexes are presently unclear. Disease, fragmented woodlands, an increasingly suburban habitat, along with various anthropogenic factors, may jeopardise the long-term viability of this island red squirrel population.

Viral enteritis causes deaths and stunting in neonatal piglets in Scotland

“…SRUC Veterinary Services can be contacted by telephone on 0131 535 3130 or by email: vcedinburgh@sac.co.uk Contact details for local SRUC VS disease surveillance centres are available at www.sruc.ac.uk/ contactvetservices and stress-related factors have also been suggested as predisposing factors. 6 Necropsy studies carried out between 2002 and 2012 did not detect amyloidosis in Scottish squirrels. 7,8 In contrast, 20 per cent of carcases examined on Jersey between 2007 and 2014 were found to have died of amyloidosis.…”

“…7,8 In contrast, 20 per cent of carcases examined on Jersey between 2007 and 2014 were found to have died of amyloidosis. 6 Further carcases were requested if any were found.…”

Amyloidosis and Longevity: A Lesson from Plants

“…However, it often occurs in a wide variety of mammals and birds, both domesticated and living in wild nature. For example, amyloidosis has been identified as an important cause of squirrel morbidity and mortality (19.3% of deaths) [34]. It is also described in a brown hare ( Lepus europaeus ) [34] and black-footed wild cat living in South Africa [35].…”

“…For example, amyloidosis has been identified as an important cause of squirrel morbidity and mortality (19.3% of deaths) [34]. It is also described in a brown hare ( Lepus europaeus ) [34] and black-footed wild cat living in South Africa [35]. Amyloidosis is found in association with different chronic diseases in cheetah ( Acinonyx jubatus ), Siberian tigers ( Panthera tigris altaica ) and mink ( Mustela vison ) [36].…”

Why do red squirrels die?

“…16,17 Since the irst serology study, the SQPV ELISA has been used extensively to monitor the spread of virus in the expanding grey squirrel population, conirming that disease in red squirrels normally follows detection of antibodies against SQPV in sympatric grey squirrels. However, studies of island populations of red squirrels, such as one by Blackett and others, which is summarised on page 503 of this issue of Vet Record, 18 have also helped enormously to decipher the role of the grey squirrels in the epidemiology of squirrelpox disease in red squirrels. Neither the study by Blackett and others on the causes of red squirrel mortality on the island of Jersey, nor an earlier study of red squirrel mortality, principally on the Isle of Wight, but also including Brownsea Island in Poole Harbour, 19 revealed squirrelpox disease as a cause of death in the resident red squirrels.…”