Craig M. Shuttleworth

Systematic assessment of the impact of adenovirus infection on a captive reintroduction project for red squirrels (Sciurus vulgaris)

PCR was used to amplify adenoviral DNA, and transmission electron microscopy (TEM) to detect adenovirus particles in tissue and intestinal content samples from red squirrels (Sciurus vulgaris) associated with a reintroduction study on Anglesey (North Wales), from other populations on the island and from stock held at the Welsh Mountain Zoo, 38 km to the east. Samples were collected during the routine surveillance postmortem examinations of all 60 red squirrels with carcases retrieved in a suitable condition between 2004 and 2010, including 29 captive and 31 free-living animals. Following significant clusters of mortality in captive red squirrels, adenovirus was identified retrospectively in faecal material from 12 of 13 (92 per cent) examined carcases from squirrels captive on Anglesey, and 14 of 16 (88 per cent) from the Welsh Mountain Zoo. Virus was identified in 13 of 31 (42 per cent) free-living wild animals, with evidence of both subclinical and clinically significant enteric adenoviral infections in wild squirrels. Without ancillary PCR and TEM testing, the extent of adenovirus infection in such populations would have been underestimated. Screening protocols that include examinations for adenovirus should, therefore, be part of the routine biosecurity measures protecting reintroduction or captive breeding programmes for red squirrels.

Adenovirus-associated deaths in red squirrels on Anglesey.

SIR, — Squirrel poxvirus is an important pathogen among native British red squirrels ( Sciurus vulgaris ) and a considerable factor in their continued decline ([Rushton and others 2006][1]). However, there is increasing evidence of significant adenovirus-associated disease. Enteric adenoviral

Confirmation of squirrelpox in Welsh red squirrels

We wish to report the first laboratory confirmed cases of disease caused by squirrelpox virus (SQPV) in wild red squirrels ( Sciurus vulgaris ) from Wales. Following a long-term grey squirrel ( Sciurus carolinensis ) management and control programme on the island of Anglesey, north Wales, a series of red squirrel translocations from a number of British captive red squirrel collections between 2004 and 2013, reinforced a natural population expansion, from a low of 40 in 1998, to around 700 animals today.1 Since 2009, small numbers have dispersed over the Menai Strait via either of the two bridge links or by swimming the Menai Strait to the Gwynedd mainland, where they have bred and colonised several coastal woodland locations, including the Faenol woodlands and Treborth Botanical Gardens. Here, both locations have small resident populations, often sympatric with small numbers of grey squirrels which are widespread in the surrounding landscape. Historical serological studies revealed two-thirds of the healthy Treborth grey squirrels tested were positive for …

A preliminary comparison of Magnum 116 body-grip traps with a live capture trap design during the control of grey squirrels ( Sciurus carolinensis )

ABSTRACT The grey squirrel is an invasive pest species in the United Kingdom and populations are controlled to protect timber crops and native fauna. Although animals are culled using a variety of methods, there are few data available on the relative efficiency of different trap designs, and in particular spring traps. We compared grey squirrel captures in Magnum 116 spring-traps set within Fineren boxes against captures in a single entry live capture trap design. Trapping was conducted in mature mixed woodland in North Wales. No significant difference in the frequency of grey squirrel captures or body mass of trapped individuals between trap designs was observed. Despite the Fineren box design limiting access by non-target species, by-catch was recorded. We make recommendations for future research to minimise this and also compare our results for Magnum 116 traps with data available on captures in Fenn IV spring traps. The findings have broad relevance to the control of grey squirrels across their wider international invasive range.

SQPV antibody detection in juvenile squirrels.

WHILE surveys of wild red ( Sciurus vulgaris ) and grey ( Sciurus carolinensis ) squirrels have revealed squirrelpox virus (SQPV) infections in both species (Atkin and others 2010), to date it has been unclear whether maternal transfer of SQPV to juveniles takes place. The observed presence of SQPV antibody in grey squirrel juveniles before leaving the nest and in young red squirrels after leaving the nest could, however, reflect maternal antibody transmission rather than direct disease exposure. We describe what we believe to be the first documented report of maternal transfer of SQPV antibody in wild grey and captive red squirrel juveniles. In the summer and autumn of 2014, a study was undertaken to investigate SQPV presence in grey squirrels that were culled by cranial dispatch from several woodland locations across a large area of northern Gwynedd, adjacent to the Menai Straits. In addition to carcases obtained from trap-based control operations, juvenile grey squirrels still in the nest were taken from nest boxes erected within a mixed deciduous woodland in …

Adenovirus detected in juvenile squirrels

SURVEYS of wild red ( Sciurus vulgaris ) and grey ( Sciurus carolinensis ) squirrels have revealed adenovirus (Everest and others 2009, 2010) and squirrelpox virus (SQPV) infections in both species (Atkin and others 2010), but, so far, it is unclear whether maternal transfer of either virus type to juveniles takes place. Here, we report evidence of maternal transfer of adenovirus DNA in juvenile wild grey and captive red squirrels. In the summer and autumn of 2014, as part of ongoing control programmes, a study was undertaken to investigate adenovirus presence in grey squirrels, killed by the approved cranial dispatch technique from several woodland locations across a large area of northern Gwynedd adjacent to the Menai Straits. In addition to carcases obtained from trap-based control operations, juvenile grey squirrels still in the nest were taken from nest boxes erected within a mixed deciduous woodland in Gwynedd and within the grounds of the Welsh Mountain Zoo, Conwy, and …