Surveillance of red fox Vulpes vulpes cardiopulmonary parasites in the UK
Brereton, Amelia Jane
Thesis or dissertation
University of Exeter
1. Angiostrongylus vasorum, Crenosoma vulpis and Eucoleus aerophilus are nematode parasites which all cause respiratory distress in domestic dogs and are maintained in wild fox populations. Although they can be treated by anthelmintic drugs they can be difficult to diagnose and treatment regimes remain under-evaluated, making it important for veterinarians and pet owners to be aware of the potential for infection with these species. The recent emergence of these species has seen a number of survey studies in Europe and Canada, with varying results for prevalence and associations with fox age, sex, body condition, seasonality and co-infections. 2. While C. vulpis and E. aerophilus are endemic in foxes across the UK, A. vasorum is hypothesised to be spreading from current foci in the south of the country, warranting repeated surveys of the fox population to monitor changes in distribution and prevalence. 3. In this study we aimed to assess the change in range of A. vasorum across the UK since previous study which used foxes from 2005-2006. We also aimed to analyse any changes in prevalence or associations with co-infection, fox condition and other factors since previous study using general linear modelling. Hearts and lungs of 103 foxes from four regions of the UK were examined for nematode parasites. 23 foxes were from the English-Scottish border region where A. vasorum has not previously been found. 4. A. vasorum was not detected in the borders region, and had not significantly increased in prevalence in known foci. E. aerophilus was still the most common species found and UKwide prevalence was 62.5% higher in the present study than in previously study although it remains within the range of other European studies. There were significant relationships between fox body condition and E. aerophilus burden and A. vasorum presence, and between season and E. aerophilus burden. Presence of E. aerophilus was significantly associated with decreased A. vasorum burden. These results differ from previous work from the UK. 5. Veterinarians should be aware of the potential for northwards spread A. vasorum, and the risks of infection from all three species elsewhere in the country. E. aerophilus may be emerging in the UK fox population, but future studies should confirm this using a standardised methodology. Detailed study of fox density in different regions, and better sampling of urban foxes would also benefit future studies, while sampling of foxes from the border region should be repeated to monitor spread.
MbyRes in Biosciences