Distribution and prevalence of ticks and tick-borne disease on sheep and cattle farms in Great Britain

Abstract

Introduction: The most abundant and widespread tick species in Great Britain, Ixodes ricinus, is responsible for the transmission of a range of pathogens that cause disease in livestock. Empirical data on tick distribution and prevalence are required to inform farm management strategies. However, such data are largely unavailable; previous surveys have been rare and are usually relatively localised. Methods: A retrospective questionnaire survey of farmers was used to assess the reported prevalence of ticks on livestock across Great Britain. Spatial scan statistics and kernel density maps were used to assess spatial clustering and identify areas of significantly elevated risk, independent of the underlying distribution of respondents. Logistic regression models were used to identify risk factors for tick presence. Results: Tick infection risk to livestock is shown to be spatially aggregated, with areas of significantly elevated risk in north Wales, northwest England and western Scotland. Overall, the prevalence of farms reporting tick presence was 13% for sheep farms and 6% for cattle farms, but in "hot spot" clusters prevalence ranged between 48-100%. The prevalence of farms reporting tick-borne disease overall was 6% for sheep and 2% for cattle, but on farms reporting ticks, prevalence was 44% and 33% for sheep and cattle farms, respectively. Upland farming, larger flock sizes, region and the presence of sheep on cattle farms were all significant risk factors for tick presence. Conclusions: These data have important implications for assessing both the risk of tick-borne disease in livestock and optimising approaches to disease management. In particular, the study highlights the need for effective livestock tick control in upland regions and the southwest, and provides evidence for the importance of sheep as tick maintenance hosts.

Epidemiology, Distribution and Identification of Ticks on Livestock in Pakistan

“…Some studies of tick prevalence in Pakistan are focused on specific regions with small sample sizes of ticks. Ticks and tick-borne diseases are neglected issues and there are few tick control products available in markets [ 35 ].…”

High morbidity associated with an outbreak of tick‐borne disease in a dairy herd, Cornwall

“…Sheep have previously been demonstrated to maintain infected tick populations in the absence of wildlife hosts, 15 and are a recognised risk factor for tick infestation in cattle. 3 We also speculate that other vertebrate hosts including birds, small rodents or deer may have contributed to the abundant tick population and maintenance of tick-borne diseases, particularly A. phagocytophilum. It is worth noting that the affected pasture in this case was mainly improved new ley pasture (Figure 1), as opposed to the rough grazing typically attributed to harbouring large tick populations.…”

Potential for online crowdsourced biological recording data to complement surveillance for arthropod vectors

“…Whilst human Lyme borreliosis incidence in the UK is low compared to other European countries [33], reported cases increase each year [34,35]. Ixodes ricinus also transmits Anaplasma phagocytophilum, Babesia divergens and Louping ill virus, which primarily affect livestock in the UK [36]. Recently, tick-borne encephalitis (TBE) virus has been detected in UK populations of I. ricinus [37,38] and the first UK-acquired human TBE case was reported shortly afterwards [39].…”