Developing an oral bait for badger vaccination - Exeter Research ...

(4) Targeting Human Activities
Although disease is a natural part of any ecological system, such widespread anthropogenic habitat
alterations has led to the dissolution of many ecological barriers important in the natural control of
disease (Polley, 2005). Anthropogenic actions can be implicated in changes in disease ecology (Deem
2001). The loss of endemic stability is one example of such as shift in disease ecology. An
endemically stable disease is one in which the agent, host and environment coexist in a manner that
results in the virtual absence of clinical disease. Ecological change provides an opportunity for
pathogen, host and the environment to interact in novel ways and can result in the emergence of
disease (Alexander et al.,2008). In many regions of the world, diseases that were previously
endemically stable are now unstable due to anthropogenic change (Deem et al., 2001). The loss of
habitat due to human activities has led different species to exploit alternative resources, for example
storks and kites foraging on rubbish dumps (Gortazr et al., 2007), and thus creating another interface
for human or domestic species pathogens to become established in new wildlife hosts. Conversely
supplementary feeding (e.g. maize feeding of white tailed deer) act to increase population densities
result in aggregations of animals, increasing the risk of transmission.
Many wild populations are subject to various harvesting regimes. Although the effects of parasites
on host population dynamics is well established (Anderson & May, 1981) infectious diseases are
have rarely been accounted for in harvest models. Choisy & Rohani (2009) present a model in which
they demonstrate that the interaction between density dependent effects and harvesting can
substantially increase both disease prevalence and the absolute number of infectious individuals.
Furthermore the effect of the timing of the harvest season on the epidemic amplitude of diseases
was explored. Specifically, they show that hunting just before the epidemic peak dramatically
decreases the epidemic amplitude, whereas hunting just after the epidemic peak can substantially
increases the amplitude. Therefore it should be ensured that knowledge of the effects of the timing
of harvesting is known by hunters, or introduce necessary restrictions surrounding disease
outbreaks.
Simple actions such as changing domestic species management practices, has potential to reduce
disease prevalence in wild and domestic animals, and transmission between them. Density of horses
turned out together was positively associated with the risk of exposure to Leptospirosis (Barwick et
al., 1998), and cattle have been observed to avoid pasture contaminated with badger urine or
faeces, except at high grazing densities (Scantlebury et al., 2004). Furthermore systematic studies
from field experiments (Garnett et al. 2002; Garnett et al. 2003; Roper et al. 2003; Tolhurst et al.
2009) using radio tracking, camera surveillance and faecal analysis have revealed the regular use of
cowsheds, feed stores, barns, and cattle troughs by badgers. Therefore to reduce the transmission
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