Forest pathogen impacts tick population
By Linda on Jan 20, 2011 in Infections | comments(0)
Excerpt:
Invasive species, including pathogens, can have important effects
on local ecosystems, including indirect consequences on native
species. This study focuses on the effects of an invasive plant
pathogen on a vertebrate community and Ixodes pacificus, the
vector of the Lyme disease pathogen (Borrelia
burgdorferi) in California. Phytophthora ramorum, the causative
agent of sudden oak death, is a non-native pathogen killing trees
in California and Oregon. We conducted a multi-year study using a
gradient of SOD-caused disturbance to assess the impact on the
dusky-footed woodrat (Neotoma fuscipes) and the deer mouse
(Peromyscus maniculatus), two reservoir hosts of B. burgdorferi,
as well as the impact on the Columbian black-tailed deer
(Odocoileus hemionus
columbianus) and the western fence lizard (Sceloporus
occidentalis), both of which are important hosts for I. pacificus
but are not pathogen reservoirs.
Abundances of P. maniculatus and S. occidentalis were positively
correlated with greater SOD disturbance, whereas N. fuscipes
abundance was negatively correlated. We did not find a change in
space use by O. hemionus.
Our data show
that SOD has a positive impact on the density of nymphal ticks,
which is expected to increase the risk of human exposure to Lyme
disease all else being equal. A positive correlation between SOD
disturbance and the density of nymphal ticks was expected given
increased abundances of two important hosts: deer mice and
western fence lizards. However, further research is needed to
integrate the direct effects of SOD on ticks, for example via
altered abiotic conditions with host-mediated indirect effects
