Results
A summary of all parasite species recorded in the mouse population is
shown in Table 1. Out of 366 recorded mice, 127 were uninfected withT. muris or S. obvelata (34.70%), 169 were infected withT. muris (46.17%) and 112 were infected with S. obvelata(30.60%). Of these mice, 42 (11.48%) were coinfected with both
parasites. Burden distributions for both species were found to
approximate a negative binomial distribution, with infections greatly
shifted towards low infection burdens, with rare individuals having
dramatically higher loads.
The T. muris binomial mixed model found the prevalence of the
parasite increasing significantly with the age estimate in days
(z=6.038, p<2x10-16, OR=1.026). There was no
association observed, however, between age and parasite abundance
(z=0.684, p=0.4941, OR=1.001), suggesting that once infection has
established, the number of parasites established in the host remains
fairly stable. The prevalence of S. obvelata was significantly
negatively associated with the number of captures per transect per day
(z=2.780, p=0.005, OR=0.613), implying a negative association between
host population density and S. obvelata prevalence.
Most captured individuals (152 out of 261) showed some level of
infection by C. hepaticum . The distribution of infection score in
infected individuals is predominantly uniform. The prevalence (z=3.921,
p=8.82x10-5, OR=1.020) and infection intensity
(z=3.163, p=0.00156, OR=1.011) of the parasite was positively associated
with age.
No Anaplasma sp. or Trypanosoma sp. were detected by PCR
in any of the mice. In 127 mice, no microparasites were detected. 123
mice were found to be infected with Bartonella sp. , and 18 were
found to be infected with Sarcocystis dispersa . Of these mice, 7
were coinfected with both parasites.
Prevalence of Sarcocystis sp. was strongly positively associated
with increasing age (z=2.487, p=0.0129, OR=1.0167). No ecological
parameters were found to significantly impact Bartonella sp.prevalence.
Four genera of mite (Myobia , Radfordia , Myocoptes& Trombicula ), and one species of flea (Nosopsyllus
fasciatus ) were found in the fur of the mice. Prevalence of fleas was
found to be positively associated with age (z=2.552, p=0.0107,
OR=1.007). Abundance of mites also showed a positive relationship with
SMI (z=2.533, p=0.0113, OR=1.060) and age (z=4.659,
p=3.2x10-6, OR=1.006).