Biology Reference
In-Depth Information
TABLE 5.2 Selection of studies in which the mouse was used as
a model for early Ascaris migration and the host
immunological response to Ascaris infection.
Study type
Reference number
Intestinal-hepatic migratory pattern
48
51
,
68
,
92
,
105
e
Hepatic-pulmonary migratory pattern
52
53
,
68
,
78
,
106
109
e
e
Hepatic pathology
22
,
68
,
110
112
e
Pulmonary pathology
22
,
60
,
74
,
111
Immunological response
22
,
59
,
66
,
76
,
110
,
113
119
e
Host and parasite genetics
59
,
73
,
120
murine species in which the parasite completes its life-cycle in a manner
similar to that in humans. This has enabled considerable dissection of the
immune response to T. muris in both inbred and gene knockout strains of
mice.
45
Heligmosomoides bakeri has proved to be an excellent model
organism for nematodes of importance in livestock.
46
Tanguay and Scott
47
explored the generative mechanisms of aggregation and predisposition
to an adult worm using both inbred and outbred mice infected with
H. bakeri.
In the case of Ascaris infection, a wide range of model organisms have
been experimentally infected, including mice, guinea-pigs, rabbits,
gerbils, rats, cows, lambs, goats, and pigs (see
Table 5.1
and Chapters 14
and 16). In all model organisms except pigs, the life-cycle is incomplete
and models only the early stages of infection (i.e. migration from the small
intestine to the liver and then from the liver to the lungs). Larval stages of
Ascaris infection do not return successfully to the small intestine to mature
and complete their life-cycle in these hosts and they are therefore referred
to as abnormal hosts. It should be noted that in the vast majority of these
models, susceptibility and resistance to Ascaris infection in either the liver
or the lungs has not been clearly established. The particular focus of this
chapter is upon the investigation of ascariasis in mice (see
Table 5.2
), and,
more specifically, the development of a murine model for resistance and
susceptibility to early infection. The use of mice to investigate vaccine
candidates for ascariasis is described in Chapter 16.
MICE AS MODEL ORGANISMS FOR EARLY
ASCARIS
INFECTION
The first published investigation of Ascaris infection in mice was by
Ransom and Foster
48
who described the intestinal
hepatic migratory
e
