A murine model for celebral toxocariasis : characterisation of susceptibility, behaviour and immune response

Abstract

Toxocara canis, the parasitic roundworm of dogs, can infect a number of paratenic hosts, such as mice and humans, due to the widespread dissemination of its ova in the environment (Glickman and Schantz, 1981). In the murine host, larvae have been shown to exhibit a predilection for the central nervous system, resulting in an increasing number of parasites in the brain as infection progresses (Sprent, 1955; Dunsmore et al, 1983; Skerret and Holland, 1997). In previous research, cerebral larval burdens have been correlated with various aherations in murine behaviour (Burright et al, 1982; Dolinsky et al, 1985; Cox and Holland, 1998; 2001a,b), and burdens have been shown to vary between individual outbred mice receiving the same inocula (Cox and Holland, 2001a; Skerret and Holland, 1997), suggesting a role of immunity and host genetics in the establishment of cerebral infection. Though T. canis has been shown to induce a Th2 systemic immune response (Del Prete et al, 1991; Buijs et al, 1994; Cuellar et al, 2001), the cerebral immune response has received no attention. The thesis presented here represents an investigation of the differential brain involvement of T. canis in mice of contrasting genetic background - with characterisation of the humoral and cerebral immune response in two inbred strains of mice, and the simultaneous assessment of cerebral larval accumulation and behavioural alterations.