Two examples illustrate the use of locusts as models for the study of brain disease and behaviour. First, immune challenge induces sickness behaviour in locusts: immune challenge with laminarin induces anorexia, paralleling phenomena seen in other animals including mammals. Laminarin-induced anorexia in locusts can be blocked by Mianserin, suggesting the involvement of serotonergic receptors. Second, the blood-brain barrier in locusts can be used to study virulence factors in Escherichia coli K1, one of the causative agents of bacterial meningitis in humans: two of the known virulence determinants in mammals, OmpA and CNF1, are also essential for invasion of the locust CNS.