2 Zoonoses Surveillance in Italy ( 2000-2009 ) : Investigation on Animals with Neurological Symptoms 1

Zoonoses are defined by the World Health Organization (WHO) as “Those diseases and infections naturally transmitted between vertebrae animals and man” (WHO 1959) (Palmer et al., 1998). They may be caused by viruses, bacteria, including chlamidiae and rickettsiae, fungi, protozoa, helminths and arthropods (Krauss et al., 2003), and transmitted directly (through contact with skin, hair, eggs, blood or secretions) or indirectly (by insect vectors and ingestion of contaminated food). Currently, 1415 pathogens for humans have been identified and of these approximately 61% (868) are agents of zoonoses, some of which manifest with neurological signs; 132 agents are also associated with emerging zoonoses (Asjo et al., 2007; Matassa, 2007; Taylor et al. , 2001). Neurological zoonoses are widespread, especially in the developing countries where they are not even diagnosed in most cases. Emerging zoonoses of recently identified pathogens are Lyme disease, cryptosporidiosis, West Nile disease, transmissible spongiform encephalopathy, and possible variants of the avian influenza virus, which have found new favourable conditions for spreading. In contrast, re-emerging zoonoses are well-known diseases considered as eradicated in a given country but recur with an exponentially increasing incidence, such as tuberculosis, leptospirosis, rabies (Matassa, 2007). Pathogens are constantly evolving and spreading in different countries through animals that act as an asymptomatic reservoir and release pathogens into the environment (Krauss et al., 2003). Among these, wild animals, both mammals and migratory birds, play an important role.