Bovine spongiform encephalopathy: the surveillance between past and future

Introduction - Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSEs), the most known in the world and the only zoonotic. It is characterized by a long incubation period, a clinical course with progressive neurological symptoms and the absence of inflammatory or immune reactions. BSE poses a serious risk to human and animal health. Several measures have been adopted by the European Community as protection of public health with specific rules for the prevention, control and eradication. Aim - The purpose of this paper is to present the evolution of the surveillance system in Italy and the practical implications of its recent recognition by the OIE as a country recognised as having a negligible BSE risk. Materials and method - The classification of countries according to their BSE risk aims at defining rules to regulate trade for each category of risk, balancing the need to ensure the protection of animal and public health in the importing countries and take preventive measures according to the risk. To this purpose, to gather the main elements to be put in relation with the epidemiological changes a revision of the Italian and European legislation was carried out. Results and discussion - The results obtained in the frame of the surveillance system in Italy since 2001 show a trend of the epidemic in terms of prevalence characterized by a strong and steady decline. Consolidated data shows that the probability of finding the disease among the animals of the risk categories (fallen stock, casualty or emergency slaughter) was 4.3 times higher than the total of the same probability in healthy slaughtered animals. Thus surveillance in the targeted risk categories gives to the surveillance system its maximum sensitivity. Conclusions - The application of effective measures led to a drastic and unquestionable reduction of the Italian cases. Furthermore, the increased average age of the cases indicates that the risk of exposure, higher in the mid-90s, has been gradually decreasing until probably disappear. However, in a global context of increased production and consumption of bovine meat the risk of reintroduction of the disease is real. So in order to establish in the future an early warning system for BSE, it is important to maintain active surveillance in cattle belonging to risk categories in which it is most likely the presence of the disease, ie all animals older than 48 months.