If you farm in a country where one or more serious infectious diseases are enzootic or where there is a risk of them occurring, and if vaccines are available and vaccination is allowed, you should vaccinate your herd routinely. This does not completely prevent your herd becoming infected but it greatly reduces the chances as well as reducing the damage. Of the diseases described in this section effective vaccines are available in enzootic countries against classical swine fever (hog cholera) and aujeszky's disease (pseudorabies). Less effective or shorter lasting ones are available in some countries against foot-and-mouth disease, porcine reproductive and respiratory syndrome and transmissible gastro-enteritis.