CHAPTER TEN - MANIFESTATIONS OF PICORNAVIRUS INFECTION

Abstract

This chapter discusses manifestations of Picornavirus infection. The Picornaviruses probably cause more clinical illness than any other group of viruses. Poliomyelitis, Foot and Mouth Disease and the common cold are actual or potential scourges of both man and animals. Vaccines have controlled poliomyelitis and in the case of FMD a combination of vaccine and slaughter is containing the disease. Poliomyelitis was known in the days of the Pharaohs. The cases of paralytic poliomyelitis occurred in children under school age. Many of the other Enteroviruses have been associated with cases of paralytic poliomyelitis. A future rise in poliomyelitis can therefore be expected with the subsequent addition of more and more antigenic types to the trivalent vaccines rendering them less efficient. At present, two types of vaccine are in use and have considerably reduced the incidence of the disease. The first vaccine in use was a formalin-inactivated vaccine while the second and more important was the Sabin live-attenuated vaccine. The spread of infection is probably similar to that of the Enteroviruses and unlike FMDV a policy of slaughter cannot control the disease, owing to the number of infections which pass unnoticed. Effective formalin-killed and live-attenuated vaccines have been produced from infected swine kidney cultures and as there is only one antigenic type, eradication of the disease is possible.