The Continuing Search for Antiviral Drugs

This chapter discusses the continuing search for antiviral drugs. Many virus diseases, both of humans and animals, have been successfully controlled by vaccines. These successes have naturally led to improvements in the spectrum and duration of protection offered by vaccines until, at present it is difficult to see how antiviral drugs could compete with vaccines in the control of many virus diseases. One may cite smallpox, yellow fever, polio, and recently measles among human diseases, Newcastle disease, Marek's disease, and infectious bronchitis among poultry diseases—an area of veterinary disease control where vaccines have been particularly important. Research into the treatment of virus diseases by drugs is at present directed toward three general areas: (1) attempts to stimulate the defense mechanism of the host animal, (2) large screening programs to find drugs which directly block some virus-specific process, and (3) alleviation of the symptoms of the disease. The treatment of the symptoms, rather than the cause of a disease, has been the mainstay of medical practice from time immemorial, and this is still the case with most virus disease. The short incubation period of many virus diseases will inevitably restrict the therapeutic use of antiviral drugs and in cases where symptoms have already appeared.