VIRUSES

Viruses are simple infectious particles composed of a coat of protein surrounding a length of nucleic acid (DNA or RNA). Viruses are not metabolically active and can only reproduce by hijacking the protein synthesis machinery of a host cell.

Viral diseases include the common cold, influenza, herpes, mumps, measles, chickenpox, smallpox, glandular fever, Dengue and Ebola. HIV (the causative agent of AIDS) is a retrovirus which has RNA rather than DNA. Because viruses lack metabolic processes, antibiotics do not work against them. Treatments must target the host cell.