Viruses can’t actually die as they aren’t alive in the first place. They do contain genetic material in the form of DNA or the related molecule RNA, but they cannot thrive independently, they must invade a host organism and hijack its genetic instructions. That said, it makes sense to talk of how long viruses can remain viable and capable of infection. The HIV virus responsible for AIDS and the influenza virus can’t survive more than a few hours outside a host organism (unless kept under carefully controlled conditions). Others, including the deadly smallpox virus, can easily remain infectious for years. The dormant smallpox viruses brought to Australia by British doctors in 1787 may have caused a mass outbreak among Aborigines some two years later.
