• Question: How do viruses kill humans?

    Asked by anon-251254 to Rachel on 22 Apr 2020.
    • Photo: Rachel Hardy

      Rachel Hardy answered on 22 Apr 2020:


      Hello – great question! There are many different types of virus in the environment (millions), each of which can infect and cause harm to us in different ways. All viruses enter cells in our body, and then grow and multiply rapidly once inside these cells.They do this by hijacking the machinery inside our cells that are needed to keep them healthy normally – for example machinery needed to make new proteins or DNA. This allows the virus to multiply within the cell, eventually reducing the function of this cell until it dies. The virus can then break out of the cell, and travel to many other cells within the body to infect them. The way that a virus can kill a human depends on the specific virus.Take the influenza (or flu) virus – this virus enters our body through the nose or mouth. Once inside, it attacks cells inside our lungs, reducing their function. Our body responds by producing lots of different of different chemicals (called cytokines), to kill the virus and make us better (this is an immune response). However, sometimes our immune system activates to a point where healthy cells as well as infected cells are damaged by cytokines. This results in organ failure and death, in a process known as a ‘cytokine storm’. In addition, the immune system may become weakened by fighting the virus, making us more likely to catch other infections, such as bacterial pneumonia. Sometimes, this may result in death (rather than the original virus).Other viruses can cause death in completely different ways. Take the human papillomavirus (HPV), which is responsible for cervical cancer. Once inside a cell, this virus can inactivate proteins that normal limit the amount a cell can grow and divide. This means that a cell can divide unchecked, resulting in the formation of an unregulated mass of cells, or a ‘tumour’.

      So, there are different ways in which a virus can kill a human. Luckily, most of the time our immune system can effectively destroy viruses, meaning that we are perfectly fine after an infection. Certain groups of individuals may be more at risk of serious complications; such as young children (as the immune system is not properly developed yet) or elderly people (as the immune system is not as effective anymore). I hope that this helps, and let me know if you want any more detail or have anymore questions!

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