Key facts Biological weapons use microorganisms like virus, bacteria or fungi to spread disease Agents such as anthrax, botulinum toxin and plague could pose a huge public health threat, killing large numbers of people A biological attack could be confused with a natural outbreak of disease, hampering the response and control There are fears that pathogens could be modified to become deadlier or more transmissible Overview Biological weapons spread infectious agents or toxins to kill humans, animals or plants or contaminate a country’s food and/or water supply. They can be deadly and highly dangerous and spread beyond a country’s borders, making them difficult to control. While infectious agents have long been used in wartime there are concerns that scientific advances – such as CRISPR gene editing tools and gain-of-function research – could be used by malign actors to modify pathogens to make them even more deadly and transmissible.…