Coloured scanning electron micrograph (SEM) of a group of the bacteria Borrelia burgdorferi, which cause the illness Lyme disease. Humans can contract Lyme disease when these bacteria are transferred via tick bite. Lyme disease causes a rash and flu-like symptoms and, if left untreated, neurological issues, cardiac abnormalities, and arthritis can develop. Treatments include antibiotics and corticosteroid drugs.