Bacteria
Bacteria typically have a single circular DNA chromosome located in the nucleoid region. Bacteria are prokaryotic organisms. Unlike some other cells, bacteria dont have a membrane around their nucleus.
Bacteria can either kill the body's cells or multiply so much in the body and lay dormant until there are so many that the body just becomes overwhelmed and is unable to deal with the bacteria attack. One major problem today is the issue that some bacteria is becoming drug-resistant by either a mutation or having a drug-resistant gene put into a plasmid giving the bacteria resistance.
Fun Fact: All of the bacteria in our body collectively weighs about 4 pounds.
The Salmonella bacteria causes typhoid fever and is responsible for the deaths of 216,000 people a year.
Syphilis is one of the most deadly and debilitating bacterias in the world.Syphilis can affect the heart and its main aorta, leading to a bobbing of the head in rhythm to the heartbeat, often ending in death.