Rickettsia are a group of bacteria that are typically transmitted to humans through the bites of infected ticks, fleas, or lice. These microorganisms are known for causing various diseases, including Rocky Mountain spotted fever and typhus. They are obligate intracellular parasites, meaning they can only survive and reproduce inside the cells of a host organism. Infection with Rickettsia can lead to symptoms such as fever, rash, and muscle aches. Diagnosis often involves blood tests, and treatment usually includes antibiotics. Preventive measures focus on avoiding contact with vectors like ticks and maintaining good hygiene to reduce the risk of flea and lice infestations.