👉 Rickettsia is a type of bacterium that causes rickettsiosis, an infection that primarily affects humans and some animals. It is characterized by its ability to spread rapidly and can cause severe symptoms such as fever, chills, muscle pain, nausea, vomiting, and sometimes diarrhea. Rickettsiella is one of the most common bacteria causing rickettsiosis in humans, affecting approximately 10% of individuals infected annually worldwide.