Rickettsial diseases are a group of infections caused by bacteria from the genus Rickettsia. These bacteria are typically transmitted to humans through bites from infected ticks, fleas, or lice. Common symptoms include fever, headache, rash, and muscle pain. Some well-known rickettsial diseases include Rocky Mountain spotted fever and typhus. Diagnosis often involves blood tests, and treatment usually consists of antibiotics. Preventive measures include avoiding areas with high tick populations and using insect repellent to reduce the risk of bites.