This is the only bacterial disease spread by vectors like ticks, mites and lice. Which of the following statements about this disease are correct?
1. It is not deadly.
2. It was discovered by C. Ricketts.
3. Its symptoms appear similar to measles.
4. This organisms is a connecting link between virus and bacteria.

Rickettsial infections are spread through ticks, mites, fleas, or lice. Rickettsiae and rickettsia-like bacteria are usually spread to people through the bites of ticks, mites, fleas, or lice that previously fed on an infected animal. Ticks, mites, fleas, and lice are called vectors because they convey (transmit) organisms that cause disease. Different rickettsial infections tend to cause similar symptoms: fever, severe headache, a characteristic rash, general feeling of illness (malaise). Because the rash often does not appear for several days, early rickettsial infection is often mistaken for a common viral infection, such as measles.