Rickettsial infections are caused by germs. They are divided into: Typhus group Spotted fever group Classic scrub typhus group Fleas, ticks, mites, and lice bite our skin. They transfer their germs when they bite. You can also get the germ from the stool of infected fleas and lice, which can be transmitted through the skin by itching or scratching. Sometimes, dust is contaminated with this material. This can be breathed into the lungs or rubbed into the eyes. The germ infects your blood and muscles. It can damage your tissues and cause serious health problems.