Anthrax spores have an RNA coating that triggers an immune system response which targets these spores. However, this signalling can disrupt the immune response to vegetative Anthrax cells. "We postulate that Bacillus anthracis has evolved to use spore-associated RNA to activate type I interferon signaling and thereby evade host immunity," researcher Park explains.
Anthrax is a very dangerous disease that can cause many symptoms, ranging from a skin infection, to vomiting to sweats. The bacteria produce toxins that spread throughout the body via the circulatory system. These toxins can be fatal. This makes it very difficult once the bacteria establishes a population living within a host's body. If the immune system detects the cell early on, the infection can be stopped befor it gets too bad. However, by suppressing the appropriate immune response, the RNA coating of the spores can delay the immune response. Antibiotics and antitoxins are the best treatments.
CDC Info on Anthrax