Fever and a rash following a tick bite can signify a true medical emergency. Ticks are important vectors of
disease worldwide, including Rocky Mountain spotted fever,
Lyme disease, and Congo-Crimean hemorrhagic fever. This paper will review the major ticks of medical importance and the diseases they transmit, including important emerging pathogens.
Rocky Mountain spotted fever continues to be the most lethal tick-borne illness in the United States and is emerging as an important
disease in South America. Other important emerging diseases include human anaplasmosis, southern tick associated rash illness, human monocytic ehrlichiosis, and a variety of rickettsial fevers including those caused by Rickettsia parkeri and Rickettsia amblyommii.
Most tick-borne illnesses respond readily to doxycycline therapy. In the case of Rocky Mountain spotted fever, therapy should be started when the
disease is suspected and should never be delayed for confirmatory tests. Accurate identification of tick vectors can help establish a diagnosis and can help guide preventive measures to reduce the burden of