DISEASES TRANSMITTED BY TICKS
a. Colorado Tick Fever Virus. This virus has been referred to as "mountain
fever" and was first noticed in the Bitter Root Valley of Montana where doctors in 1902
noted that febrile cases occurred without skin rash. The cause was shown to be a virus
transmitted by ticks and is recognized as the only tick transmitted disease common in
North America. Affecting victims in all the Rocky Mountain states, the Black Hills of
South Dakota and western Canada, the disease is indicated by a sudden onset of fever,
headache, retro-orbital pain, and severe muscle pains. The disease is frequently
diphasic where the symptoms and the remission period last for 2 to 3 days. In the case
of children, serious complications in the form of encephalitis and severe bleeding may
occur; however, no lasting complications have been reported. Oregon and California
have reported the infection in their states, also.
b. Rocky Mountain Spotted Fever.
(1) General. The Rocky Mountain spotted fever has been referred to as the
Mexican spotted fever, Tobia fever, and the Sao Paulo fever; it has been recognized in
the Bitter Root Valley of Montana since 1982. Many people call it "tick fever, black
fever, blue disease, or black measles." It is a rickettsial disease that principally affects
the endothelial cells of the small blood vessels. It is found in the United States (US), in
some parts of Canada, in Mexico, and parts of South America, and it affects the population
of those who have outdoor occupations (that is, agriculture). The infection follows a vicious
chain. The tick feeds on an infected reservoir animal in any stage of the tick's life; larvae
ingest this infected blood. The adult in turn passes the pathogen on through their eggs to the
larvae of the next generation. Since crushed tick tissues and feces might produce
infection, crushing ticks with fingernails can be dangerous.
(2) Signs and symptoms. A constant symptom is a rash observed about the
second to the fifth day on the victim's wrists, ankles, and later spreading to all parts of
the body. At first, the rash lesions are macular and pink, but later they become
maculopapular and darker. The lesions become petechial in about 4 days. The victim
suffers headaches (frontal and occipital), vomiting, myalgia, intense itching in the
lumbar region, organ dysfunction, and marked malaise. The incubation period usually
lasts 2 to 5 days but lasts 3 to 14 days for more severe infections. In the more virulent
infections, the victim experiences 104-106F fever and death is usually between the
ninth and fifteenth day.
(3) Treatment. The victim is administered broad-spectrum antibiotics such
as tetracycline, chloramphenicol, chlortetracycline, or oxytetracycline. Parenteral fluids
and oxygen may need to be administered.