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Dr. Pease - Why You Don't Want Tic Fever

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The article below was published in conjunction with a conference of health officials held in Missoula April 5th and 6th, 1923 by the State Board of Health. By the spring of 1926 a new vaccine was being administered in the Missoula area.

P. D. PEASE, M. D.

City and County Health Officer,

Missoula, Montana.

Maxey defined "Rocky Mountain spotted fever" as an acute endemic, non-contagious but probably infectious disease, characterized clinically by a continuous moderately high fever, severe arthritic and muscular pains, and a profuse petechial eruption in the skin, appearing first on the ankles, wrists and forehead, spreading rapidly to all parts of the body.

Wolbach, in view of our knowledge of the etiology and pathology, defined the disease as "an acute specific endangeitis, chiefly of the peripheral blood vessels, transmitted by a tick Dermacentor venustus, and characterized by onset with chill, continued fever, severe pains in bones and muscles, headache, and a macular eruption becoming petechial, Avhich appears first on wrists, ankles and back, then over the whole surface of the body."

Owing to the opposition to the tick theory by some, and to numerous tick bites on others of those suffering from tick fever, considerable difficulty has been experienced in arriving at a correct period of incubation.

McCalla's experiment upon two men gives an incubation period in one as three, and in the other nine days. Various observers, basing their opinion upon a small number of cases, give the incubation period from three to twelve days.

The onset of Rocky Mountain tick fever is similar to numerous other infectious diseases. It may be sudden with a distinct chill, severe headache, dizziness, vomiting, epistaxis, intense pains referred to the bones and muscles, especially in the lumbar region. The conjunctivae become injected and the face flushed. The tongue becomes coated with a white fur and a red tip. There is often a slight cough without sputum. In the severer cases delirium makes its appearance early.

In the milder types of the disease the onset is less abrupt. There may be chilly sensations, malaise, slight headache and a moderate elevation of temperature.


In the milder cases there is a gradual rise of temperature similar to that of typhoid fever until it reaches its maximum of 103° or 104° at the beginning of the second week. In the severer types of the disease, ushered in with a distinct chill, the temperature reaches 104° or 105° on the second or third day. During the second week the temperature is continuous with a slight morning drop. In those cases in which recovery takes place the temperature falls by lysis, usually reaching normal by the end of the third week. In fatal cases the temperature remains high, though in some the temperature falls to normal followed by a sudden rise just before death.


The eruption, which is the deciding factor in the diagnosis, makes its appearance from the third to the seventh day. It shows first on the Avrists and ankles, spreading rapidly over the body, the abdomen being the last part affected and where it shows the least, In character the rash consists of rose colored unelevated macules from two to four mm. in diameter. At first the eruption disappears upon pressure, but soon becomes petechial and permanent as well as confluent. McCullough speaks of the fully developed eruption as having the appearance of a turkey egg. Frequently subcutaneous hemorrhages varying in size, make their appearance. As the disease advances, the skin upon the back and thighs becomes dark red or bluish in color, due to stasis.

With the subsidence of the fever the rash gradually fades, followed by desquamation.

Occasionally casts of the hands and feet similar to scarlet fever are seen. Cases of necrosis of the skin have been reported. The parts most frequently affected are the scrotum, prepuce, fingers, toes and ears. In addition to the eruption the skin is always jaundiced. This is first noticed in the conjunctivae. As there is no evidence of bile in the urine or an absence of bile in the intestinal tract, the jaundice should be classified as nonobstructive or toxemic.

Gastro-intestinal symptoms.

The tongue becomes covered with a white fur with red edges and tip. As delirium or coma comes on, the tongue and lips become dry, fissured and covered with sores, similar to other febrile diseases. Vomiting may occur during the first week. Later on in the disease the vomited material may contain blood. Anorexia is present, although not marked during the first week. Constipation is the rule.

Pulse and respiration.

During the first few days of the illness the pulse is full and strong, with only a moderate increased rate. In severe or fatal cases the pulse soon reaches 140 to 150. The systolic blood pressure gradually drops, and the first sound of the heart becomes muffled and indistinct. The respirations increase in proportion to the pulse and temperature. In cases where pneumonia or hypostatic congestion supervene, the rate reaches 50 to 60 per minute.

The lungs are negative unless complicated with pneumonia, when the usual signs of that condition will be found.

Nervous symptoms.

In severe cases delirium and restlessness are early symptoms. The delirium may be active or of the low muttering type similar to typhoid fever. Coma in fatal cases comes on shortly before death, hyperesthesia of the skin and marked stiffness has been reported about the muscles of the neck and back, very much resembling that of cerebro-spinal meningitis. Convulsions have been observed in children and in a few adults just prior to death.

Urinary symptoms.

There is considerable variation in the reports upon the examination of the urine. Maxey states that he never found albumin present. In cases coming from the Bitter Root region, albumin, blood, granular, hyaline and epithelial casts are usually present. The pathology of the kidneys, both gross and microscopic would not warrant a negative report upon the urine. The amount of urine is of considerable prognostic value. There is always a lessened amount. If the output of urine only reaches from one-third to one-half of the normal, the case is almost sure to terminate fatally. Whether the lessened secretion of urine is due to changes in the kidneys or to a failing circulation, has not been definitely settled.

Blood changes.

Anderson, Wolbach, Parsons, and Michie each report blood examinations in two cases. The examinations began number of days after the onset and are too few in number to come to reliable conclusions as to the blood changes. The examinations of the blood showed a white count of from 8,000 to 12,000. A moderate decrease in the erythrocytes and hemoglobin, and a prolongation of the coagulation time was shown. The differential count gave a decrease in some of the cases of the neutrophils and an increase in the endothelials. The increase in the endothelial cells was the only constant change and may prove to be of some value in differential diagnosis.

Differential diagnosis.

In common with the other infectious eruptive diseases it is not possible to make a positive diagnosis before the appearance of the rash. Before the appearance of the eruption, the severe headache, pain in the bones, muscles and back, might confuse the disease with influenza or smallpox.

In mild cases of tick fever with a delayed or possible absence of the eruption, the disease may simulate typhoid fever. A positive blood culture or Widal would clear up the diagnosis.

In the early days in the Bitter Root Valley, the disease was thought to be a severe type of measles, or black measles.

No difficulty should be experienced in separating the two conditions by one who has seen a case of tick fever.

In localities where typhus and tick fever might co- exist there would be great difficulty in differentiating between the two conditions. The period of incubation, mode of onset, eruption, course of the disease, termination and increase in the endothelial cells are very similar in both. The two diseases differ from each other in the leukocyte count and location of the rash when it first makes its appearance.

In cases where active delirium, hyperesthesia and stiffness of the muscles of the neck are prominent symptoms, difficulty may be experienced in differentiating it from cerebro-spinal meningitis, but in the latter disease there would be a marked leukocytosis and a cloudy spinal fluid.

In going over the literature and case histories of tick fever, I have not been able to obtain any data as to the length of residence in the localities where the infection took place. In the Lo Lo and O'Brien canyons, the two infected districts in Missoula County, I am of the opinion that the newcomer is much more subject to infection than those who have lived in the localities for some time. If this condition is true throughout the Bitter Root region, then it raises the question as to whether or not some of the old settlers have had at some time a very mild and unrecognized type of the disease which has rendered them immune.

Last Updated on Friday, 20 November 2015 18:05