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Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Prevention

RMSF is not transmitted person to person; the disease is transmitted to individuals by the bite of a tick infected with R. rickettsii, so the key to prevention is to avoid a tick bite. Researchers suggest that only about 1%-3 % of the predominant tick species in the U.S. are infected with R. rickettsii, so not every tick bite can transmit RMSF. In addition, infected ticks can take up to six hours attached to the skin before R. rickettsii is transmitted to humans. Although this data suggests that an individual's chance of contracting the disease is not high, it is still significant enough that precautions should be taken to prevent exposure to ticks.

Ticks are found throughout the U.S., especially where there are woods, tall grasses, and wild animals. Tick bites start to increase in April and decrease in September. The chance of getting tick bites increases when humans and dogs enter such environments at these times of year. Infected ticks on dogs can then be vectors of RMSF to humans. Parents should tuck a child's pant legs into socks to prevent ticks from crawling up legs (this works for the parents, too!); long-sleeved shirts may also reduce exposure. Light-colored clothing allows people to see the dark-colored ticks. People should check their children and their own hair and scalp for ticks after spending time outdoors.

A chemical spray containing DEET (n,n-diethyl-m-toluamide) can be sprayed on clothing or skin to repel ticks. Caution is advised, as high amounts of DEET can make children and some adults ill; application instructions should be followed carefully. Acaricides (chemicals that kill ticks and other disease vectors) have been used to reduce tick populations; some biological agents (for example, fungi, nematodes) have also been used, but all of these methods seem to only be useful in small areas.

Currently, there is no vaccine available for RMSF. However, if a person becomes infected with RMSF, the patient can develop an immune response to R. rickettsii that seems to protect the individual from the organisms, but the length of time for this immunity to last is not well documented.