Rocky Mountain Spotted Fever

Abstract

The tick-borne disease Rocky Mountain spotted fever (RMSF) can have deadly outcomes unless treated appropriately, yet nonspecific flu-like symptoms complicate diagnosis. Occupational health nurses must have a high index of suspicion with symptomatic workers and recognize that recent recreational or occupational activities with potential tick exposure may suggest RMSF.

R ocky Mountain spotted fever (RMSF), a public health concern with mandatory reporting, is a tick-borne disease caused by the bacterium Rickettsia rickettsii. Rocky Mountain spotted fever exists throughout the western hemisphere; in the United States, more than 60% of cases occur in North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri with the highest incidence rates ranging from 19 to 63 cases per million individuals (Centers for Disease Control and Prevention [CDC], 2010).

The most common U.S. vector, American dog ticks, congregate along walkways in wooded grassy locations, residential areas, and city parks in eastern, central, and Pacific coastal regions. In 2003, the brown dog tick, Mexico’s primary RMSF vector, spread into Arizona and the United States for the first time. Between 2003 and 2013, American Indian reservations in Arizona reported more than 300 cases of RMSF and 20 deaths (Biggs et al., 2016).

Tick bites mainly occur in the summer, but ticks can bite year round. Risk exposure includes working in forestry, farming, landscaping, grooming, veterinary, and animal control; participating in disaster relief, military exercises, and outdoor recreational activities such as camping, gardening, or hunting; and living near forested areas or high grass.

Symptoms of RMSF are typically nonspecific and include acute fever, headache, cough, gastrointestinal complaints, red eyes, and myalgia. Small, flat, pink, non-itchy macules without eschars on the wrists, forearms, and ankles may appear 2 days to 5 days after fever onset and spread to the palms or soles. The characteristic petechial rash, indicative of more severe disease progression, occurs 6 days after initial symptoms in up to 60% of cases. A rash may not develop, or appear very different from the description above, which can lead to misdiagnosis. Occupational health nurses should have a high index of suspicion with symptomatic workers and recognize that recent recreational or occupational activities with potential tick exposure may suggest RMSF. The painless tick bites often are unnoticed and have a 2 day to 14 day incubation period for RMSF. The disease can be severe or fatal unless treated within the first few days of nonspecific symptoms.

Doxycycline is the drug of choice for everyone, including children; treatment must begin immediately and continue at least 3 days after fever subsides (Biggs et al., 2016). Other antibiotics are ineffective or worsen RMSF. Laboratory confirmation of RMSF takes 7 days to 10 days after symptoms begin, but adverse outcomes are more likely if antibiotic treatment begins after the fifth day of symptoms (CDC, 2010). Children below age 10, American Indians, individuals with immunosuppression, and individuals who delay treatment are more likely to die from the disease.

Occupational health nurses can educate workers about preventing tick exposure and recognizing RMSF symptoms so they receive prompt treatment. Before going outdoors, workers should use repellents containing 20% DEET (N, N-Diethyl-m-toluamide) on exposed skin; treat clothing, boots, and gear with permethrin; and remove tick habitants by treating pets for ticks. After being outdoors, workers should check their clothing for ticks and remove them, shower within 2 hours after being outdoors to help wash off unattached ticks, and perform a body tick check. Although ticks can be found anywhere on the body, they are commonly found in and around the hair and ears, inside the belly button, between the legs, and on the back of the knees. Proper tick removal is important. Never coat ticks with nail polish or petroleum jelly, or use heat to promote tick detachment; instead, use fine-tipped tweezers to grasp ticks at skin insertion site and pull upward with steady pressure without twisting or jerking to avoid embedding mouthparts. Dispose of ticks by submersing them in alcohol, sealing in a container, or flushing in a toilet; avoid crushing ticks with fingers (CDC, Division of Vector-Borne Diseases, 2015). After removing the tick, cleanse the bite area and hands with rubbing alcohol or soap and water.