Tick Bites: Facts You Need to Know Now

Which of these statements is/are true regarding illnesses caused by tick bites?

a. Rocky Mountain Spotted Fever (RMSF) is more common in the US mid-Atlantic states.
b. If a bull’s eye-looking rash occurs, you have made the diagnosis of Lyme borreliosis.
c. An allergy to red meat may be a result.
d. In mostly all circumstances, the tick must feed for more than 24 hours to transmit disease.
e. All of the above.

Please click here for the answer and discussion.

ANSWER: E
 

There are many diseases transmitted by tick bites. Most are bacterial or viral, although one toxin-induced disease- tick paralysis-occurs.¹

While it is true that the rickettisial infection RMSF was initially described by Howard Ricketts in Idaho’s Bitter Root Valley in Idaho in the early 1900s, the highest frequency of this potentially fatal vascular endothelial infection¹ is highest in the Mid-Atlantic area of the eastern USA- including Virginia and North Carolina. Prompt recognition is necessary to avoid increased morbidity and mortality.² This infection is also found in Central and South America.

Erythema migrans (Figure 1) is a distinctive feature, although not always present, of early infection with Borrelia burgdorferi, the cause of Lyme disease. The rash, however, is not pathognomic of this infection and can be found in Southern tick-associated rash illness (STARI). STARI is of unclear etiology, tends to be found in states such as Missouri where Lyme disease is uncommon, and is associated with the Lone Star tick, Amblyomma americanum (Figure 2).³

Indeed, in 2009, a novel, delayed form of IgE-mediated anaphylaxis has been described related to antibodies directed against the oligosaccharide galactose-alpha-1,3-galactose (known as alpha-gal). It appears that bites from A americanum or other ticks can stimulate the immune reaction and has been described in the USA and elsewhere.⁴ 

Many of the more common tick borne infections, such as RMSF and Lyme disease, require prolonged feeding. In tick borne relapsing fever,⁵ which is caused by certain Borrelia species, the feeding times of this soft tick is much shorter, however. The infection, found in the USA primarily in the southwestern states, causes bouts of recurrent fever. During the febrile period, the spirochete can be seen on a standard Wright’s stain of the peripheral blood.

References
1. Buckingham SC, Marshall GS, Schultze GE, et al. Clinical and laboratory features, hospital course, and outcome of Rocky Mountain spotted fever in children. J Pediatr. 2007;150:180-184.
2. Masters EJ, Olson GS, Weiner SJ, Paddock CD: Rocky Mountain spotted  fever. A clinician’s dilemma. Arch Intern Med. 2003;163:769-774.
3. Masters EJ, Grigery CN, Masters RW. START, or Masters disease: Lone Star tick-vectored Lyme-like illness. Infect Dis Clin North Am. 2008;22:361-376.
4. Commins SP, James HR, Kelly EA, et al. The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose, alpha-1,3-galactose. J Allergy Clin Immunol. 2011;127:1286-1293.
5. Cutler SJ.  Relapsing fever –a forgotten disease revisited. J Appl Microbiol. 2010;108:1115-1122.