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Rapid response to:

Practice 10-Minute Consultation

Tick bite

BMJ 2020; 370 doi: (Published 13 August 2020) Cite this as: BMJ 2020;370:m3029

Rapid Response:

Re: Tick bite

Dear Editor

Razai et al, in their consultation on tick bite, missed an important message to learners (1). As the incidence of Lyme disease increases, there is also greater likelihood of co-transmission of other pathogens carried by I scapularis and I pacificus ticks. Since symptoms of these co infections are non-specific and may overlap with Lyme’s disease, accurate diagnosis becomes more difficult. It is therefore important that a high level of suspicion is maintained for these co-infections so patients receive accurate diagnosis and adequate treatment.

The most common infectious agents transmitted by Ixodes species ticks in North America that have the potential for co-infection with B burgdorferi are Anaplasma phagocytophilum, Babesia species, deer tick (Powassan) virus, Borrelia miyamotoi, and the Ehrlichia muris–like agent (2).

A phagocytophilum is transmitted by the same Ixodes ticks as B burgdorferi in the United States and causes fever, chills, headache, myalgia, and fatigue arising 1 to 3 weeks following tick exposure. Most cases are mild and self-limited. However, severe manifestations may include respiratory failure, adult respiratory distress syndrome, peripheral neuropathy, rhabdomyolysis, acute renal failure, pancreatitis, and coagulopathies.

It has been found that in Wisconsin, approximately 3% of I scapularis ticks examined were co-infected with B burgdorferi and A phagocytophilum (3). A similar study in 11,000 ticks in public parks of New York State’s Hudson Valley Region found that co-infection rates of nymphs and adults were 0.5% and 6.3%, respectively (4).

The frequency of humans with Lyme disease simultaneously co-infected with A phagocytophilum from various studies ranges from 2% to 10% (5,6). Similirly, Babesiosis is transmitted through the bite of infected I scapularis and I pacificus ticks. Most patients are asymptomatic or have mild, self-limited disease but may be complicated by renal failure, acute respiratory distress, and shock.

In a study of patients with Lyme disease from southern New England, approximately 10% were co-infected with babesiosis (7).

Unlike Lyme disease and Anaplasmosis, doxycycline is not an effective treatment of babesiosis and requires atovaquone and azithromycin or combination of clindamycin with quinine, making it imperitive to consider this diagnosis in mind in patients with tick bite.

Of the 3 species of Ehrlichia in United States, only E muris–like (EML) agent is transmitted by I scapularis is the vector of this emerging pathogen(8).

Possible co-infections should be considered in any patients who are diagnosed with tick bite or Lyme disease, especially those who have unexplained leukopenia, thrombocytopenia, or anemia, or who fail to respond to treatment for Lyme’s disease.

1- Razai MS, Doerholt K, Galiza E, Oakeshott P. Tick bite. BMJ 2020;370:m3029
2- Caulfield AJ, Pritt BS. Lyme disease Coinfections in the United States. Clin Lab Med 2015;35:827–846.
3- Lee, X, Coyle DR, Johnson DK, et al. Prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum in Ixodes scapularis (Acari: Ixodidae) nymphs collected in managed red pine forests in Wisconsin. J Med Entomol 2014;51:694-701.
4- Prusinski MA, Kokas JE, Hukey KT, et al. Prevalence of Borrelia burgdorferi (Spoirochets: Spirochaetaceae), Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae), and Babesia microti (Piroplasmida: Babesiidae) in Ixodes scapularis (Acari: Ixodidae) collected from recreational lands in the Hudson Valley Region, New York State. J Med Entomol 2014;51:226-36.
5- Horowitz HW, Aguero-Rosenfeld ME, Holmgren D, et al. Lyme disease and human granulocytic anaplasmosis coinfection: impact of case definition on coinfection rates and illness severity. Clin Infect Dis 2013;56;93-9.
6- Steere AC, McHugh G, Suarez C, et al. Prospective study of coinfection in patients with erythema migrans. Clin Infect Dis 2003;36:1078-81.
7- Krause PJ, Telford SR, Spielman A, et al. Concurrent Lyme disease and babesiosis – evidence for increased severity and duration of illness. JAMA 1996;275:1657-60.
8- Pritt BS, McFadden JD, Stromdah E, et al. Emergence of a novel Ehrlichia sp. agent
pathogenic for humans in the Midwestern United States. 6th International Meeting
on Rickettsiae and Rickettsial Diseases. Heraklion (Greece), June 5–7, 2011.

Competing interests: No competing interests

21 August 2020
Habib ur Rehman
Saskatchewan Health Authority
Suite 100, 2550 12th Ave, Regina, SK, S4P 3X1, Canada