Rickettsia sibirica mongolitimonae Infections in Spain and Case Review of the Literature

Abstract

Rickettsia sibirica mongolitimonae is an emerging cause of tickborne rickettsiosis. Since the bacterium was first documented as a human pathogen in 1996, a total of 69 patients with this infection have been reported in the literature. Because of the rising rate of R. sibirica mongolitimonae infection cases, we evaluated the epidemiologic and clinical features of 29 patients who had R. sibirica mongolitimonae infections confirmed during 2007-2024 at the Center for Rickettsiosis and Arthropod-Borne Diseases, the reference laboratory of San Pedro University Hospital-Center for Biomedical Research of La Rioja, Logroño, Spain. We also reviewed all cases published in the literature during 1996-2024, evaluating features of 94 cases of R. sibirica mongolitimonae infection (89 in Europe, 4 in Africa, and 1 in Asia). Clinicians should consider R. sibirica mongolitimonae as a potential causative agent of rickettsiosis, and doxycycline should be administered promptly to avoid clinical complications.

Keywords: Europe; Rickettsia; Rickettsia sibirica mongolitimonae; Spain; bacteria; eschar; lymphangitis; rash; rickettsiosis; spotted fever; tick bite; vector-borne infections; worldwide; zoonoses.

Figure 1

Number of confirmed rickettsioses cases in study of Rickettsia sibirica mongolitimonae infections in Spain. Numbers of patients with a confirmed case of R. sibirica mongolitimone infection and total numbers of other tickborne rickettsioses are indicated for each year during 2007–2023. Cases were diagnosed at the Center for Rickettsiosis and Arthropod-Borne Diseases, La Rioja, Spain.

Figure 2

Monthly prevalence of Rickettsia sibirica mongolitimonae infections in Spain during 2007–May 2024. Patients sought medical care for R. sibirica mongolitimonae infections during March–September of each year.

Figure 3

Eschar from Rickettsia sibirica mongolitimonae infection located on lower limb of patient in Spain.

Figure 4

Eschar from Rickettsia sibirica mongolitimonae infection located on upper limb of a pediatric patient in Spain.

Figure 5

Eschars from Rickettsia sibirica mongolitimonae infections of 2 patients in Spain, located on the abdomen of 1 patient (A) and on the iliac fossa of another patient (B).

Figure 6

Numbers and body locations of tick bites and inoculation eschars in patients with Rickettsia sibirica mongolitimonae infections during 2007–2024, Spain, and from published literature. Patients manifested single or multiple eschars. Cases were diagnosed at the Center for Rickettsiosis and Arthropod-Borne Diseases, La Rioja, Spain and/or identified in PubMed.