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Updated: Sep 29, 2025
Author Spotlight: Controlled Human Exposure Model for Tick Research and Lyme Disease Studies
Published on: December 1, 2023
Human Co-Infections between Borrelia burgdorferi s.l. and Other Ixodes-Borne Microorganisms: A Systematic Review
Pierre H Boyer1, Cédric Lenormand1,2, Benoît Jaulhac1,3
1Institut de Bactériologie, Fédération de Médecine Translationnelle de Strasbourg, University of Strasbourg, UR7290, ITI InnoVec, 3 Rue Koeberlé, F-67000 Strasbourg, France.
Abstract:
When it comes to tick-borne diseases, co-infections are often mentioned. This concept includes several entities. On the one hand, tick vectors or vertebrate reservoir host can harbor several microorganisms that can be pathogenic for humans. On the other hand, human co-infections can also be understood in different ways, ranging from seropositivity without clinical symptoms to co-disease, i.e., the simultaneous clinical expression of infections by two tick-borne microorganisms. The latter, although regularly speculated, is not often reported. Hence, we conducted a systematic review on co-infections between B. burgdorferi s.l., the etiological agent of Lyme borreliosis, and other microorganisms potentially transmitted to humans by Ixodes spp. ticks. A total of 68 relevant articles were included, presenting 655 cases of possible co-infections. Most cases of co-infections corresponded to patients with one tick-borne disease and presenting antibody against another tick-borne microorganism. Co-disease was particularly frequent in two situations: patients with clinical symptoms of high fever and erythema migrans (EM), and patients with neurological symptoms linked to the TBEv or a neuroborreliosis. No impact on severity was evidenced. Further studies are needed to better appreciate the frequency and the impact of co-infections between several tick-borne microorganisms.
Insights
Tick-borne co-infections, including Lyme borreliosis (LB) and other tick-borne diseases, are complex. This review found co-disease occurred in specific clinical scenarios but had no evident impact on severity.
Area of Science:
- Infectious Diseases
- Microbiology
- Epidemiology
Background:
- Tick-borne diseases are a significant public health concern.
- Co-infections, the simultaneous presence of multiple pathogens, can complicate diagnosis and treatment.
- Understanding co-infections between Lyme borreliosis and other tick-borne agents is crucial.
Purpose of the Study:
- To systematically review co-infections between Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) and other tick-borne microorganisms.
- To analyze the frequency and clinical presentation of co-infections and co-disease.
- To assess the impact of co-infections on disease severity.
Main Methods:
- Systematic literature review of articles reporting co-infections with B. burgdorferi s.l.
- Inclusion of 68 articles detailing 655 cases of potential co-infections.
- Analysis of clinical manifestations and serological findings.
Main Results:
- Most reported co-infections involved seropositivity for one agent alongside a diagnosed tick-borne disease.
- Co-disease (simultaneous clinical expression) was observed, particularly with fever/erythema migrans or neurological symptoms (TBEv, neuroborreliosis).
- No significant impact on disease severity was identified in the reviewed cases.
Conclusions:
- Co-infections with Borrelia burgdorferi s.l. and other tick-borne pathogens occur, with co-disease presenting in specific clinical contexts.
- Further research is necessary to fully elucidate the prevalence and clinical significance of these co-infections.
- Current evidence does not support increased disease severity due to co-infection.
