Editorial : Coinfections of Lyme disease and other tick-borne diseases

Abstract

Lyme borreliosis (LB), caused by Borrelia burgdorferi sensu lato (s.l.), is the most common tick-borne disease (TBD) in the northern hemisphere. Beyond Borrelia, ticks can transmit other pathogens, such as Rickettsia, Babesia, Anaplasma, Ehrlichia, viruses, etc. The last two decades have seen a sharp increase in TBDs with around 300,000 LB cases every year in the United States and 100,000 cases in Europe. Considering the low sensitivity of current diagnostics, we have only seen the “tip of the iceberg” with regard to the actual cases of TBDs. Ticks, deemed as the second most important arthropod vector of diseases after mosquitoes, often carry multiple species of pathogens and/or opportunistic pathogens, which can infect people simultaneously following the ticks' bite. In other words, it is called multi-species infections, or coinfections. With ticks able to transmit several pathogens in one bite, coinfections may be “the rule, not the exception.” Comorbid human infection with more than one tick-borne pathogen (TBP) is often detected worldwide. Coinfection is of particular human health importance and is getting increased attention due to the interaction of pathogen species within the host, which makes diagnosis and treatment more challenging. The B. burgdorferi s.l. infection can cause temporary human immunosuppression and has been documented to boost transmission of Babesia microti. Therefore, additional tick surveillance and awareness programs are required for early detection of the TBPs-risk to human health.