[Lyme's disease. A critical analysis of its presence in Argentina]

Lyme disease (LD) is caused by bacteria of the Borrelia burgdorferi sensu lato complex and transmitted by the bite of ticks of the Ixodes ricinus complex. To date, no autochthonous cases have been reported in Argentina. Its diagnosis involves serological tests included in a two-step algorithm. The study proposes to report the results of laboratory tests, describe the clinical-epidemiological characteristics of consultations received due to suspected LD, and critically evaluate the scientific evidence on alleged autochthonous cases of Lyme in Argentina.

From 09/2014-05/2022, a study was carried out that included 53 individuals who consulted due to suspected LD at a reference laboratory. Serum samples were obtained and referred to the Centers for Disease Control and Prevention (CDC) for determination of IgM and IgG antibodies. The samples met one or both inclusion criteria: Travel to an area where the transmitting vector circulates; positive diagnostic tests reported by national and international laboratories.

Only five cases (9%) with positive results from these laboratories were confirmed by the CDC, all of them had a travel history. The rest were reported as negative by the CDC and ruled out as autochthonous cases. The comparison of the results sent by private laboratories and those obtained by the CDC showed 91% (n = 48) of false positives.

The diagnosis of LD should only be considered based on the presence of typical symptoms of infection in patients with a history of exposure to the vector, and always use FDA-approved assays and recommended interpretation criteria.