Lyme disease vs Baggio–Yoshinari syndrome in a returned traveller from Brazil

A 26-year-old male with no past medical history was evaluated for a rash resembling erythema migrans (EM) in the context of recent travel to Brazil. He had travelled to Brazil for 17 days, first visiting urban areas of Sao Paulo, then rural regions near Florianopolis and lastly urban areas of Rio de Janeiro. During his travels, he ate prepared meals in restaurants, drank bottled water and stayed in local budget hotels. The patient noted an EM like-rash on his right thigh (Figure 1) while in Rio de Janeiro 6 days after leaving Florianopolis, however he did not recall any tick bites during his trip. He had no evidence of systemic illness while travelling or upon his return to Canada. He was asymptomatic when evaluated in clinic 1 week following his return and his physical examination and routine lab work (complete blood count, electrolytes, liver enzyme testing, creatinine) were unremarkable at that time apart from his resolving EM lesion. Of note, he had no history of prior Lyme infection or travel to a Lyme-endemic region. Serologic studies drawn at his clinic visit were negative for rickettsia, however Lyme serology (performed at the Ontario Public Health Laboratories) demonstrated positive IgM and IgG enzyme-linked immunosorbent assay (EIA), a positive IgM Western blot (bands 24 and 39 reactive), and negative IgG Western blot (bands 41, 66 and 93 reactive; band 45 weakly reactive), consistent with acute borreliosis infection. Five reactive bands are considered diagnostic for a positive Lyme IgG.1 Given his compatible epidemiologic exposure, dermopathy and serologic results, he was treated for Lyme or the Lyme-like Baggio–Yoshinari syndrome (BYS) with 3 weeks of doxycycline (100 mg PO BID). The patient tolerated his medications without issue and remained asymptomatic 1 month later. His EM-like lesion completely resolved. Erythema migrans-like rash on a patient’s thigh while travelling through rural and urban regions of Brazil Lyme and related borrelioses are uncommon but increasingly recognized infectious entities in Brazil. These infections have been documented to occur in the southeastern states of Espírito Santo, Rio de Janeiro and Sao Paulo, the northern states of Amazonas and Tocantins, and the Midwestern region of Mato Grosso do Sul.2 In addition, other studies have also identified patients with BYS in the urban areas of São Paulo, Juquitiba, Cotia and the region around Billings dam, as well as in the city of Manaus.3–5 BYS, first described in 1992, stems from infection with borrelia species in Brazil and is reported to have similar clinical features as Lyme although it may have more relapsing characteristics.4,6,7 Borrelioses in Brazil are transmitted primarily by the Rhipiciphalus and Dermacentor nitens ticks however Amblyomma species are also suspected to play a role in transmission.2,7 Brazilian borrelioses have similar clinical features and are treated with antimicrobials such as ceftriaxone, amoxicillin and doxycycline.3 Diagnoses of these infections stems from a compatible epidemiologic and clinical history. Laboratory diagnosis of specific borrelia species requires specialized laboratory settings, however many of these infections may cross-react with conventional Borrelia burgdorferi serologic testing.4 Clinicians should be aware that Lyme and related borrelioses are present in Brazil. This may facilitate pre-travel advice on tick avoidance measures and shape post-travel care by expanding the differential diagnosis in ill-returned travellers from Brazil. Conflict of interest: None declared.

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