The Baggio–Yoshinari syndrome (BYS), formerly known as the Brazilian Lyme-like disease and Brazilian human borreliosis, is a disease transmitted by the Amblyomma cajennense tick, but the organism that causes the infection is still unknown. Clinical features resemble those of Lyme disease (LD).
In 1989, Brazilian researchers Professors Domingos Baggio (an entomologist from the Biomedical Sciences Institute of the University of São Paulo), Paulo Yasuda (a microbiologist from the same institute) and Natalino Hajime Yoshinari (a physician from the Rheumatology Department at University of São Paulo's Medical School) started research on Lyme disease in Brazil, by suggestion of Dr. Allen Steere. At that time, LD was almost unknown among Brazilian physicians.
The first cases were described in Brazil in 1992 in siblings from Cotia, São Paulo that developed symptoms as erythema migrans, general flu-like symptoms and arthritis after being bitten by ticks. Although the symptoms were similar to those presented by patients of Lyme disease, clinical and laboratorial results were considerably different. Ticks of the Ixodes ricinus complex were not found at the risk areas; bacteria from the Borrelia burgdorferi sensu lato complex were not isolated in biological fluids and tissues whatsoever. Blood analysis of patients on electron microscopy exhibited structures resembling spirochaete-like microorganisms. For these reasons, the Brazilian zoonosis was named Baggio–Yoshinari Syndrome (BYS) and defined as:
- "Exotic and emerging Brazilian infectious disease, transmitted by ticks not belonging to the Ixodes ricinus complex, caused by latent spirochetes with atypical morphology, which originates LD-like symptoms, except for occurrence of relapsing episodes and auto-immune disorders".
A distinct feature of the syndrome is its prolonged clinical evolution, with relapsing episodes and autoimmune dysfunction. If diagnosed in its early stages, the symptoms respond well to antibiotics. If the disease evolves to a chronic phase, it can potentially cause oligoarthritis, cognitive impairment, meningoencephalitis and erythema nodosum, with the patient risking to develop both articular and neurological sequelae.
The neurological manifestations of BYS were first described by Yoshinari et al. including patients with peripheral neuritis, meningitis and cranial neuritis (facial nerve palsy, diplopia and deafness).
- Revista Brasileira de Reumatologia, vol.49 no.5, São Paulo, Sept./Oct. 2009: Neurological manifestations in Baggio-Yoshinari Syndrome (Brazilian Lyme-like disease syndrome)
- Revista Brasileira de Reumatologia, Vol.54, Issue 2, March–April 2014, Pages 148–151. Chronic lymphomonocytic meningoencephalitis, oligoarthritis and erythema nodosum: report of Baggio-Yoshinari syndrome of long and relapsing evolution
- Revista Brasileira de Pesquisas Médicas e Biológicas vol.40 no.4 Ribeirão Preto Apr. 2007: Description of Lyme disease-like syndrome in Brazil. Is it a new tick borne disease or Lyme disease variation?
- Revista da Associação Médica Brasileira vol.56 no.3 São Paulo, 2010: Brazilian Lyme-like disease or Baggio-Yoshinari syndrome: exotic and emerging Brazilian tick-borne zoonosis