title: Malaria, a difficult diagnosis in a febrile patient with sub-microscopic parasitaemia and polyclonal lymphocyte activation outside the endemic region, in Brazil.
abstract: A case of autochthonous Plasmodium vivax malaria with sub-microscopic parasitaemia and polyclonal B-cell activation (PBA) (as reflected by positive IgM and IgG serology for toxoplasmosis, cytomegalovirus, and antinuclear and rheumatoid factors) was diagnosed by polymerase chain reaction (PCR) after consecutive negative rapid diagnostic test results and blood films. The patient, a 44-year-old man from Rio de Janeiro state, Brazil, had visited the Atlantic Forest, a tourist, non-malaria-endemic area where no autochthonous cases of 'bromeliad malaria' has ever been described. The characteristic pattern of fever, associated with PBA, was the clue to malaria diagnosis, despite consecutive negative thick blood smears. The study highlights a need for changes in clinical and laboratory diagnostic approaches, namely the incorporation of PCR as part of the current routine malaria diagnostic methods in non-endemic areas.
authors.affiliation: Laboratório de Doenças Febris Agudas, Instituto de Pesquisa Clínica Evandro Chagas (IPEC), Fundação Oswaldo Cruz (Fiocruz), Av, Brasil 4365, Manguinhos, Rio de Janeiro, RJ CEP 21,045-900, Brazil. patricia.brasil@ipec.fiocruz.br.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Brasil
authors.forename: Anielle P
authors.initials: AP
authors.lastname: Costa
authors.forename: Cecilia L
authors.initials: CL
authors.lastname: Longo
authors.forename: Sidnei
authors.initials: S
authors.lastname: da Silva
authors.forename: Maria F
authors.initials: MF
authors.lastname: Ferreira-da-Cruz
authors.forename: Cláudio Tadeu
authors.initials: CT
authors.lastname: Daniel-Ribeiro
mesh_terms: D000328:Adult; D001938:Brazil; D006801:Humans; D008213:Lymphocyte Activation; D016780:Malaria, Vivax / Q000175:diagnosis* / Q000469:parasitology; D008297:Male; D018512:Parasitemia / Q000175:diagnosis* / Q000469:parasitology; D010966:Plasmodium vivax / Q000276:immunology* / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*