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Malaria, a difficult diagnosis in a febrile patient with sub-microscopic parasitaemia and polyclonal lymphocyte activation outside the endemic region, in Brazil

Patrícia Brasil14*, Anielle P Costa14, Cecilia L Longo1, Sidnei da Silva24, Maria F Ferreira-da-Cruz34 and Cláudio Tadeu Daniel-Ribeiro34

Author Affiliations

1 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

2 Serviço de Parasitologia, IPEC, Fiocruz, Av. Brasil 4365. Manguinhos, Rio de Janeiro, RJ CEP 21.040-900, Brazil

3 Laboratório de Pesquisas em Malária, Instituto Oswaldo Cruz (IOC), Fiocruz, Pavilhão Leônidas Deane - 5° andar, Av. Brasil 4365, Manguinhos, Rio de Janeiro, RJ CEP 21.045-900, Brazil

4 Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal), Fiocruz, RJ, Brazil

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Malaria Journal 2013, 12:402  doi:10.1186/1475-2875-12-402

Published: 7 November 2013


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.

Atlantic forest; Rio de Janeiro; Fever of unknown origin; Malaria; PCR diagnosis; Polyclonal lymphocyte activation