Prolonged Zika virus viremia in a patient with Guillain-Barré syndrome in Trinidad and Tobago.

An emerging mosquito-borne flavivirus, Zika virus (ZIKV) is a significant public health concern because of the syndromes associated with the infection. In addition, ZIKV is considered a major problem due to large-scale spread of the disease and the possible clinical complications for the central nervous system, especially Guillain-Barré syndrome (GBS) and microcephaly. Since the introduction of ZIKV in the Caribbean, molecular detection of the viral RNA has been utilized as a more specific and sensitive approach to demonstrating acute infection. However, it is generally accepted that the virus has a short viremic period, generally less than 5 days. Serologic testing has the inconvenience of strong cross-reactivity among flaviviruses, such as dengue and yellow fever. As part of the laboratory surveillance activities for Zika and other arboviruses at the Caribbean Public Health Agency, in 2016 a sample from a male who was clinically diagnosed with GBS tested positive for Zika virus by real-time polymerase chain reaction (rRT-PCR). The serum sample had been taken on day 21 after the onset of symptoms. The case had initially been characterized as a typical ZIKV infection (mild fever with a generalized maculopapular rash). Later, weakness of limbs and other peripheral neurological symptoms appeared. Enzyme-linked immunoassay (ELISA) showed that the sample was negative for IgM antibodies against Zika, Chikungunya, and dengue viruses. The plaque reduction neutralization test was positive for ZIKV. This indicated parallel development of viremia and immune response against ZIKV. Recent reports have demonstrated a longer duration of the viremia in ZIKV infections. However, our report is the first one that links the infection with extended viremia and the development in parallel of a GBS case.