Clinical Manifestations of Zika Virus Infection, Rio de Janeiro, Brazil, 2015
Abstract
Zika virus infection, which has been associated with microcephaly and other neurologic disorders, has reached the level of public health emergency of international concern (1). Zika virus (family Flaviviridae, genus Flavivirus) is transmitted by mosquitos of the genus Aedes (2). The virus was first isolated from a serum specimen from a rhesus monkey in the Zika Forest of Uganda in 1947 (3). After 2007, a rapid geographic expansion of the virus was observed, including outbreaks in the Pacific region (4) and, more recently, in South America. Brazil reported the first autochthonous case of Zika virus disease in April 2015 (5), and subsequently, increasing numbers of cases have been reported, especially in northeastern Brazil (6).
Studies on the natural history of Zika virus infection are scarce. Previous research defined Zika virus infection as a dengue-like illness, typically characterized by fever, maculopapular rash, arthralgia, and conjunctivitis (4). Although some patients have all of these symptoms during early onset, fever is not an early symptom for all. Here we describe the frequency of signs and symptoms from a sample of clinic patients in Rio de Janeiro, Brazil, who were later confirmed to have Zika virus disease by using real-time reverse transcription PCR (rRT-PCR).
We retrospectively collected clinical data on a convenience sample of 57 patients found to be Zika virus–positive by rRT-PCR who had medical attention at the 24-hour acute care clinic of Manguinhos in Rio de Janeiro during April 28–June 8, 2015. Data were collected from electronic medical records and surveillance reports. Data were anonymized and included age, sex, and signs and symptoms documented on the first clinic visit of patients who reported acute rash, dengue-like illness, or both. Fever was documented either through direct measurement in the clinic or by patient self-report. Pregnancy status was not assessed. We collected blood samples for serum sample testing during each patient’s initial visit to the clinic and tested for Zika virus using rRT-PCR as described by Lanciotti et al. (7); all samples were collected within 7 days of illness onset. Patients were not tested for dengue or chikungunya viruses. We did not measure the duration of any sign or symptom.