2016 dengue outbreak in Buenos Aires: A case series

Abstract

Background: In 2016, the Metropolitan Area of Buenos Aires suffered the largest dengue outbreak ever recalled with 12495 cases assisted in the city. The main circulating serotype was DEN-1 and affected a population predominantly non-immune. Methods & Materials: Description of clinical and biochemical characteristics of suspected dengue cases (as defined by argentinian guidelines), in adults attended on a specialized hospital between the 11th and the 18th epidemiological week of 2016, when the outbreak was officially announced. Results: 1728 adults with an acute febrile illness were assisted; 1468 fulfilled the inclusion criteria. 57 cases had recently travelled to areas with active circulation of dengue and 124 had risk factors for severe dengue. The median age was 34 (range 18-80) and 50% were women. The symptoms most frequently associated were headache (87%), myalgia or arthralgia (83%), nausea or vomiting (55%), diarrhea (24%), abdominal pain (29%), rash or pruritus (36%). 7.5% presented with bleeding, mainly epistaxis (28%), gingival hemorrhage (29%) and metrorrhagia (22%). Blood tests were performed in 1300 patients. Before the fifth day of symptoms (n = 924), 66% of patients presented with laboratory findings suggestive of dengue: hematocrit > 47 (11%), leucopenia (44%) and thrombocytopenia (41%). During the overall follow-up period (median of 2 consults, range 1-10), 82% showed laboratory findings suggestive of dengue, mainly thrombocytopenia (64%), leucopenia (54%) and relative lymphocytosis (32%). 222 patients required IV fluids and 49 of them were hospitalized. Conclusion: In these series, there was a high frequency of gastrointestinal symptoms, supposing a challenge for the differential diagnosis. The course of the illness was benign in most cases. A normal CBC before the fifth day of symptoms should not exclude the diagnosis of dengue. In the context of an outbreak, a close follow up is essential for the diagnosis and the early detection of alarm signs, in order to prevent the progression to severe dengue.