Zika virus infections imported from Brazil to Portugal, 2015

Abstract

Zika virus is an emerging arbovirus transmitted by Aedes sp. mosquitoes like the Dengue and Chikungunya viruses. Zika virus was until recently considered a mild pathogenic mosquito-borne flavivirus with very few reported benign human infections. In 2007, an epidemic in Micronesia initiated the turnover in the epidemiological history of Zika virus and more recently, the potential association with congenital microcephaly cases in Brazil 2015, still under investigation, led the World Health Organization (WHO) to declare a Public Health Emergency of International Concern on February 1, 2016.Here, we present the clinical and laboratory aspects related to the first four imported human cases of Zika virus in Portugal from Brazil, and alert, regarding the high level of traveling between Portugal and Brazil, and the ongoing expansion of this virus in the Americas, for the threat for Zika virus introduction in Europe and the possible introduction to Madeira Island where Aedes aegypti is present.

First detection of Zika virus infection in a Croatian traveler returning from Brazil, 2016

“…Many ZIKV imported cases in travelers returning to Europe were reported after 2013 [15][16][17][18][19]25]. Due to similar clinical symptoms and geographical distribution as well as possible co-infections with dengue and chikungunya, DENV and CHIKV should be considered in the differential diagnosis in febrile travelers [7,26,27].…”

“…In Europe, the first imported case of Zika fever was reported in 2013 in a German traveler returning from Thailand [15], and thereafter imported cases were continuously noted [16][17][18][19].…”

The Application and Interpretation of IgG Avidity and IgA ELISA Tests to Characterize Zika Virus Infections

“…IgM and IgG for DENV were determined using commercial ELISA (Panbio, Standard Diagnostics Inc., Geonggi-do, South Korea) (Spanish samples) or by in-house immunofluorescence as previously described [ 3 ] (Portuguese samples); IgM and IgG for ZIKV were determined using commercial ELISA kits (Euroimmun, Lübeck, Germany). DENV IgM in ELISA was confirmed by a background assay as described [ 10 ].…”

“…Travelling for work or tourism between Portugal and Spain and Latin America is very common. Portugal reported ZIKV infections imported from Brazil for the first time in June 2015 [ 3 ]. In Spain, the first case of imported ZIKV infection was confirmed in January 2016 [ 4 ].…”

Biological and historical overview of Zika virus

“…Between 1947 and 2006, < 20 cases of Zika virus infection have been reported[ 5 ]. There have been recent reports of imported cases of Zika virus infections in 18 travelers returning to the Netherlands from Surinam, which is in South America near the northern border of Brazil, and the Dominican Republic[ 33 ], 13 infections were imported from Venezuela, Fiji/Samoa, or Suriname to China[ 34 ], and 4 infections were imported from Brazil to Portugal[ 35 ]. Autochthonous cases were reported in places such as Mexico[ 36 ], Colombia[ 37 ], and Easter Island, which was the first outbreak (51 cases) reported in a territory of the Americas in early 2014[ 38 ].…”