Zika virus infection, a new public health challenge

Brazil is an endemic area for Dengue virus (DENV) infections. Recently, the country was affected by an outbreak caused by Chikungunya virus, and in the last year, a third arbovirus (Zika virus – ZIKV), caused a large number of infections.1 ZIKV is transmitted by mosquitoes, and was first isolated from a rhesus macaque placed as sentinel during a study about yellow fever in the Zika Forest, Uganda, Africa in 1947.2 Since that time, sporadic viral isolations from humans and from a variety of mosquitoes Aedes sp have been reported in Africa and Asia. ZIKV, a positive-sense, single-stranded RNA virus, member of genus Flavivirus, family Flaviviridae, is another flavivirus of a public health importance. The virus has been circulated in Southeast Asia for at least the past 50 years, and a recent epidemic on Yap Island, Federated States of Micronesia, demonstrated that ZIKV is also capable of causing human disease and is expanding its geographic distribution.3 In Bahia, in the first months of 2015, patients at Santa Helena Hospital in Camacari, a city distant 50 km from Salvador, the third largest city in Brazil, were given a presumptive diagnosis of an acute viral illness by emergency department physicians. The illness was characterized by maculopapular rash, fever, myalgias/arthralgia, conjunctivitis, severe rash in arms and legs, and low grade fever. This atypic, dengue-like illness was investigated to confirm the presence of several arbovirus by conventional RT-PCR: West Nile, Mayaro virus, Sant Louis virus and DENV. Since all tests resulted negative, there was only one more possibility to investigate: ZIKV. On March 26 2015, Campos et al. identified ZIKV in sera of affected patients, demonstrating, for the first time, circulation of ZIKV in Brazil and Latin America.4 It was immediately informed to the national health authorities (Ministry of Health, Brazil) and the presence of ZIKV (autoctones cases) in Bahia was