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Zika virus infection: clinical management and research priorities

Zika virus infection is a mosquito-borne viral disease caused by the flavivirus Zika virus (ZIKV). ZIKV was first isolated in 1947 in a Rhesus monkey in the forest of Zika (Uganda). Infection in humans was initially demonstrated by serological studies (1956) and posteriorly the virus was isolated from human samples in Uganda and Nigeria (1969). Serological surveys suggested a more complex geographical dispersion including the presence in several African and Asiatic countries. In 2007 the first major outbreak of ZIKV took place on the island of Yap (Micronesia) where 185 suspected cases were reported. This was the first outbreak outside of its traditional endemic areas. Subsequently (2013) an outbreak in French Polynesia was recorded with more than 30,000 cases. ZIKV is an emerging infectious disease with potential of rapid spread to new areas where the vector Aedes mosquito is present.

The disease course is usually mild and symptoms consist of pruriginous rash (typically maculopapular), mild fever, conjunctivitis, headaches, arthralgia, myalgia and asthenia. Zika infection may be indistinguishable from dengue, chikungunya or other viral infections with fever and/or rash. Asymptomatic infections seem common and it is estimated that only one in four people infected with ZIKV develop symptoms.

Since the beginning of 2015, autochthonous Zika cases have been reported in the Pacific region (Samoa, Fiji, New Caledonia, the Solomon Islands, and Vanuatu). Autochthonous transmission of ZIKV has been reported in Brazil since April 2015 and until 17 December 2015, nine countries in the Americas, in addition to Brazil, reported local ZIKV transmission (Colombia, El Salvador, Guatemala, Mexico, Panama, Paraguay, Suriname, Honduras and Venezuela). Cape Verde also reported more than 1000 suspected cases recently.

In November 2015, the Brazilian Ministry of Health reported an unusual increase in cases of microcephaly, with a causal link between Zika infection during pregnancy and congenital abnormalities. 2,401 microcephaly cases are under investigation in Brazil (December 2015), with 134 cases confirmed related to Zika virus infection. Investigations are on-going to assess a possible relation between ZIKV and Guillain-Barré Syndrome and other neurological events.

 

For more information see also: 

ECDC: Epidemiological update
http://ecdc.europa.eu/en/healthtopics/zika_virus_infection/Pages/index.aspx

CDC: general information and for healthcare providers
http://www.cdc.gov/zika/

PAHO/WHO: Zika surveillance in Americas
http://www.paho.org/hq/index.php?option=com_topics&view=article&id=427&Itemid=41484&lang=en

Brazilian Ministry of Health: Microcephaly investigation and clinical management.
http://portalsaude.saude.gov.br/index.php/o-ministerio/principal/leia-mais-o-ministerio/197-secretaria-svs/20799-microcefalia