Rapid risk assessment: Zika virus epidemic in the Americas: potential association with microcephaly and Guillain-Barré syndrome - 4th update, 10 December 2015

Risk assessment

European Centre for Disease Prevention and Control. Rapid risk assessment: Zika virus epidemic in the Americas: potential association with microcephaly and Guillain-Barré syndrome – 10 December 2015. Stockholm: ECDC; 2015.

​A Zika virus outbreak in the Americas and the South Pacific is evolving rapidly, and its spread is likely to continue as the vector species Aedes aegypti and Aedes albopictus are widely distributed there.

This is the fourth ECDC rapid risk assessment on Zika virus; the first one was published in February 2014.

Executive summary

​Following the Zika virus outbreak evolving rapidly in the Americas and the South Pacific and the potential association of the virus to microcephaly, Guillain-Barré syndrome and other neurological complications being investigated, ECDC assesses the risk of Zika virus transmission in the EU, as well as the risk to EU travellers to the affected countries. 

ECDC risk assessment

With the Zika outbreak in the South Pacific and Americas evolving, the risk of imported travel-related Zika cases in the EU is increasing, while the risk of onward local transmission in the EU by the Aedes mosquitoes – potential vectors of the virus, remains extremely low during the winter season, states the ECDC risk assessment.
Public health authorities in EU/EEA should consider mitigation options. The authorities in the Member States should enhance their vigilance to detect imported Zika cases in travellers from affected areas, increase the awareness of clinicians and travel health clinics about the outbreak and the endemic areas as well as advise travellers to affected areas to take personal preventive measures against mosquito bites.
Travellers to affected countries are at risk of getting infected with Zika virus through mosquito bites. Since neither treatment nor vaccines are available for Zika, prevention is based on personal protection measures against mosquito bites. These should be taken during the day, as the Aedes mosquitoes, vectors of Zika, bite during daytime. 

Zika outbreaks in the Pacific region and the Americas

In 2013 and 2014, Zika virus outbreaks were notified in several islands of the Pacific region: French Polynesia reported an outbreak with 8 750 suspected cases, the autonomous transmission further spread to other islands in the Pacific region.  
In 2015, autochthonous cases of Zika virus infection have been reported in the Pacific region (Samoa and Solomon Islands, New Caledonia, Fiji, Vanuatu) and into the Americas, with autonomous transmission in Brazil, Colombia, El Salvador, Guatemala, Mexico, Panama, Paraguay, Venezuela and Cape Verde.

Possible link of Zika virus infection to microcephaly and other complications - under investigation

Since October 2015 an unusual increase in microcephaly cases was reported by the Brazilian Ministry of Health in the north-eastern states of Brazil: 1 248 suspected cases of microcephaly in 2015, compared to 150–200 children with microcephaly born per year in Brazil between 2010 and 2014. On 11 November 2015, the Brazilian Ministry of Health declared the event a public health emergency and is since investigating the possible links between Zika virus infection in pregnancy and microcephaly.
In parallel, investigations are ongoing in Brazil and French Polynesia to establish if a link exists between the Zika virus infection and other neurological syndromes, in particular Guillain–Barré syndrome. During the Zika virus outbreak in French Polynesia, 74 patients which had had Zika symptoms, later developed neurological or autoimmune syndromes - out of them, 42 were diagnosed as Guillain–Barré syndrome. In Brazil, 121 cases of neurological manifestations and Guillain–Barré syndrome (GBS) were reported, all cases with a history of Zika-like symptoms.