The introduction of human cases of Zika virus disease (crew or passengers, symptomatic or asymptomatic) through ship travel is considered very low since most travelers in the affected countries return to European Union Member States (EUMS) through air travel.

Moreover, it is unlikely that ships can introduce Zika virus disease to the population in the EU through Zika virus infected mosquitoes from affected areas. However, it is certainly known that specific types of imported goods including used tyres and ornamental plants (e.g. Dracaena sanderiana – lucky bamboo) introduce invasive mosquito species (IMS) to EU, usually at the egg life stage that is able to survive transportation.

These two categories of imported goods can be infested with mosquitoes including Aedes aegypti and Aedes albopictus. Since imported symptomatic and asymptomatic human cases are continually arriving in EUMS through air transport, and Aedes albopictus mosquito, which is competent to transmit Zika virus has been established in a number of areas in EUMS, the possibility for local transmission of the disease in the future, especially in the summer months cannot be excluded.

Further information for risk assessment can be found in the updated risk assessment published by ECDC. Imported used tyres, and ornamental plants (mainly plant cuttings requiring water during transportation) can: a) re-introduce Aedes aegypti in Europe, which is the main vector of Zika virus disease and other diseases such as yellow fever and dengue fever; b) introduce Aedes albopictus and other IMS in areas not currently present or established; c) import additional Aedes albopictus mosquito populations and other mosquito species in areas where are currently established and influence the mosquito population dynamics and density.