Zika virus disease is caused by a virus transmitted by Aedes mosquitoes. People with Zika virus disease usually have a mild fever, skin rash (exanthema) and conjunctivitis. These symptoms normally last for 2–7 days. No specific treatment or vaccine is currently available. The best form of prevention is protection against mosquito bites.
The Zika virus was first isolated in 1947 from a monkey in the Zika forest of Uganda. In 2007, the virus extended its geographical range to cause the first documented outbreak, in the Pacific islands of he Federated States of Micronesia. Between 2013 and 2014, four additional Pacific island nations documented large outbreaks of Zika virus disease.
The outbreak in the Americas
In 2015, the virus was detected in the Americas, where it is now spreading widely. Arrival of the virus in some countries of the Americas, notably Brazil, was associated in November 2015 with steep increases in the number of babies born with abnormally small heads and of cases of Guillain-Barré syndrome, a poorly understood condition in which the immune system attacks the nervous system, sometimes resulting in paralysis. Causal relations between Zika virus infection and birth defects and neurological syndromes have not been established but are strongly suspected.
A public health emergency of international concern
In response, on 1 February 2016, the WHO Director-General declared that the recent clusters of cases of microcephaly and neurological disorders in Latin America and the Caribbean constitute a "public health emergency of international concern" under the International Health Regulations (2005).
The risk to Europe
Every European country in which Aedes mosquitos are present can be at risk for the spread of Zika virus disease. A number of travellers infected with Zika have entered Europe, but the disease has not been transmitted further, as the mosquito is still inactive. With the onset of spring and summer, the risk that Zika virus will spread will increase.
Aircraft disinsection for mosquito control
Standard WHO recommendations regarding disinsection of aircraft and airports can be implemented as a precautionary measure in an attempt to control the vector (Aedes spp. mosquito) that spreads the Zika virus. It should be noted that a decision to implement WHO disinsection recommendations should be taken only after an individual country risk assessment has been made of whether vector control is necessary. If countries and other entities, after a risk assessment, choose to implement aircraft and airport disinsection, it should be done according to standard WHO recommendations. WHO has provided guidelines on how to do so safely.