Guidance on symptoms of Zika virus infection and complications of the disease.
After an infected mosquito bites a human, the first symptoms of Zika can develop in 3 to 12 days but it can be shorter or longer in some people.
The majority of people infected with Zika virus have no symptoms. For those with symptoms, Zika virus tends to cause a mild, short-lived (2 to 7 days) illness.
Signs and symptoms suggestive of Zika virus infection may include a combination of the following:
- itching or pruritus
- arthralgia or arthritis
- lower back pain
- retro-orbital pain
The symptoms of Zika are similar to dengue (caused by a related flavivirus) or chikungunya (an alphavirus), which are often co-circulating in areas where Zika virus is present. Laboratory testing is essential for the correct diagnosis.
There is no specific antiviral treatment for Zika. Supportive nursing care and relief of symptoms are the standard treatment.
Serious complications and deaths from Zika are not common. Based on a systematic review of the literature up to 30 May 2016, WHO concluded that Zika virus infection during pregnancy is a cause of congenital brain abnormalities, including microcephaly (also referred to as congenital Zika syndrome); and that Zika virus is a trigger of Guillain-Barré syndrome (GBS).
There are case reports describing acute disseminated encephalomyelitis (ADEM) and encephalopathy in patients with confirmed Zika virus infection. To date, a small number of deaths have been reported in adults and children, predominantly in individuals with underlying health conditions.