A-Z syndromes: Congenital Zika syndrome
First identified in 2015, there is no vaccine for this virus
First identified in 2015, there is no vaccine for this virus, which can have devastating effects on the unborn child
Congenital Zika syndrome is caused by fetal exposure to a virus present in an infected mother. Zika is a virus transmitted when a mosquito bites a human.
The disease in older children or adults may pass unnoticed or cause a short, mild, period of sickness typically involving a mild fever, muscle pain, joint pain and headache. Zika can also be transmitted by sexual contact with an individual who has been infected with the virus. It is possible that the virus could also be passed on through blood transfusions.
The Zika virus was first identified in humans in 1952. The first public health emergency caused by Zika was in Brazil when the congenital syndrome was identified in 2015.
The syndrome is diagnosed as a unique pattern of birth defects:
- The presence of a severe microcephaly – defined as a measurement >3 standard deviations below the mean.
- The infant head displays findings consistent with a fetal brain disruption, which includes a partially collapsed skull, overlapping skull sutures, prominent occipital bone and redundant scalp skin.
There are also a range of other impairments that can emerge as the infant grows and develops: motor disabilities, cognitive impairment, hypotonia, irritability, dysphagia (swallowing dysfunction), hearing loss and epilepsy.
Antenatal screening may confirm microcephaly by ultrasound from about 20 weeks. However, to make sure a diagnosis is accurate the healthcare team may perform additional scans and this delays diagnosis until the third trimester. In some cases, microcephaly is not diagnosed until after birth, when the circumference of the head is compared with growth reference charts.
How the virus can affect some infants and not others is not well understood, the mechanism by which it disrupts normal fetal growth and development is also not clear. Evidence is emerging that infants who had been born to Zika-infected mothers who had apparently escaped the syndrome can have neurological defects in later life.
Treatment and management
Research continues, but there is no vaccine or drug that prevents Zika virus infection. There is no cure for congenital Zika syndrome or a treatment for microcephaly that can return the head to a normal size or shape. Management priorities include strategies to minimise the impact of the condition on the individual, reduce emerging neurological disability and support the family. Early childhood intervention programmes include: physiotherapy, speech and language therapy, play and occupational therapy. The multidisciplinary team can all work together to help maximise the child’s abilities and minimise dysfunction. Medications are used to control seizures, hyperactivity and neuromuscular spasm.
The emphasis is on the prevention of infection in prospective parents. However, Public Health England no longer provides detailed travel health advice about the virus. Travellers are directed to country information pages to assess risk for themselves.
Lorna and Mario work as cabin crew for an airline. They travelled to Brazil for the World Cup and to the countryside, including some remote jungle areas.
On their return home, Lorna discovered she was pregnant. They were aware of mosquito-borne diseases such as malaria and took antimalarial prophylaxis, but they had never heard of the Zika virus.
During the first ultrasound scan taken at 12 weeks the sonographer spent some time going over the head area and was not particularly reassuring or forthcoming. She said she would send the images to a senior colleague for review and advised that they may be asked to return for another scan. The findings were highly suggestive of microcephaly.
Within a week they had a consultation with a fetal medicine specialist who was friendly, but frank, and took time over the scanning process. The couple could see the baby’s face through 3D images.
The approach taken by the team was to allow the family time to consider their options by adopting a caring, non-directive, non-judgemental and supportive approach. Lorna and Mario were going to have to make a difficult decision and it would have to be the right one for them to face the future.
Healthtalk.org (2019) Ending a Pregnancy for Fetal Abnormality. University of Oxford, Oxford. (Last accessed: 10 June 2019.)
Medscape (2016) CDC Defines Congenital Zika Syndrome. Last accessed: 10 June 2019.)
World Health Organization (2019) Zika Factsheet. (Last accessed: 10 June 2019.)
Doreen Crawford is nurse adviser with consultancy Crawford McKenzie