Maternal, newborn, child and adolescent health


Zika is here to stay and remains a significant public health challenge


18 November 2016 -- Zika virus and associated consequences remain a significant public health challenge requiring intense action, but they no longer represent a Public Health Emergency of International Concern.

Get the WHO Zika app for health care workers and the general public

WHO/U. Zhao

WHO’s Zika app aims to provide essential information on Zika virus disease and its potential complications. Designed primarily for health care workers and responders, the app can also be a source of real-time information for the general public.

Download and use the app on IOS or android and have easy-to-use information at your fingertips. Access WHO’s technical guidance and other useful resources, follow ongoing Zika related-research and development, stay updated about the latest news, and follow the international response to Zika. New content, including trainings will be added to the app in weeks to come.

"Fight Zika": using animation to spread the word

WHO supports governments and response agencies to communicate the risk from the Zika virus disease and its suspected complications to their citizens and visitors. In collaboration with Scientific Animators Without Borders (SAWBO), WHO has produced this "Fight Zika" video focusing on controlling the Aedes mosquito which transmits Zika as well as deadly diseases such as chikungunya, dengue and yellow fever.

More language versions will follow for use in more than 60 countries currently affected by the outbreak of Zika.



Microcephaly is a rare condition when the head size is smaller when compared with other babies of the same sex, gestational or postnatal age. It can occur when the brain is affected either in utero or in infancy. It can be associated with intellectual and physical disabilities.

Measuring the head circumference of all newborns after birth is a key step in screening. Follow up for assessing neurologic development and detection of associated problems such as seizures, vision and hearing problems is necessary.

WHO announces a public health emergency of international concern


5 February 2016 -- WHO declared a Public Health Emergency of International Concern on 1 February after a substantial spike in cases of microcephaly and Guillain-Barré syndrome in the Americas. These cases are strongly suspected to be linked to Zika virus, a mosquito transmitted disease that has spread to more than 25 countries and territories in the region. This page links all WHO information to its response on this Public Health Emergency of International Concern.

There are many potential causes of microcephaly, but often the cause remains unknown. The most common causes include infections in the womb: toxoplasmosis (caused by a parasite found in undercooked meat), rubella, herpes, syphilis, cytomegalovirus and HIV; exposure to toxic chemicals: maternal exposure to heavy metals like arsenic and mercury, alcohol, radiation, and smoking; genetic abnormalities such as Down syndrome; and severe malnutrition during fetal life.

Key messages

  • Microcephaly can be caused by a variety of factors, including infections in the womb, perinatal asphyxia, and genetic causes.

Many babies born with microcephaly may demonstrate no other symptoms at birth but go on to develop epilepsy, cerebral palsy, learning disabilities, hearing loss and vision problems. Some children with microcephaly will develop entirely normally.

Key messages

  • Babies born with microcephaly are at risk for intellectual disability and may also develop convulsions and suffer physical disabilities as they grow older.

Early diagnosis of microcephaly can sometimes be made by fetal ultrasound. Ultrasounds have the best diagnosis possibility if they are made at the end of the second trimester, around 28 weeks, or in the third trimester of pregnancy.

Babies should have their head circumference measured at least 24 hours after birth using standardized methods and compared with WHO growth standards. The measurement is interpreted in relation to the gestational age of the baby, and also the baby’s weight and length. Suspected cases should be reviewed by a paediatrician, have brain imaging scans, and have their head circumference measured at monthly intervals in early infancy and compared with growth standards. Doctors should also test for known causes of microcephaly.

Key messages

  • There are no specific tests to determine if a baby will be born with microcephaly, but ultrasound scans late in the second trimester or in the third trimester of pregnancy can sometimes identify the problem.
  • The most reliable way to assess whether a baby has microcephaly is to accurately measure head circumference 24 hours after birth, compare the value with WHO growth standards, and continue to measure the rate of head growth in early infancy.

There is no specific treatment for microcephaly. A multidisciplinary team is important to assess and care for babies and children with microcephaly. Early intervention with stimulation and play programmes may show positive impacts on development. Family counselling and support for parents is also extremely important.

Key messages

  • There is no specific treatment for microcephaly.

Epidemiological information

General information

Media centre

Regional information on Microcephaly

Video: What is Microcephaly?

This page links all WHO information to its response on the Public Health Emergency of International Concern.

Contact information

Department of Maternal, Newborn, Child and Adolescent Health (MCA)
World Health Organization
20 Avenue Appia
1211 Geneva 27

Tel.: +41 22 791 3281
Fax: +41 22 791 4853