Mounting reports link Zika infection in pregnant women to a wider range of birth defects than previously known.
Since the seriousness of the growing Zika epidemic became clear several months ago, most of the news — and worries — about infection with the virus during pregnancy have centered on microcephaly. And there’s no doubt that Zika can cause this devastating birth defect, marked by a smaller than normal head size and abnormal brain development.
However, it turns out, based on research, cases reported by doctors and unpublished data sent to the World Health Organization (WHO), Zika virus may cause a far wider range of other birth defects and symptoms in babies. In fact, WHO now says these health problems constitute a new congenital syndrome.
WHO is working with researchers to define congenital Zika syndrome more specifically and warns there could be other, as-of-yet unrecognized complications from Zika virus that can affect babies.
Anthony Costello, MD, who head’s WHO’s department of maternal, newborn, child, and adolescent health and a team of other WHO researchers and public health experts outlined the case for the new syndrome in The Bulletin of the World Health Organization.
“The range of abnormalities seen and the likely causal relationship with Zika virus infection suggest the presence of a new congenital syndrome,” Costello and his team wrote. “The scope of the syndrome will expand as further information and longer follow-up of affected children become available.”
So far, in addition to microcephaly, the syndrome includes seizures, spasticity, an assortment of eye conditions, irritability, and dysfunction of the brainstem — the part of the brain which regulates vital functions including the ability to swallow, heart rate, and blood pressure.
Neuroimaging of some Zika-exposed babies’ brains has also revealed calcifications and disorders of the cerebral cortex, which is the part of the brain responsible for higher functions of the nervous system, such as voluntary muscle activity and language.
The WHO researchers noted the symptoms of congenital Zika syndrome may not be limited to infants born with microcephaly. Doctors have reported some Zika-exposed babies born with neurological abnormalities have a normal head size.
What’s more, it’s not only the brain that may be damaged in some babies who are exposed to Zika before birth, according to Costello and colleagues. Reports of cases from Colombia and Panama sent to WHO suggest the virus can also affect the heart, digestive system, and genital and urinary organs.
Due to the quick spread of the Zika virus — which has now been reported in 37 countries and territories in both South and North Americas — the WHO team studying Zika congenital syndrome estimate that “many thousands of infants” may be born with neurological and other congenital disabilities.
A surveillance system first created to monitor microcephaly cases caused by Zika has been expanded to include other congenital abnormalities possibly associated with the virus, and WHO is asking researchers to share their information about any observed congenital manifestations that appear to be linked to the Zika virus.
“The Zika virus public health emergency is distinct because of its long-term health consequences and social impact,” Costello and his team concluded. “A coordinated approach to data sharing, surveillance and research is needed. WHO has thus started coordinating efforts to define the congenital Zika virus syndrome and issues an open invitation to all partners to join in this effort.”
June 17, 2016