The Zika news was good news—the public health emergency declared by the World Health Organization in early 2016 came to an end in November of that year. After a consistent rise in cases, the spread of the virus was finally leveling off and with it the rise in cases of neonatal microcephaly and Guillain-Barre Syndrome had slowed.
But as John England, MD, of the Louisiana State University Health Science Center explained at the AANEM annual conference in September 2017, we haven’t seen the final repercussions of the outbreak, and neurologists will be the ones facing them head on.
Zika virus is a flavivirus that was first isolated from a primate in 1947 in Uganda. After that time it was occasionally isolated in humans, but it wasn’t until 2007 that a significant outbreak occurred in Micronesia. Then 2015 happened and Bahia and Brazil were hit hard by the mosquito-borne illness. By 2016 cases were spread throughout South and Central America and then through the Caribbean up into the southernmost United States.
And now we find ourselves in 2017. As is the case with many viral diseases, most infected individuals often develop no symptoms at all, and for most who fall ill the disease is self-limited with non-specific viral symptoms. For the small minority of cases where more severe disease develops, neurological complications are a significant problem.
In Congenital Zika Syndrome, brain maldevelopment, intracranial calcifications, eye malformations, and even fetal death result.
In addition, Fetal Brain Disruption Sequence can occur with Zika. More than microcephaly caused by Zika in early pregnancy, this is the result of the skull collapsing over a shrinking brain later in pregnancy. It is characterized by microcephaly, overlapping sutures, an occipital shelf, and a redundant, wrinkled scalp.
Furthermore issues are beginning to appear later in childhood among children who were normal at birth after a Zika-affected gestation. These include vision, hearing and developmental problems.
Beyond congenital Zika, there is also the association with Guillain–Barré syndrome (GBS). Twenty-one countries reported an increased incidence of GBS along with the rise in Zika. In 2016 the WHO issued guidelines for GBS diagnosis and surveillance 2016 to identify cases for epidemiological purposes.
There appear to be other possible consequences of the virus that are not yet completely understood.
Medina et al, reported on a case of reversible polyneuropathy associated with Zika infection in the Journal of the Neurological Sciences.
Cleto et al, reported a case of sensory polyneuropathy in a 13-year-old girl due to Zika infection in Pediatric Neurology.
The reality is that we won’t completely understand the full impact of Zika infection, particularly of its neurological implications for years to come. Dr. England suggests that we need resources to improve our understanding and response to the disease. These include:
- Improved surveillance of mosquito populations or the presence of the virus as well as of human populations for signs of disease
- More pointed vector control with traditional insecticides as well as more modern approaches such as genetic and modification and irradiation of mosquitoes
- Improved education of the public and healthcare providers
- Financial backing for research, vaccines, and treatment of the disease
Zika presents a new set of issues, many of which are neurological in nature, for which patients will need a lifetime of care. This means that neurologists will find themselves on the front lines of Zika policy and care for years to come.