“The Zika virus is more and more showing its ugly face, and the international community increasingly realises the dimensions of this problem. Neurological expertise is crucial to deal with the consequences of what proves to be a devastating epidemic”, says Prof Raad Shakir (London), President of the World Federation of Neurology (WFN): “The WFN is therefore joining forces with all organisations and agencies, and in particular with WHO efforts, to cope with this serious situation. A new WFN Work Group on Zika virus has just been established which will contribute the neurological angle and expertise to the coordinated global response to help affected countries and health care providers deal with the crisis.”
Neurological Zika complications: More than microcephaly – larger groups at risks
The neurologists’ contribution is particularly relevant because there is growing concern and evidence about the increasing number of neurological complications involved in the spread of the Zika virus. While a large percentage of persons with Zika virus disease are either asymptomatic or show a mild course, with fever, skin rash, conjunctivitis, muscle and joint pain and headache, which does not need major medical intervention, possible neurological consequences can be devastating.
“The latest evidence suggests a clear association of the virus with a congenital syndrome of brain mal-development and an increased incidence of Guillain-Barré syndrome (GBS) and other neurological conditions, such as myelitis and meningoencephalitis,” says Prof John England (Louisiana State University, New Orleans) who chairs the new WFN Work Group on the neurological complications of Zika virus. “While a lot of public attention has been drawn to microcephaly, which has already affected thousands of babies in Brazil and French Polynesia, this dramatic condition is only one of several documented birth abnormalities associated with Zika infection during pregnancy. Other grave outcomes include foetal death, placental insufficiency, foetal growth retardation, and injury to the central nervous system which will lead to many more complications which we will only see in the long term.”
Zika virus infection can also cause major complications in adults. “13 countries and territories have reported an increase in the incidence of GBS in conjunction with the wave of Zika virus outbreak”, Prof England reports. “GBS leads to paralysis due to immunological effects of the virus on the peripheral nervous system. The morbidity is high and approximately 25 to 30 percent of affected individuals require respiratory support with ventilators.“ Latest research from Recife, Brazil, just presented at the ongoing meeting of the American Academy of Neurology, associates Zika virus infections also with Acute Disseminated Encephalomyelitis (ADEM), another autoimmune disorder that attacks the brain’s myelin similar to MS.
“So there are a lot more risks involved in Zika infections than pregnancy complications and microcephaly. The risk group is broader than originally thought and the modes of transmission go beyond mosquito bites, it is now known that they include also sexual contacts,” Prof England stresses.
Zika virus is now most prevalent in the northern region of South America, and in Central America. As of 20 April 2016, Zika virus transmission was documented in a total of 66 countries or territories, 42 countries are experiencing a first outbreak of Zika virus since 2015, with no previous evidence of circulation, and with ongoing transmission by mosquitos. Eight countries have now reported evidence of person-to-person transmission of Zika virus.
Prof England: “Of great concern is the fact that the geographical distribution of the virus has steadily and rapidly expanded. There is great concern that the virus outbreak will continue to spread to other countries and territories. It has already reached the Caribbean countries and may spread to the southern United States and other countries where the virus mosquito vector (Aedes aegypti) thrives.
Lack of resources in neurological care
Apart from many aspects of the epidemic and its neurological complications that still need to be answered by research, the appropriate care of Zika victims is a particular challenge, according to WFN President Prof Shakir: “The resources available for neurological diagnosis and therapy and access to neurological care are very unevenly distributed globally, as the WHO Atlas shows.” The number of neurologists per 100,000 inhabitants is significantly lower in low-income versus high-income regions (0.03/100,000 versus 2.96/100,000). Brazil, for example, has 1.66 neurologists per 100,000 inhabitants.
“In many areas particularly hit by Zika virus there is a clear lack of neurological resources, a shortage of neurologists, in particular also child neurologists, a lack of neurophysiological testing possibilities, and scarce intensive care facilities,” says Prof Shakir: “If we do not overcome these problems there shall be more unnecessary deaths which would not have happened if the affected individuals would have lived in less deprived parts of the world.” “Management for the Zika virus infection is already straining health systems in affected regions, and there is a serous lack of financial resources available,” Prof England adds.
Broad expertise and geographic distribution
The WFN Work Group on Zika virus represents a broad range of specialized neurological expertise; it includes child neurologists, specialists for infections in neurology as well as experts on GBS and other neuro-immunological diseases. The 18 members of the group represent several regions of the world, including most affected countries such as Brazil, Honduras, Mexico or Columbia.
Members of the Work Group will, in the course of the next months, contribute to important upcoming meetings devoted partly or entirely to the current developments, such as the International Child Neurology Congress (May 2-5 in Amsterdam), or a meeting of seven Central American countries, to promote research and prevention (May 5–6 in Honduras). Zika virus will also be high on the agenda of the World Health Assembly on 28 May.
“It will be very important that we are also involved in the work on the ground. Of course, increased surveillance, enhanced mosquito control, development of reliable diagnostic tests, and vaccine development are priorities right now. We will also need to find answers to most urgent questions such as: how prevalence is developing as the virus spreads; if there are specific risk factors influencing the development of neurological symptoms; why Zika virus appears to have such a strong association with GBS and potentially other immune-mediated diseases of the nervous system”, Prof England states. “There are many questions that still need further research and further data, and many of these questions will become even more relevant with a view to the upcoming Olympics with thousands of athletes and visitors travelling to Brazil. Collaborative interdisciplinary research on Zika infection and its neurological complications is being organised, but funding is severely lacking at this stage. As an important first step to enhance research collaboration and provide for transparent data sharing, the Neurovirus Emerging in the Americas Study (NEAS, www.neasstudy.org) is being organised. The situation is rapidly evolving; therefore, all information is subject to modification as we learn more about this emerging crisis.”