Whether you follow Twitter or Facebook or still read the newspaper, it is difficult to dispute that social media has a meaningful impact on everyone. One could argue that social media was the primary source of political information for many in the United States in the recent presidential election, influencing the tenor and even outcome of the race.
If the new role of social media in our political discourse is distressing, you may find it refreshing to hear that a tool that can be used to spread rumors and innuendo is now an agent in furthering medical research and patient care, especially in areas that need the most help — the battle against Zika virus.
A total of 28,723 cases of Zika infection were confirmed in the United States and its territories as of October 2016, and 2,027 pregnant women have tested positive for the virus, according to the Centers for Disease Control and Prevention. Infected mothers could give birth to babies with microcephaly, which could result in developmental delay and intellectual disability depending on the severity of the condition. Yet much remains unknown when it comes to this debilitating disease.
What we do know, however, is that Zika virus, transmitted by Aedes aegypti mosquitoes, was first identified in 1947 in a rhesus monkey in the Zika forest of Uganda. It was not until 1952 that the first cases of human infection were detected in Uganda and the United Republic of Tanzania. Sporadic outbreaks were found mainly in the African continent and Southeast Asia. The largest outbreak to date was detected through public health screening in 2015 that found an increase in children born with microcephaly in Brazil. This outbreak, anticipated to affect more than a million people, prompted the World Health Organization (WHO) to declare a Level 1 public health emergency in February 2016. (Arq Neuropsiquiatr 2016;74:253.)
Like other members of the flavivirus family, such as dengue, the West Nile virus, yellow fever, and Japanese encephalitis, Zika virus infection manifests with acute fever, non-purulent conjunctivitis, headache, arthralgia, myalgia, asthenia, and a maculopapular rash, which resolves clinically after four to seven days. Most infections are asymptomatic. Clinically significant infections are treated with supportive care such as antihistamines for the rash while avoiding NSAIDs, which cause hemorrhagic complications in similar flavivirus infections. A commercially available vaccine is not yet available for Zika, but the National Institutes of Health (NIH) has begun human testing of one.
Zika's Neurologic Reach
The neurologic manifestations of Zika virus infection, including Guillain-Barré syndrome (GBS), encephalitis, meningoencephalitis, paresthesia, facial paralysis, and myelitis, were first recognized in a 2013 outbreak on the islands of French Polynesia. A definitive link between Zika and these neurological symptoms could not be established at that time, however, because Zika infection was not demonstrated by polymerase chain reaction (PCR) amplification (the gold standard for detection) in most patients. It remains possible that some cases may have been caused by other viruses such as dengue or West Nile.
Basic research has now established a direct link between Zika infection and neurologic pathology. A mouse model of Zika infection has demonstrated that Zika destroys nerve tissue and damages the central nervous system, in part by inducing excessive immunopathology. (Arch Gesamte Virusforsch 1971;35:183.) Zika virus also directly infects and replicates within neurons and astroglial cells, reducing their viability and halting developmental neurogenesis. (Brain 2016;139[Pt 8]:2122.)
Microcephaly, now the most feared consequence of prenatal Zika infection, is associated with many common viruses and rare genetic diseases. Zika can be detected in human amniotic fluid and fetal tissue, and recent data show a temporal association between microcephaly and outbreaks of Zika.
One small observational study of children whose mothers had PCR-confirmed Zika showed that microcephaly is a consequence of multiple brain injury mechanisms such as ventriculomegaly, and it pointed to microcephaly as part of a congenital Zika syndrome. (JAMA Neurol 2016 Oct 3 [Epub ahead of print].) The theorized correlation between Zika and microcephaly has now been directly replicated in mouse models demonstrating that Zika infection of pregnant mice leads to fetal brain infection and growth restriction. (Cell 2016;166:1247.)
Despite these recent advances in our understanding, many questions about the neurologic consequences of Zika infection remain unanswered. The role of Zika in GBS, which has also been associated with dengue and chikungunya, remains poorly studied. It remains unclear why Zika virus persists (up to several weeks after acute infection) in pregnant women longer than similar viruses.
Social Media against Zika
Research into the etiology, pathophysiology, and treatment of emerging viral pathogens and their consequent diseases is challenging in the regions where they are most devastating: the resource- and infrastructure-limited developing world. Organizations like the WHO and NIH are using systematic research tools and funding laboratory studies to improve our understanding of the neurologic sequella of Zika and other viruses, and innovative researchers are using social media to tackle these important questions in new and exciting ways. (N Engl J Med 2016;374:1506.)
Ferreira da Silva, et al., have harnessed the power of social media to identify new cases, review diagnostic data, and offer remote consultation to isolated patients in Brazil. (Neurology 2016;87:e180.) The RIO GBS-ZIKV Research Network utilizes WhatsApp, which allows end-to-end encryption and a confidential communication tool for their hospital network. Through WhatsApp, this group has identified a larger number of patients in the first three months of 2016 than all cases identified in 2013-14. Other forms of social media, such as YouTube, Facebook, and Twitter, are being deployed to spread public service announcements that will curb infection rates, especially in pregnant women, and Google has partnered with the United Nations Children's Emergency Fund to map potential outbreaks.