The following editorial offers a fleeting glimpse into the far-reaching and extremely complex issue of the ZIKA virus pandemic, that is currently wreaking unbridled havoc through South-America. The editorial addresses some of the pitfalls (both avoidable and unavoidable) that led to difficulties in the initial recognition of the spiralling incidence, and the now irresistible spread of the virus throughout the continent. Nevertheless, reference is also made to recent promising trends in data and epidemiology, indicating that a shift in power in the war against this disease could be just around the corner.
Prior to a few months ago, I had never come across the relatively obscure Zika virus. I came across this dengue related virus purely through chance, whilst perusing the Spanish internet-based news page, BBC Mundo. Whether it was my pre-existing interest into the world of tropical medicine, or purely the lure of a name so exotic as “Zika”, I chose to open the article. Having read this typically news-driven superficial overview of Zika virus, I decided to delve a little deeper.
The virus itself
The Zika virus has been around for well over half a century now and originated in the Zika jungle in Uganda in a resus monkey in 1947. With strong links to dengue, chikungunya, Japanese encephalitis and West Nile, it had always previously been observed to present asymptomatically or in the mould of a mild, short-lived illness. Within the space of one year, the disease has now acquired the potential to become pandemic, and the vector responsible for its primary mode of transmission (the ubiquitous Aedes mosquito) only acts to augment the risk for global transmission (1).
Baffled doctors and severe consequences
The first waves created by the Zika virus, were in reality, nothing more than ripples in a vast lake of water. A mother and daughter doctor team, working in the small seaside city Recife, began noticing some unusual changes in their patient cohort, particularly within newborns (2). When they described what they saw, the words that were recurring included “small-heads”, “no forehead” and “why?” What these doctors were describing was in fact the initial signs of the pandemic that was to come. The uncontrollable spread of a virus previously deemed mild, and overshadowed by its more feared sister viruses, dengue and chikungunya. Until 2013, no evidence existed that Zika had ever hospitalized any individual – this had all changed. Brazil has reported nearly 4000 cases of microcephaly within the year 2015 alone, a 20-fold increase on the figures seen between 2010-2014 (3). Whether a scientific link exists yet seems inconsequential, the epidemiology paints a very clear picture of the situation faced by these countries.
Even more worrying was that it is not only an increase in microcephaly that has been seen, but also in the paralytic-immune mediated disease Guillain-Barré. A neurologist in Recife, Northern Brazil, reported that she had treated 50 cases of Guillain-Barré in 2015, compared to just 14 in 2014, and 13 in 2014 (4). Although researchers have not yet established a link between Zika and Guillain-Barré, these recorded cases only give further credence to the suggested relationship. Regardless, following a recent WHO chaired emergency committee meeting in which 18 experts met by phone conference to assimilate a collective understanding of these events, the conclusion was arrived at that (whilst not scientifically proven at this stage) a causal relationship between Zika infection in pregnancy and microcephaly is highly suspected. The problems are further inflamed due to the scarcity of viable vaccines and reliable screens and the lack of indigenous population immunity in newly involved countries (5).
At this present moment, the situation mitigated by the Zika virus has become so dire that governments have begun issuing unprecedented advice to their populations: ‘Women, please refrain from having children’. WHO, the principal agency for issues relating to public health, have subsequently issued a public health warning. Furthermore, they have advised at risk groups (including pregnant women) to avoid affected areas where possible, and even to avoid sexual contact with individuals returning from these areas (6). With the 2016 Olympics in Rio de Janeiro fast approaching this summer, and the unavoidable influx of a huge number of foreigners from almost every continent, the urgency with which actions needed to be taken increased ten-fold.
Island-Hopping: the modern day phenomenon
Cases of Zika fever (the physical manifestation of viral infection) have been documented to occur at low levels within a narrow equatorial belt from Africa to Asia since the 1950s (7). However, for those who have been watching, Zika virus has been making a slow, ponderous (but nevertheless relentless) journey eastwards towards
the Americas. Zika made use of the ever-growing increase in travel in our modern day world in order to navigate its way across the scattered islands acting as stepping stones between continents. The virus landed on its first island (Yap Island) in 2007 leading to an epidemic with 5000 infections (7). This pattern repeated itself as the virus made its way from island to island, nestled within unknowing hosts. The French Polynesian islands were some of the worst affected, but it has only been retrospectively that a relationship has been suggested between an explosion of microcephaly cases here, and the arrival of Zika.
Scientists were at a loss to explain how the virus had arrived in Brazil. The first case detected in Brazil was in May 2015 in the Northeastern region of the country. One of the most popular theories stems from the general consensus that the first outbreak of Zika occurred in the Northeastern city, Natal. Natal was designated as one of the host cities for the 2014 football world cup held in Brazil, and the inundation of football fans from all over the world offers a very plausible explanation for how Zika came to arrive in Brazil. The other offered explanation is that the virus arrived several weeks after the world cup during another national sporting event, the Va’a World Sprint, a canoe event welcoming several teams from the Polynesian Islands (4).
Changing perceptions of the virus and turning the tide
It became clear that the previous impressions of the virus’s virulence or gravity were now antiquated. This was not a virus to be dismissed or belittled, as had been the case with the comments from the previous Brazilian health minister, Dr. Arthur Chioro (and in fairness to him) many hundreds of other eminent persons within the field of healthcare (8). The epidemiological data (quoted earlier) emerging from Brazil, and now several other Latin-American countries, provides harrowing reading and demands that our perception of this virus changes.
The absence of a vaccine remains a glaring issue at this stage and intervention programmes instigated by organisations such as WHO and the French, Intitut Pasteur, are centered on the prevention of transmission and on furthering understanding of the pathogen. Recently however, evidence was seen that hope (whilst not yet on the metaphorical horizon) could be at least tangible in the future. In the State (within which resides Recife) where the first cases of Zika virus were thought to have originated in Brazil, microcephaly cases have been reported to be decreasing for several weeks. As to why, scientists cannot answer that question, but the majority would suggest that it is the down-slope on the ‘epidemic-curve’ that is being observed (8). However, this is a down-slope commencing almost a year after the microcephaly cases began in this area, and so if precedence is as concrete a notion as we believe, the effects of Zika are only just beginning in areas more recently acquainted with this virus. The difference this time however, unlike in the tragic case of Brazil, is that scientists are ready.
1. Lucey DR, Gostin LO. The Emerging Zika Pandemic. Enhancing Preparedness. JAMA. 2016;
2. TIME. Ground Zero of Brazil’s Zika Outbreak. http://time.com/4208233/brazil-recife-zika-outbreak/. Accessed Feb. 2016.
3. Fauci AS, Morens DM. Zika Virus in the Americas: yet another Arbovirus threat. N Engl J Med. 2016. doi:10.1056/NEJMp1600297.
4. The New York Times. Zika Virus May be Linked to Surge in Rare Syndrome in Brazil. http://www.nytimes.com/2016/01/22/world/americas/zika-virus-may-be-linked-to-surge-in-rare-syndrome-in-brazil.html. Accessed Feb. 2016.
5. WHO. WHO Director-General summarizes the outcome of the Emergency Committee regarding clusters of microcephaly and Guillain-Barré syndrome. http://www.who.int/mediacentre/news/statements/2016/emergency-committee-zika-microcephaly/en/. Accessed Feb. 2016.