Zika Outbreak – Summary of a Public Health Emergency

Jessica Lewis
December 17, 2016

The current Zika epidemic is a testimony to the unforeseen and pernicious consequences of the ever growing economic and social interdependence that is globalization. The Zika virus, once considered an innocuous microorganism to found in remote regions of Africa, is now the cause of a “Public Health Emergency of International Concern”, a warning issued by the World Health Organization (WHO).

Pandemics have the potential of being major disruptions in our modern life, however, with Zika this does not seem to be the case, at least for the moment. The aim of this article is not to speculate over an apocalyptic scenario, but to provide useful information on what Zika is, how an infection manifests itself, precautions against a possible infection, the history of the virus and the actual magnitude of the epidemic.

Being a problem of this magnitude, the volume of information on the virus, the diseases it can cause and the actions undertaken against its spread. Any such problem goes far beyond the medical profession or field, it speaks about what we have come to refer to as the global society. We will also be touching on that subject. Before we get there, however, let us get briefly acquainted with the history of the Zika virus and the current state of affairs regarding the fight against the epidemic.

Zika History and Current Outbreak

The story of the Zika virus begins 60 years ago, in 1947 to be exact, in the Ugandan tropical forest which has lent the virus its name. A team of researchers from the local Virus Research Institute isolated the virus from a rhesus monkey in a wider project that was mainly concerned with closely related viruses that cause dengue fever and yellow fever, diseases with a “much richer” history than Zika, at the time. “Ziika” in the local Gandan language means “overgrown”.

A year later, it becomes established that mosquitos are carriers of the virus, particularly a local species called Aedes Africanus, as is the case with the aforementioned viruses. Due to this fact, the Zika virus is classified as an arbovirus, meaning that its spread is facilitated by arthropods.

At first, there were no signs that Zika can infect humans, the situation continuing because of the mild symptoms associated with the infection, confusing them with dengue or yellow fever. Diagnosing Zika even today is no easy task, however, more on that later.

Four years would pass before the first instances of human infections would be reported and recorded in Uganda and nearby Tanzania. During the 1950’s researchers in the area document two further strains of the Zika virus, though no connections to disease in humans would be made until 1964. A virologist studying strains of the virus experienced a short illness marked by fever episodes accompanied by a flat, generalized, reddish rash. His description of the outcome made it seem that the immune system of the average healthy person would have no problem in tackling the infection, with the symptoms disappearing after less than a week. Moreover, when compared with the outcomes of diseases caused by other arboviruses, Zika infections were deemed particularly harmless, a conclusion reinforced by the fact that it did not seem to be transmissible among humans. (1)

Over the next more than 40 years, the Zika virus lay dormant, at least from the attention of the press. When we take into account the fact that an infection usually brings about a condition that irritating rather than dangerous, it is of little surprise that during this 40-year period there have been about a dozen documented Zika cases in humans.

Between 2007 and 2013 Zika resurfaced with a series of fairly serious outbreaks that originated in the Caroline Islands (located in the Northwestern Pacific Ocean, north of New Guinea) and rapidly engulfed many archipelagos in the western Pacific. The swift evolution of the outbreak was surprising, given the fact that we are not talking about a continuous land mass. During this time, scientists began to make connections between the emergence of the virus in the Western Hemisphere and the growing numbers in serious conditions such as microcephaly in newborns and various autoimmune disorders.

In March 2015 the first cases appeared in northeastern Brazil, an outbreak of a then-unidentified illness causing fever and a large rash. With the benefit of hindsight it is obvious why Brazil proved to be the ideal breeding ground for the Zika virus: a great population density (with an important percentage of the population living in cramped, unhygienic conditions below the poverty line),  the tropical climate, plus a penchant for large public gatherings (traditional seasonal manifestations such as the Rio Carnival have been enhanced in recent years by widespread massive public protests against the government spurned by corruption allegations, not to mention the string of sporting events held in Brazil – the 2013 FIFA Confederations Cup, 2014 FIFA World Cup – and the effects of the 2016 Summer Olympic Games are still being ascertained). [1]

By the end of 2015, the outbreak in Brazil had become a truly international, if not continental epidemic, with a host of countries in South America and the Carribean signaling infections and higher rates of associated microcephaly. The situation became critical in the first months of 2016 with the Public Health Emergency warning issued by the World Health Organization on February 1.

Illnesses Brought On by Zika Infection

There are three ways of getting infected with the Zika virus. The first, and by far the most common, is through the bite of mosquitos from the Aedes species. The second, less likely and with differing opinions among the scientists regarding the importance of evident symptoms, is through sexual contact (most common from a man who has already experienced the symptoms of a Zika infection to a woman, nevertheless all other permutations do pose a certain risk). The third, the least likely yet the one which can cause the most dramatic consequences (e.g., microcephaly and other anomalies of the central nervous system), is from a pregnant woman to the fetus.

One of the many problems with the Zika virus and consequent illnesses is that approximately 80 percent of those infected do not exhibit any symptoms, even when considering that the incubation period of up to 12 days may render an individual exposed to a host of other infections, especially in the infectious haven that is a tropical climate.

A definitive diagnostic confirming the infection is another tricky operation, adding to problems caused by the frequent absence of symptoms. The WHO recommends a scrupulous method that, at first glance, seems available only to people in developed countries. When suspicion arises (exposure in the last 2 weeks in regions with epidemiologic status, coupled with the presence of a rash and fever plus secondary manifestations like conjunctivitis or arthritis), a laboratory blood or urine test must be performed in order to confirm the presence of the IgM antibodies against Zika or the RNA (genetic material) of the virus. [2]

A typical case of infection results in (besides the rash and fever) arthralgia (pain in the joints), myalgia (muscle pain), general fatigue and headaches. In rarer cases, there have been mild digestive disorders reported – diarrhea, constipation and abdominal pain. As there is no vaccine currently available against the virus, the only methods of retaliation are through prevention and containment. Those mentioned above may seem fairly harmless, yet the danger of Zika lies in the high infection rate which makes the fraction of cases that lead to complications a threat to public health. (3)

Fetal Microcephaly is the condition where there are major anomalies in the development of the brain and skull of a fetus, with Zika infection proving to be an essential factor in the increase of cases in the affected areas. Without anything being clear as to the risk percentages or the mechanisms that the presence of the infection causes such abnormalities, presenting the preliminary data should paint a relevant picture. To illustrate, between late 2014 and early 2016, in the Brazilian areas affected by the epidemic there were about 20 times more fetal microcephaly cases reported than in the previous five years altogether. Moreover, a large portion of the mothers in question exhibited symptoms associated with Zika during the course of their pregnancies.

The prognosis for children that are born with microcephaly is a grim one, with only a very limited percentage going on to have a standard intellectual development. In addition to the mental deficiencies, these children are at a much higher risk for epilepsy, vision, and/or hearing loss or cerebral palsy than the rest of the population. [3]

Further research on the issue is warranted, however, it has been established that the critical period in linking infection to fetal microcephaly is the first trimester of a pregnancy. It appears that infection of the fetus during this interval results not only in strained development but also in the atrophy of already developed tissues.[4]

GUILLAIN-BARRÉ SYNDROME (GBS) is a complex nervous autoimmune disease. It causes local and/or general muscle dysfunction, therefore it is a very serious and potentially deadly disease, which can result in paralysis or death by respiratory arrest. Prognosis is favorable for more than half of patients, nevertheless about a quarter of those diagnosed end up requiring artificial ventilation. Despite adequate medical care, between 3 and 10 percent of all cases result in death, with the mortality being significantly higher in areas lacking sufficient resources.

Infections or a history of infectious disease seem to be the trigger of GBS, with Mycoplasma, Epstein-Barr or Varicella-zoster viruses already suspected as culprits.

The increase in the incidence of GBS in affected areas in South America (and especially Brazil) are even higher than the increase in fetal microcephaly, around 40-fold, yet the evidence is still mostly circumstantial, given the many triggers the onset of GBS entails.

Almost 20 countries have reported to the WHO a sudden rise in the number of Guillain–Barré cases, doubled by the confirmation of Zika infection in a majority of patients. [5]

The Fight Against Zika

Nature and Magnitude of the Epidemic

Before moving to the discussion surrounding the sheer numbers of the current Zika outbreak, a few preliminary arguments should be taken into consideration. The first one involves the fast evolution of the epidemic. Previous episodes where the WHO has issued a declaration of a Public Health Emergency of International Concern – the 2009 swine flu declaration, the 2014 polio declaration, and the 2014 Ebola declaration – involved viruses that moved at a much slower pace. This means that some traditional steps of fighting against epidemics (such as strict containment of the disease awaiting the development of a vaccine) may not be too feasible in the context of a highly infectious virus, as Zika is. Furthermore, this particular type of virus is prone to fast and highly unpredictable mutations.

The latest reports (August 25th) on the worldwide status of Zika infections come to confirm its rapidly evolving nature:[6]

  • 70 countries have announced Zika transmission through mosquitos, with the overwhelming majority of them (67 out of 70) since the beginning of 2015;
  • 11 countries have documented human-to-human transmission;
  • 53 out of 70 are experiencing full-blown outbreaks;
  • 20 countries have reported strong suspicions in the linking of a growing number of microcephalic births to the Zika outbreak;
  • 18 countries have documented a growing number of Guillain–Barré Syndrome cases in the same type of circumstances, with confirmations of infection among some GBS patients.

Institutional Endeavors

In February 2016, a detailed Strategic Response Plan was initiated by the World Health Organization, which along with 60 strategic partners have been handling the situation ever since, on the international level. On the continental level, PAHO ( the Pan-American Health Organization) has been supervising the joint efforts of the affected countries.

Despite the repeated warnings issued by the WHO culminating in the February declaration of Zika as a Public Health Emergency, there are significant funding gaps that impede the full implementation of the Strategic Response Plan, more than six months since its inception. The most significant single instance of support in the fight against Zika has been from the US Centers for Disease Control.

The Plan stresses not only detection and prevention, but also allocating the necessary resources to underdeveloped areas in order to cope with the costs of the care and support of those affected by illnesses associated with Zika, and research (especially in the practical tools of containing and controlling the Aedes mosquito populations). For the goals of the plan to materialize, the WHO has called for funding in excess of $120 million. [7]

The WHO and partnering organizations have a constantly updated list of countries and territories, which forms the first step in the chain of disseminating information on Zika to the worldwide public. Countries have been grouped into:[8]

  • low risk – Zika has a past presence, yet recent infections (more than three months) have not been reported.
  • moderate risk – infections are consistently being reported, in small numbers,
  • high risk – countries where the number of infections is steadily and alarmingly increasing.

Individual Prevention

One can argue that individual action is the only true solution to life’s important problems, as collective endeavors are marred by endless hesitations because of the need to accommodate diverging interests. This is certainly true when it comes to protecting oneself from illness, and the case at hand is no different.

Protection against mosquitos is the most elementary means of protection against possible Zika infections, particularly in areas with signaled existence of the Aedes subspecies of mosquito. This can be done with the aid of insect repellents (beware of the contraindications each of these products stipulate, in the case of infants for example), through covering as much skin as possible with light colored fabrics (possibly treated beforehand with insecticide), and careful screenings of the rooms where one sleeps.

Human-to-human transmission can ve avoided by following a sort of “Zika-updated rulebook” of sexual protection. Unprotected sexual contact of any kind with a person that has traveled to moderate-risk or high-risk territories should be avoided for at least 8 weeks, and if pregnancy is considered then the “safe” timeframe is extended to six months. Although the overwhelming majority of infections have occurred from a male infected partner to a female, protection should be used at all times, irrespective of the partners’ genders.

The guidelines are more complex in the special case of pregnant women. It is strongly recommended that they do not travel at all to countries or territories posing a moderate or high risk of infection. Nevertheless, if at any time during the pregnancy a woman experiences at least two of the aforementioned symptoms of Zika infection, then a test can bee performed on the amniotic fluid (called RT-PCR, which is an acronym for  reverse transcription-polymerase chain reaction) to determine if the infection has been passed on from mother to the fetus. In cases where the infection has occurred, series of ultrasounds at an interval of no more than two weeks are recommended to monitor brain development. Further action can be taken through referrals to experts in infectious disease and pregnancy management.[9]

The Zika epidemic has not yet evolved into a pandemic, however, the warning signs are upon us. The unfortunate news comes from the lack of will (political will especially) to supply the competent national and international agencies with the necessary funds deemed indispensable for a correct administration of a disease that has far-reaching implications.

If this epidemic will become a pandemic, then it will test the capacities of “living together” of humankind as a whole, providing a measure of how civilized we actually are. One can hope that such a scenario will remain in the realm of the imagination, and considering the information presented in this article the situation does not seem to be very troubling, particularly due to the very nature of the Zika virus and subsequent outbreak – highly infectious, but mild and certainly not as devastating as historical epidemics have been.

The rational attitude regarding this outbreak is to remain cautiously optimistic that a treatment will be devised, or that the disease will not spread to the Northern Hemisphere and a satisfying containment will be achieved.