Zika: The Epidemic of 2016 (1977 words)

Abstract

For as long as man has walked the earth evidence gathered from their remains shows that there has been sickness and disease. Though the earlier man may not have understood the etiology of disease and that pathogens caused infection, it was evident that it was present nonetheless. As humans evolved, pathogens did as well and since that time, thousands of diseases and bacteria have been identified, and have survived to present day. More than 60 years ago in the south-western region of Africa, while searching for yellow fever a different virus was inadvertently discovered in monkeys and named after the forest of discovery, Zika (World Health Organization, WHO 2017). With only a minute number of human cases later reported, research regarding the infection was minimal. However, scientists did not anticipate the global impact it would one day have.

In 2015, many watched the news astonished and saddened to hear about the mass outbreak of an infection whose name was entirely new to many, Zika. As the months continued, every night it seemed the news broadcasters were reporting the rise in the number of those infected, while simultaneously reporting the urgency to avoid traveling to certain areas, and controversy behind the use of condoms and abstinence within the population. A sudden rise in two additional diseases in these areas, which effected newborns and adults, was linked to Zika. Infection pandemics occur commonly in developing countries due to poor sanitation, lack of education and limited health access, however, the United States, a developed country with western medicine practices, would never expect the infection to invade, until it arrived in the summer of 2016.

Disease Description

Zika is a vector-borne viral infection, or arbovirus, spread predominately through infected mosquito bites, specifically the Aedes mosquito that thrive in warm tropical and subtropical areas, according to the Center for Disease Control. The virus can also be spread between people via sexual contact, body fluids and birth. Its mechanism of action and the way it attacks the body is like other viral infections. It invades the body via mosquito bite, sexual encounter or body fluid; the virus then invades or hijacks the healthy living cells of the host. The cells infected with the virus then multiply and divide, further invading the body, which makes you sick. Unfortunately, antibiotics do not work on viral infections because the virus is within the living cells of the host and therefore protected from medicine that may pass through the bloodstream. Over the counter medications can be purchased or prescribed by a physician to treat the symptoms it causes, as the virus continues to thrive and multiply, eventually it reaches its life capacity and dies off.

History of Disease

The first human case of Zika occurred in 1952, just five years after it was first discovered in the Zika Forest of Uganda. Before 2007, approximately 14 cases had been documented ranging from the tropical areas of Africa, Southeast Asia, and the Pacific Islands. Since Zika symptoms mimic many other viral infections and diseases, such as dengue and chikungunya which are also spread via mosquito bite, many other cases were most likely not reported. In May of 2015, Brazil reported its first outbreaks of Zika. Since then, it has spread to most of South America, Mexico, the Pacific Islands, Papua New Guinea, Africa and some regions of the United States with millions of people infected with the virus.

Symptoms

The symptoms of Zika are generally mild, such as rash, fever, body aches, headache and conjunctivitis. Symptoms are also rarely life threatening or warrant hospital visits. Zika usually subsides in a few days to a few weeks and is suspected to provide immunity from future infections. There is currently no treatment for the virus, as with many other viral infections, rest, fluids, and acetaminophen is recommended to fight off symptoms while the virus takes its course. According to Rishi Desai, MD, MPH of the Osmosis Youtube Channel, only 1 in 5 people get sick from the infection.

The leading concern for medical officials regarding the virus has been the increase in birth defects caused to fetuses and newborns. The single-stranded positive RNA virus has been increasingly found in the amniotic fluid of affected newborns (PubMed 2016), potentially linking children of women confirmed to have Zika, with being born with defects such as hearing deficits, eye defects, impaired growth, microcephaly and death to name a few. There has also been an increase in Guillain-Barre Syndrome or GBS, in areas infested with the Zika virus, which is a rare disease. Since there is insufficient research on the long-term effects of the virus, however it is recommended that women do not become pregnant for at least two years following the infection.

Microcephaly is also a rare, lifelong disease in which the head of newborns are much smaller than expected. It occurs when brain growth in the womb has stopped or development after birth has stopped. “With viral-induced brain injury, such as with the Zika virus, there is often widespread tissue and cell death leading to brain shrinkage rather than simply impaired growth. The Zika virus is also associated with retinal lesions in about a third of cases, often leading to blindness” (National Institute of Neurological Disorders and Stroke 2016). Fortunately, this disease can be detected during pregnancy with an ultrasound, allowing parents the opportunity to evaluate make more informed decisions regarding the health of the expectant baby. Microcephaly interferes with the growth of the cerebral cortex which can cause seizures, developmental delays, intellectual disabilities, hearing loss, vision problems, difficulty swallowing and movement and balance issues. It can also be associated with Down’s syndrome, chromosomal syndromes, and neurometabolic syndromes (CDC 2016). There is no cure and treatment options are dependent on the severity of the case. Milder cases generally only suffer small heads, while severe cases can present much more complex treatment options. Close monitoring and frequent checkups are imperative for the health of these children.

GBS, is an autoimmune syndrome, in which the immune system attacks and damages the myelin sheath of neuron cells, causing weakness and paralysis in the legs, body and sometimes a complete loss of the function to breathe, due to weakened respiratory muscles. Symptoms generally start with leg and arm weakness or tingling and can lead to loss of the ability to walk as well as needing to be placed on a ventilator. Reflexes, of the knees especially, can be lost due to the damaged neurons and slower nerve signals. A nerve conduction velocity test can be used to diagnose GBS, as well as a spinal tap due to the abnormally high levels of protein found in the cerebrospinal fluid (CDC 2016). Most people generally make a full recovery after several weeks to several months from diagnosis. It is not clear what specifically causes GBS, or why some are affected and not others but, infections, vaccinations and some surgeries have been linked to trigger it. There is currently no cure for GBS.

Reemergence

Since the first reported case in 2015, there have been more than 70 countries infected with Zika and over 1.5 million reported cases with over 42,000 cases in the United States and US Territories, according to the CDC. It is unclear the reason for the reemergence of Zika and the impact it had globally, since in previous years only small clusters of infected persons had been reported in only a few countries (CDC 2016). What may have caused such wide spread globalization of the disease is that generally flaviviruses are unable to replicate within the human host adequately to infect other vectors, however Zika can do so, thereby spreading the infection to others (Desai 2016). Another reason it may have spread is due to travelers. According to Shuaib Waqas, MD of The American Journal of Medicine, during August 2014 and September 2015 more than 2.7 billion travelers from Brazil to the US and its territories which include Puerto Rico, Guam, American Samoa and the US Virgin Islands. Additionally, though no direct link connects the two, Jorge A. Alfaro-Murillo of the Public Library of Science Journal states that in Brazil the incidence of microcephaly increased during the outbreak from 0.5 per 10,000 births to 12 per 10,000 births with an outbreak birthrate of 14.9 per 1000 population.

The incidence of probability of these diseases was estimated, and were resulted as “microcephaly in infants born to Zika-infected women (0.49% to 2.10%). We also estimated the probability of GBS arising from Zika infections in Brazil (0.02% to 0.06%) and Colombia (0.08%). We calculated that each microcephaly and GBS case incurs the loss of 29.95 DALYs and 1.25 DALYs per case”, (Alfaro-Murillo 2016). The economic outcome was estimated at $180, 000 USD lifetime expenses per case for microcephaly and approximately $57,000 USD per case of GBS. This data provides the framework with which organizations, such as WHO, can use to determine whether advocating prevention or maintenance would be cost effective or not. It was found that method used to prevent the disease would be more cost effective than to allow the disease to continue is course and only maintain the health of those infected.

Methods of Control

The major outbreak of Zika has warranted a rapid increased need in research for the virus. The CDC, WHO, as well as many other organizations are continuing to research the long-term effects of Zika and treatment options. They are continually updating the public of the infected areas, community teaching, documenting cases, and recommending people follow travel advisories and prevention methods. Precautions are being urged for the public, especially women, to heighten strict environmental hygiene, mosquito control and personal protective measures both locally and during travel to guard against mosquito-borne diseases. These measures include, wearing long sleeves and pants, applying bug repellant, and preventing the blockage of stagnant water. There are currently no treatments for the virus but over the counter medications can alleviate some symptoms, it is also recommended to replenish fluids to avoid dehydration. However, more serious cases may require hospitalization, it usually resolves within a few days to a few weeks.

Conclusion

In our post Ebola society, worries about international spread of infections and the prevention of global epidemics has caused scientists and epidemiologists to revamp their methods and funding allotments for research and potential vaccines. As the epidemiologic transition continues to change, thorough research must be conducted to prevent if not eradicate these communicable infections. The public needs to continually be updated and informed of hot spots and risk factors. We will never be able to completely wipe out infection, however, if armed with the right tools we can contain and prevent the spread future epidemics.

References

1. Alfaro-Murillo, J.A., Parpia, A.S., Fitzpatrick, M.C., Tamagnan, J.A., Medlock, J., Ndeffo-Mbah, M.L., Durland, F., Ávila-Agüero, M.L., Marín, R., Ko, A.I, Galvani, A.P. (2016, May 20). A Cost-Effectiveness Tool for Informing Policies on Zika Virus Control. PLOS Neglected Tropical Disease, Volume 10, Issue 5: e0004743. https://doi.org/10.1371/journal.pntd.0004743
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