Analysis of Zika Virus: Birth Defects, Research and Impact on Brazil

This report provides a detailed analysis of the Zika virus, a mosquito-borne disease transmitted by Aedes mosquitoes, focusing on its impact in Brazil and its association with significant birth defects. The report discusses the virus's symptoms, transmission methods, and detrimental effects, particularly on pregnant women, leading to conditions like microcephaly and other brain anomalies in newborns. It examines the evidence supporting the causal relationship between prenatal Zika virus infection and these birth defects, utilizing criteria established by Thomas Shepherd and Bradford Hill. The analysis concludes that there is a proven connection between the Zika virus and brain abnormalities prevalent among newborns in affected areas, emphasizing the importance of medical attention for infected individuals, especially pregnant women. Desklib offers a platform to explore similar solved assignments and research papers for students.

Running head: ZIKA VIRUS
ZIKA VIRUS
Name of the Student
Name of the University
Author note

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Introduction:
Zika virus is one of the most dangerous diseases which have endangered human lives
in recent times. It is a disease borne by mosquitoes and transmitted by Aedes mosquitoes. Its
various symptoms include headache, muscle pain, joint pain, conjunctivitis and mild fever. It
can be transmitted through sexual contact, blood transfusion and into the fetus of pregnant
women. The concerned task deals with a detailed analysis of this virus with special emphasis
on Brazil and the various birth defects associated with it.
Discussion:
Zika Virus:
It is a disease borne by mosquitoes more specifically by Aedes Aegypti, a yellow
fever mosquito ("Zika virus", 2018). They bite both during day and night. It causes Yellow
fever, Japanese encephalitis and West Nile viruses. It was first discovered in the year 1947.
From 2007-16, it had spread eastward across the pacific, towards the Americas and it went on
to become a virus epidemic (Calvet et al., 2016).
Getting exposed to the virus and its treatment:
The most important cause of the outspread of Zika virus is mosquito bite. These
mosquitoes bite during the day, peaking at early morning and continuing till afternoon and
late in the evening. The most astonishing fact, which comes out of the investigation
conducted by WHO, is that most people who get infected through these mosquitoes do not
realise it until some symptoms rise to the surface (Chang et al., 2016). These symptoms are
usual in nature, such as headache, joint and muscle pain, rashes etc. They are mild in nature
and stay till two to three days. It has no specific treatment. There are no vaccines or

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medicines available (Calvet et al., 2016). Usually the disease is mild and requires no serious
treatment. Plenty of rest, intake of fluids and treatment of fever with normal medicines
should be suffice. However, if the situation worsens, proper medical attention is advised.
Detrimental effects:
The most notable effects of Zika virus has been known to cause pregnant ladies some
serious issues and their effects are listed below:
 Occurrence of Microcephaly (under developed brains in new born babies).
 Other fatal brain anomalies in the foetuses.
 Eye defects.
 Hearing loss.
Moreover, the Guillain-Barré Syndrome (GBS) has been strongly been associated with
Zika, with several researches asserting the pr3esence of the syndrome in Zika affected areas
(Heukelbach et al., 2016). In GBS, weakness in the legs occurs which spreads to the entire
body and if severe, it can cause total paralysis and interference with breathing, heart rate and
blood pressure.
Birth defects connected with the Virus:
According to New England Journal of Medicine article, the birth defects associated
with Zika virus are profound. The case of Zika virus during pregnancy has been heavily
linked to serious pregnancy cases and birth outcomes; most alarming are the cases of
Microcephaly and various brain anomalies (Adibi et al., 2016). This proposition has been
holistically researched upon and has been a subject of intense scrutiny. With sufficient
evidence collected it has been established that there exists a cause and effect relationship

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between antenatal Zika virus and Microcephaly and other brain abnormality (Rasmussen et
al., 2016).
The causal relationship has been proved with the help of the criterions laid down by
Thomas Shepherd and Bradford Hill. The criteria’s of Shepherd which have proved a causal
relationship have been discussed below:
Criteria: Evidence:
Proven exposure to the agent during prenatal
developments in one or more critical times.
On the basis of various case studies, the timing of
Zika virus infection association with serious
Microcephaly occurs during the late first or early
second trimester pregnancy cycle.
Careful depiction of clinical cases with findings
of a fault.
The phenotype has been pretty evident in babies
with presumed inbred Zika virus infection, which
includes microcephaly, arthrogryposis and eye
findings. The phenotype in other infants matches
with the fatal brain disruption pattern, which has
been detected after infection with various viral
teratogens.
Scarce environmental exposure that is connected
with scarce defects.
Reports of babies with severe microcephaly, born
to women who briefly visit Zika affected
countries are a rare exposure. Moreover, inbred
microcephaly is very rare, with a count of 6
infants out of 10,000 infants (Heukelbach, 2016).
Association having a biological connection. Animal models have proved that this virus is
related to the growth of nervous tissue and it
suggests biological feasibility.

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Bradford Hill’s seven criterions consisting of strength of association, consistency,
specificity, temporality, plausibility, coherence and analogy have been met. Thus, on
reviewing the available criterions and evidences, causality has been established between
antenatal Zika virus and Microcephaly and other brain abnormalities in child births.
Conclusion:
It can be concluded from the concerned report that Zika virus is a fatal disease which
has a proven connection with brain anomalies and other brain diseases which are prevalent
among new born in Zika affected areas. The nature of this disease is mild in nature and has
normal symptoms, but considering the severity of the patient, medical attention becomes
indispensable.

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References:
Adibi, J. J., Marques Jr, E. T., Cartus, A., & Beigi, R. H. (2016). Teratogenic effects of the
Zika virus and the role of the placenta. The Lancet, 387(10027), 1587-1590.
Calvet, G., Aguiar, R. S., Melo, A. S., Sampaio, S. A., De Filippis, I., Fabri, A., ... &
Tschoeke, D. A. (2016). Detection and sequencing of Zika virus from amniotic fluid
of fetuses with microcephaly in Brazil: a case study. The Lancet infectious
diseases, 16(6), 653-660.
Chang, C., Ortiz, K., Ansari, A., & Gershwin, M. E. (2016). The Zika outbreak of the 21st
century. Journal of autoimmunity, 68, 1-13.
Heukelbach, J., Alencar, C. H., Kelvin, A. A., de Oliveira, W. K., & de Góes Cavalcanti, L.
P. (2016). Zika virus outbreak in Brazil. The Journal of Infection in Developing
Countries, 10(02), 116-120.
Rasmussen, S. A., Jamieson, D. J., Honein, M. A., & Petersen, L. R. (2016). Zika virus and
birth defects—reviewing the evidence for causality. New England Journal of
Medicine, 374(20), 1981-1987.
Zika virus. (2018). World Health Organization. Retrieved 8 March 2018, from
http://www.who.int/mediacentre/factsheets/zika/en/