Science, People & Politics issn:1751598x. Iss. one 2017

ZIKA VIRUS FEATURE | 18

Emphasis in the PNAS paper is placed on non-normal consequences of Zika infection. That is,
the paper reports cytopathologies noted following controlled infection of host cells with Zika.
Pathologies of interest in viral infection include: cell dysregulation, cell hypertropthy - where the
cell is excessively large, cell proliferation, apoptosis, and cell death triggered by oxidative
stress. Host cell irregularities exist in illnesses and birth defects associated with Zika infection.

The researchers are interested also in the impact of Zika on a process known as autophagy, in
which cell content - both its architectural structural lipids and proteins, and its "worker" proteins
orchestrating the cell cycle - are digested by enzymes of the same cell. Think of autophagy as
the orchestral score, and Zika as an unwelcome band joining the performance, highjacking the
bassoons, say, and integrating its own music in both seeming harmony, and dissonance.

Though the paper by Li et al dives deeply into basic science, and into fast-moving, newly-
uncovered scientific insights, it is human medical need which drives the research. Human
surrogate cells were needed to conduct a genome-wide analysis of the Zika viral proteins, their
subcellular locations, and functional impact. Genome-wide analysis simply means locating
each protein coded by a genome in relationship to that genome as a whole.

Li et al chose the fission yeast S. Pombe for their study. It is a single-cell eukaryote, with a
biological nature allowing experimental findings to be extrapolated to the human biology.

For the insatiably curious a eukaryote is any organism with a cell nucleus bound by a plasma
membrane, and that covers a large portion of biology on Earth, from unicellular organisms to
mammals. Zika is a positive-sense (meaning DNA and RNA in the same direction), single-
stranded RNA virus of the flavivirus family. It has some aggressive viral "cousins", such as
dengue virus, and the family is responsible for several unpleasant medical conditions.

Zika hit the headlines in 2015 following an increase in infections in Brazil. In September of that
year some of the babies born to women who had had pre-birth Zika viral infection were noted to
have abnormally small heads (microencephaly) and other brain anomalies. Medicine some-
times applies seemingly inhuman language like anomaly to avoid the harm of using precise
language incorrectly, which could be dangerously misleading, overly prescriptive, or premature.

Then in April 2016 The New England Journal of Medicine (NEJM) published a paper arguing
authoritatively that there is a causal link between prenatal Zika viral infection and congenital
defects. The arguments are complex, and do not mean pregnant women infected with Zika will
have a child with microencephaly. They do mean that avoiding mosquito bites is a good idea,
as is consulting a doctor about when in the pregnancy Zika infection occurred.

Zika is also associated with the auto-immune disease - Guillain-Barré syndrome, which can
occur at all ages.

Confirmation of a causal link between Zika viral infection and congenital abnormalities in babies
born to women who had been infected with Zika is only the beginning of the fight back against
Zika. It is a confirmation which, not unusually, reveals the chasm between medicine and
science. Following the NEJM publication of April 2016, medicine has become sure footed.
Science is on slippery ground. The two need to be in sync, and at the moment they are not.

Issue 1 (Jan-Mar), 2017............................................Science, People & Politics ISSN 1751-598X print and online