Zika viral infection by Dr.T.V.Rao MD

1. ZIKA VIRAL INFECTION
an update
Dr.T.V.Rao MD
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 1

2. EMERGING VIRAL INFECTIONS A
GREAT THREAT TO EVERYONE
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 2

3. HISTORY OF ZIKA VIRUS
The virus was first isolated in April 1947 from a rhesus
macaque monkey that had been placed in a cage in
the Zika Forest of Uganda, near Lake Victoria, by the
scientists of the Yellow Fever Research Institute.
A second isolation from the mosquito A. africanus
followed at the same site in January 1948. When the
monkey developed a fever, researchers isolated from
its serum a transmissible agent that was first
described as Zika virus in 1952
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 3

4. Zoonosis is a emerging problem
with Viral infections
• The recent outbreaks are
another example of virus
transferring from animals to
human beings. The sudden
spurt of zoonotic diseases
in the last few years has
caught the world
unprepared. It includes
Ebola hemorrhagic fever
and microcephaly caused by
Zika virus.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 4

5. Prior to 2015, Zika virus outbreaks had
occurred in areas of Africa, Southeast
Asia, and the Pacific Islands.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 5

6. 18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 6

7. Zika Virus
• Zika virus belongs to the family
Flaviviridae and the genus
Flavivirus, thus is related to the
dengue, yellow fever, Japanese
encephalitis, and West Nile
viruses. Like other flaviviruses,
Zika virus is enveloped and
icosahedral and has a
nonsegmented, single-stranded,
positive-sense RNA genome.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 7

8. ZIKA VIRAL INFECTION IS ARBOVIRUS
INFECTION
•Zika virus (ZIKV) is a
member of the
Flaviviridae virus
family and the
Flavivirus genus,
transmitted by
daytime-active Aedes
mosquitoes, such as
A. aegypti
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 8

9. ZIKA VIRUS
•Basic biology of viruses contributes to their capacity to
cause disease. Most human viruses replicate almost
instantaneously and in huge numbers. As a result,
mutations arise at a high rate in the genetic code of a
virus. This allows the virus to adapt quickly to
an adverse environment, such as the human
immune system or drugs. It may also allow a virus
to jump from an animal host to humans.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 9

10. lineages of Zika virus
•There are two lineages of Zika virus, the African
lineage and the Asian lineage. Complete genome
sequences of Zika viruses have been published.
Recent preliminary findings from sequences in the
public domain uncovered a possible change in non-
structural protein 1 codon usage that may increase
the viral replication rate in humans
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 10

11. Should I be worried about
Zika?
• Anyone can get Zika if they haven’t been infected before.
• Most people infected with Zika don’t have symptoms, so they
might not even know they have the virus.
• Zika is of greatest concern to a pregnant woman’s
developing baby. Zika can cause birth defects if a
pregnant woman becomes infected.
• It is important to avoid areas with Zika, prevent mosquito
bites, and practice safe sex to prevent the spread of Zika
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 11

12. Basic facts on Zika Virus
( WHO )
• The incubation period of the virus is estimated to be 3–14 days
with the symptoms lasting for 2–7 days. According to the World
Health Organization (WHO), most people with Zika virus
infection do not develop symptoms. Aedes aegypti is the same
mosquito species that transmits dengue, chikungunya and
yellow fever.
• For the majority of people, Zika virus infection is not a serious
issue but can be very dangerous among pregnant women as the
virus can easily transmit from a pregnant woman to her foetus.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 12

13. HOW THE ZIKA VIRUS
INFECTION SPREADS
• Zika is spread mostly by the bite of
an infected Aedes species
mosquito (Ae. aegypti and Ae.
albopictus). These mosquitoes
bite during the day and
night.
• Zika can be passed from a
pregnant woman to her fetus.
Infection during pregnancy can
cause certain birth defects.
• There is no vaccine or
medicine for Zika.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 13

14. Mosquito Vectors for Zika
• Aedes aegypti and Aedes
albopictus mosquitoes
• • Also transmit dengue and
chikungunya viruses
• Live in and around households
• Lay eggs in household or
backyard containers
• − flower pots, old tires, pet
dishes
• Aggressive daytime biters
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 14

15. Spread of Zika Virus
• Zika virus can migrate
between humans through
sexual contact and it can also
cross the placenta, affecting an
unborn fetus. Another already
infected with Zika virus near
the time of delivery can pass
on the virus to her new-born
around the time of birth,
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 15

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17. • Zika can be spread through
• Mosquito bites
• From a pregnant woman to her fetus
• Sex with an infected person
• Laboratory exposure
• Zika may be spread through blood
transfusion.
• No reports of infants getting Zika through
breastfeeding.
How is Zika spread?
18-07-2021

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19. How does Zika affect people?
• Many people with Zika will not
have symptoms or will only have
mild symptoms.
• Symptoms last several days to a
week.
• People usually don’t get sick
enough to go to the hospital.
• People very rarely die of Zika.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 19

20. • For people with symptoms, the
most common symptoms
of Zika are
• Fever
• Rash
• Headache
• Joint pain
• Conjunctivitis (red eyes)
• Muscle pain
What are the
symptoms?
18-07-2021

21. 18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 21

22. Zika viral infection during
pregnancy
• Zika virus infection during
pregnancy can cause infants to
be born with microcephaly
and other congenital
malformations, known as
congenital Zika syndrome.
Infection with Zika virus is
also associated with other
complications of pregnancy
including preterm birth and
miscarriage.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 22

23. A greater threat with
Involvement of CNS
•An increased risk of
neurologic complications
is associated with Zika
virus infection in adults
and children, including
Guillain-Barré syndrome,
neuropathy and myelitis.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 23

24. Zika and Guillain-Barré syndrome
• A link between Zika and
Guillain-Barré syndrome
was first proposed in
2014 in French
Polynesia. With the
World Health
Organisation reporting
the “explosive spread”
of Zika virus, there are
concerns that Guillain-
Barré syndrome levels
may also increase.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 24

25. Guillain-Barré syndrome
• The exact cause of Guillain-Barré syndrome is still unclear, but it
generally develops after a lung or gut infection and appears to be an
autoimmune disease. This means that symptoms are caused
by our own immune system attacking our body.
The initial infection can be caused by either bacteria or viruses, and a
large number of infections have been linked to Guillain-Barré
syndrome. The most commonly associated infections are the bacteria
Campylobacter jejuni, cytomegalovirus and Epstein-Barr virus.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 25

26. How can Zika affect pregnancies?
• Congenital Zika syndrome
• Distinct pattern of birth defects in fetuses and infants of women infected
during pregnancy
• Associated with 5 types of birth defects not seen or rarely seen with other
infections during pregnancy
• Severe microcephaly (small head size) resulting in a partially collapsed
skull
• Decreased brain tissue with brain damage
• Damage to the back of the eye with a specific pattern of scarring and
increased pigment
• Limited range of joint motion, such as clubfoot
• Too much muscle tone restricting body movement soon after birth
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 26

27. About sexual transmission
• Zika can be passed through sex from a person who has Zika
to his or her sex partners.
• Sex includes vaginal, anal, and oral sex and the sharing of sex
toys.
• Zika can be passed through sex before symptoms start, during,
and after symptoms end.
• It can be passed even if the infected person does not have
symptoms at the time or never develops symptoms.
• Zika virus can stay in semen longer than in vaginal fluids,
urine, and blood.
18-07-2021

28. • Pregnant women who live in or
frequently travel to areas with risk of
Zika
• Pregnant women who have a fetus
with prenatal ultrasound findings
consistent with congenital Zika virus
infection and
• Live in or traveled to any area with
risk of Zika, or
• Had unprotected sex with a partner
who lives in or traveled to any area
with risk of Zika
Who should be tested for Zika?
18-07-2021

29. CDC recommends laboratory testing for
• All infants born to mothers with
laboratory evidence of Zika virus infection
during pregnancy
• Infants who have abnormal clinical or
neuroimaging findings suggestive of
congenital Zika syndrome and a mother
with a possible exposure to Zika virus,
regardless of maternal Zika virus testing
results
Testing babies for Zika
18-07-2021

30. What tests we should do to confirm
Zika Viral Infections
• The most commonly and widely
used diagnostic technique for
ZIKV diagnosis is based on the
virus molecular detection by
conventional or real-time RT-
PCR, and some protocols have
been described for detecting
ZIKV within the group or
specific to the virus .
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 30

31. Triplex kits
• triplex kits to detect Dengue
fever, Chikungunya and Zika
and 500 single-plex kits to
test Zika virus were supplied
to Thiruvananthapuram
medical ...
• RTPCR test is conducted to
confirm Zika virus infection.
Samples of blood and urine
will be tested to detect the
virus. NIV has also
recommended confi...
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 31

32. Molecular basis of ZIKA diagnostic
method
•The viral genome detection by
molecular techniques provides a
definitive diagnostic result, but as
viremia is transient, this approach
is most reliable if performed within
the first week of the disease .
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 32

33. Quantitative methods in Zika
Infections
• By using quantitative RT-
PCR, the RNA viral load in
blood (7.28 × 106 to 9.3 ×
108 copies RNA/ml), urine
(2.5 × 103 to 8 × 106 copies
RNA/ml), semen (1.1 × 107
to 2.9 × 107 copies RNA/ml)
and breast milk (2.9 × 104
to 2 × 106 copies RNA/ml)
could be determine.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 33

34. Other specimens we Can detect
Zika virus
•Although the ZIKV
genome has been
detected on amniotic
fluid, cord blood, CSF
and placenta by RT-
PCR, the method's
sensitivity on those
specimens is unknown
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 34

35. Other Serological tests done in Zika
diagnosis
• Anti-ZIKV IgM and IgG
antibodies can be detected
by serological assays.
However, the results should
be carefully analyzed due to
false-positive results from
possible cross-reactivity
with other flaviviruses.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 35

36. Ig M detection in Zika viral infections
• The virus-specific IgM may
be detectable more than 5
days after onset of
symptoms. In some case,
these biomarkers, indicative
of an active infection, may
rise as early as day 3 of
illness and last over 2
months [
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 36

37. Errors in Serology
•Seroconversion represented by at least a four-fold
increase in paired sera, acute and convalescent sera,
is desirable for a more reliable result. In a flavivirus-
naive patient, a minimal cross-reactivity is obtained,
but a significant cross-reactivity in patients exposed
to a previous flavivirus infection is observed, even on
yellow fever vaccinated patients.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 37

38. Cross reactions in Zika Dengue
viral Infections
•Additionally, Zika and dengue virus antibodies
cross-react, making it difficult to diagnose which
virus is the cause of the current illness. None of
these probable cases have tested positive
using molecular testing, which detects the
presence of the virus in the body and is the
best indicator of a recent infection.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 38

39. Wait and watch do not start Anti
viral treatments hastily
•It is important to note here that not all the
people who show these signs or symptoms
need medical treatment. If the symptoms are
mild, it is advised to wait for a few days as most
of them disappear on their own. This is
basically due to the activation of body’s own
defense mechanism that destroys the virus and
make the symptoms to fade away
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 39

40. Treatment
• There is no specific treatment
for infection with the Zika
virus. To help relieve
symptoms, get plenty of rest
and drink plenty of fluids to
prevent dehydration. The
over-the-counter (OTC)
medication acetaminophen
(Tylenol, others) may help
relieve joint pain and fever.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 40

41. Use of DEET in prevention of
Mosquito bites
• DEET (chemical name, N,N-
diethyl-meta-toluamide) is the
active ingredient in many
repellent products. It is widely
used to repel biting pests such
as mosquitoes and ticks. Every
year, an estimated one-third of
the U.S. population use DEET to
protect them from mosquito-
borne illnesses like West Nile
Virus, the Zika virus or malaria
and tick-borne illnesses like
Lyme disease and Rocky
Mountain spotted fever.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 41

42. To conclude
•Our current understanding of the
pathophysiology of ZIKV infection needs to be
strengthened and epidemiological studies and
animal models of the disease need to be
developed.. Accurate, portable and inexpensive
point-of-care tests are in need to better identify
cases, especially where other arboviruses co
circulate
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 42

43. Improvements in Public Policy
• Public policies need to be
implemented, effective
preventive measures such
as vaccines created and
improving efforts to reduce
transmission through
vectors and more studies on
sexual transmission are
necessary
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 43

44. Our Vision to future
• Accurate, portable and
inexpensive point-of-care
tests are in need to better
identify cases, especially
where other arboviruses
co circulate. Due to the
difficulties in propagating
the virus, antigen
availability in many
laboratories poses a
burden for the diagnosis,
and the development and
use of recombinant
antigens are desirable
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 44

45. Emerging solutions to deal
with Zika Virus Infections
• The recent outbreaks of Zika
virus (ZIKV) infections and
associated microcephaly in
newborns has resulted in an
unprecedented effort by
researchers to target this virus.
Significant advances have been
made in developing vaccine
candidates, treatment
strategies and diagnostic assays
in a relatively short period of
time.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 45

46. Vaccines in Development
•Being a preventable disease, the first line of defense
against ZIKV would be to vaccinate the highly
susceptible target population, especially pregnant
women. Along those lines, several vaccine
candidates including purified inactivated virus (PIV),
live attenuated virus (LAV), virus like particles (VLP),
DNA, modified RNA, viral vectors and subunit
vaccines have been in the pipeline with several
advancing to clinical trials.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 46

47. Current Scenario in Kerala India as on
15/07/2021 press information
• As Kerala battles COVID-19, the state recorded four new cases of Zika
virus, bringing the total number of cases to 23 on Wednesday, 14 July,
according to India Today.
• State Health Minister Veena George said that a 16-year-old
Thiruvananthapuram girl was found infected with the virus.
• Among the affected was also a 38-year-old doctor from a private
hospital in Thiruvananthapuram and two others, including a woman,
India Today reported.
• On Monday, Thiruvananthapuram Medical College began testing
samples. Fifteen were tested, out of which one was found to be infected
with Zika, and another with dengue, according to the report.
18-07-2021 Dr.T.V.Rao MD @ Zika Viral infection update 47

48. Source of Information
• NIH USA
• World Health organization updates on Zika virus
• CDC Atlanta Zika as a emerging infection
• Press trust of India
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