3. • Zika virus infection is a mild febrile viral illness
transmitted by mosquitoes.
• Zika virus is enveloped and icosahedral with a non
segmented Single stranded RNA virus
• Genus Flavivirus, family Flaviviridae
• It is related to dengue, yellow fever, West Nile and
Japanese encephalitis, viruses that are also members of
the virus family Flaviviridae..
4. EPIDEMIOLOGY
• It was discovered in the Zika Forest, a tropical forest
near Entebbe in Uganda in 1947isolated from a rhesus
monkey.
• It was subsequently identified in humans in 1952 in
Uganda and the United Republic of Tanzania.
• Outbreaks of Zika virus disease have been recorded in
Africa, the Americas, Asia and the Pacific.
• The first large outbreak of disease caused by Zika
infection was reported from the Island of Yap (Federated
States of Micronesia) in 2007.
5. • In July 2015 Brazil reported an association between Zika
virus infection and Guillain-Barré syndrome.
• In October 2015 Brazil reported an association between
Zika virus infection and microcephaly.
• On 1 February 2016 WHO has already declared the Zika
virus as a Public Health Emergency of International
Concern over its suspected link to microcephaly and
neurological disorders.
• On 15 may 2017 the MoHFW reported three laboratory
confirmed cases of Zika virus disease in Bapunagar area,
Ahmedabad ,Gujrat
6. Transmission
• Zika virus is transmitted to people through the bite of an infected
mosquito from the Aedes genus, mainly Aedes aegypti and Aedes
albopictus mosquito.
• Transmission from a infected pregnant mother to her baby during
pregnancy or around the time of birth.
• A person infected with zika virus can pass it to her or his sexual partners
and has been detected in semen, blood, urine, amniotic fluids, saliva as
well as body fluid found in brain and spinal cord.
• Zika virus may be spread through blood trasnfusions.
• Laboratory exposure.
• There is no evidance that zika is spread through breast milk touching,
coughing, or sneezing.
7. Pathogenicity
After inoculation by a mosquito
Virus replicate in skin dendritic cell
Which then migrate to lymph node
Where virus replicate further
Enter the blood stream
And in some individual crosses BBB
In CNS virus infect neurons
8. Signs and Symptoms
The incubation period of ZIKA VIRUS disease is not clear, but is likely to be
a few days.
About 1 in 5 people infected with Zika are symptomatic.
Symptoms typically begin 2 to 7 days after being bitten by an infected
mosquito.
Symptoms include:
Fever (mild)
Rash (mostly maculopapular)
Headache
Joint pain
Conjunctivitis (red eyes)
Muscle pain
9. Presentation is similar to dengue and chikungunya infection
Features Zika Dengue Chikungunya
Fever ++ +++ +++
Rash +++ + ++
Conjunctivitis ++ - -
Arthralgia ++ + +++
Myalgia + ++ +
Headache + ++ ++
Hemorrhage - ++ -
10. Zika Virus Infection and Pregnancy
• A range of manifestations has been reported among babies up to 4
weeks old where there has been exposure to zika virus in utero.
There includes
Malformation of head ( Microcephaly)
Involuntary movements
Seizures irritability
Brainstem dysfunction such as swallowing problems, limb
contractures, hearing and sight abnormalities and brain
anomalies.
Others – Miscarriages and stillbirths.
11. The spectrum of congenital abnormalities that associated with
Zika virus exposure of foetus during pregnancy are known as
“Congenital Zika virus syndrome” these are:-
1. Severe microcephaly in which skull has partially collapsed.
2. Decrease brain tissues with specific pattern of brain damage,
including subcortical calcification
3. Damage of the back of the eye , including macular scarring
and focal pigmentary retinal mottling
4. Congenital contractures, such sa clubfoot or arthrogryposis
5. Hypertonia restricting body movements soon after birth.
12. Zika and microcephaly
• Microcephaly is a birth defect in which
a baby’s head is smaller than expected
when compared to babies of the same
sex and age. Babies with microcephaly
often have smaller brains that might not
have developed properly.
• Zika virus infection during pregnancy
is a cause of microcephaly. During
pregnancy, a baby’s head grows
because the baby’s brain grows.
Microcephaly can occur because a
baby’s brain has not developed
properly during pregnancy or has
stopped growing after birth
13. Diagnosing Microcephaly
Diagnosis Pregnancy Outcome
Definite Congenital Microcephaly For Live Births: Head circumference (HC) at
birth less than the 3rd percentile for gestational
age and sex OR if HC at birth is not available,
HC less than the 3rd percentile for age and sex
within the first 2 weeks of life
For Stillbirths and Elective Terminations: HC
at delivery less than the 3rd percentile for
gestational age and sex
Possible Congenital Microcephaly For Live Births: If earlier HC is not available,
HC less than the 3rd percentile for age and sex
beyond 6 weeks of life For All Pregnancy
Outcomes: Microcephaly diagnosed or suspected
on prenatal ultrasound in the absence of available
postnatal HC measurements
14.
15. Zika and Guillain-Barré Syndrome
• Guillain-Barré syndrome (GBS) is an uncommon sickness of the nervous system
in which a person’s own immune system damages the peripheral nerve cells,
causing muscle weakness, and sometimes, paralysis.
• It is a rare condition, and while it is more common in adults and in males, people
of all ages can be affected.
• The first symptoms of Guillain-Barré syndrome include weakness or tingling
sensations. They usually start in the legs, and can spread to the arms and face.
• These symptoms can lead to paralysis of the legs, arms, or muscles in the face.
In 20%–30 % of people, the chest muscles are affected, making it hard to
breathe.
• The ability to speak and swallow may become affected in severe cases of
Guillain-Barré syndrome. These cases are considered life-threatening, and
affected individuals should be treated in intensive-care units.
16. Causes of Guillain-Barré syndrome
• Guillain-Barré syndrome is often preceded by an
infection. This could be a bacterial or viral infection.
Guillain-Barré syndrome may also be triggered by
vaccine administration or surgery.
• In the context of Zika virus infection, unexpected
increase in cases of Guillain-Barré syndrome has been
described in affected countries. The most likely
explanation of available evidence from outbreaks of Zika
virus infection and Guillain-Barré syndrome is that Zika
virus infection is a trigger of Guillain-Barré syndrome.
17. Diagnosis
Several methods can be used for diagnosis, such as
• viral nucleic acid detection,
• virus isolation
• and serological testing.
Diagnosis by serology can be difficult as the virus can
crossreact with other flaviviruses. Thus, viral nucleic
acid detection remains the preferred method for
diagnosis.
18. Laboratory testing for Zika virus infection
Diagnostic RT-PCR
• Nucleic acid detection by reverse transcriptase-polymerase chain reaction
targeting the non-structural protein 5 genomic region is the primary means
of diagnosis. Standard RT-PCR and quantitative RT-PCR provide a rapid,
specific and sensitive method for ZIKV early detection.
• Viral RNA has been detected in serum up to day 10 after the onset of
symptoms. ZIKV RNA also has been detected in urine or saliva samples.
• Detection of IgM antibodies to Zika virus by diagnostic ELISA.
Serology by testing IgM antibodies in blood. This is not the main stay of
diagnosis as cross reactivity with other flaviviruses is very high.
• Plaque Reduction Neutralization Test (PRNT): this is a confirmatory
diagnosis.
• Immunohistochemical (IHC) staining for viral antigens or RT-PCR on
fixed tissues
19. Specimens
•Specimens for nucleic acid testing (NAT) testing:
Whole blood , serum collected in a dry tube and/or urine
collected from patients presenting with onset of symptoms
≤ 7 days.
• Serology (IgM detection): Whole blood collected in a
dry tube and serum collected from patients presenting
with onset of symptoms ≥ 7 days. Wherever possible,
paired serum specimens should be collected at least 2-3
weeks apart, ideally with the first serum specimen
collected during the first 5 days of illness
20. Recommendations
• Symptomatic people who live in or recently traveled to an area
with active Zika transmission, and
• People who have had unprotected sex with someone confirmed to
have Zika virus infection or who lives in or traveled to an area
with active Zika transmission.
• Pregnant women with possible Zika exposure and signs or
symptoms consistent with Zika virus disease should be tested.
• Pregnant women with ongoing risk of possible Zika virus
exposure and who do not report symptoms of Zika virus disease
should be tested in the first and second trimester of pregnancy
21.
22.
23. Treatment
• There are no vaccine or medicine for Zika infection.
• Treat the symptoms of Zika
• Rest
• Drink fluids to prevent dehydration
• Take acetaminophen to reduce fever and pain
• Do not take aspirin or other non-steroidal anti-
inflammatory drugs (NSAIDS) until dengue can be
ruled out to reduce the risk of bleeding.
26. Infants with confirmed or possible Zika infection
Problems among fetuses and infants infected with Zika virus
before birth, including
• Microcephlay
• Miscarriage
• Stillbirth
• Absent or poorly developed brain structures
• Defects of the eye
• Hearing deficits
• Impaired growth
28. Evaluation for all infants with positive Zika
virus test results
• Physical examination, measurement of head
circumference, and assessment of gestational age
• Evaluation neurologic abnormalities, dysmorphic
features, enlarged liver or spleen, and rash/other skin
lesions
• Cranial ultrasound
• Opthalmologic evaluation
• Evaluation of hearing
29. Prevetion
• Should not travel to areas with zika.
• If they must travel to areas with zika, protect themselves from mosquito
bites .
This can be done by
Wearing clothes (preferably light-coloured) that cover as much of
the body as possible.
using physical barriers such as window screens or closing doors
and windows.
Sleeping under mosquito nets;
Using insect repellent containing DEET, IR3535 or icaridin
Cover, empty or clean potential mosquito breeding sites in and
around houses.
30. • Take steps to prevent sexual transmission during and after
travel.
Sexually active men and women be correctly counselled and
offered a full range of contraceptive methods to be able to make
an informed choice about whether and when to become
pregnant in order to prevent possible adverse pregnancy and
fetal outcomes.
Pregnant women should practice safer sex (including correct
and consistent use of condoms) or abstain from sexual activity
for at least the whole duration of the pregnancy.
