Zika virus is a mosquito-borne virus that causes mild fever and rash. It was first discovered in Uganda in 1947 and recent outbreaks have occurred in the Americas. The virus is transmitted primarily through the bites of infected Aedes mosquitoes. While most infections cause mild symptoms, infection during pregnancy can cause microcephaly and other birth defects. There is no vaccine or treatment currently available, so prevention focuses on reducing mosquito habitat and exposure through clothing and repellents.

1. ZIKA VIRUS: A REVIEW
SONIKA SHRIVASTAV

2. ZIKA
 Zika virus infection is a mild febrile viral illness transmitted by mosquitoes. The Zika virus
is a member of the Flavivirus genus in the family Flaviviridae.
 It is related to dengue, yellow fever, West Nile and Japanese encephalitis, viruses that are
also members of the virus family Flaviviridae..
 It was discovered in the Zika forest in Uganda in 1947.
 The Zika virus' incubation period is about 3 to 12 days after the bite of an infected
mosquito.
 The vast majority of infections are not contagious from person to person.

3. Zika virus Epidemiology
 The very first known case of Zika fever was in a rhesus monkey in the Zika Forest in
Uganda in 1947.
 The first human cases were reported in Nigeria in 1954. A few outbreaks have been
reported in tropical Africa and in some areas in Southeast Asia.
 The first major outbreak, with 185 confirmed cases, was reported in 2007 in the Yap
Islands of the Federated States of Micronesia.
 In 2013 another large outbreak was reported in French Polynesia that was thought to be
from an independent introduction of the virus from Asia than the Yap Island outbreak.
 In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the
first confirmed Zika virus infections in Brazil. Mosquito-borne Zika virus is suspected to
be the cause of 2,400 cases of microcephaly and 29 infant deaths in Brazil in 2015.

4.  The emergence of Zika virus in South America led to a rapid spread throughout South and
Central America, reaching Mexico in November 2015.
 It has appeared sporadically in travellers to the United States and Europe.
 Because of the "growing evidence of a link between Zika and microcephaly" the CDC
issued a travel alert on January 15, 2016 advising pregnant women to consider
postponing travel to the following countries and territories: Brazil, Colombia, El
Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama,
Paraguay, Suriname, Venezuela, and the Commonwealth of Puerto Rico.
 The agency also suggested that women thinking about becoming pregnant should consult
with their physicians before traveling.

5. Transmission of zika virus
 Through mosquito bites:
 Zika virus is transmitted to people primarily through the bite of an infected Aedes species
mosquito (A. aegypti and A. albopictus).
 These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls,
animal dishes, flower pots and vases. They prefer to bite people, and live indoors and outdoors
near people.
 Mosquitoes that spread chikungunya, dengue, and Zika are aggressive daytime biters. They can
also bite at night.
 Mosquitoes become infected when they feed on a person already infected with the virus. Infected
mosquitoes can then spread the virus to other people through bites.

6.  From mother to child:
 A mother already infected with Zika virus near the time of delivery can pass on the virus to
her newborn around the time of birth.
 It is possible that Zika virus could be passed from a mother to her baby during pregnancy.
 To date, there are no reports of infants getting Zika virus through breastfeeding. Because
of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas where
Zika virus is found.

7.  Through sexual contact:
 Zika virus is transmitted to the people through sexual activity.
 Dallas County Health and Human Services (DCHHS) has received confirmation from the
Centers for Disease Control and Prevention (CDC) of the first Zika virus case acquired
through sexual transmission in Dallas County in 2016.
 The patient was infected with the virus after having sexual contact with an ill individual
who returned from Venezuela,a country where Zika virus is present.

8. Symptoms of Zika virus
 Low-grade fever (between 37.8°C and 38.5°C)
 Arthralgia, notably of small joints of hands and feet, with possible swollen joints
 Myalgia
 Headache, retro-ocular headaches
 Conjunctivitis
 Cutaneous maculopapular rash
 Post-infection asthenia which seems to be frequent.
 More rarely observed symptoms include
 Digestive problems
 Abdominal pain
 Diarrhea
 Constipation mucous membrane
 Ulcerations
 Pruritus

9. Risk of Zika during pregnency
 According to pediatric neurologists in Brazil that some pregnant women infected by zika
virus have given birth to the babies with a birth defect called microcephaly.
 Microcephaly, which comes from the Greek words for small head is a broad term used to
describe a smaller-than-average head circumference in babies (at least two standard
deviations below the mean for his or her sex and age). It can be caused by a wide range of
things, from diseases to malnutrition.
 Because of the potential for birth defects, the CDC(Centers for Disease Control and
Prevention) issued travel guidance for pregnant American women and women of
childbearing age who may become pregnant, warning them to avoid visiting places where
the virus is currently circulating.

10. Diagnosis
 IgM, IgG and PCR for Zika virus.
 acute serum (taken within 5 days of symptom onset) and convalescent serum (2–3 weeks
later) should be taken. The two samples are important to rule out false positive tests due to
cross reactivity with similar viruses such as Dengue.
 Provide overseas travel details and clinical history including the onset day and patient’s
DHB. Onset date is extremely important to ensure that the most appropriate test is
performed.
 The local laboratory will forward samples to ESR who will arrange testing at an Australian
Arbovirus Reference Laboratory (no labs in NZ currently test for Zika virus).

11. Precaution & prevention
 Prevention involves reducing mosquito populations and avoiding bites, which occur
mainly during the day. Eliminating and controlling Aedes aegypti mosquito breeding
sites reduces the chances that Zika will be transmitted. An integrated response is
required, involving action in several areas, including health, education, and the
environment.
 To eliminate and control the mosquito, it is recommended to:
 Avoid allowing standing water in outdoor containers (flower pots, bottles, and
containers that collect water) so that they do not become mosquito breeding sites.
 Cover domestic water tanks so that mosquitoes cannot get in.
 Avoid accumulating garbage: Put it in closed plastic bags and keep it in closed
containers.
 Unblock drains that could accumulate standing water.

12.  Use screens and mosquito nets in windows and doors to reduce contact between
mosquitoes and people
 To prevent mosquito bites, it is recommended that people who live in areas where there are
cases of the disease, as well as travelers and, especially, pregnant women should:
 Cover exposed skin with long-sleeved shirts, trousers, and hats
 Use repellents recommended by the health authorities (and apply them as indicated on the
label)
 Sleep under mosquito nets.
 People with symptoms of Zika, dengue, or chikungunya should visit a health center.

13. Treatment
 There is no commercial vaccine or specific antiviral drug treatment for Zika virus
infection.
 Treatment is directed primarily at relieving symptoms using anti-pyretics and analgesics.

14. References
 http://zikavirusnet.com/epidemiology.html
 http://www.cdc.gov/zika/transmission/
 http://www.redaccionmedica.com/contenido/images/zika%20servicio%20de%20salud%20de%2
0dallas.pdf
 http://www.health.govt.nz/our-work/diseases-and-conditions/zika-virus
 http://www.vox.com/2016/1/28/10861094/microcephaly-zika-virus-birth-defect-pregnancy
 http://www.paho.org/hq/index.php?option=com_content&view=article&id=9183%3A2015-
preguntas-frecuentes-virus-fiebre-zika&catid=8424%3Acontent&Itemid=41711&lang=en
 http://www.medicinenet.com/zika_virus/article.htm
 http://www.health.govt.nz/our-work/diseases-and-conditions/zika-virus
 http://www.microbiologyinfo.com/zika-virus-structure-genome-symptoms-transmission-
pathogenesis-diagnosis/
Sonika Shrivastav