Zika virus infection

Zika virus infection

The Zika virus was first identified in monkeys in the Zika Forest, Uganda, in 1947. In 1952, this virus was found in humans in Uganda and the United Republic of Tanzania.

‚ÄčZika and Pregnancy
A Zika infection during pregnancy has been associated with an increased risk of microcephaly (when a baby is born with an abnormally small head due to the brain not developing properly) and other fetal abnormalities, as well as miscarriage and stillbirths.

What are the chances of the baby having microcephaly when the mother is infected?
Due to a lack of data currently, there is no definite answer. But scientists have released estimates based on the limited data available. Data from a Zika epidemic in French Polynesia in 2013-2014 puts the estimate at around 1% of infected pregnant woman having a baby with microcephaly. Data from Rio de Janeiro suggests that 29% may have babies with brain-related birth defects (including microcephaly and other problems). According to work from the US Centers for Disease Control and Prevention, there is suggestion that the earlier the infection in the stages of pregnancy, the higher the risk of microcephaly, though this does not mean that there is no risk if the mother is infected in the second trimester.

Zika in adult humans
It has also been associated with neurological problems in adults such the Guillain-Barré syndrome (a condition where the body’s immune system attacks the nerves, eventually resulting in full body paralysis). There have also been hypotheses about an association between the Zika virus and Alzheimer’s.

How does Zika spread?
When an Aedes mosquito takes blood from an infected person, it becomes infected itself, and transmits the virus to the other people it bites. In Singapore, the common species of Aedes mosquitos are the Aedes aegypti and the Aedes albopictus. The Aedes mosquito is also responsible for spreading other diseases such as dengue and yellow fever. 

The female mosquitoes are the ones that bite people. The Aedes aegypti bite mostly in the day (though they can even bite at night, in well-lit homes.) The problem is that instead of biting one human for one meal, they bite many people for their one meal, taking only a little bit of blood from each person. This is partly why the Zika is spreading so fast – this mosquito bites many and can hence infect many.

Zika can also be spread through sexual contact, from a pregnant woman to her baby, and possibly through blood transfusion (though this is not confirmed). 

How do I know if I have Zika?
Most patients who are infected will not show any symptoms. For the 1 in 5 people who do, it will be very mild. Common symptoms are fever, rash, joint pain, red eyes, muscle pain and headache. These can last for several days to a week. Because it is so mild, people usually don’t have to be rushed to a hospital, nor do they usually die from it.

What can I do?
The national Ministry of Health (MOH) has released an advisory statement on their site. It states various things such as how travellers returning to Singapore from affected areas should monitor their health carefully for 14 days and contact a doctor immediately if presenting symptoms of a Zika infection.

Pregnant women should use precautions to prevent mosquito bites and try to postpone trips to countries and areas with ongoing cases of outbreaks.

Treatment for Zika
There is currently no vaccine or cure for the Zika virus. People usually recover on their own without any problems. A Zika diagnosis is confirmed through a blood or urine test. 

Preventing Zika
The best way to prevent it is to try to protect yourself from mosquito bites, by using repellant and covering well when out. People should also be vigilant by making sure there is no stagnant water for mosquitoes to breed in their living and working environment. Mosquito control is everyone’s business.

In Singapore, there are also intensive efforts to control the mosquito population with fogging operations, spraying chemicals into drains to prevent breeding etc.

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