A pattern of other birth defects, called congenital Zika syndrome, has been found, which is unique to fetuses and infants infected with Zika virus before birth. Prenatal Zika virus infection has been linked to adverse pregnancy and birth outcomes, most notably microcephaly and other serious brain anomalies.
Zika virus First time discovered in Uganda, in 1947 and recognised as a member of Flavivirus family. Flavivirus cause dengue, yellow fever and West Nile fever. Zika virus is primarily transmitted to humans through the bite of infected Aedes aegypti mosquitoes. Most people who become infected with Zika virus do not become sick. Only 20 percent people are effected by Zika. Virus is generally eliminated from the body after few weeks but it remain longer in semen.
Facts about Zika
- 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 women to her fetus. Infection during pregnancy can cause certain birth defects.
- There is no vaccine or medicine for Zika. Research are going on.
- Local mosquito-borne Zika virus transmission has been reported in the continental United States.
- The link between maternal Zika virus infection and infant microcephaly is now confirmed Brazil, in particular, has seen a surge in infants born with microcephaly since October 2015. These rates have been reported to be 10 times higher than those in previous years.
- There have been no known transmissions of the virus from mother to infant during breast-feeding.
- According to the Pan American Health Organization (PAHO), “the French Polynesia health authorities hypothesize that Zika virus infection may be associated with these abnormalities if mothers are infected with the virus during the first or second trimester of pregnancy.”
- There is also a potential risk that the Zika virus could spread through infected blood. As a result, the U.S. Food and Drug Administration (FDA) have advised people who have travelled to a region with active Zika virus transmission to defer from donating blood.
What is Microcephaly ?
Microcephaly is a condition where a baby’s head is much smaller than expected. 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, which results in a smaller head size.
There is no evidence that Zika virus infection during pregnancy is a cause of microcephaly. We do not know the fact about microcephaly develop during pregnancy or afterbirth.
Microcephaly can be diagnosed during pregnancy or after the baby is born.
First Trimester Screening
First trimester screening is a combination of tests completed between weeks 11 and 13 of pregnancy. This screen includes a maternal blood test and an ultrasound.
Maternal Blood Screen
The maternal blood screen measures the levels of two proteins, human chorionic gonadotropin (hCG) and pregnancy associated plasma protein A (PAPP-A). If the protein levels are abnormally high or low, there could be a chromosomal disorder in the baby.
The ultrasound for the first trimester screen looks for extra fluid behind the baby’s neck. If there is increased fluid found on the ultrasound, there could be a chromosomal disorder or heart defect in the baby.
Second Trimester Screening
Second trimester screening tests are completed between weeks 15 and 20 of pregnancy.
Maternal Serum Screen
The maternal serum screen is a simple blood test used to identify birth defects, such as neural tube defects or chromosomal disorders such as Down syndrome. It is also known as a “triple screen” or “quad screen” depending on the number of proteins measured in the mother’s blood.
This test is usually completed around 18–20 weeks of pregnancy. The ultrasound is used to check the size of the baby and looks for birth defects or other problems with the baby.
High resolution Ultrasound
This ultrasound, also known as a level II ultrasound, is used to look in more detail for possible birth defects or other problems with the baby It is usually completed between weeks 18 and 22 of pregnancy.
Chorionic Villus Sampling (CVS)
CVS is a test where the doctor collects a tiny piece of the placenta, called chorionic villus, which is then tested to check for chromosomal or genetic disorders in the baby. It is completed between 10 and 12 weeks of pregnancy, earlier than an amniocentesis.
AFP stands for alpha-fetoprotein, a protein the unborn baby produces. A high level of AFP in the amniotic fluid might mean that the baby has a defect.
AChE stands for acetylcholinesterase, an enzyme that the unborn baby produces. This enzyme can pass from the unborn baby to the fluid surrounding the baby if there is an opening in the neural tube.
After the Baby is Born
Certain birth defects might not be diagnosed until after the baby is born. Sometimes, the birth defect is immediately seen at birth. For other birth defects including some heart defects, the birth defect might not be diagnosed until later in life.
Relation between Pregnancy and Zika Virus
New study Showed that the possible importance of Zika virus RNA testing of serum obtained from pregnant women beyond the first week after symptom onset, that time detailed evaluation of the fetal intracranial anatomy by means of serial fetal ultrasonography or fetal brain MRI. The isolation of Zika virus from fetal brain provides additional evidence for the association between congenital Zika virus infection and fetal brain damage and provides tools. Its exact pathogenesis is not clear.
Zika virus infection is mild disease but pregnant women and fetus are affected badly. Studies have confirmed that microcephaly is caused by Zika virus. But its pathogenesis is unclear. Medication and vaccine haven’t clear their clinical test. So we don’t have any medication. Research and studies are going on and found targeted protein inside the virus which would be the reason of controlling them.
Only precautions are the solution for protection.