Zika virus: Potential birth defects associated with this virus

The Zika virus, a viral illness, like Dengue and Chikungunya, predominantly transmitted by bite of an infected Aedes mosquito, has become a significant global health concern, especially for pregnant women and women of reproductive age. This virus is also transmitted through sexual intercourse and from an infected mother to her baby during pregnancy.

Approximately 80% of Zika virus infections are asymptomatic or present with mild symptoms such as fever, rash, conjunctivitis, muscle and joint pain, malaise, and headache. These symptoms typically last for a few days to a week and are often indistinguishable from other viral infections.

Zika virus infection is particularly concerning for pregnant women due to the serious complications leading to a range of complications associated with infection, such as congenital malformations, and preterm or still-births. Risk of congenital malformations following infection in pregnancy is estimated to be around 5-15%. These malformations occur following both symptomatic and asymptomatic infection.




The most notable birth defect associated with Zika virus infection during pregnancy is microcephaly, a condition where babies are born with smaller heads due to abnormal brain development. This can lead to significant developmental and intellectual disabilities. This virus may also lead to other congenital malformations including hearing loss, eye abnormalities, limb contractures, and high muscle tone in babies. These malformations are collectively referred to as ‘congenital Zika syndrome’.

Diagnosis

A diagnosis of Zika virus can only be confirmed by laboratory tests of blood and other body fluids. There are two types of tests which can be used to diagnose Zika infections:
Molecular tests: Nucleic acid amplification test, a PCR test, is a preferred method of diagnosis for confirmation of infection. This checks for Zika virus genetic material in blood and urine.
Antibody tests: This test detects Zika virus antibodies in blood samples. However, this test is less specific than the molecular test.

Who should get tested

• Symptomatic individuals residing in or traveling to areas where active cases of Zika have been detected
• Pregnant women residing in or traveling to areas where active cases of Zika have been detected.
• Pregnant women and symptomatic individuals who have engaged in unprotected sexual intercourse with someone who has traveled to areas where there is risk of Zika.
• Pregnant women with abnormal ultrasound findings.

(Author: Dr. Abhilasha Kochhar, Sr. Consultant Microbiology and Molecular Biology, Metropolis Healthcare)