Zika virus is an emerging mosquito transmitted infection in South and Central America and is a possible threat to pregnant women travelling to these regions.
Several organisations like RCOG (Royal College of Obstetricians and Gynecologists) have issued the guidelines on do’s dont’s and tests and prevention for the disease.
Mode of transmission:
The Aedes mosquito (Aedes aegypti) is the vector of the virus and the disease occurs by the mosquito bites. It can be transmitted through sexual contact and through blood transfusions. The vertical transmission occurs from mother to fetus for this virus but the risk of transmission through breast feeding is not proven.
It doesn’t transmit through mere human to human contact (eg. sneezing, shaking hands etc.)The incubation period is usually 3-12 days but can be longer or shorter.
Know the symptoms:
Symptoms of the infection include low grade fever, maculopapular rash with itching , red eyes, joint pains in joints of hands and feet, body ache and headache, There is no evidence that pregnant women are more vulnerable to acquiring ZIKV infection or that this infection causes a more serious illness in pregnant women, but there have been reported cases of very severe foetal infections in pregnant ladies leading to foetal microcephaly (very small heads in babies), ventriculomegaly (brain disease) ,cataract and others. The virus crosses the placental barrier and is found in the foetal blood and tissues. The risk of infection is greatest in early pregnancy however the evidence is limited.
The mainstay of testing for ZIKV in maternal serum is reverse transcription polymerase chain reaction (RT-PCR) for symptomatic patients with onset of symptoms within the previous week. ZIKV RT-PCR can also be performed on amniotic fluid although it is currently not known how sensitive or specific this test is for congenital infection.
But all the pregnant mothers with ultrasound signs of affected foetuses must be tested. A foetal MR may be performed to see for other abnormalities not detected on ultrasound. In case of termination the histopathology and immunohistochemical staining of placenta and ZIKV RTPCR on foetal tissue must be performed.
Aedes is a daytime mosquito unlike others.
Travellers can use mosquito repellents like N-diethyl meta toluamide (DEET) based repellents. They can avoid mosquito bite by wearing full sleeves, light coloured clothes .Mosquito nets should be used.
For pregnant women, it is advised that they avoid travelling to the affected regions. If travel is mandatory, then they must take adequate precautions as stated above.
In case of those having symptoms similar to the infected ones stated above, they must consult an obstetrician and subjected to RTPCR .
If identified positive, the woman should be referred to a foetal medicine consultant for further assessment.
If the lab test is negative, serial (4-weekly) foetal ultrasound scans should be considered to monitor foetal growth and anatomy.
Testing for ZIKV is not recommended for women whose symptoms have resolved by the time of presentation, but they too should be offered serial (4-weekly) foetal ultrasound
Routine testing of asymptomatic women (those who remained asymptomatic while travelling and for two weeks after their return from a ZIKV affected area) is not recommended. However, serial foetal ultrasound scans as above should be considered (as ZIKV infection is associated with minimal symptoms in the majority).
Women planning to be pregnant:
Those who have returned from the travel to the affected countries should avoid getting pregnant for atleast 4 weeks after return.
For a partner travelling to the affected countries: