Novel emerging infectious diseases in pregnancy

Last two decades have seen epidemics of several infectious diseases which were previously not so prevalent worldwide. Pregnant mothers are especially prone to many infections because of anatomical and physiological changes that accompany pregnancy. The immune tolerance to semiallogenic fetus is because of down regulation of immunity, which puts the pregnant women at high risk of other infectious diseases reports a paper published in May 2017 issue of Journal Obstetrics and Gynecology.

The world has seen epidemics of four major and other minor emerging infectious diseases in the last two decades such as severe acute respiratory syndrome, the 2009 H1N1 pandemic influenza, Ebola virus, and, most recently, the Zika virus. Each of this infection has unique implications in pregnant women that are distinctly different from general population.

Each of this infectious disease has different clinical course, complications and future implications when occurring in pregnant women and requires special technique and skills and coordination at national and international levels to contain the outbreak, some basic principles are common to all for diagnosing and limiting the spread of these diseases.

A number of epidemiological factors have contributed towards emergence and widespread occurrence of these infection in pregnant women like global travel, development of microbial resistance and barriers towards vaccinations in pregnant women in-spite of increasing evidence of distinct benefits to mother and fetus.

Although the general principles of disease containment are common to all, some disease specific measures for treatment and prevention of individual infections in pregnancy are:

SARS: During the severe acute respiratory syndrome (SARS) outbreak by coronavirus in 2003, standard non-pharmaceutical measures were applied, and global containment was achieved in 5 months.

Influenza: All pregnant women should get influenza vaccine every year as soon as it is available and should not wait for the unpredictable influenza season to start. It is safe in all the trimester. The rapid influenza tests currently available has low sensitivity resulting in many false negative results. Hence, to err on the side of safety it is always recommended to prescribe oseltamivir as precaution and is recommended both by Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists.

Ebola virus: Women are always at high risk for contracting Ebola during an epidemic as they are the primary caregivers to other infectious family members. Women who are pregnant with the virus during acute Ebola epidemic usually transmit virus to the fetus, leading to intrauterine fetal death, stillbirth, or neonatal death. Ebola virus is also excreted in breast milk.

They also transmit the virus to healthcare providers and caregivers during labor or abortion. Standard precaution including the use of personal protective equipment (PPE) during labor and delivery for protection against blood and body fluids should be used along with rigorous hand hygiene, appropriate waste, sharps and laundry management and cleaning and decontamination.

WHO states that women who get pregnant after having being recovered from Ebola infection are not infectious but standard precautions and use of PPE should be implemented all the time during handling such patients. 

Zika virus: Zika virus is a flavivirus that has potential for sexual and vector born transmission by Aedes (Stegomyia) species of mosquitoes. It was declared as a public health emergency by the World Health Organization from 2016. A pregnant woman is susceptible to Zika virus in all three trimesters. Maternal Zika infection is associated with a range of adverse neonatal complications, most important of which is microcephaly. Peripartum transmission is also known to occur.

In absence of antiviral vaccine, CDC recommends that all pregnant women should postpone their travel to Zika infected areas and those who are in such areas should avoid mosquito bite especially during the day.

Pregnant women with laboratory-confirmed Zika virus infection can be offered amniocentesis to test for Zika virus RNA by RT-PCR after 15 weeks of gestation.

Deliveries of mothers with positive Zika infection should take place at specialized center.   

No specific antiviral treatment is available.

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WHO guide to Ebola disease in pregnancy

Media courtesy: InfectiousDiseaseAdvisor and Coherent news.