How Zika Virus Affects Pregnancy

There is a new silent threat for women who wish to become pregnant and for those who are currently pregnant.

Zika virus is a member of the Flaviviridae virus family and is mainly transmitted by Aedes mosquitoes, which are also known as Asian tiger mosquitoes for the distinct black and white striping found on the body of these insects. The Zika virus is in the same family as yellow fever, West Nile, chikungunya and dengue. Of these viruses, only Zika has been linked to birth defects.

It is unclear at this time if Zika passes through breast milk.

Zika can be transmitted sexually, although this is very rare.  Three sexually-transmitted cases of Zika have been documented thus far. CNN news articles reported that in French Polynesia in 2013, “semen and urine samples from a 44-year-old Tahitian man tested positive for Zika even when blood samples did not.” CNN reported that Colorado microbiologist Brian Foy contracted Zika after traveling to Senegal in 2008. Days after his return from Senegal, his wife was infected with the virus despite her not having left Colorado and not being exposed to a mosquito carrying the virus. The likely source of her virus was through sexual contact with her husband. A third sexually transmitted case of Zika virus occurred in February 2016 in Dallas County, Texas.

Adults infected with Zika experience either no symptoms or experience the mild flu-like symptoms of joint pain, muscle pain, headache and mild fever sometimes combined with rash and/or conjunctivitis, or red eyes. These symptoms last from one week to ten days.

Zika is a tropical illness that originated in Africa and was first identified in a monkey in 1947. The virus derives its name from a forest near Lake Victoria, Uganda, that was home to the first rhesus monkeys infected with the virus. According to the World Health Organization, within a few years the virus in Uganda had jumped from monkeys to humans.

Just like with malaria, people are the source of Zika virus transmission. A female mosquito bites a person infected with Zika and then bites an uninfected person, transmitting the virus from the first person to the next. The infected mosquito will continue to bite other people, thus infecting each of them with Zika, and this cycle will continue until the mosquito dies.

People infected with Zika travel from area to area, which means that in any country where Asian tiger mosquitos are found can become a new area of localized Zika infection. A region in which Zika is present permanently is said to be endemic. A pandemic is when an infection spreads across large regions, such as an entire continent.

The Zika virus is now spreading locally in more than 20 countries which are mostly located in Latin America and in the Caribbean. According to the Centers for Disease Control and Prevention (CDC), areas of the growing pandemic include Barbados, Bolivia, Brazil, Cape Verde, Columbia, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, Samoa, the U.S. Virgin Islands and Venezuela.

In Brazil, a link between the Zika virus and birth defects is suspected. Pregnant women infected with Zika have an increased chance of their babies being born with microcephaly, which is a congenital condition in which a baby is born with an abnormal smallness of the head which results in incomplete brain development. Sometimes fetuses that develop microcephaly in utero are miscarried. Babies born with the condition sometimes die during birth or shortly after birth.

Those babies born with microcephaly who survive their births tend to suffer from seizures, physical developmental delays, intellectual disabilities, problems with movement and balance, feeding problems such as difficulty swallowing, hearing loss and vision problems. The severity of these issues range in severity to life-threatening and often last a lifetime.

Autopsies were conducted on a few Brazilian babies with microcephaly who died shortly after birth. Samples of these babies’ brains showed the presence of Zika virus. Other investigations have shown that babies born with microcephaly to women infected with Zika virus have varying degrees of the disease and the difference seems to hinge on when the mothers were infected with Zika.

When mothers are infected with Zika during their first trimester, or first three months of pregnancy, have babies born with microcephaly, the severity of birth defects are greater than babies born to mothers infected later in pregnancy. First trimester infected babies born with microcephaly have brains that are smooth and void of the characteristic ridges of a normal human brain. Scientists believe this lack of ridges is why the degree of microcephaly is more severe for these babies.

In the United States, microcephaly is not a common condition. According to the CDC, between 2 babies per 10,000 live births to about 12 babies per 10,000 live births are born with the condition. A baby boy born recently in Hawaii was diagnosed with microcephaly; his mother had been infected with Zika while she was traveling in Brazil. This is so far the only documented case of microcephaly in the U.S. due to Zika.

In Brazil, 146 babies were born with microcephaly in 2014. That numbered skyrocketed to nearly 4,000 cases since November 2015 alone. Of this second group of babies, 51 have died so far. It is suspected that the rapidly increasing rate of Zika infection is the reason behind the increase in Brazilian babies born with microcephaly.

At this time, there is no blood test available for the detection of Zika, which is why women who are or who can become pregnant who are living in or traveling to countries where the disease is spreading are being cautioned about contracting the Zika virus.

There is no vaccine, treatment or cure for Zika either. Prevention is the best medicine when it comes to limiting the reach of this particular virus.

“Out of an abundance of caution,” the CDC recommends that “pregnant women in any trimester should consider postponing travel to the areas where Zika virus transmission is ongoing.” Airlines have started refunding ticket costs to pregnant women whose destinations are in Zika-infected areas.

The CDC advises that all people traveling to any areas infected with Zika use mosquito repellent, reapply repellent as instructed on the package labeling, wear long sleeves and long pants and use netting around beds while sleeping to prevent mosquito bites from occurring in the first place.

The U.S. Department of Defense is offering voluntary relocation to pregnant employees and their beneficiaries who are stationed in countries where Zika is found.

Government officials in Brazil, El Salvador, Colombia and Jamaica have told young women in their respective countries to postpone pregnancy for up to two years in an effect to limit the chances of having a baby born with microcephaly. It is still unknown how long the virus in an infected woman can impact a pregnancy as this causal link between Zika and microcephaly is a new development.

Women’s rights groups in El Salvador are using the Zika virus and its effect on pregnancy as an opportunity to discuss that country’s complete ban on abortion, which went into effect in 1998. These groups are hoping abortion laws will be relaxed to allow women infected with Zika more options should they become pregnant.

Researchers at the British company Oxitec are attempting to reduce Zika transmission using OX513A, a genetically modified male Aedes aegypti, which critics have dubbed “mutant mosquito” or “Robo-Frankenstein mosquito.” This mutated male mosquito, which carries a fluorescent marker for easy identification, passes along a gene that makes his offspring die. Since female mosquitos mate only once a lifetime, this gene mutation may curb the population of the Aedes aegypti mosquitos.

Trial releases of the OX513A mosquitos in Brazil have proved to be successful with a 99 percent population reduction in a 2011 field trial and a 92 percent population reduction in a 2014 field trial.

As science and governments try to battle the spread of Zika, residents and travelers in affected areas can protect themselves by regularly using mosquito repellents and reapplying as needed, wearing clothing that covers arms, legs, ankles and necks, using mosquito netting over beds and reducing or eliminating standing water, which are breeding grounds for mosquitos, in their neighborhoods.

For residents and travelers who are fertile, using condoms during sexual encounters can help reduce the chances of pregnancy during Zika outbreaks. Women of childbearing potential in affected areas should consider the use of birth control until at least the link between Zika and microcephaly can be scientifically explained, at which time perhaps the rates of Zika will have declined or will be eliminated entirely.


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