Zika in Breastmilk: Are your Patients at Risk?

By Bri Ziganti

In a recent meeting with one of our NICU clients, discussion centered around one thing: Zika, and how this virus is going to affect breastmilk quality and tracking.  Clinical managers are always worried about providing enough healthy nutrition to their preemies, since early birth often prevents mothers from producing enough breastmilk for their infants.  The recent upswing in human milk donation has made a huge impact on patient outcomes.  But this latest viral outbreak and the seemingly associated rise in microcephaly has caused many neonatal professionals concern for their milk supply.

Breastmilk, as with any bodily fluid, has the potential to spread disease.  All facilities using human breastmilk need to have a reliable method for tracing and isolating contaminated or expired product.  Unfortunately, not all of them do, and these facilities are left to wonder whether their milk is safe.  But is Zika actually the catalyst of Brazil’s birth defects?  And is breastfeeding a possible risk factor?  Scientists aren’t yet sure.

What is the Zika virus?

the zika virus may be passed in breastmilkThe Zika virus is a typically mild illness initially spread through the bite of a mosquito.  Those infected with Zika experience fevers, rashes, join pain, and conjunctivitis (redness in the eyes), with symptoms lasting about a week.   In many ways, the Zika virus is not unlike the common flu, related to the virus families of dengue fevers, yellow fevers, and West Nile diseases of the tropics, and is rarely fatal.  Most people who contract this disease won’t even feel sick enough to go see a doctor.  Some won’t even present any symptoms at all.  As far as researchers can tell, the only real worry is if a pregnant woman becomes exposed to the virus.

How is Zika spread?

The Zika disease is distributed throughout a population by the bite of the Aedes mosquito.  These insects are native to tropical areas in the Southern Hemisphere, the Gulf Coast, Hawaii, and Florida, but breed easily in small pools of warm, stagnant water.  Aedes mosquitos have even been found in Washington D.C.  This species of bug typically bites during daylight hours.  Asian tiger mosquitos can also transmit Zika, though perhaps not as efficiently as their Aedes cousins.  However, Asian tigers live even further north, traveling into New York and Chicago in the summer months.

While it has been established that Zika can also be transmitted through sexual contact, only three confirmed cases have been reported.  Of course, this raises concerns that Zika may be able to travel not only through semen, but other bodily fluids such as blood transfusions and breastmilk.  As researchers come to understand more about the virus, stringent testing of donating blood and breastmilk may be necessary to prevent widespread infection.

Why is Zika such a concern?

While Zika is not fatal or even especially dangerous in children or adults, it is thought to cause severe brain damage and a condition called microcephaly in developing fetuses.  After the widespread outbreak of Zika in May 2015 in Brazil, doctors noticed a worrying upswing in this relatively rare condition.  Ordinarily, Brazil’s medical community receives about 150 reported cases of this condition each year.  This past year, they’ve already seen nearly 4,000 new cases arise, leaving Zika as their most likely culprit.  To reduce risk, the World Health Organization has announced that Zika will remain an international public health emergency until more is known.

microcephaly is a condition that is thought to be caused by the zika virusMicrocephaly is almost always a congenital birth defect caused by inherited recessive genes or trauma to the brain in utereo.  Less often, microcephaly can develop due to receiving certain injuries as an infant.  These factors interfere with the brain’s maturation and cause the skull and brain not to grow to the proper size.  Brain damage can be caused by substance abuse, inadequate nutrition, or exposure to chickenpox or toxoplasmosis while the mother is pregnant.  Damage can also be instigated by lack of oxygen as a baby, brain injury, or down syndrome.  While the main symptom of microcephaly is an abnormally small head, other signs include a failure to thrive as well as behavioral defects such as poor appetite, unusually high-pitched crying, speech delays, impaired balance and motor functions, and involuntary muscle contractions.

Microcephaly is usually rather uncommon, affecting an average of only 25,000 children per year in the U.S.  Some of these children display mild symptoms and experience little-to-no form of neurological or cognitive disabilities.  Many will struggle with significant learning problems and seizures.  Though the condition can manifest later in infancy, the inherited form of microcephaly may be able to be detected with a prenatal ultrasound during the pregnancy’s third trimester, when the head is more developed.

Unfortunately, as of today there is no known cure for this condition.  Babies affected with microcephaly will often require years of therapies and specialized hardware like hearing aids to help them function.

Whether or not Zika actually causes brain defects in fetuses is still up for debate; however, since microcephaly is an incurable and devastating disorder, and potentially spread as easily as malaria, caution should be taken by pregnant and non-pregnant people alike.  Because the virus was largely isolated in Africa and Asia, the Western hemisphere has no built-up immunity.  South Americans and Americans living in the southern states of the U.S. are at risk for infection.  It’s not a far stretch to imagine Zika infiltrating a community too quickly to protect its vulnerable pregnant members.

Is Zika dangerous for breastfeeding infants?

So, the question that still lingers for every NICU and donor milk bank: can Zika be passed through breastmilk?

The CDC is still studying the ways in which Zika is spread; however, they have found that an infected mother can pass the virus to her baby during pregnancy, or in rarer cases, during delivery.  To date, there are no reports of the Zika virus being transmitted through breastfeeding.  Unfortunately, this doesn’t mean transmission isn’t possible.  The few cases of transmission by sexual contact and blood means that it may be possible to pass Zika through other bodily fluids, which includes breastmilk.  Until all transmission agents are known, NICUs and milk banks should be even more careful with their milk supply.  Feeding an already delicate preemie the milk from an infected donor or parent could be catastrophic.

How Can I Protect My Patients?

All feeds should be tracked electronically so that a contaminated milk lot can be quarantined.  An automated system that can trace a bottle of milk from the donor, through pasteurization, to storage, and finally to the patient itself, can ensure that your patients will not be fed dangerous nutrition.  If your milk bank or hospital has concerns over the safety of your milk supply, the SafeBaby team is here to answer any questions you may have.

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