The American Zika Virus Threat: What You Need to Know


Microcephalic Babies Are Tied to Zika viral infections during their first 3 months of fetal development. Source

Zika virus (Zv) infects people via daytime mosquitoes carrying it, and rarely via sex with infected partners. Mosquitoes can bite infected people and then bite others, transmitting Zv to new people.


  1. in individuals, Zv typically causes no to mild symptoms (joint pain, irritated eyes, fever), dies out in the body after a week, and leaves the person immunized from further infection.
  2. a Zv infected woman in her first 3 months of pregnancy risks giving birth to a small brained (microcephalic) baby, who is likely to have serious developmental problems, often resulting in a relatively short lifespan.


Zv, related to dengue, yellow fever, and West Nile viruses, is kept alive via a wild host population in Africa. Immunized people are no longer hosts, but sources are maintained in wild animals that carry the virus.


The Current Spread of Zika Virus. Source Center for Disease Control and Prevention

  1. In 2015 Zv spread probably from Pacific islands to Central America, where vast human populations are potential temporary hosts to the virus.
  2. Nearly 4000 Brazilian microcephalic babies, born between October 2015 and January 2016, indicate the explosive spread of Zv throughout Brazil in early 2015. A sharp rise in Zv is reported in several other Latin American countries.
  3. The World Health Organization predicts Zv to spread wherever carrier mosquitoes occur – that is, throughout South and North America, except in Canada and Chile.*


Mosquitoes Transmit Zika Virus, but the sources are in animals that carry the virus.
Credit James Gathany at Wikimedia Commons

*Ultimately, widespread vaccination within human populations will likely keep Zv to manageable levels, but not wipe it out. Those same mosquitoes will probably infect American animals, which will be American carrier hosts. Such animals carry the live virus in their blood on a long-term basis, and are perpetual sources of it. Knowing which species are carriers and killing them all off simply isn’t feasible.


No vaccines exist yet, although manufacturers say one could be available for emergency use by October 2016.

CDC Short-term Guidelines

For pregnant women who have traveled or are in Zv zones: get tested for it. See the CDC page for details. If you test positive, consider serial ultrasounds to track fetal development.


Go When You’re Not Pregnant to Mexico and the following countries below, says the Center for Disease Control, to prevent any fetal harm. Source

For pregnant women: postpone travel to Zv zones, which now include:

  • Central and South America: Mexico, Bolivia, Ecuador, Guyana, Brazil, Colombia, El Salvador, French Guiana, Guatemala, Honduras, Panama, Paraguay, Suriname, Venezuela
  • Caribbean: Barbados, Saint Martin, Haiti, Martinique, Puerto Rico, Guadeloupe
  • Oceania: Samoa
  • Africa: Cape Verde


DEET Containing Repellents Are Safe to use and effective at repelling mosquitoes.Source

Prevention In the Zv Zone:

Use mosquito repellent, and mosquito nets when napping.

For women travelers: avoid pregnancy. Use highly effective contraceptives.

For men travelers: make sure highly effective contraceptives are used if you have sex.

For women living long-term in Zv zones – consider postponing pregnancy (as several countries suggest) until:

  • a vaccine becomes available, or
  • you test positive for Zika virus antibodies: this indicates that you have already been infected with, and subsequently immunized against, Zv.


Swiss Cheese Model for accident causation. Failures in various prevention factors (holes in the cheese) can cause a Zika epidemic. Source Davidmack via Wikimedia Commons


Understand how the spread occurs, via, for example, the Swiss Cheese Modelof accident causation.


Stopping Deforestation Slows Climate Change, and Zika Virus Spread

Develop an overall system for preventing its spread, which includes:

  • Get vaccinated for Zv.
  • Minimize mosquito breeding grounds in urban areas.
  • Minimize activities that create breeding grounds, such as deforestation.
  • Prevent further climate change, which helps mosquitoes proliferate and spread.

For more on Climate Change, check out my weekly columns at the HuffingtonPost, Climate Change This Week


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About melharte

Mel (Mary Ellen) Harte is a biologist (PhD) and climate change educator. She co-authored the free online book, COOL THE EARTH, SAVE THE ECONOMY, available at www.CoolTheEarth.US, and writes the CLIMATE CHANGE THIS WEEK column at the HuffingtonPost. Living summers in the alpine Rockies, she is on the frontlines of watching what climate change can do. Her diagnostic digital photographs of wildflowers have appeared in numerous publications.
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2 Responses to The American Zika Virus Threat: What You Need to Know

  1. I taught the multiply handicapped, and had a student whose mother was bitten by a mosquito with the Dengue virus. That student was microcephalic and had little awareness about her surroundings. Pregnant women need to avoid this at all costs!

    • melharte says:

      Now that’s fascinating — although, given the absence in the literature of a connection between dengue and microcephaly AND the fact that the zika virus is closely related to the dengue virus, I wonder if her mother was actually infected with the zika virus, and someone misidentified her virus?

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