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Zika Virus Epidemic

March 04, 2016
The first cases of Zika Virus have just been confirmed in the U.S., including one in Philadelphia. How does this disease travel? What is being done by policymakers to stop the virus’s spread? These, and other questions are answered here by Wonk Tank’s Health, Education, and Welfare team.


Zika virus disease is caused by the Zika virus, which is spread through the bite of an infected Aedes species mosquito.[1] There also are a few confirmed cases where the disease was spread through sexual contact.[2] This virus is not dangerous for men or women who are not pregnant- symptoms include joint pain, fever, a rash, and conjunctivitis. There is not anything a doctor can do for someone who isn’t pregnant who contracts Zika virus disease, and the general recommendation is to stay home, drink fluids, rest, and avoid getting bitten by mosquitoes (which would further spread the disease). The disease usually lasts about a week, and one infection usually protects a person from future infections.[3]

In pregnant women, Zika virus disease has been linked to some serious birth defects, including microcephaly. Microcephaly is a birth defect where an infant is born with an unusually small head and (usually) underdeveloped brain functioning. This can cause problems ranging from hearing loss to intellectual disability. While the link has not been determined to be causal yet, the correlation between Zika virus disease and birth defects is significant enough that it is considered a risk for women who are pregnant or may become pregnant. In order for birth defects to be a serious concern, the woman must have contracted Zika while pregnant- infection prior to the pregnancy has a very low chance of affecting the child. Zika virus disease may also cause miscarriages.[4]

How The Zika Virus Spreads<br/>Source: Vox

Source: Vox

Zika virus disease affects about 1 in 5 people who are exposed to Zika virus. Zika virus is also difficult to diagnose, since its symptoms are very similar to those of a few other diseases caused by bites from the same type of mosquitoes.[5] No vaccine exists for the prevention of Zika virus disease,[6] but by staying away from mosquito breeding grounds and preventing mosquito bites however possible, the virus’s spread can be limited.[7] If you suspect that you might have Zika virus disease, a doctor can run specialized blood tests to confirm the diagnosis.[8]

The Zika virus was first discovered in 1947 in Uganda, and was named after the Zika forest in Uganda. The first human cases of Zika virus disease were confirmed in 1952. Since then, outbreaks of Zika have occurred in Africa, Southeast Asia, and the Pacific Islands. At least 14 cases were confirmed prior to 2007, and there were likely many more that were simply undiagnosed.[9]

The Current Epidemic

On February 1st, 2016, the World Health Organization declared the Zika virus an international public health emergency.[10] This announcement came as Zika spread through Latin America and the Caribbean, among suspicions–now shared by the WHO–that the disease was linked to microcephaly. Although Zika was first isolated by Ugandan researchers in 1947, the virus did not garner widespread attention until an outbreak occurred in May 2015 in Brazil.11 Before the Brazilian outbreak, the virus had never been associated with birth defects; compared to other diseases that ravaged the same areas, like dengue, its impact was mild. Now, researchers are scrambling to study previous outbreaks in order to determine whether or not the connection is causal. A retrospective investigation into a 2013 outbreak in French Polynesia found an alarming number of birth defects, but for now, public health officials remain hesitant to establish any linkage.12 Currently, teams of health workers led by agents from the United States Center for Disease Control are searching Brazil for mothers to enroll in a study that could determine whether or not the Zika virus is truly causing birth defects. In order to do so, they will extensively study both babies born with microcephaly and babies born without the condition, along with their mothers, to rigorously assess all factors that could be the source of the problem.13


Countries with Confirmed Zika Cases <br/>Source: dailystar.co.uk

Source: dailystar.co.uk

The WHO has also refrained from imposing travel restrictions, although it warns pregnant women against traveling to areas affected by the disease.14 The organization’s reluctance to restrict travel may be, in part, political; Brazil will host the 2016 Olympics, and a decrease in tourism could have troubling consequences for the country’s economy.15 Scientists in America worry about the long-term spread of the virus. The primary vector of Zika virus is the aedes aegypti mosquito, which is concentrated in the southern United States.16 But global warming, experts warn, could drive the aedes aegypti further north. Even more alarming, aedes albopictus–the common tiger mosquito–has not been ruled out as a competent vector for the disease.17

Mosquitos are not a new problem, given the impact of malaria and dengue fever, but some see Zika as yet another indication that governments must prioritize mosquito eradication. While genetic engineering is a popular idea when it comes to insect control, the technology remains less advanced than the need, and for now insecticides may be the most effective option.18 Currently, insect control is not a standard part of the public health infrastructure in countries like the United States. Furthermore, there are concerns of spending vast amounts of money on insecticides that mosquito populations may have developed resistance to, and which could harm other organisms in the ecosystem.19 But as long as countries lack coordinated mosquito control programs, their populations stay largely vulnerable to the disease.20


  1. “About Zika Virus Disease”, Centers for Disease Control and Prevention, February 29, 2016, http://www.cdc.gov/zika/about/index.html.

  2. Donald McNeil, Catherine Saint Louis, and Nicholas St. Fleur, “Short Answers to Hard
Questions About Zika Virus”, The New York Times, February 24, 2016, http://www.nytimes.com/interactive/2016/health/what-is-zika-virus.html?_r=0.

  3. “Symptoms, Diagnosis, & Treatment”, Centers for Disease Control and Prevention, February 29, 2016, http://www.cdc.gov/zika/symptoms/index.html.

  4. Donald McNeil, Catherine Saint Louis, and Nicholas St. Fleur, “Short Answers to Hard
Questions About Zika Virus”, The New York Times, February 24, 2016, http://www.nytimes.com/interactive/2016/health/what-is-zika-virus.html?_r=0.

  5.“Symptoms, Diagnosis, & Treatment”, Centers for Disease Control and Prevention, February 29, 2016, http://www.cdc.gov/zika/symptoms/index.html.

  6.“Symptoms, Diagnosis, & Treatment”, Centers for Disease Control and Prevention, February 29, 2016, http://www.cdc.gov/zika/symptoms/index.html.

  7. “Zika virus”, World Health Organization, February 29, 2016, http://www.who.int/mediacentre/factsheets/zika/en/.

  8. “Symptoms, Diagnosis, & Treatment”, Centers for Disease Control and Prevention, February 29, 2016, http://www.cdc.gov/zika/symptoms/index.html.

  9. “About Zika Virus Disease”, Centers for Disease Control and Prevention, February 29, 2016, http://www.cdc.gov/zika/about/index.html.

  10. “WHO Director-General summarizes the outcome of the Emergency Committee regarding clusters of microcephaly and Guillain-Barré syndrome”, World Health Organization, February 1, 2016, http://www.who.int/mediacentre/news/statements/2016/emergency-committee-zika-microcephaly/en/.

  11. Sabrina Tavernise and Donald G. McNeil Jr., “Zika Virus a Global Health Emergency, W.H.O. Says”, The New York Times, February 1, 2016, http://www.nytimes.com/2016/02/02/health/zika-virus-world-health-organization.html.

  12. Jason Beaubien, “Zika in French Polynesia: It Struck Hard in 2013, Then Disappeared”, NPR, February 9, 2016, http://www.npr.org/sections/goatsandsoda/2016/02/09/466152313/zika-in-french-polynesia-it-struck-hard-in-2013-then-disappeared.

  13. Jenny Barchfield, “US-Brazil teams seek mothers, babies for Zika research”, The Huffington Post, February 23, 2016, https://www.washingtonpost.com/world/the_americas/us-brazil-teams-probe-link-between-zika-and-microcephaly/2016/02/23/c4f74e80-d9ea-11e5-8210-f0bd8de915f6_story.html.

  14. Lauren Weber, “World Health Organization Warns Against Travel, Trade Bans for Zika Virus”, The Huffington Post, February 1, 2016, http://www.huffingtonpost.com/entry/world-health-organization-zika-virus_us_56aa8608e4b00b033aae57eb

  15. Eli Rosenberg, “C.D.C. Urges Pregnant Women to Avoid Travel to Olympics Over Zika Fears”, The New York Times, February 27, 2016, http://www.nytimes.com/2016/02/28/us/cdc-urges-pregnant-women-to-avoid-travel-to-olympics-over-zika-fears.html.

  16. Julia Belluz, “Here’s what it will take to stop the Zika virus”, Vox, January 27, 2016, http://www.vox.com/2016/1/27/10838286/how-to-stop-zika-virus-outbreak.

  17. “Surveillance and Control of Aedes aegypti and Aedes albopictus in the United States”, The Center for Disease Control, http://www.cdc.gov/chikungunya/resources/vector-control.html

  18. Brad Plumer, “The Unsexy Truth About How To Kill Off Mosquitos And Stop the Zika Virus”, Vox, February 7, 2016, http://www.vox.com/2016/2/4/10908754/zika-virus-mosquito-eradication

  19. “Mosquito control: Can it stop Zika at source?”, The Center for Disease Control, February 17, 2016, http://www.who.int/emergencies/zika-virus/articles/mosquito-control/en/.

  20. Maryn McKenna, “Disorganized Disease Control Will Make U.S. Vulnerable To Zika”, National Geographic, February 29, 2016,  http://phenomena.nationalgeographic.com/2016/02/29/zika-mosquito-control/

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