Genomics Blog

January 31, 2016 3:20 PM
Reading the News about Zika virus
Filed Under: Gerry Ward

The headline shouts: “Zika virus could be bigger global health threat than Ebola, say health experts”. The World Health Organization is meeting soon to determine whether the Zika virus should be declared an international emergency. While the recent news about Zika virus is disturbing, I am skeptical about some of the claims I am reading in the press. I have seen news which links the spread of Zika virus to climate change (1, 2) and even some claims that the “Zika outbreak Epicenter [is] In Same Area Genetically-Modified Mosquitoes Released In 2015”. Let’s examine the evidence and the risk factors so that we can decide for ourselves. Educators, consider using this example as a current model to discuss ‘reading the news’ with your students.

First, there is evidence that globalization and world travel represent a major factor in the rapid spread of diseases. It is believed that the Zika virus was brought to Brazil during the recent World Cup event. The Amazon basin was already a tropical rain forest with ample mosquito populations. Once the virus arrived in the blood of a sports fan or soccer player, all it took was for a mosquito to bite them and the rest is history. From European bunnies in Australia to zebra mussels in the Great Lakes, there is a long list of invasive species inadvertently transported by humans into a new habitat since the earliest days of sail. Now with widespread jet travel, the opportunity for disease vectors to invade new countries is a major problem monitored by the World Health Organization and national health agencies.

Notwithstanding the dramatic and troubling rise of babies born with microcephaly, Zika virus seems to cause only a mild fever, skin rash and conjunctivitis. These symptoms last for 2-7 days. On the other hand, the death toll for Ebola in West Africa exceeded 4,000, a mortality rate of almost 50%. There were huge concerns about keeping this virus isolated in West Africa and preventing it spreading around the world.

Aedes aegypti is the mosquito responsible for spreading Zika virus. This mosquito, found mainly in tropical regions, is also responsible for the transmission of dengue, chikungunya and yellow fever. Dengue is a leading cause of serious illness and death among children mostly in urban and semi-urban areas of some Asian and Latin American countries. Chikungunya symptoms include an abrupt onset of fever frequently accompanied by joint pain, muscle pain, headache, nausea, fatigue and rash. This virus can lead to chronic disease. Yellow fever is now controlled somewhat through vaccination. At one time it led to devastating outbreaks. The symptoms include fever, muscle pain, headache, shivers, loss of appetite, nausea and vomiting. In worst case scenarios, a toxic phase results in death after 10 – 14 days.

With regard to risk, we in Canada probably need to worry more about superbug infections causing death. Published statistics indicate that “there are more than 200,000 Canadians who acquire a healthcare-associated infection each year and that 8,000 of them die as a result.” And let’s not forget that the number of motor vehicle fatalities is about 2,000 per year. Between the years 2000 and 2008, the leading cause of death among young people under 30 years of age was motor vehicle accidents.

So, is the Zika virus a bigger threat than the Ebola virus? Perhaps it is, now that hard working scientists and health care workers have developed ways to contain and control Ebola. Are there other things to worry about? Statistics say yes. Let’s continue to ‘read the news’ with a skeptical eye.

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