Veronica 2

By Veronica Neumann, Milwaukee Area Technical College microbiology instructor, School of Liberal Arts & Sciences

Neumann joined the MATC faculty in 2002. In 2007, she created a course at MATC called “Plagues, People & Power” about the historical impact human activity has had on infectious disease outbreaks and how they have, in turn, shaped human society. The course also examines emerging and re-emerging infectious diseases. Prior to coming to MATC, she worked for 10 years at PowderJect Vaccines, based in in Madison, Wis., and Oxford, England, where she conducted vaccine research and development.

In May 2015, the Pan American Health Organization (PAHO) confirmed the first case of Zika virus infection in Brazil; before this, Zika virus was not present in the Americas. It is thought to have arrived in Brazil during the 2014 World Cup. The Zika virus can now be found in Mexico, Central and South America and several Caribbean island nations. To date there have been 107 travel-associated cases of Zika virus reported in US states and 39 cases of locally acquired Zika virus infection in US territories (including Puerto Rico).

What is unusual about the outbreak in Brazil is that it appears to be associated with cases of microcephaly. Microcephaly occurs when a baby is born with a small head and may be associated with developmental delays if the brain has not fully developed. The outbreak also coincides with an increase in the number of cases of Guillain-Barre Syndrome (GBS), which can lead to paralysis, which usually is temporary. Zika virus infections are typically associated with mild disease symptoms and only one in five infected people develop any symptoms at all. Typical symptoms include fever, rash, joint pains and conjunctivitis (red eyes).

 

veronica in plague doctors outfit

Neumann poses in her “Plague Doctor’s” outfit. These were worn in Europe in the 17th century during outbreaks of the plague. It was an early form of personal protective equipment. A doctor would wear a wax-covered robe, boots, gloves, a cowl, a hat, goggles and a mask which looked like a bird’s beak stuffed full of spices and oils which were meant to cover up the smell of dead, decaying tissue and was also thought to protect the wearer.

 

The Zika virus is named after the Zika forest in Uganda where it was first isolated in 1942. It is primarily transmitted through the bite of an infected female Aedes mosquito. The virus also can be transmitted to the fetus during pregnancy, but not through breastfeeding. It also can be transmitted through sexual contact and blood transfusions. Currently, there is no treatment or prevention available.

One species of mosquito that carries Zika virus, Aedes aegypti, can be found in South America, Central America, the American southeast and parts of the southwest (including Texas and part of California). Another species, Aedes albopictus, can be found in the American southeast and as far north as southern Illinois and New York. Neither of these species of mosquitoes is found in Wisconsin. Both species of mosquitoes can also transmit yellow fever, dengue and chikungunya viruses.

Other Viruses Entering the Americas – Chickungunya and Dengue

Although it hasn’t drawn the attention which Zika virus has, chikungunya (which means “that which bends up” because of the way people bend up with pain) is another virus that arrived in the Americas in 2013. Although up to 90 percent of people infected with chikungunya will develop symptoms, it is rarely fatal. Infection with the dengue virus is sometimes referred to as “breakbone fever” because of the severe pain in the joints it causes and has a higher fatality rate than Zika or chikungunya. The symptoms of Zika can resemble those of chikungunya and dengue.

It remains to be confirmed whether the Zika virus is responsible for the increase in cases of microcephaly and GBS in Central and South America given that these symptoms have never been associated with Zika virus before.  However, there was a hint that Zika virus could lead to GBS when Zika virus was first detected in French Polynesia in 2013. Given the increase in cases of microcephaly in Brazil, a look back at cases of microcephaly in French Polynesia seems to have also occurred with the arrival of the Zika virus. One theory as to why Zika virus may be causing microcephaly and GBS is that the disease is more severe in an immunologically naïve population which has never been exposed to the disease before. This is what happened when Europeans first arrived in the Caribbean and the Americas – approximately 95 percent of the native people were killed by measles, smallpox and influenza — diseases to which the Europeans had built up immunity. Another theory is that it may be due to co-infection with another disease-causing organism. Or could it be that the virus has mutated.

If you are planning on traveling to areas in which the Zika virus occurs, or if you are planning on traveling to Brazil to attend the 2016 Summer Olympic Games, the Centers for Disease Control and Prevention (CDC) recommends covering exposed skin, using insect repellents and sleeping in air conditioned rooms. Women who are pregnant or are trying to become pregnant should consider postponing travel to areas with an ongoing Zika virus outbreak.

 Effects of Climate Change on Spread of Viruses

The current outbreak foreshadows the impact climate change may have on insect-borne diseases which favor warmer climates. Scientists were surprised to find the mosquitoes which carry Zika, dengue, chikungunya and West Nile Virus could be found year-round around Washington, D.C. Previously it was thought that the mosquitoes could not survive year-round so far north. The range of Aedes mosquitoes has expanded greatly, not just horizontally, but vertically as well as higher altitude areas are increasingly invaded by mosquitoes. Global warming may not only increase the range of these disease-carrying mosquitoes, but warmer temperatures also speed up their life cycles.

In the 1960s and 1970s, it was thought that with an arsenal of antibiotics and vaccines at our disposal and improvements in hygiene, the war against infectious diseases was over. However, the current Zika virus outbreak is just the most recent example of how the battle between man and microbe will never be over. On the contrary, human activities such as increased urbanization, increased travel, deforestation, overpopulation, climate change and overuse of antibiotics will most likely accelerate the rate at which new outbreaks occur.

 

 

 

 

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