Cracking Zika’s DNA

Scientists are using biotech tools to crack open Zika's genetic code.

Officials have begun spraying insecticide in a 10-square-mile area north of downtown Miami this week to eradicate Zika-carrying mosquitoes, but researchers still must answer many of the most fundamental questions relating to the virus — and support for their efforts is coming from some unlikely places. 

Zika, which can cause birth defects in pregnant women, took six decades to cross from Africa to Brazil. But, it apparently took just 60 weeks for the germ to reach South Florida, where 15 locally acquired cases have been reported. 

Zika’s American journey began in March 2015, when Brazilian authorities put in a call to World Health Organization officials. 

Doctors in the country’s northeastern states had reported thousands of cases of an unidentified illness with a characteristic skin rash, some with fever and some without.

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The more we know, the worse things look.

National labs had analyzed blood samples from a number of patients, and only a tiny portion came back positive for dengue, a mosquito-borne virus that elicits similar symptoms.

Subsequent tests for other suspects — chikungunya, enterovirus, measles, rubella and parvovirus B19 — were all negative.

It was enough to make even a jaded epidemiologist raise an eyebrow.

Was there a new microscopic predator hunting in South America’s most populated country? The answer came quickly.

In late April, a state lab confirmed 16 cases of Zika infection, the first known local acquisition and transmission of the virus in the Americas.

Previously seen only in Africa and Asia, the flavivirus first discovered in a Ugandan forest in 1947 had finally reached the New World.

The effort to understand and fight Zika is happening in earnest both in the Americas where the latest outbreak is centered and in other parts of the world, including at GE Healthcare labs in Cardiff, Wales, more than 5,000 miles from the shores of Brazil.

The 30-acre site, set along the River Taff and sandwiched between two golf clubs, supplies Zika sleuths with chemicals that help them isolate and analyze the virus’ RNA blueprints.

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Zika catches a ride on the Aedes aegypti mosquito

To date, the virus has spread to 67 countries and territories by catching a lift on the Aedes aegypti mosquito, the same species that transmits dengue fever and other tropical diseases, and through sex.

It may have infected more than 1 million people in the region, though many may not have reported it because associated symptoms of fever, rash and pink eye are mild or nonexistent.

But other worrying symptoms — that the virus might be linked to a birth defect of incomplete brain development called microcephaly and adult-onset Guillain–Barré syndrome, where the immune system attacks the nervous system — led the WHO to declare a public health emergency of international concern.

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At this stage, based on the evidence available, WHO does not see an overall decline in the outbreak

“The more we know, the worse things look,” said Dr. Margaret Chan, WHO’s director-general.

“A pattern has emerged in which initial detection of virus circulation is followed, within about three weeks, by an unusual increase in cases of Guillain-Barré syndrome. Detection of microcephaly and other fetal malformations comes later, as pregnancies of infected women come to term.”

As of June 1, 60 countries and territories were still reporting ongoing Zika transmission.

Eleven countries or territories worldwide had reported cases of microcephaly or other central nervous system malformations, and 13 had reported increased rates of Guillain–Barré syndrome.

“At this stage, based on the evidence available, WHO does not see an overall decline in the outbreak,” the organization said in its most recent situation report.

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Fighting the infection

Nobody has yet developed a vaccine to prevent infection or a cure once the virus has been transmitted to a person.

To date, efforts to stop it have focused on educational campaigns for people in areas where the mosquito carrier lives, instructing them to wear insect repellent, put up window screens and remove standing water from around their homes.

Other efforts involve mosquito-limiting efforts such as spraying and experimental population control.

The most high-tech methods focus on targeting Zika’s genetic materials.

Scientists in the field collecting mosquito samples use a special fiber paper manufactured by GE in Cardiff.

This coffee-filter-like material, called Whatman FTA paper (see below), has magical properties if you’re a microbiologist. It is chemically treated to break down cells and destroy proteins that would otherwise damage the DNA that sticks to its fibers.

The result: Squishing a mosquito in the paper lets researchers transport samples without refrigeration over long distances, a requirement if you happen to be in the middle of the Amazon.

Identifying patients who have been infected with the virus is a difficult process only recently made possible by modern technology.

One method, called the polymerase chain reaction PCR), rapidly produces multiple copies of the virus’s RNA so that medical workers can identify it in a patient’s blood.

The Cardiff facility produces PCR beads that Zika researchers with the U.S. Army are using to study infection.

Much still needs to be done to contain and then eradicate the Zika epidemic.

Rapid diagnostic tools are being developed on a massive scale, as are potential vaccines. All will take time.

But for many at the GE Healthcare Cardiff facility, contributing their labor to help end the disease brings a sense of pride to often seemingly mundane work.

“For the people making and boxing the papers, PCR beads and other lab consumables, these products might not normally look like much more than water in a tube or coffee filters,” says Michael Igoe, the site’s product operations manager.

“But hidden in the tube and the paper are complex products that are providing a huge benefit to communities. We’re making products that make a real difference in the world. They have meaning.”goldbrown2

This article first appeared on GE Reports and was republished with permission. 


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Mike Keller is a writer for GE Reports.

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