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Where Zika Came From

ZIKA FOREST, Uganda ― In a tangle of trees by the shores of East Africa’s mighty Lake Victoria, the soaring metal tower poking out of the forest canopy looks like a giant Olympic diving platform.

“It is where the scientists do the testing,” said Gerald Mukisa, forest guardian at the research site of the nearby Uganda Virus Research Institute, which carries out critical work to identify, trace and understand emerging diseases.

“Monkeys are placed at different heights and blood samples are taken,” Mukisa said, pointing to boards jutting out of the frame. The dozens of mosquito species in the forest here live and bite at different heights, so the boards help monitor their preferences.

Scientists used the 118-foot tower way back in 1947 to first identify a virus that, in 2015, became a global health emergency due to its ability to cause brain-related birth defects. They named the virus Zika, after this 30-acre forest in southern Uganda.

Zika never caused the panic in Uganda that it did when it swept across the Western Hemisphere several years ago. Indeed, it was thought of as relatively harmless at first.  But experts believe Zika has mutated since its discovery.

The virus did not originate in Uganda, but was only identified here. The virus that caused concern in the Americas is believed to have migrated from a strain from Southeast Asia, moving via an infected traveler, or on boats with mosquitoes carrying the virus.

Now experts from the UVRI are hunting for the next mosquito-borne virus they fear could sweep around the globe.

“The world is a global village. Any disease that is here today can be anywhere else within 24 hours,” said virologist Dr. Julius Lutwama. He heads the team that searches for emerging infections at the Ugandan government-backed UVRI center. They focus on arbovirology, the study of insect-borne viruses.

“I can leave here having been bitten by a mosquito but not be sick, but a few days later I could have taken a virus to an area far away,” he added.

The scientists who first described Zika here found it during a study into another virus, the acute viral hemorrhagic disease yellow fever. It is just one in a long line of over 60 new viruses identified by the center since its founding in the 1930s.

In Uganda, people had developed immunity to the virus, but elsewhere it would be a major problem.

As the virus traveled through communities without immunity, it rapidly multiplied and its nature evolved. Scientists believe that was due to a mutation around 2013, roughly the time the medical community began to blame the virus for horrific birth defects.

Three years ago, when the virus hit Latin America, the Caribbean and the southern United States, it put the whole world on edge because of its links to microcephaly (causing babies to be born with unusually small heads, physical disabilities and cognitive impairments) and Guillain-Barré syndrome (an autoimmune disorder that can cause paralysis).

Brazil – the country hardest hit – recorded its first cases in 2015 of babies born with microcephaly. More than 2,000 cases of Zika-related birth defects were reported in Brazil over the next two years.

The old research suddenly became vital.

Panic caused by the Zika threat has eased a little as people cannot become infected twice. Meanwhile, researchers are working hard to develop a vaccine.

Yet it was the research done over half a century ago into what was then an obscure virus ― at this virology center in the sleepy lakeside town of Entebbe ― that gave scientists a crucial head start. 

“The science and research that has been done at UVRI has helped us understand the viruses that are circulating in Uganda and the African region, but also has global importance,” said Lisa Nelson, the Uganda country director for the U.S. Centers for Disease Control and Prevention (CDC).

The CDC is a key backer of the Ugandan center, providing some $23 million of funding since 2013, supporting research into HIV, hemorrhagic fevers and other infections.

Rising global traffic means the wider and faster spread of viruses. That includes both the easy movement of people and of mosquitoes, with their eggs accidently carried across the globe in shipping containers.

As scientists warn of changing global temperatures, mosquito species are expected to move into new areas.

Lutwama, who is UVRI’s deputy director, heads surveillance teams that spend half their time in remote lands researching insect-borne diseases. They collect mosquitoes, then return to analyze samples and to map and monitor the spread of the viruses.

“Which is the most likely next disease outbreak? For me, it is going to be an arbovirus,” said Lutwama, who has been hunting mosquito-borne viruses for over three decades.

“Invasive species of mosquito are moving into Europe and into the Americas, and as they do that more of the viruses will spread,” he said.

As viruses meet with new communities without immunity ― especially in dense, urban populations ― they multiply unhindered, changing rapidly.

“Now when there is an outbreak, it spreads easily,” he said. “If it comes to a city, the mosquito moves within small areas but among many people.”

Uganda hosts 224 mosquito species alone, Lutwama noted, with some 77 different arboviruses carried by insects, including West Nile virus and Dengue fever.

Back in the Zika forest ― which means “overgrown” in the local Luganda language ― twisting paths vanish in the bush. But the forest is shrinking. Once, trees grew all along the lake’s edge, but construction of new homes has encroached onto ancient forest lands. 

Globally, Lutwama said, there are staggering numbers of organisms still unknown to science.

“We know that there are up to 15 million species of living things that have not been identified yet, and the majority of these are microorganisms,” Lutwama said. “Many of these are living in areas we have not encroached upon yet, but we are starting to enter their territories. The likelihood that these become a problem to us is increasing every day.”

Indeed, the next big disease might already be waiting to be identified.

“Most viruses in Africa go undiagnosed,” he said.

So the race is on to find it and study it before the next outbreak.

In the depths of the trees, there is a thin, high whine of mosquitoes, and then up in the treetops, the laughing chatter of monkeys enjoying the breeze.

“We have to be prepared for all eventualities,” Lutwama said, glancing up at the trees. “We have to look for them, before they get to us.”

This article is part of HuffPost’s Project Zero campaign, a yearlong series on neglected tropical diseases and efforts to fight them. The series is supported, in part, by funding from the Bill & Melinda Gates Foundation. All content is editorially independent, with no influence or input from the foundation.

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