He spent his life studying mosquitoes, and then it became personal.

On Aug. 30, 2008, Brian Foy had just gotten home from a research trip in Senegal, a country in West Africa, when he began to feel sick.

Foy is a biologist specializing in insect-transmitted diseases and an associate professor at Colorado State University. He had been in rural Senegal with a graduate student researching malaria and noticed that when he got back, he felt not quite right.

Foy (right) with equipment for aspirating mosquitoes in Senegal. Image via Brian Foy, used with permission.

"It started out by me just feeling really exhausted," Foy says. "It was hard to really know if this was just jet lag or not ... and then that exhaustion just progressed into a vague headache. I really needed to cover my eyes and kind of shy away from the light."

He developed a rash across his torso and joint pain. He later got prostatitis as well.

Foy immediately called the graduate student who had been working with him in Senegal. He had many of the same symptoms.

Both suspected that their symptoms were classic signs of an arbovirus — a type of virus, such as dengue, that is often caught after being bitten by mosquitoes.

The Aedes aegypti mosquito is the species that transmits the Zika, chikungunya, dengue, and yellow fever arboviruses. Photo by Luis Robayo/AFP/Getty Images.

After all, they had been working in remote villages for about a month and a half, collecting mosquitoes for a malaria study. And both of the researchers had been bitten numerous times by numerous different kinds of mosquitoes.

"We’d work into the late evening with shorts and sandals," Foy remembers. So, it made sense that they caught the virus while they were there.

But then, Foy’s wife got sick too.

She hadn’t been to Senegal. She hadn’t even left northern Colorado for a while, but she had many of the same symptoms: sensitivity to light, a rash, swollen joints, muscle pain, and bloodshot eyes. In fact, he says, her symptoms almost seemed more severe. "To this day, she has trouble opening and closing cans, jars, and lids, things like that," he says.  

All three sent their blood to be tested at the Centers for Disease Control and Prevention.

A lab technician analyses blood samples. Photo by Vanderlei Almeida/AFP/Getty Images

But the CDC couldn’t determine what they had right away. It wasn’t until a whole year later — after all three had long recovered — that they received a diagnosis.

They had Zika.

Zika is indeed a mosquito-borne arbovirus, as Foy had suspected he had, but it just wasn’t one that he (or the CDC) had thought to test for in 2008.

"Even though I had heard of the Zika virus, I didn’t really know much about it," Foy says. "[And] the first time we tested our blood, the CDC wasn’t really thinking about Zika either."

It was only after Foy’s graduate student went back to Senegal that he got the recommendation to re-test their blood for Zika, which was beginning to become more widely known due to rising infection numbers. "So, it took a long time — unfortunately that’s science sometimes," he adds.

This is a digitally-colorized transmission electron microscopic (TEM) image of Zika virus, which is colored red. Image via Cynthia Goldsmith/Centers for Disease Control and Prevention.

Zika has been around since 1947, but it has become a lot more widely known — and covered in the news — since it reached pandemic proportions in South America in 2015 and 2016. And in September 2016, urged by numerous organizations including the March of Dimes, Congress approved $1.1 billion to help fight the spread and effects of the Zika virus through vaccine research and health care.

The virus doesn’t always cause symptoms, but when it does, the more common symptoms are the ones that Foy, his wife, and his graduate student experienced.

However, it can also cause complications, such as Guillain-Barré syndrome, and a Zika infection during pregnancy can cause birth defects, notably microcephaly, where a baby's head is smaller than expected and typically includes brain damage. In severe cases, it can cause a range of other health problems — including seizures, hearing loss, or vision problems — or be life threatening.

The fact that Foy’s wife was diagnosed with Zika too, without traveling, and that their kids were not sick meant something important: The virus was most probably transmitted through sex.

Until that point, it had been assumed that Zika could only be spread by the bite of the Aedes aegypti mosquito.

Aedes aegypti mosquitos in a lab. Photo by Mario Tama/Getty Images.

Foy wrote about his experience with sexual transmission of Zika in a scientific journal in 2011, but his case was considered largely anecdotal until this past year, when the CDC officially confirmed that Zika is sexually transmittable.

"In places like Brazil, where people are being bitten by mosquitoes and having sex, it’s hard to distinguish what the route of transmission was," he says. It is only when travelers come home that it becomes clear that it has been transmitted sexually.

And the fact that Zika can be sexually transmitted is incredibly important information, especially to families that are thinking of having a baby. The news even prompted some affected countries, such as El Salvador, to advise women not to get pregnant until 2018 (sparking controversy in some countries where birth control and abortions are hard to obtain or banned).

Since this discovery, the CDC has issued a number of guidelines to help protect travelers from Zika.

The CDC says that tourists — especially pregnant women — should protect themselves while they are in these countries, but they should also continue to protect themselves, either by abstaining from sex or using condoms, when they get home so they don’t pass along the virus to their partners. Women are advised to use condoms for at least eight weeks after travel, men for at least six months.

Women should be especially careful if they are pregnant. The CDC says it might be worth postponing any nonessential travel to countries with the virus to avoid getting a mosquito bite in the first place.

Aedes aegypti mosquitos in containers at a lab in Sao Paulo, Brazil. Photo by Nelson Almeida/AFP/Getty Images.

Foy’s case shows just how important further research on Zika is.

And this is why, today, he is continuing his work on Zika, with the goal to better understand sexual transmission of the virus. In particular, he is hoping to understand why women contract it more often than men — and if, as in the case of his wife, their symptoms are more severe.

With further research, the goal for all scientists is to not only better understand the virus, but also help all of us better learn how to protect ourselves and those we love.