There was a moment in Swaziland that will stick with me forever.

I had just met a 12-year-old girl named Nokubheka — a cheerful little girl who loved dancing, flowers and the color pink. I was standing in an alley outside her house, filming, as a nurse showed up with news that would change her life forever.

Nokubheka was told she had multi-drug-resistant tuberculosis. It was the same disease that had killed her mother two weeks earlier, leaving her and her brother orphans. The nurse said that to prevent infecting her brother, Nokubheka would now have to go to the country’s TB hospital for at least six months—just the beginning of a multi-year course of treatment that would involve more than 14,000 pills and more than 200 injections.

In that moment, a tear fell down the little girl’s cheek, and she began to cry.

I was in Swaziland filming TB Silent Killer, a documentary on the rise of drug-resistant tuberculosis for FRONTLINE. As a human being, I wanted to comfort Nokubheka;  she’d just lost her mother, and now this, too?  Her whole life had just been ripped apart.

But as a filmmaker, I knew I had to capture this moment, not change it. I also knew, suddenly, that she had this potentially deadly form of tuberculosis. And to tell her story, from there on out, I would have take extra precautions: wear a special TB mask, sanitize my hands, and limit my time with her to 20 minute intervals.

I also knew there was still no guarantee that I wouldn’t be infected by TB — an airborne disease, spread simply by a cough or a sneeze.

As a filmmaker who often operates in conflict zones, I’m used to working with a certain level of risk. I’ve filmed undercover in Zimbabwe, in Tibet, in Gaza. I’ve been on fishing boats that have been shot at by the Israeli Navy.

But this was a different kind of risk, and a different kind of situation.

Nokubheka had opened up her life to me, my co-producer Rebecca Stewart, and our translator Sandile Mashaba, a Swaziland native. Health protocol is one thing, and of course none of us wanted to contract TB.  Interviewing people about their innermost feelings and fears is a delicate process that takes time.  So when people would start to open up, often breaking down and crying in front of me, and the time code on the camera was inching towards 20 minutes, how could I say, “Oops! Can you hold that thought? I’m out of here – let’s pick this up next time.”

Same thing with the masks. As a documentary filmmaker, and especially on this film, the whole thing hinges on building relationships with the people who are sharing their lives with you. You need your whole face to communicate. You want your subjects to feel comfortable. Having a camera pointed at them is already a big deal. Suddenly, we were supposed to wear these masks that makes you look like some sort of alien being – a demented duck!

So we had to make decisions. We had to take calculated risks.

There comes a point, where with someone like Nokubekha — someone so young, someone so fragile, someone so vulnerable — opening themselves to you, you have to honor that by taking a risk to make sure this story gets told.

And that’s an urge I felt very strongly. Most people think TB is not a problem any more. But there are more than 8 million new infections every year. It’s actually the world’s second-leading cause of death from an infectious disease. And when it comes to treatment for drug-resistant strains, the regimens are old, long, isolating, and expensive, with serious side effects.

TB today is an under-told story that was brought to my attention by Médecins Sans Frontières (Doctors Without Borders).  The relief group has been helping the government of Swaziland deal with its TB epidemic, along with one of the highest rates of HIV infection in the world.

The group helped us immensely inside the country, and introduced us to so many people like Nokubheka, who were incredibly brave, and whose stories were heart-breaking and inspiring.

Since I’ve been back from Swaziland, every time I cough, people give me a worried glance. And I’m often asked: “Did you catch TB?” The answer is, like nearly 1 in 3 people in the world, I could be carrying the TB bacteria. And I could have gotten it in Swaziland. But because I’m healthy, with a strong immune system, chances are I will never get sick from TB or infect my wife, my two kids, or anyone else.

Sometimes, though, I think about the people we spoke to in Swaziland who were seemingly healthy and still got sick, or even died from these new, deadly, multi-drug resistant forms of TB.  And I know that the risk is not over. It’s a bit of a waiting game. If I’m working in a war zone or something, and I end up being given infected blood or my immune system breaks down, I could very well become very sick from TB.

At the end of the day, though, we made a choice to be in Swaziland. We had a choice to make this film, to take this risk. Nokubheka had no choice in facing TB. She couldn’t have told her mother, “Oh, I’m not sleeping in the same room as you, mom.” Where else would she sleep at night?

And how could we sleep at night if, having met her, we didn’t see it through, and do everything we could to tell her story?

Jezza Neumann’s latest film, TB Silent Killer, airs on FRONTLINE Tuesday, March 25 at 10 p.m. (check local listings). Neumann is a BAFTA-award winning filmmaker who has made documentaries about child poverty (FRONTLINE’s Poor Kids), child trafficking (China’s Stolen Children) and life in occupied Tibet (Undercover in Tibet).