It was the missing schoolgirls who first made an obscure Nigerian Islamist group into a household name.

More than 200 students were kidnapped by Boko Haram insurgents in northern Borno state in April 2014. The #BringBackOurGirls campaign was born and soon mushroomed into an international cause. Celebrities and political figures like first lady Michelle Obama tweeted appeals for the release of the young women. That's when the world got serious about defeating the militants. There was suddenly more money, more drones and more interest in a remote stretch of West Africa.

Two years later, that interest has faded. There are other, more advanced Islamist groups to think about. There is a U.S. presidential campaign in which Africa is not exactly playing a defining role.

But while the world has looked away, the crisis in northeastern Nigeria has morphed into something much more deadly. Insurgents are no longer the biggest threat. Now, it’s hunger.

More than 3 million people are affected by what is becoming one of the world's largest humanitarian disasters. UNICEF has warned that as many as 75,000 children could die in Borno and two adjacent states over the next year unless more assistance arrives.

But it has been incredibly difficult for groups to raise funds for food or health care for these victims, who have fled Boko Haram or are trapped in towns still threatened by the group. UNICEF, for example, has raised only $28 million of the $115 million it has asked for – a weak showing compared to its other country-specific appeals. At the U.N. General Assembly in September, the crisis was barely mentioned. Even Nigeria’s own media has focused on other matters, like a nationwide economic crisis.

It wasn't the kind of sudden natural disaster that spurred immediate interest. And the story line of the Nigerian schoolgirls – nearly all of them still missing – has faded along with the hope of finding them.

“In some ways Nigeria is seen as an old story,” said Simon Taylor, deputy head of office for the U.N. Office for the Coordination of Humanitarian Affairs in Nigeria.

That lack of funding and interest is now obvious all over northeastern Nigeria. For a while, it was extremely dangerous for humanitarian groups to try to reach the victims suffering from hunger and disease. But even in places that have become safe enough to work, there is not enough food or nutritional supplements for malnourished children. Humanitarian teams are still understaffed.

Boko Haram fighters are still launching attacks around Borno state, preventing aid workers from accessing as many as 2 million people, seven times the population of besieged eastern Aleppo.

In a recent trip to the region, photographer Jane Hahn and I visited three cities in the state where aid workers had just arrived in very small numbers. They had set up makeshift clinics and had begun distributing tents, but a huge portion of the victims I met had received little or no assistance. In some cases, aid representatives told me, their limited operations were a function of security concerns and the fact they hadn't been on the ground very long. Others said they were hampered by a lack of funding and a lack of worldwide interest in the crisis.

Some of the aid workers had previously served during the Ebola outbreak in West Africa in 2014, which prompted donations of billions of dollars in foreign assistance and the deployment of more than 2,000 U.S. military service members. When I covered that outbreak, I was struck by the scale of the response once the world mobilized. By comparison, Nigeria feels like a forgotten crisis.

“Children’s lives are literally hanging by a thread,” said Afshan Khan, UNICEF’s director of emergency programs. “We are reaching new areas to provide critical humanitarian assistance but we need greater international support to further scale up and reach all children in dire need."

Sarah Ndikumana, Nigeria country director at the International Rescue Committee, has called it "one of the biggest and most underfunded crises in the world.”

In each of the cities I visited, extended families crept out from the bombed-out buildings left behind by Boko Haram. Other people slept in stick huts. Still others spent the nights outside, without mosquito nets, in spite of the rampant malaria.

Adama Adam and her family escaped one of the villages controlled by militants in Borno. They made it to the city of Banki, where a small number of aid workers had just arrived.

The family had almost nothing to eat. Adam was so poorly nourished she was unable to breastfeed. Her 6-month-old baby, Fana Ali, had grown weak after contracting malaria. Shortly after I met the family, the infant died at a clinic run by Doctors Without Borders, one of hundreds of children that most likely lost their lives in September from hunger or curable disease, according to experts.

Aid workers have an idea why this crisis has drawn such limited attention and funding. There are other places of more geopolitical importance. There are other major crises that require a response. Some people see Nigeria, the second-wealthiest country in Africa, as capable of handling its own humanitarian assistance.

But the delays and lack of attention have caused many deaths, experts say, and they wonder how much the situation will have to deteriorate before the world notices.