Are we able to learn the right lessons when disaster strikes? Five years ago, a devastating outbreak of Ebola in west Africa claimed more than 11,000 lives, and sparked an international panic as it reached the US and Europe. The experience led to the vaccine and experimental treatments now being used in the Democratic Republic of Congo. But this outbreak has become the second most deadly despite efforts to combat it over the last year. More than 1,600 people in the north-east of the country have died. Now, with the virus flaring up again in places where it had been contained, reaching the major city of Goma on the border with Rwanda, and spreading over 500km, with cases identified in Uganda, the World Health Organization has declared it an emergency of international concern.

This is a very different challenge from 2014’s. It is not only a public health but a humanitarian crisis, taking place in a conflict zone, with widespread malnutrition, a struggling health system, and deep suspicion hampering efforts to control the disease: this year has seen 174 attacks on health workers fighting the outbreak. The fear and distrust of outsiders has been compounded by Ebola’s high fatality rates. Vaccines cannot protect those who have already contracted the disease, and though people are more likely to survive with proper treatment, many delay because they do not trust those offering help: by the time they are finally seen, it is far harder to help them. Those around them may wrongly conclude that vaccines or health workers are the problem and not the cure. They see more international groups at work, and more deaths.

The need for community understanding and engagement – made clear by the 2014 outbreak – is more critical than ever. That means dialogue, not instruction: “We need to listen with the ferocity with which we want to be heard,” says an emergency medical manager for Médecins Sans Frontières. With their most basic health needs unmet, a rapidly spreading measles outbreak, and ongoing problems with cholera, people may not see Ebola as a priority, particularly if their other concerns are not even acknowledged. Some experts believe that community leaders and local staff must take the lead in the response, and that supporting home care as an interim, if far from ideal, measure may be necessary.

But if solutions must be implemented on the ground, they require proper support. WHO hopes that the designation of an emergency will push governments to respond. Its director general, Dr Tedros Adhanom Ghebreyesus, has warned that hundreds of millions of dollars are needed to fight this outbreak; only half of the money pledged has been delivered. Jim Yong Kim, when president of the World Bank, said the west African outbreak could have been snuffed out in months with sufficient funding. But help only trickled in when western countries began to worry about the potential danger to their own citizens.

The risk is that neighbours may close their borders – crippling the economy, increasing hostility and suspicion, and driving transmission chains further underground as people take unmonitored routes or mask their symptoms at crossings. In 2014, WHO’s advice against travel restrictions was ignored by governments and airlines.

As the WHO chief said, the decision to call this an emergency should not be used to stigmatise or penalise the very people who most need help. The humanitarian case for backing the fight against Ebola is simple and undeniable. Mothers, fathers, siblings and children are dying, in communities that have already suffered so much. If that is not enough to compel greater action, perhaps self-interest will help. One lesson from the 2014 outbreak was that real international commitment can bring the disease under control. Another was that without such efforts it poses a far broader risk.