Kinshasa, Democratic Republic of the Congo – The latest Ebola outbreak in eastern Democratic Republic of the Congo is unfolding against the backdrop of one of the world’s most complex humanitarian crises.

Conflict involving armed groups and intercommunal violence has displaced large numbers of people, while insecurity has made it difficult for health workers to reach many communities, particularly camps for internally displaced people (IDPs).

Officials say the lack of access is hampering case detection, contact tracing and treatment, while communities that have long been deprived of basic services remain sceptical of an Ebola-focused response.

Al Jazeera speaks to Jean Kaseya, Director General of the Africa Centres for Disease Control and Prevention (CDC) about the humanitarian challenges hampering the response, the funding gap and what it will take to bring the outbreak under control.

Al Jazeera: What are the main priorities?

Jean Kaseya: We are in a region where around a million people are living in camps for internally displaced people. These people cannot access even the most basic services and reaching those camps is a major challenge.

Some of the people coming from the camps to seek treatment are telling us there are many more cases there, but we cannot access them. We are talking about close to two million people.

Al Jazeera: You cannot go there because of security reasons?

Jean Kaseya: We cannot go there because of security concerns, which are linked not only to rebel groups but also to conflict between the Hema and Lendu communities. The people living in these camps have not received humanitarian support for a very long time.

When health workers go there to raise awareness about Ebola, people ask: “Why are you coming now? Is it because of your disease?”

They tell us they do not have enough water, food or medicines for other diseases.

They ask our volunteers: “Why are you only coming here because of Ebola?” It is a difficult question to answer.

Al Jazeera: You recently met Democratic Republic of the Congo President Felix Tshisekedi and African Union Chairperson and Burundian President Evariste Ndayishimiye. What came out of those meetings?

Jean Kaseya: We met the two heads of state together with the Ebola task force and the humanitarian affairs ministry. We concluded that we need around $1.4bn over the next six months to deal with this humanitarian crisis if we are serious about stopping the outbreak.

At our meeting on June 16, we received pledges of $910m, but that was for the health response only. The Democratic Republic of the Congo has provided $50m out of the $200m requested for the health response plan.

Now, because of the scale of the humanitarian crisis, those needs are being reviewed. We are talking about $1.4bn on top of the $200m required for the health response.

Al Jazeera: $1.4bn is a great deal of money at a time of donor fatigue. Why is that level of funding necessary?

Jean Kaseya: I want to make this very clear. Without addressing the humanitarian crisis, we will not stop the outbreak. That is what makes this outbreak more complex and more difficult than others we have seen in the past.

You cannot contain an Ebola outbreak without addressing these humanitarian challenges.

Al Jazeera: How will you secure that funding?

Jean Kaseya: It is a matter of choice. No one is protected. If our partners are serious, they will provide the funding needed to stop this outbreak where it is now.

If they do not act and tomorrow the outbreak spirals out of control, they could also be affected. Then they will realise that responding to the outbreak in their own countries will cost five to 10 times more than what we are requesting today to stop it at its source.

Al Jazeera: Another major challenge is contact tracing. Why?

Jean Kaseya: One of our key indicators is that we are seeing cases coming from camps for displaced people. There are three or four major camps and we are struggling to carry out contact tracing there.

Most of those affected are between the ages of 15 and 45. They are young and economically active. Anyone exposed to the virus needs to be isolated and monitored for 21 days, which means they cannot go to work or run their businesses.

We need to compensate them, provide them with food and give them somewhere to stay. Some of them do not even have a home.

Al Jazeera: What is your biggest concern?

Jean Kaseya: The case fatality rate is now approaching 25 percent and we do not know where the situation is heading.

We know that Ebola case fatality rates are usually around 20 percent, but the symptoms we are seeing are changing. Some are different from what we have seen in previous outbreaks. There are still many unknowns.

We must provide the support needed to stop the virus where it is. Closing borders is not the solution.

This interview has been edited for length and clarity.