A year ago today, Sierra Leone was declared Ebola free, but thousands of children orphaned by the virus are still suffering immense difficulties.

Mariatu, now 16, lives in Freetown with her two younger brothers, aged 12 and nine. She became the head of her household when their parents both died after contracting Ebola.

"My mother attended a funeral service of a neighbour who died [of Ebola], when she came back she said that she felt feverish. My father accompanied her to the hospital. She died and my father came back to the house. A week later he started to vomit," she told UK NGO Street Child.

"He advised us not to go near him and he stayed in my mother's room, we went to stay with a friend of theirs. My brother passed by the window of my father's room and saw him dead inside. A burial team came to take him away. Until this day we don't know where he and my mother are buried."

After Mariatu's father died, she and her brothers were forced to leave the family home because the landlord was afraid of them passing on the disease, but they have since moved back.

"I do petty trading to try and support both my brothers through school but it is very hard to raise the money for fees, books and uniforms. I also do all the cooking in the house. We receive support from no-one, not even the community. We have aunts and uncles but they don't care and they don't help us," she said.

"I want to be somebody, I want to finish school and become a soldier. I also really want my brothers to finish education and get well paid jobs. I get on very well with both my brothers, we look after each other".

Mariatu is just one of more than 12,000 children orphaned by Ebola, which killed more than 11,000 people in West Africa between 2014 and 2015.

She and her brothers are now being helped by Street Child, but the NGO today warned that many others are still suffering alone.

"Whilst there has been some welcome recovery for many Ebola impacted families and thousands of orphans have been helped by Street Child and others, some of the most at-risk orphans are still in acute conditions," said Street Child CEO Tom Dannatt.

"We should celebrate that the Ebola epidemic is over but we must recognise that for the most complex and vulnerable cases, the crisis certainly isn't. In fact in many ways it is at its most dangerous – because international support and interest has largely moved on."

In addition to orphaned children looking after siblings alone, often having to drop out of school to do so, another major concern is teenage mothers who fell pregnant after exchanging sex for food during and in the aftermath of the Ebola crisis. The UN Development Programme estimates that teenage pregnancy rose by up to 65 per cent in some communities, and a total of 18,119 teenage girls became pregnant during the outbreak.

Sierra Leone is also now suffering a food crisis. The price of a bag of rice – a staple food in the country – has more than doubled since 2014, while wages have stagnated.

A report published last week by UN food agencies and the Sierra Leone government warned that half the population – more than 3.5 million people –  are facing food shortages.

"The double kick from Ebola and then the collapse of its main commodity, iron ore, means that the post-Ebola celebrations ended long ago," Dannatt said.

"A collapsed economy that's no longer propped up by the aid given during and immediately after Ebola means that life is very hard for everyone. If economic recovery does not happen soon, more parents will struggle to send their children to school, more families will go hungry and more girls will be forced to sell their bodies to get by."

Street Child is now running a programme to help teenage mothers return to education, and has provided 8,000 households impacted by Ebola with support including food packages, school fees and business grants.

More than 5,500 orphaned children have been helped to return to school, and the NGO is aiming to provide another 20,000 children with the same support.

"At least three-quarters of Ebola impacted families have had significant support from Street Child and others since the epidemic but what we have been able to do has not been enough for the toughest and most complex cases – child-headed households, grand-parent headed households, households where the numbers of children now run into double-figures. We recently identified 1,400 seriously at-risk Ebola orphans who need significant extra support but to do that we urgently need to raise more funds," Dannatt said.

"Sierra Leone has faced so much tragedy – with the civil war followed by Ebola. It is heartbreaking to see the recovery stunted by an economic crisis. The children of Sierra Leone deserve a better future. It is vital that the international community does not turn away yet."

To find out more about Street Child's work in Sierra Leone, visit www.street-child.co.uk.