He has been in a coma for 24 hours.

Abuk Yum is seven years old and suffering from the disease that is the scourge of Africa: malaria. Along with hunger, malaria makes for a deadly combination among the poorest people across the African continent, including here in South Sudan.

Little Abuk had been brought to this ramshackle clinic in Nyamiel by his mother. It is three hours by truck along the clay tracks that pass for roads here to the nearest "big" town of Aweil.

For Abuk and his mother, however, walking was the only option when coming from their even more isolated rural village to this most basic of health facilities in Nyamiel.

Often wading through flash floods brought on by downpours at the end of the rainy season, it had taken mother and son three hours to get to the clinic with Abuk weakening with every step.

Sprawled now on a flimsy metal framed bed and connected to a cluster of tubes from a series of intravenous drips, only the occasional deep and disquieting moan from the youngster serves as a sign that there is still life in his exhausted body.

The little boy's prognosis is not good, health workers at the clinic tell me. With Abuk suffering from what appears to be potentially fatal cerebral malaria, plans have already been made to take him by road to Aweil, three hours' drive away, to a hospital there run by international medical aid agencies.

Outside the clinic in Nyamiel, a mud-spattered and battered jeep with the word "ambulance" barely visible on its side lies ready to ferry the youngster away.

Just a few feet from the bed where Abuk lies, another child, 21-month-old Lual Boi, sits oblivious to the little boy's struggle for survival.

"She had pneumonia and it was very dangerous for a while but now she is getting better," the child's mother, Nyibol Mejok, tells me with a smile.

On arriving here at the clinic, Abuk and Lual Boi were both also badly malnourished. It is this hunger that so often contributes to and compounds the myriad diseases that strike the young here.

As part of the frontline fight to combat this hunger and disease in these remotest South Sudanese rural communities, humanitarian agency Concern Worldwide runs a series of programmes, primarily located in the Aweil West and Aweil North areas in the Northern Bahr el Ghazal region of the country.

Among the poorest states of South Sudan, here the local government has little means to provide basic services and Concern's work focuses on improving nutrition and health as well as income generation and emergency response schemes.

"This is the hunger gap season so disease impacts in conjunction with malnutrition, and right now we have the rainy season incidence of malaria," one local Concern worker tells me as we sit outside the clinic in Nyamiel, as preparations for the transfer of Abuk gets under way.

Here, as elsewhere in the country, Concern runs a project known by the rather clumsy acronym CMAM - the Community Management of Acute Malnutrition programme - and also supports the South Sudan ministry of health to run clinics in impoverished rural areas such as Nyamiel.

In places like this, food - its availability and distribution, which have an impact on the health of families and children - is the leitmotif for existence. The spectre of hunger has been a constant threat for generations past and present, its vagaries dictating people's movements and life patterns, aspirations and fears across South Sudan.

One of the many beneficiaries of Concern's work on nutrition and income generation in Aweil is Aker Maynol Bol. Now 36, Aker was forced to leave South Sudan as a girl because of food shortages and found herself in the Adila camp for displaced people in Darfur.

"We were given food aid there and if you had five children you were given one cup," she told me, describing the daily hardships of camp life.

Some years later Aker made the decision to return to South Sudan, where, with her two young children and no means of income, her vulnerability made her eligible for support from Concern to help her generate a little money and get enough food for her children.

"I'm not sure why I was chosen but perhaps I was recognised for being hard-working,"Aker tells me with a mischievous smile as we look around her small farming plot.

The change in Aker's life came about as a result of a simple Concern scheme that supplies local farmers with a metal plough and a donkey, enabling them not only to feed their own family but have enough of a small surplus to pass on to other vulnerable families like that of Aker and her children.

In her case it is local farmer - another Concern beneficiary - Kiir Yum Kiir, with whom Aker has this community working partnership that allows her to have a supply of ground nuts and sorghum to eat and sell. From the little profit she makes, Aker is able in turn to buy seed she can plant for the following season, providing a degree of what humanitarian agencies like Concern call food security.

Not content with simply being a recipient of her fellow beneficiary's modest surplus yield, Aker, clearly feisty and resourceful, says she aims in the near future to have a plough and donkey of her own to increase her family's income and generate a little business.

It is this small-scale but intense work at local community level that can have such a dramatic impact on people's lives. Nowhere is this more evident than the approach Concern has pioneered in dealing with acute malnutrition.

CMAM has proved so effective that it is now the preferred way of tacking malnutrition. Previously, the focus was on therapeutic feeding programmes, through which malnutrition was treated using large feeding centres where patients were admitted for an average of 30 days. The problem with this, of course, is not only the fact that carers of malnourished children in such remote regions of South Sudan often have to travel long distances to access these centres, but also many have to leave the rest of their children at home for up to a month or longer, creating yet more problems and strains at family and community level.

By contrast, CMAM aims to treat malnourished children in their homes, resulting in a far greater number of them being reached.

Children admitted to Concern's programme are provided with weekly medical treatment and given one week's supply of therapeutic food to take home. This vitamin-enriched food, called ready-to-use therapeutic food, is the key to success.

Oil-based, it has a huge advantage over traditional water-based mixtures. Even someone with no access to clean water - not uncommon here - can use it to nurse a malnourished child back to health. This, combined with the deployment of community volunteers and local Concern outreach staff, means a child's health is monitored far more effectively.

Such is the positive impact of CMAM that a number of United Nations organisations have now committed to using it, and recommended that governments should incorporate the programmes into their health and nutrition policies.

At the Mayom healthcare unit in Aweil West, I see for myself these programmes in action.

"The levels of malnutrition vary but always it is worse in the rainy season when malaria, pneumonia and respiratory infections are rife," says Peter Akech, Concern's community health worker at Mayom.

As we speak, all around us ­mothers gather with their children waiting in turn for the Concern team to distribute the therapeutic food - known by the brand name of Plumpy Nut - along with mosquito nets and soap.

The youngest children are also weighed and measured as part of a nutritional assessment and arrangements are made for outreach workers to visit the most vulnerable in their communities.

The complex factors that affect the care of children in such communities is brought home by the case of an orphaned boy called Ngor Lual.

Ngor's guardian, a woman named Nyarou, says she has no idea how old the child is, but estimates Ngor's age to be about 18 months.

She says: "All I know is that the Ngor's parents separated and the father was a soldier who was killed in Juba [South Sudan's capital] and no-one knows where the mother is." A mother herself of five children, I asked Nyarou why she had she taken on the added responsibility of another child - especially when

her own husband was also dead and she struggles to make ends meet?

"I could not leave him to starve, but he is often sick now," Nyarou explains, adding that without the Concern nutrition and health programme she would not be able to cope.

"I am a widow but have no problem in taking responsibility of the boy; we must look after each other, just as they are doing here," Nyarou says, casting a look at the local Concern workers around her.

Marvelling at her selflessness and humility in the face of such challenges, I ask when she was most happy in life?

"The happiest moments of my life were when my husband was alive," she tells me, before explaining that he was killed in a car accident in 2012.

Time and again while in South Sudan I was to encounter such selflessness among local people, despite the enormous hardships they face in staying alive simply by ensuring they have enough to eat.

Every year hunger worldwide kills 3.1 million children and leaves another 161 million children stunted. Children who are undernourished have substantially lower chances of survival and their ability to grow and learn is permanently damaged - indeed, by the time a child is just two years old, the effects of malnutrition are irreversible.

For too long now hunger has plagued South Sudan. In real terms this means that one-third of the country's 11 million people are facing hunger, the maternal mortality rate is among the highest on the planet, while on the Fragile States Index, which measures a nation's vulnerability, South Sudan has hovered near the top since it gained its independence in 2011.

Tackling this hunger is an enormous task that Concern Worldwide has now taken on board with its Hunger Stops Here appeal in partnership with the UK Department for International Development. This appeal is match-funded, which means that every donation given up to and including today, December 14, will be matched pound for pound by the UK Government, doubling the amount that people can use to make a difference in tackling hunger for the world's poorest children in countries like South Sudan.

Over the course of the last few years I have made a number of trips to this long-suffering country and if one thing is evident it's that the needs of its poorest people, through no fault of their own, are greater than ever.