Accompanied by Waweru, an HIV counselor, a woman walks into a consultation room of the Medecins Sans Frontieres (MSF) 'Blue House' clinic in Nairobi. She is carrying a child and looks weary. Her loosely tied headscarf looks as if it is about to fall off.

She has her hands full with a traditional woven bag - a "kiondo" - hanging from her shoulder and her three year old son, Titus, all swaddled up on her arms. He has a fever and is wrapped in two pieces of cloth, one wool and the other a light cotton fabric, locally known as "lesso". He looks a lot bigger than his actual size.

He has AIDS and is already taking the Anti-Retroviral Therapy (ART) which slows the process of the disease and should allow him to live a normal life.

On asking Elizabeth how Titus is doing, she picks a paper bag out of the "kiondo." She pulls out Lamivudine and Zidovudine syrups, followed by a little ziplock with big bright yellow Stocrin 200mg capsules. She explains that the syrups are administered twice a day in equal amounts of 12.5ml each time. Titus also takes one capsule of Effavirenz daily as well.

This is never easy with a small child when living in a cramped one room shack. The procedure is challenging as it requires basic things such as clean water which is not readily available in the slums. Children who are a little older than Titus are prescribed tablets, taken once daily.

Mothers have to break a tablet into two for accuracy. Most children are unable to swallow the half tablet so it is crushed up and mixed into food, one half in the morning and the other at bedtime. The measurements need to be precise or the treatment will fail. And of course, as the child grows, the dosage also has to be constantly adapted.

Elizabeth explains that Titus prefers to swallow the pill rather than break it open and mix it up due to the undesirable taste. But the capsules look enormous for the tiny child.

"Adults have to take only two pills a day and this has a clear positive effect on adherence," explains Christine Genevier, MSF head of mission. "Children are denied the same luxury because an adapted treatment does not exist. Until they are big enough to cope with adult treatment they take a mixture of syrups and pills which are difficult to administer in the required precise dosage. It is more like the job of a chemist than a mother."

Like the vast majority of the 250 000 people in the Mathare slum who the 'Blue House' serves, Elizabeth and Titus live on barely a dollar a day. The slum itself is made up of little mud walled rooms with roofs made of scrap metal, with all the houses tightly knit. A huge number of the residents are unemployed and those that do work, do so irregularly.

There are no roads, but rather narrow dirt walk ways dotted with human waste. The few shared pit latrines are never cleaned due to inaccessibility to water.The entire slum is littered with dirty tattered plastic and paper waste. During the rainy season the dirt paths become virtually impassable. The air is characterized by an offensive smell, heightened by the local brew dens.

MSF offers free consultations as well as treatment, otherwise it would not be affordable for them.

In Kenya, children continue to be born HIV positive. It seems a ridiculous statement given the overwhelming prevalence of AIDS in Africa, but this is specifically a developing world problem. In the west, the number of children born with the HIV-AIDS is very low due to mother-to-child-transmission (MTCT) programmes where HIV positive mothers can take treatment that will limit the chance of passing on the infection to their unborn babies.

In Kenya, where there is not even an adapted diagnosis tool that exists for children below 18 months of age, the situation is catastrophic. The figures show that 33% of children with HIV positive mothers are born with the disease and 50% of suspected HIV positive children are dead by the time they reach two years of age.

"Avoiding transmission is possible, but it requires a basic healthcare system which many parts of Kenya lack," explains Christine Genevier, MSF head of mission. "Coupled with a lack of diagnostic tools, it is a deadly combination."

Even if a child avoids transmission during birth, the virus can be caught through breast-feeding and many mothers are too poor to buy substitute milk formula.

Lactating mothers who come to 'Blue House' are fortunate; they get a supply of dry tinned milk until the baby is six months old. Above that age they are weaned onto 'unimix,' a compound of ground maize and soya beans, rich in mineral and vitamins.

MSF recommends that breastfeeding be avoided by HIV positive mothers as the baby could contract the HIV virus through the breast milk. The chance of transmission is even greater when the child is being given food and breast-fed at the same time. Micro lesions in the stomach caused by the change in diet may allow the virus to be transmitted. Whichever the method of transmission, AIDS is a terribly efficient killer of children

This is starkly clear to Elizabeth. She has horror in her eyes as she begins to recount how at six years old, her daughter had fallen sick and died. She never got to know the cause, but it is not hard to guess. Then she lost her second child at birth. Also cause unknown.

"Titus is the only child I have now," she fears, "I am hoping that he will get better." This is a phrase that she repeats several times as she speaks.

What is notable is that Elizabeth makes an effort not to speak of her own HIV status. Being afraid of HIV/AIDS testing is commonplace amongst women in Kenya and especially with those who are married for fear of being abandoned by their husbands who are the sole bread winners. Consequently the woman is left with no income but still caring for the children.

More often than not, one or more of them will also be HIV positive. The mother has to juggle her time between seeking good healthcare for herself and her children, putting food on the table and working. It is a Herculean task.

It is estimated that over 150 000 children are HIV positive in Kenya. Currently the Blue House clinic has a total of 450 child patients. Of the total number, 158 are currently on ARVs.

"The number may seem small," explains Genevier, "but due to the extreme difficulty of care, these children are amongst the very few receiving treatment in Kenya."

In a strange way Titus is lucky. As well as receiving treatment, he has a mother and father to care for him.

But unless the situation changes dramatically in terms of diagnostics and treatment, the vast majority of the children outside the MSF projects will not even reach 10 years of age.

As it stands now, children in the developing world are left to their fate.