NAIROBI, Kenya, Nov 22 - Mystery surrounds the death of eight inmates at the Kamiti Maximum prison after cholera tests turned negative.

The Ministry of Public Health said on Sunday that sample results taken from sick inmates had tested negative to cholera and now a second test was being carried out with results expected on Monday.

"Our first samples did not show cholera so it may be any other bacteria. We are now trying to make sure that we treat this as an acute diarrhoea and take all the measures to ensure that we contain the outbreak here," said Director of Public Health Dr Shahnaaz Sharif.

Dr Sharif said food samples had also been taken to establish the illness that had left 21 inmates hospitalised and another 61 isolated after presenting the same symptoms of severe diarrhoea and vomiting.

According to the World Health Organisation (WHO), cholera is an acute intestinal infection caused by ingestion of food or water contaminated with a bacterium known as Vibrio Cholerae.

But the Nairobi Water and Sewerage Company has ruled out contamination of water as a possible cause of the outbreak.

"The most common thing is to check whether the water has bacteria and we have found it has no bacteria. We then take samples to the laboratory where we check whether there are some biological organisms in the water and so far none has been found both from both sources," said the company's Chief Executive Officer Francis Mugo.

The Kamiti Maximum Prison, the largest correction facility in Kenya, gets its water from the Nairobi Water Company and a borehole.

Among the measures taken by the Ministry of Public Health to prevent further spread of the mystery disease was to restrict prison transfers from the prison with immediate effect.

"And even within the prison itself we want to confine prisoners where they are so that there is no cross contamination from one cell to the other cells," Dr Sharif said.

"We want to make sure that we minimise contacts between several cells so that we can isolate the cells that have inmates who show any symptoms," he added.

Commissioner of Prisons Isiah Osugo said more suspected cases had come up since the first case on Saturday and were receiving the required attention.

"We have formed some working committees and we don't wish to lose any of the cases now. I cannot say whether the situation is very bad or good because like the last case we lost somebody who was happy and we were talking and when he was given some meal and he went to the rest houses he passed on," he said.

Meanwhile relatives of inmates accused the prison authorities of keeping them in the dark over the outbreak.

Those interviewed by Capital News outside the prison said they had not been allowed to visit their relatives and were worried because they did not know whether their kin were among the victims.

"They have refused to even print out the names and place them at the gate to show who is sick," complained one relative.

"I can't sleep; I can't eat because I don't know whether my son is in the mortuary or is sick. There is no need for them to refuse us entry and at the same time they are not giving us information," she added.

The relatives said they had been asked to wait until Wednesday to be briefed on the situation inside the prison.

"I have my son who is in remand here and I have been informed he is sick with diarrhoea and vomiting but I have not been allowed to see him since yesterday," said another relative.