The mystery illness at a jail outside Lae in Papua New Guinea is reportedly more serious than first thought.
The Post Courier says an inspection of the Buimo prision by health authorities this week discovered 31 inmates suffering from nervous disorders.
The unknown illness has caused two deaths at the jail within the last two weeks.
Provincial Health program adviser, Dr Likei Theo, says the situation was very serious.
Dr Theo says during an inspection of the prison they found 31 inmates suffering from conditions such as swelling in their bodies.
He says they also had difficulty walking, and had balance problems.
And he says the jail's mess facilities and general living conditions are below human tolerance.
Dr Theo says the cells are like chicken houses with no ventilation and he says if he had his way the jail would be closed.
Tests are to be carried out on food, water and various facilities, with results being analysed along with the post-mortem results of the two deaths.