Fatima Ben Moussa, head of the Tunisian Association of Kidneys and head of nephrology at Al-Rabta Hospital (one of the largest hospitals in Tunisia) said the country was leading in the field of kidney transplantation, especially in Africa with "more than 25 years of experience”. Around 8900 patients experience renal failure in Tunisia every year. She said to Arabstoday on the occasion of  "World Kidney Day" there were two types of renal failure, the first acute renal failure, which can be treated, and the second chronic renal failure, where the organ becomes unable to perform its functions. "This can result in hemodialysis, which requires patients to undergo permanent medical tests, so that the case is not complicated further," said Moussa. The doctor said: "There are two main reasons, first is the possibility that hormones produced by the kidneys, which maintain the balance in blood pressure and the work of red blood cells, as well as adjusting the amount of calcium in the blood can be easily affected with any defect in the organ." "The second reason is a pollution that can cause blockage of the urinary tract, diabetes, high blood pressure, obesity, sepsis in the kidney, smoking, and kidney inflammation...all these things directly affect the kidney’s job." To avoid such diseases, she advised, people need to "drink plenty of water, because it prevents the formation of kideny stones". Moussa also said "genetic factors or the activity of certain glands can be a cause of infection with kidney stones". On World Kidney Day and under the slogan  “Donate your kidney...one is sufficient", Moussa revealed her association intended to conduct free checkups in Tunisian hospitals and blood banks for the prevention of disease. She also planned to use awareness-raising activities, social networking and SMS services to illustrate the importance of kidney donation’. Tunisia has 145 blood filter centres with only 45 under state supervision, leading to severe overcrowding. "The haemodialysis centres in Tunisia are visited by several nationalities, due to the positive image of healthcare in Tunisia in general and renal transplantation in particular. Those centres are mainly visited by patients from Libya, Europe, Mauritania, Senegal and Algeria,” said the nephrologist.