While the majority of occurrences of the disease known as "nodding syndrome" have been relatively recent, it appears that the condition was first documented in 1962 in southern Tanzania. More recently, nodding syndrome had become most prevalent in South Sudan, where in 2003 approximately 300 cases were found in Mundri alone. By 2009, it had spread across the border to Uganda's Kitgum district, and the Ugandan ministry of health declared that more than 2000 children had the disease. As of the end of 2011, outbreaks were concentrated in Kitgum, Pader and Gulu. More than 1000 cases were diagnosed in the last half of that year.