A mystery disease has killed over 100 people and infected more than 2,000 in northern Uganda.

The disease, first reported in September 2009, has since been dubbed "nodding disease" as it leaves its victims nodding, Xinhua reported.

Spread over the region's five districts, the disease is characterised by head nodding, mental retardation and stunted growth and affects children and young adults. It causes young children and adolescents to nod violently while eating.

Scientists are to launch a series of investigations as the previous efforts couldn't identify the disease's cause.

The two previous samples and tests carried out by Centres for Disease Control (CDC) scientists in Atlanta in the US failed to identify the cause of the disease, said Richard Nduhura, minister of state for health in charge of general duties.

A team of scientists from the ministry of health, World Health Organisation (WHO) and CDC is going to carry out new tests, said Nduhura, who is leading a fact finding mission in the affected areas