Nodding disease or nodding syndrome is an obscure disease which recently made its appearance in Sudan. First discovered in the 1960s, the disease primarily affects children between 5 to 15 years of age. It is currently contained within Tanzania, Northern Uganda and South Sudan.
Nodding disease gets its name from the characteristic pattern of involuntary nodding of the head. Neck movements such as nodding and turning the head from side to side are made possible by a long band of muscle called the sternocleidomastoid muscle, which is supplied by the hypoglossal nerve. The symptoms of nodding disease include stunting, mental retardation, memory loss and absent mindedness.
Severe seizures can cause the child to collapse; burns and injuries are common because during the seizure the child may be unable to move away from cooking stoves, sharp knives etc.
The cause of the disease is not currently known, but it is believed to be connected to:
- Onchocerca volvulus, which was found present in 93.7% of the patients.
- Severe malnutrition, especially of Vitamin B6 (pyridoxine).
- Autoimmune disease.
- Extreme temperatures. Very hot or very cold temperatures could trigger the nodding.
- Allergy to certain foods especially legumes.
- All the children that are nodding have been in camps before.
- No cases have been found in town.
- All cases are malnourished.
- Trigger, yet to be known.(WHO, Uganda, 2012)
Prevalence and epidemiology
Most of the people suffering from the disease are found to have the Onchocerca volvulus in their bodies. Humans are the definitive hosts for the worm, and the black fly acts as the intermediate host. The black fly found in droves along river banks. But strangely enough, Nodding syndrome is more common in areas where there are no rivers or black flies. No cases have been found in the cities.
Some more studies in the following areas will help researchers understand the disease better and possibly devise a cure:
- Burden of disease (prevalence and incidence).
- A prospective cohort.
- Case studies.
- Autopsy study.
- Knowledge, attitude and beliefs of the locals.
- Toxicology study.
- Clinical study.
- Special needs.
- Psychological study.
World Health Organization, Uganda
Edited and Illustrated By: Nisha Salim
Federation of African Medical Students’ Associations