Winterbottom's sign is seen in the early phase of African trypanosomiasis, a disease caused by the parasites Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense which is more commonly known as African sleeping sickness. Dr Anthony Martinelli describes Winterbottom's sign as the swelling of lymph nodes (lymphadenopathy) along the back of the neck, in the posterior cervical chain of lymph nodes, as trypanosomes travel in the lymphatic fluid and cause inflammation.