Laboratories: accidental infections, for example, through the handling of blood of an infected person and organ transplantation, although this is uncommon. Blood transfusion
Sexual contactHorse-flies (Tabanidae) and stable flies (Muscidae) possibly play a role in transmission of nagana (the animal form of sleeping sickness) and the human disease form. Pathophysiology
Tryptophol is a chemical compound produced by the trypanosomal parasite in sleeping sickness which induces sleep in humans. Diagnosis
The gold standard for diagnosis is identification of trypanosomes in a sample by microscopic examination. Samples that can be used for diagnosis include chancre fluid, lymph node aspirates, blood, bone marrow, and, during the neurological stage, cerebrospinal fluid. Detection of trypanosome-specific antibodies can be used for diagnosis, but the sensitivity and specificity of these methods are too variable to be used alone for clinical diagnosis. Further, seroconversion occurs after the onset of clinical symptoms during a T. b. rhodesiense infection, so is of limited diagnostic use.Trypanosomes can be detected from samples using two different preparations. A wet preparation can be used to look for the motile trypanosomes. Alternatively, a fixed (dried) smear can be stained using Giemsas or Fields technique and examined under a microscope. Often, the parasite is in relatively low abundance in the sample, so techniques to concentrate the parasites can be used prior to microscopic examination. For blood samples, these include centrifugation followed by examination of the buffy coat; mini anion-exchange/centrifugation; and the quantitative buffy coat (QBC) technique.
The CDC is setting up a task force to investigate the causes and to find treatments. == References ==