Causing fever, sleep disruption, neurological damage and, if untreated eventual death, sleeping sickness or African trypanosomiasis is caused by the parasitic protozoan Trypanosoma brucei. The majority of cases are in western and central Africa; while over 7000 cases were reported in 2012, the World Health Organisation believes the actual number to be nearer 30,000 per year. Although increased drug availability has led to a reduction in reported cases over the last 50 years, still little is known about how these parasites cross the blood-brain barrier and infect the central nervous system (CNS). Pictured are trypanosomes (in yellow) interacting with four insect cells via a protein called claudin-11 on the cells’ surface. Claudin proteins have an important role in CNS function and researchers have found that trypanosomes may be attracted to them and use them to gain entry into the cells allowing them ultimately to cross the blood-brain barrier.
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