Trypanosomiasis

Protozoal infection with Trypanosoma brucei (African sleeping sickness, tsetse-fly-borne) or T. cruzi (Chagas disease, in the Americas, via triatomine “kissing” bugs). Sleeping sickness is potentially fatal.

African trypanosomiasis — two forms

	T. b. gambiense (West/Central Africa)	T. b. rhodesiense (East Africa)
Share of cases	>90%	<10%
Course	Chronic (months–years)	Acute (weeks–months)
Chancre	Rare	Common (70–80%)
Lymphadenopathy	Posterior cervical (Winterbottom sign)	Epitrochlear/axillary
CNS phase	Late (6 months–years)	Early; cardiac involvement may kill before CNS disease

Clinical phases

• Haemolymphatic — weeks after the bite: malaise, intermittent fever, headache, arthralgia, itch, facial/limb swelling, lymphadenopathy, anaemia; myopericarditis, DIC and renal impairment can occur.
• Meningoencephalitic — parasites cross the blood–brain barrier: insomnia, anorexia, behavioural/mood change, apathy, tremor, gait/speech disturbance, seizures. Classic reversed sleep pattern (nighttime insomnia, daytime somnolence) progressing to deep somnolence. Kerandel sign (delayed deep-pressure pain) may be present.
• Skin — a chancre (indurated red/purple nodule with a necrotic eschar) ~48 h after the bite, healing in 2–3 weeks; a transient trypanid rash 6–8 weeks later.

Diagnosis and treatment

• Diagnosis — demonstrate the parasite in blood, the chancre, a lymph-node aspirate, or CSF (CSF examination stages the disease).
• Treatment (specialist / expert advice) — pre-CNS: pentamidine or suramin (don’t cross the BBB). CNS phase: melarsoprol, eflornithine (± nifurtimox), or newer oral fexinidazole. These agents are largely not registered in Australia/NZ.
• Prevention — bite avoidance (tsetse flies bite through lightweight clothing); no vaccine or chemoprophylaxis.