NAME: Trypanosoma brucei
SYNONYM OR CROSS REFERENCE: African Trypanosomiasis, African Sleeping Sickness
CHARACTERISTICS: Hemoflagellates, occur as mature elongated trypomastigotes in blood of mammals (slender, 25-30 µm long, curved, flagella), epimastigote stage and infective-stage trypomastigotes (metacyclic trypomastigotes) occur in insect vector
PATHOGENICITY: Systemic protozoal disease; infection occurs in three stages - chancre at primary tsetse fly bite site, hemolymphatic stage with fever, lymphadenopathy and pruritis, meningoencephalitic stage with invasion of the CNS causing intense headaches, somnolence, abnormal behaviour, loss of consciousness and coma; death may follow within a few months or several years; frequently fatal if untreated
EPIDEMIOLOGY: Confined to tropical Africa, corresponding to distribution of the tsetse fly; up to 30% population infected in some endemic areas; outbreaks when human-fly contact is intensified; infection occurs mainly along streams in West and Central Africa and over broader dry savannas in East Africa (due to distribution of vectors)
HOST RANGE: T. b. rhodesiense - wild and domestic animals, humans
T. b. gambiense - primarily humans
INFECTIOUS DOSE: Unknown
MODE OF TRANSMISSION: By bite of infective tsetse fly of the genus Glossina; fly is infected by ingesting blood that carries trypanosomes, parasites multiply in fly for 12-30 days until infective form develops in salivary glands; fly remains infective for life (no transovarial passage); congenital transmission can occur in humans; may be contracted during blood transfusion or organ transplantation
INCUBATION PERIOD: T. b. rhodesiense - usually 3 days to 3 weeks
T. b. gambiense - usually longer and extremely variable (may be several months or years)
COMMUNICABILITY: Parasitemia is extemely variable in untreated cases and occurs in late as well as early stages of the disease
RESERVOIR: T. b. gambiense - primarily humans
T. b. rhodesiense - wild game, domestic cattle, carnivores (lions, hyenas)
ZOONOSIS: Yes, especially for T. b. rhodesiense; by bite of fly infected by ingesting blood on animals that carry trypanosomes
VECTORS: Glossina palpalis, G. tachinoides, G. morsitans, G. pallidipes, G. swynnertoni, G. fuscipes
DRUG SUSCEPTIBILITY: Early stages - suramin (T. b. rhodesiense), pentamidine isethionate (T. b. rhodesiense); melarsoprol or DL-alpha-difluromethylornithine (DFMO) for CNS infection (less effective for treatment of T. b. rhodesiense)
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde, formaldehyde
PHYSICAL INACTIVATION: Inactivated by heat (50-60° C)
SURVIVAL OUTSIDE HOST: Does not survive outside the host or culture
SURVEILLANCE: Monitor for symptoms; trypanosomes demonstrated in lymph node aspirates, chancre fluid, bone marrow, blood or CSF by microscopic examination
FIRST AID/TREATMENT: Administration of appropriate drug therapy
IMMUNIZATION: None
PROPHYLAXIS: None
LABORATORY-ACQUIRED INFECTIONS: Up to 23 reported laboratory acquired infections with trypanosomes
SOURCES/SPECIMENS: Infective stages may be present in blood, lesions exudates, and infected arthropods
PRIMARY HAZARDS: Accidental parenteral inoculation, transmission by arthropod vectors, skin penetration
SPECIAL HAZARDS: Aerosol or droplet exposure of the mucous membranes of the eyes, nose, or mouth with trophozoides are potential hazards when working with tissue homogenates or blood containing hemoflagellates
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices, containment equipment and facilities are recommended for activities with infective stages; infected arthropods should be maintained in facilities which preclude the exposure of personnel or their escape to the outside; primary containment (biological safety cabinets) are indicated when working with tissue homogenates or blood
PROTECTIVE CLOTHING: Laboratory coat; gloves are recommended for activities where there is the likelihood of direct skin contact with infective stages
OTHER PRECAUTIONS: Other precautions may be indicated (wearing a face shield when handling tissue homogenates or blood containing hemoflagellates)
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towels and apply 1% sodium hypochlorite, starting at perimeter and working towards the centre; allow sufficient contact time before disposal (30 min)
DISPOSAL: Decontaminate before disposal - steam sterilization, incineration, chemical disinfection
STORAGE: In sealed containers that are appropriately labelled
Date prepared: May, 2001
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001