Trypanosomiasis Trypanosoma brucei (African trypanosomes) sleeping sickness Trypanosoma cruzi (American trypanosomes) Chagas’ disease S. and Central America

transmission A bite from an infected tsetse fly causes African trypanosomiasis . Blood transfusions are a rare cause of parasitic transmission. In rare cases, accidental transmission in the laboratory has been implicated.

Morphology 1- trypanosmes is an elongated , spindle-shape cell with a single nucleus near the middle of parasite. 2- it has kinetoplast. 3- it has undulating membrane. 4- possess a slender-single flagella at the anterior end. 5- flagellum serve as organ of attachment and locomotion. 6- there are four stages in life cycle :-

A –trypomastigote:- postnuclear kinetoplast , flagellum start from anterior end with undulating membrane , found in vertebrate and insects . B –epimastigote:- kinetoplast anterior to nucleus flagellum emerging from the body and continuing to the anterior end with short undulating membrane. C –promastigote:- kinetoplast at the anterior end. Flagellum emerging from anterior end of the body . there is no undulating membrane. D–amastigote:- spherical or oval in shape without undulating membrane . flagellum not extend from outside the membrane , start from the kinetoplast .

Trypomastigote Epimastigote Promastigote Amastigote FORM

Kinetoplast Nucleus

A trypomastigote of Trypanosoma brucei sp

There are two Types of HAT Trypanosoma brucei rhodesiense  Acute -- can cause death in weeks or months Trypanosomoa brucei gambiense Chronic --lasts years

Disease Course and Symptoms invasion of blood characterized by irregular fever and headache (acute stage) T. gambiense can be self-limiting or progressing to a more serious disease (chronic) includes invasion of lymphatics and CNS

parasites crossing blood-brain barrier(BBB) result in CNS involvement and nervous impairment described as meningoencephalitis increased apathy and fatigue confusion and somnolence motor changes including tics, slurred speech, incoordination convulsions, coma, death

100% Fatal if left untreated cardiac failure or from the infection itself

Life cycle Trypanosomes are parasites with a 2-host life cycle: mammalian and arthropod. The life cycle starts when the trypanosomes are ingested during a blood meal by the tsetse fly . The trypanosomes multiply over a period of 2-3 weeks in the fly midgut; then, the trypanosomes migrate to the salivary gland, where they develop into epimastigotes. The metacyclic trypomastigotes infect humans.

Trypanosoma cruzi and Chagas Disease Transmitted by triatomine bugs Inefficient transmission (parasite in feces of bug) Associated with infestation of houses with triatomines (rural poverty) Urban transmission associated with blood transfusions Leading cause of cardiac disease in South and central America

Clinical Course of Chagas Acute Phase active infection (1-4 months) most are asymptomatic (children most likely to be symptomatic) Indeterminate Phase 10-30 years of latency seropositive with no detectable parasitemia Chronic Phase 10-30% of infected exhibit cardiomyopathy conductions defects congestive heart failure

Diagnosis Direct microscopy Blood smear Lymph node aspirate Clinical Features travel or residence in endemic area irregular fever and enlarged lymph nodes behavioral changes/mental symptoms Laboratory Diagnosis Direct microscopy Blood smear Lymph node aspirate demonstration of trypanosomes in blood, lymph node aspirates, cerebral spinal fluid

Animal inoculation Serology Culture Antigen detection tests based on enzyme-linked immunosorbent assay (ELISA) technology have been developed. Culture of CSF, blood, bone marrow aspirate, or tissue specimens can be performed in liquid media. Other tests developed like polymerase chain reaction (PCR) Animal inoculation

Treatment Early stage - most recover Late stage - upto 5% relapse Suramin Melasporol Pentamidine Late stage - upto 5% relapse Only Melasporol

Destruction of animal reservoir Control Destruction of animal reservoir Vector Control Diagnosis & treatment