Some patients can become asymptomatic carriers of African trypanosomiasis (sleeping sickness).
Features of an asymptomatic carrier:
(1) The patient is asymptomatic.
(2) The patient may have a past history of a clinical episode consistent with sleeping sickness with recovery.
(3) The patient shows evidence of African trypanosomiasis (trypanosomes in peripheral blood smear, positive PCR, etc.)
(4) The patient has a past history of exposure to a region endemic for African trypanosomiasis.
(5) Exclusion of recent exposure to African trypanosomiasis.
Asymptomatic carriers have been identified in association with:
(1) sexual transmission of African trypanosomiasis
(2) congenital transmission of African trypanosomiasis
(3) blood transfusion
People who have been identified as carriers:
(1) expatriates of an endemic country
(2) soldiers formerly stationed in an endemic country
In theory an asymptomatic carrier can become a source for spread outside of an endemic area if a suitable vector is present.
