| Mechanical
transmission of Trypanosoma evansi (South American origin) and T.
congolense of Kilifi DNA type (Kenyan origin) was studied in
laboratory mice using the African stable flies Stomoxys niger niger
and S. taeniatus. Altogether, 355 flies were interrupted after
feeding on infected blood and then transferred immediately to an
uninfected mouse to complete feeding. Microscopy and subinoculation of
triturated flies into uninfected mice demonstrated the survival of T.
congolense in Stomoxys for up to 210 min and T. evansi
for up to 480 min. Parasites survived for much longer periods in the
digestive tract than inside or on the mouthparts. Trypanosoma
congolense was transmitted only by S. n. niger, and only at
low rates of 3, 8 and 10% using flies of different feeding histories fed
on blood the previous day, freshly caught, and teneral. Trypanosoma
evansi was transmitted by both Stomoxys species at higher
rates S. taeniatus range 13-18%; S. n. niger range 17-35%.
The highest transmission rate occurred with the combination of teneral S.
n. niger and T. evansi. |