Background Tsetse fly-transmitted African animal trypanosomosis causes annual
losses that run into billions of dollars. The disease is assumed to cause
hunger and poverty in most sub-Saharan countries since it represents a serious
impediment to sustainable livestock production. Both a cross-sectional and a
longitudinal study were carried out from November to December 2007 to evaluate
trypanosomosis risk and susceptibility of trypanosomes to trypanocidal drug
treatment in village cattle populations in south-east Mali. Methods Eight
purposively selected villages participated in the study. In each village,
eight traps deployed along drainage lines over 24hour duration were used to
catch tsetse. One hundred systematically selected cattle in the study villages
were examined for trypanosomes. All trypanosome-positive cattle were randomly
allocated into two treatment groups: a group treated with 0.5 mg/kg bw.
isometamidium chloride (ISMM) and a group treated with 3.5 mg/kg bw.
diminazene aceturate (DIM). The cattle were monitored for trypanosomes at day
14 and 28 post-treatment. Results Of the 796 cattle examined, 125 (15.7%) were
trypanosome-positive. Village trypanosome prevalences ranged between 11% and
19%. There were no significant (p > 0.05) differences in the village
trypanosome prevalences. Trypanosoma congolense was the dominant trypanosome
species accounting for 73% (91/125) of the infections and T. vivax the
remainder. Twenty (31.7%) of the 63 cattle on 0.5 mg/kg bw. ISMM treatment
were still positive14 days post-treatment. Of the 43 aparasitaemic cattle
monitored to day 28, 25.6% (11) became parasitaemic, resulting in a cumulative
failure rate of 49.2% (31/63). Trypanosoma congolense accounted for 77.4%
(24/31) of failed ISMM treatments. The 62 cattle treated with 3.5 mg/kg bw.
DIM resulted in 30.6% (19/62) failed treatments. Although 42.2% (19/45) of T.
congolense positive cattle did not respond to DIM treatment, all T. vivax
positive cattle responded positively to DIM treatment. Conclusions The
overreliance on trypanocides in the control of trypanosomosis will ultimately
lead to multiple drug-resistant trypanosome populations as detected in
villages in south-east Mali rendering the use of drugs doubtful. Effective
alternative methods for trypanosomosis control ought to substitute
chemotherapy to ensure sustainable cattle production in these villages. Since
there is no single strategy for containing trypanocidal drug resistance,
promotion of an integrated approach combining proven trypanosomosis control
approaches in high trypanosomosis risk areas is most desirous. The best-bet
strategy this study recommended for areas with multiple drug resistance
included area-wide community tsetse control, control of co-infections to
exploit self-cure against resistant trypanosome populations and the rational
use of trypanocidal drugs which should be urgently promoted at all levels as a
way of containing or reversing resistance.
500 Naturwissenschaften und Mathematik::570 Biowissenschaften; Biologie
Detection of multiple drug-resistant Trypanosoma congolense populations in
village cattle of south-east Mali
Parasites and Vectors. 2012 Aug 1;5:155.
Institut für Parasitologie und Tropenveterinärmedizin