Glossina palpalis gambiensis and G. tachinoides were the only tsetse species detected in the study area, with the former dominating. Savannah tsetse species were not detected during this survey. They are believed to have disappeared from the area following destruction of their habitat  hence tsetse trapping by this study was limited to the drainage lines where palpalis species are found. The presence of riverine tsetse species has important implications for tsetse control planning since emphasis must be placed on riparian habitats.
A variability in tsetse catches was observed across the study villages during this survey. The FTD for G. p. gambiensis (5.6) was considerably lower than the FTD 15–20 reported for the same species across the border in the Samorogouan pastoral area of Burkina Faso during surveys in 1994.
This study confirmed that trypanosomosis is an important disease in Sikasso. Variability in trypanosome prevalence across study villages was similar to what was observed in the Kénédougou Province of Burkina Faso . Trypanosome prevalence measured in this study is consistent with those for the same area [9, 11]. Also consistent with the two earlier studies, Trypanosoma congolense dominated T. vivax. The same pattern had been observed in neighbouring Kénédougou Province in Burkina Faso [7, 8]. Since T. congolense is the most pathogenic trypanosome of cattle its dominance is likely to increase trypanocidal drug use and in the process accelerate the development of resistance against trypanocidal drugs .
One of the undeniable pathogenic effects of trypanosome infections in cattle is the occurrence of anaemia, indicated by low PCV [23–25]. The present study found the expected relationship with trypanosome-positive cattle having significantly lower PCV on average than negative ones. The results also suggested that Trypanosoma congolense-positive cattle had lower mean PCV than T. vivax-positive cattle, though not statistically confirmed. This agrees with what was observed in Kénédougou Province in Burkina Faso, Mandiana in Guinea and south-east and south west Mali  and in a pastoral area of south-western Burkina Faso .
Monitoring effectiveness of treatments given to cattle under field conditions and drug sensitivity tests in mice and ruminants under laboratory conditions are used to characterize susceptibility of trypanosomes to trypanocidal drugs . Drug sensitivity studies are generally expensive, time-consuming and labour intensive. Doing sensitivity studies in mice has an additional disadvantage that T. vivax and some T. congolense do not readily grow in mice. In-vitro assays are suitable for characterizing T. brucei although they are time-consuming . The drug incubation Glossina infectivity test (DIGIT) is a sensitive method  although its use is dependent on the availability of laboratory-reared tsetse flies. Some genetic markers have been developed [28, 29] but their use is very limited due to lack of appropriately equipped laboratories and skilled personnel in SSA.
In the present study, an abbreviated 28-day field protocol based on treatment of naturally infected cattle  was preferred over the longer follow-up protocol . Although there was risk of underestimating the resistance as detection was only limited to parasitological methods , the abbreviated protocol was still preferred over other resistance characterization methods because of certain advantages. Firstly, this protocol uses cattle of known trypanosome infection status and takes only one month to generate results at a reasonably low cost. Secondly, the abbreviated protocol makes it possible to simultaneously estimate resistance of both DIM and ISMM. Lastly, the drop-out rate of participating herd owners/study animals where the abbreviated protocol is applied is lower than for the long follow-up protocol. To increase the precision of resistance estimates, the survey was timed to coincide with the period of highest trypanosomosis risk (end of the rainy season) to ensure a large population of naturally trypanosome-infected cattle.
Within the cattle cohort that received ISMM treatment, persistent trypanosomes were detected 14 days post-treatment across the study villages indicative of resistance against this drug. Trypanosoma congolense accounted for about 90% of the ISMM resistant trypanosomes. The few cattle with T. vivax failed ISMM treatments were mostly detected at day 28 post-treatment which seemed to suggest that at high plasma ISMM concentrations, T. vivax are effectively suppressed, only flourishing as ISMM plasma concentration wanes.
Re-treatment of ISMM treatment failures with 7 mg/kg DIM led to the apparent clearance of all persistent T. vivax infections. Since residual levels of ISMM are still present in animals, this is likely to influence the treatment outcome of the second drug, hence caution is suggested when interpreting such parasitological outcomes .
There was high variability in the DIM treatment failures across the study villages. Indeed, molecular analysis using PCR-RFLP technique of filter paper blood samples collected during the drug sensitivity test confirmed presence of DIM resistant T. congolense populations in the study area . A slightly higher percentage of treatment failure (36.8%) after DIM treatment was observed in the Kénéndougou Province of Burkina Faso . The sensitivity of T. vivax to 3.5 mg/kg DIM treatment reported by this study is consistent with earlier findings of other studies [7, 8]. Re-treatment of the cattle positive for persistent T. congolense with a double dose (7 mg/kg) of DIM did not completely clear trypanosomes in 26.3% of the re-treated cattle. Doubling the dose of DIM only slightly improved therapeutic efficacy on T. congolense strains resistant to 3.5 mg/kg DIM . In other studies, higher doses like 17.5 mg/kg DIM  and 14 mg/kg DIM  still failed to clear the T. congolense resistant to 3.5 mg/kg DIM.