Abstract:
A longitudinal study assessed the chemoresistance to isometamidium chloride (ISM) and
diminazene aceturate (DA) in the region of the Boucle du Mouhoun in Burkina Faso. A preliminary
cross-sectional survey allowed the identification of the 10 villages with the highest
parasitological prevalences (from 2.1% to 16.1%). In each of these 10 villages, two herds of
approximately 50 bovines were selected, one being treated with ISM (1 mg/kg b.w.) and
the other remaining untreated as control group. All animals (treated and untreated herds)
becoming infected were treated with DA (3.5 mg/kg b.w.). In total, 978 head of cattle were
followed up. Fortnightly controls of the parasitaemia and PCV were carried out during 8
weeks. The main trypanosome species was Trypanosoma vivax (83.6%) followed by Trypanosoma
congolense (16.4%). In two villages, less than 25% of the control untreated cattle
became positive indicating no need to use prophylactic treatment. These two villages were
not further studied. Resistance to ISM was observed in 5 of the remaining 8 villages (Débé,
Bendougou, Kangotenga, Mou and Laro) where the relative risk (control/treated hazard
ratios) of becoming infected was lower than 2 i.e. between 0.89 (95% CI: 0.43–2.74) and
1.75 (95% CI: 0.57–5.37). In contrast, this study did not show evidence of resistance to DA
in the surveyed villages with only 8.6% (n = 93) of the cattle relapsing after treatment. Our
results suggest that because of the low prevalence of multiple resistances in the area a
meticulous use of the sanative pair system would constitute the best option to delay as
much as possible the spread of chemoresistance till complete eradication of the disease by
vector control operations.
