Insecticide and Repellent Mixture Pour-On Protects Cattle against Animal Trypanosomosis

Abstract

BackgroundAfrican animal trypanosomosis (AAT), transmitted by tsetse flies and tick-borne diseases are the main constraints to livestock production in sub-Saharan Africa. Vector control methods such as pour-on offer individual protection against ticks but not against tsetse so far, for which protection has always been communal, through a reduction of their density. The latter requires the treatment of a large part of the herd in a given landscape and is not instantaneous.Methodology/Principal FindingsTwo prospective surveys were conducted to evaluate the efficacy and persistence of a pour-on formulation composed of cypermetrhin, chlorpyrifos, piperonyl butoxid and citronella (Vectoclor, CEVA Santé Animal). In experimental conditions, tsetse flies were exposed to treated and control cattle. Flies knockdown and engorgement rates were determined and the product persistence was assessed as the time for these parameters to drop below 50% (T50). T50 was 37 days (95%CI: [33–41] days) and 46 days (95%CI: [39–56] days) for the knockdown and engorgement rates respectively. In field conditions, two cattle herds were monitored following a case-control experimental design, in the Adamaoua region of Cameroon. One herd was treated once with Vectoclor pour-on (treated group) and the second used as a control group (not treated). Ticks infestation rate, trypanosomosis prevalence and packed-cell volume were measured over the two months following treatment. The treatment was highly effective against ticks with a complete elimination three days after application in the treated group. Trypanosomosis prevalence was also significantly reduced during the study (by 4, P<0.001) and PCV of the treated group increased significantly in the same time (P<0.001), contrary to the control group.Conclusions/SignificanceThe protection of this new pour-on against tsetse bites and trypanosomosis is demonstrated here for the first time. Moreover, this insecticide and repellent mixture offer a longer persistence of the efficacy against both tsetse and ticks than similar products currently on the market. It offers a great new opportunity for an integrated AAT control strategy including the treatment of residual cases with trypanocides. It might also allow controlling the spread of resistance against these trypanocides.

Heterogeneity in Prevalence of Bovine Trypanosomosis and its Associated Risk Factors in Pastoral and Agro Pastoral Communities Surrounding Murchison Falls National Park, Uganda.

“…Although from our study, there was no signi cant difference between bovine trypanosomosis prevalence and body condition (Table 3), animals in good body condition score are more resilient to trypanosomosis infection compared to those in poor body condition in wet season as reported in Cameroon by (Gimonneau et al, 2016). The most likely possible explanation for lack of signi cant difference was that at the time of conducting this study, animals nutritional body reserves were not yet depleted and therefore no considerable variation in the body condition score was evident.…”

Impact of an integrated control campaign on tsetse populations in Burkina Faso

“…At the beginning of the survey, sampled cattle were treated with diminazene aceturate (DA), and dewormed with albendazole (Vermitan®, CEVA, Libourne, France) (7.5 mg/kg). They received every two months a pour-on formulation mixing cypermethrin and amitraz (Cypertraz®, CEVA, Libourne, France) [ 18 ].…”

6. Integrated control of trypanosomosis

“…Today, although no insecticide resistance has been identified in tsetse, combination of different insecticides and molecules can significantly increase the formulation effect (Gimonneau et al 2016). Application of repellents on cattle to reduce trypanosomosis incidence was tested, and it was concluded that the repellent technology was not sufficiently efficient under natural tsetse challenge to merit commercial development (Bett et al 2010).…”

“…A new pour-on containing two insecticides, a pyrethroid synergist and a repellent have recently been developed and compared to a standard pour-on (i.e. based on one pyrethroid) (Gimonneau et al 2016). Results showed in the laboratory that the repellent and insecticides formulation was significantly more efficient than the classical formulation with a longer knockdown effect (37 and 28 days, respectively; Figure 5A).…”