Reproductive Performance of Glossina palpalis gambiensis (Diptera: Glossinidae) when fed frozen or fresh bovine blood meals

The tsetse and trypanosomoses control by sterile insect technique (SIT), requires mass production of quality tsetse pupae and consequently high-quality blood meal for the fly feeding. The reproductive performances of Glossina palpalis gambiensis (Diptera : Glossinidae), fed frozen or fresh blood meals has been studied. Three diets of slaughtered bovine blood stored at -18 °C for six months (R6), three months (R3) and one month (R1) were used in the present investigation. Fresh blood samples stored at 4°C and renewed every four days were used as control (R0). The defibrinated blood was packaged in batches of 30 x 20 ml vials. For each blood meal, 30-day feeding tests were conducted at the beginning and end of freezing. All blood meal was irradiated using 137 caesium irradiation before being used. The parameters monitored daily were: the number of dead flies (fed and unfed), the number and weight of pupae and the emergence rate. No difference in survival rates was observed for the three regimes (df: 15; Chi-square: 7.53; p > 0.05), on average 32.1% (R0), 32.4% (R6), 37.5% (R3) and 38.2% (R1). However, flies fed with the six-month-old frozen blood were less efficient in pupa production (df: 3; F: 6. p < 0.001) and pupae weight (df: 3, F: 3.24, p < 0.05) compared to the control. The mortality rate was affected by the duration of freezing: 26.7% for R6 and 8% for the other diets (p <0.05). The implications of our results in terms of blood meal management for efficient production of insectary pupae were discussed

Tsetse and trypanosomes relationship in Southwestern part of Burkina Faso

African Animal Trypanosomosis (AAT), transmitted by tsetse flies, are one of the main constraints for the development of livestock farming in Burkina Faso. The objective of this study was to understand the impact of the level of degradation of tsetse habitat on the epidemiology of AAT. Entomological and parasitological surveys were carried out in two different landscape areas: conserved (Folonzo) and fragmented (Moussodougou) in southwestern part of Burkina Faso. The results revealed that the diversity, abundance and infection rate of tsetse flies were related to the conservation status of the habitat. In Folonzo, four species of tsetse were present (84.76% (2870/3386)) versus a single species (15.24%) in Moussodougou. The tsetse infection rate was also higher in Folonzo (21% (133/633)) than in Moussodougou (7.8% (23/294)). In addition, in Folonzo, the tsetse flies were infected with all 3 species of trypanosomes. However, in Moussodougou, G. p. gambiensis (the only species present) was infected primarily with T. congolense (68.44% (13/19)). We suggest that the current fragmentation of tsetse habitats does not reduce the risk of trypanosomiasis, but leads to selection and maintaining the best trypanosome and tsetse (G. p. gambiensis / T. congolense) pair that may affect the epidemiology of AAT

Gamma-radiation of

African animal trypanosomoses are vector-borne diseases that cause enormous livestock losses in sub-Saharan Africa, with drastic socio-economic impacts. Vector control in the context of an area-wide integrated pest management program with a sterile insect technique component requires the production of high-quality sterile male tsetse flies. In our study, we evaluated the effect of irradiation on the fecundity of Glossina palpalis gambiensis to identify the optimal dose that will induce maximum sterility while maintaining biological performance as much as possible. In addition, male mating performance was evaluated in semi-field cages. The irradiation doses used were 90, 100, 110, 120, 130, 140, and 150 Gy, and untreated males were used as the control. The results showed that pupal production and emergence rates were higher in batches of females that had mated with fertile males than in those that had mated with irradiated males with any experimental dose. A dose of 120 Gy administered to male flies induced 97–99% sterility after mating with virgin females. For the semi-field cage experiments, males irradiated with 120 Gy showed good sexual competitiveness as compared to fertile males and those irradiated with 140 Gy, considering the level of filling of spermatheca and the number of pairs formed. The optimal radiation dose of 120 Gy found in this study is slightly different from the traditional dose of 110 Gy that has been used in several eradication programmes in the past. The potential reasons for this difference are discussed, and an argument is made for the inclusion of reliable dosimetry systems in these types of studies