Optimizing the feeding frequency to maximize the production of sterile males in tsetse mass-rearing colonies.

Soumaïla Pagabeleguem,Mamadou Ira,Abdou Salam Belem,Bénéwendé Aristide Kaboré,Issa Sidibé,Adrien Marie Gaston Belem,Kiswendsida Mikhailou Dera,Gisèle Marie Sophie Ouedraogo/Sanou,Lassané Percoma,Sié Hermann Pooda,Ange Irénée Toé,Ahmed Ibrahim Hasaballah

doi:10.1371/journal.pone.0245503

Abstract

Tsetse flies are cyclical vectors of trypanosomes, the causative agents of sleeping sickness or Human African Trypanosomosis and nagana or African Animal Trypanosomosis in Sub-Saharan Africa. The Insectarium de Bobo-Dioulasso (IBD) was created and equipped in the frame of Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) with the main goal to provide sterile males for the different eradication programs in West Africa which is already the case with the ongoing eradication program in Senegal. The aim of this study was to identify the best feeding regime in mass-rearing colonies of Glossina palpalis gambiensis to optimize the yield of sterile males. We investigated the mortality and fecundity for various feeding regimes and day alternation (3×: Monday-Wednesday-Friday, 4×: Monday-Wednesday-Friday-Saturday, 4×: Monday-Wednesday-Thursday-Friday and 6×: all days except Sunday) on adult tsetse flies in routine rearing over 60 days after emergence. The day alternation in the 4 blood meals per week (feeding regimes 2 and 3) had no effect on tsetse fly mortality and fecundity. The best feeding regime was the regime of 4 blood meals per week which resulted in higher significant fecundity (PPIF = 2.5; P = 0.003) combined with lower mortality of females (P = 0.0003) than the 3 blood meals per week (PPIF = 2.0) and in similar fecundity (PPIF = 2.6; P = 0.70) and mortality (P = 0.51) than the 6 blood meals per week. This feeding regime was extended to the whole colonies, resulting in an improved yield of sterile males for the ongoing eradication program in Senegal and would be more cost-effective for the implementation of the next-coming sterile insect technique (SIT) programs in West Africa.

Highlights

Tsetse flies transmit trypanosomes which cause sleeping sickness or Human African Trypanosomoses (HAT) and nagana or African Animal Trypanosomoses (AAT), a debilitating diseases affecting humans and livestock, respectively [1]
The statistical analysis showed that there was no link between the number of deaths with or without blood in the insect’s abdomen and the feeding regime and sex (P > 0.05)
The comparison between feeding regimes showed that the mortality rate was similar between flies fed 4 times a week and flies fed 6 times a week (P > 0.2)

Summary

Introduction

Tsetse flies transmit trypanosomes which cause sleeping sickness or Human African Trypanosomoses (HAT) and nagana or African Animal Trypanosomoses (AAT), a debilitating diseases affecting humans and livestock, respectively [1]. In Burkina Faso, 83% reduction of densities was observed for Glossina palpalis gambiensis and 92% reduction for G. tachinoides on 40000 km has been achieved through an integrated control campaign including insecticide targets, traps and cattle, sequential aerial treatment (SAT) and the mass treatment of livestock using trypanocidal products, from June 2006 to December 2013 [8]. During this phase of PATTEC Burkina, a mass-rearing facility named Insectarium de Bobo-Dioulasso (IBD) was built and equipped with capacities to produce about 1,000,000 sterile males weekly in cruise production.

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Discussion

Conclusion