Previous studies have shown that δ-octalactone is an important component of the tsetse-refractory waterbuck (Kobus defassa) repellent odour blend. In the present study, structure-activity comparison was undertaken to determine the effects of the length of the side chain and ring size of the lactone on adult Glossina pallidipes and Glossina morsitans morsitans. The responses of the flies to each compound were studied in a two-choice wind tunnel. Increasing the chain length from C3 (δ-octalactone) to C4 (δ-nonalactone) enhanced repellency to both species (G. pallidipes from 60.0 to 72.0%, and G. m. morsitans from 61.3 to 72.6%), while increasing the ring size from six (δ-octalactone) to seven members (ε-nonalactone) changed the activity from repellency to attraction that was comparable to that of the phenolic blend associated with fermented cow urine (p>0.05). Blending δ-nonalactone with 4-methylguaiacol (known tsetse repellent) significantly (p<0.05) raised repellency to 86.7 and 91.7% against G. pallidipes and G. m. morsitans respectively. Follow-up Latin Square Designed field studies (Shimba hills in coastal areas in Kenya) with G. pallidipes populations confirmed the higher repellence of δ-nonalactone (with/without 4-methylguaiacol) compared to δ-octalactone (also, with/without 4-methylguaiacol). The results show that subtle structural changes of olfactory signals can significantly change their interactions with olfactory receptor neurons, and either shift their potency, or change their activity from repellence to attraction. Our results also lay down useful groundwork in the development of more effective control of tsetse by 'push', 'pull' and 'push-pull' tsetse control tactics.
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http://dx.doi.org/10.1016/j.actatropica.2016.04.011 | DOI Listing |
Tsetse flies and trypanosomosis significantly impact bovine production and human health in sub-Saharan Africa, exacerbating underdevelopment, malnutrition, and poverty. Despite various control strategies, long-term success has been limited. This study evaluates the combined use of entomopathogenic fungi (EPF) and the sterile insect technique (SIT) to combat tsetse flies.
View Article and Find Full Text PDFVet Med Sci
January 2025
Faculty of Veterinary Medicine, Hawassa University, Hawassa, Ethiopia.
In sub-Saharan Africa, animal trypanosomosis is a wasting disease that reduces livestock's health and productivity. A recurrent cross-sectional investigation was carried out in the Dara district of the Sidama region in dry and wet seasons to estimate the apparent density of Glossina spp. and the seasonal prevalence of bovine trypanosomosis.
View Article and Find Full Text PDFParasite Epidemiol Control
November 2024
Department of Biomedical Science, College of Veterinary Medicine and Animal Science, University of Gondar, Gondar, Ethiopia.
Parasite Epidemiol Control
November 2024
The Institute of Pest Management, Sokoine University of Agriculture, P.O. Box 3110, Morogoro, Tanzania.
The successful control of tsetse flies largely depends on understanding of the species available and abundance. This study assessed the species richness, abundance and apparent density of wild collected tsetse flies from selected human-wildlife-livestock interface in Tanzania. Seasonal trapping using baited NZI, Pyramidal and Biconical traps was done across selected wards.
View Article and Find Full Text PDFParasite Epidemiol Control
August 2024
Faculty of Veterinary Medicine, Hawassa University, Hawassa, Ethiopia.
African animal trypanosomosis is one of the main obstacles to the development of livestock and agricultural output in Ethiopia. It usually results in a severe, frequently fatal sickness, and the infected animals were more weakened as the disease progress and become unfit for work. A cross sectional study design was conducted from December 2021 to April 2022 with the aim of estimating the prevalence of trypanosome infection both in spp.
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