Is resistance developing in tsetse flies? Susceptibility to two chlorinated hydrocarbon insecticides in sprayed and unsprayed populations of Glossina pallidipes in Kenya

2020 ◽  
pp. 17-26
Author(s):  
D.A. Turner ◽  
T.K. Golder
Keyword(s):  
Glossina Pallidipes ◽  
Tsetse Flies ◽  
Chlorinated Hydrocarbon

scholarly journals An update on the distribution of Glossina (tsetse flies) at the wildlife-human-livestock interface of Akagera National Park, Rwanda

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Richard S. Gashururu ◽  
Samuel M. Githigia ◽  
Methode N. Gasana ◽  
Richard Habimana ◽  
Ndichu Maingi ◽  
...  
Keyword(s):  
National Park ◽  
Control Strategies ◽  
Glossina Pallidipes ◽  
Distribution Patterns ◽  
Tsetse Flies ◽  
Wet Season ◽  
Chi Square ◽  
Large Numbers ◽  
Surrounding Areas ◽  
Biconical Traps

Abstract Background Glossina (tsetse flies) biologically transmit trypanosomes that infect both humans and animals. Knowledge of their distribution patterns is a key element to better understand the transmission dynamics of trypanosomosis. Tsetse distribution in Rwanda has not been well enough documented, and little is known on their current distribution. This study determined the current spatial distribution, abundance, diversity, and seasonal variations of tsetse flies in and around the Akagera National Park. Methods A longitudinal stratified sampling following the seasons was used. Biconical traps were deployed in 55 sites for 6 consecutive days of each study month from May 2018 to June 2019 and emptied every 48 h. Flies were identified using FAO keys, and the number of flies per trap day (FTD) was used to determine the apparent density. Pearson chi-square (χ2) and parametrical tests (t-test and ANOVA) were used to determine the variations between the variables. The significance (p < 0.05) at 95% confidence interval was considered. Logistic regression was used to determine the association between tsetse occurrence and the associated predictors. Results A total of 39,516 tsetse flies were collected, of which 73.4 and 26.6% were from inside Akagera NP and the interface area, respectively. Female flies accounted for 61.3 while 38.7% were males. Two species were identified, i.e. G. pallidipes [n = 29,121, 7.4 flies/trap/day (FTD)] and G. morsitans centralis (n = 10,395; 2.6 FTD). The statistical difference in numbers was significant between the two species (p = 0.000). The flies were more abundant during the wet season (15.8 FTD) than the dry season (4.2 FTD). Large numbers of flies were trapped around the swamp areas (69.1 FTD) inside the park and in Nyagatare District (11.2 FTD) at the interface. Glossina morsitans was 0.218 times less likely to occur outside the park. The chance of co-existing between the two species reduced outside the protected area (0.021 times). Conclusions The occurrence of Glossina seems to be limited to the protected Akagera NP and a narrow band of its surrounding areas. This finding will be crucial to design appropriate control strategies. Glossina pallidipes was found in higher numbers and therefore is conceivably the most important vector of trypanosomosis. Regional coordinated control and regular monitoring of Glossina distribution are recommended. Graphic Abstract

scholarly journals Comparative performance of traps in catching tsetse flies (Diptera: Glossinidae) in Tanzania

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Imna I. Malele ◽  
Johnson O. Ouma ◽  
Hamisi S. Nyingilili ◽  
Winston A. Kitwika ◽  
Deusdedit J. Malulu ◽  
...  
Keyword(s):  
Glossina Pallidipes ◽  
Abundant Species ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Comparative Performance ◽  
Control Programmes ◽  
Fly Control ◽  
Tsetse Fly Control ◽  
Species Being ◽  
Biconical Traps

This study was conducted to determine the efficiency of different tsetse traps in 28 sites across Tanzania. The traps used were biconical, H, NGU, NZI, pyramidal, S3, mobile, and sticky panels. Stationary traps were deployed at a distance of 200 m apart and examined 72 h after deployment. The results showed that 117 (52.2%) out of the 224 traps deployed captured at least one Glossina species. A total of five Glossina species were captured, namely Glossina brevipalpis, Glossina pallidipes, Glossina swynnertoni, Glossina morsitans, and Glossina fuscipes martinii. Biconical traps caught tsetse flies in 27 sites, pyramidal in 26, sticky panel in 20, mobile in 19, S3 in 15, NGU in 7, H in 2 and NZI in 1. A total of 21 107 tsetse flies were trapped, with the most abundant species being G. swynnertoni (55.9%), followed by G. pallidipes (31.1%), G. fuscipes martinii (6.9%) and G. morsitans (6.0%). The least caught was G. brevipalpis (0.2%). The highest number of flies were caught by NGU traps (32.5%), followed by sticky panel (16%), mobile (15.4%), pyramidal (13.0%), biconical (11.3%) and S3 (10.2%). NZI traps managed to catch 0.9% of the total flies and H traps 0.7%. From this study, it can be concluded that the most efficient trap was NGU, followed by sticky panel and mobile, in that order. Therefore, for tsetse fly control programmes, NGU traps could be the better choice. Conversely, of the stationary traps, pyramidal and biconical traps captured tsetse flies in the majority of sites, covering all three ecosystems better than any other traps; therefore, they would be suitable for scouting for tsetse infestation in any given area, thus sparing the costs of making traps for each specific Glossina species.Keywords: tseste; traps; densties; Glossina; mobile; stationary; Tanzania

Aircraft Applications of Insecticides in East Africa. VI.—Applications of a coarse Aerosol containning DDT to control the Tsetse Flies, Glossina morsitans Westw., Glossina swynnertoni Aust. and Glossina pallidipes Aust.

1954 ◽  
Vol 45 (3) ◽  
pp. 585-603 ◽  
Author(s):  
K. S. Hocking ◽  
D. Yeo ◽  
D. G. Anstey
Keyword(s):  
Random Effects ◽  
Glossina Pallidipes ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Median Diameter ◽  
Coarse Aerosol ◽  
Savannah Woodland ◽  
Mass Median ◽  
Glossina Swynnertoni ◽  
Mass Median Diameter

An experiment is described where applications of a coarse aerosol were made to savannah woodland containing the tsetse flies, Glossina moritans Westw., G. swynnertoni Aust. and G. pallidipes Aust.Seven applications were made, each at a nominal dosage of 0·25 lb. of technical DDT per acre and 0·25 gallons of solution per acre. The applications in any particular part of the treaed woodland covered an interval of 90 days, or rather more than two pupal periods.The coarse aerosol was produced by emitting the insecticidal solution under pressure through fine nozzles fitted to a boom. It had a mass median diameter of approximately 60 microns, and droplet dismeters varied from a few microns to approximately 200 microns.The population of G. pallidipes was so drastically reduced that it has subsequently dies out. The reduction of G. morsitans was approximately 95 per cent. The differences between the reductions are attributed mainly to differences between the ease with which the three species can be killed. It is pointed out that this is not necessarily equivalent to differences in susceptibility.Comparisons are made with previous experiments, and the different results of the various experiments are difficult to explian satisfactory. The increased cover in savannah areas during the leafy period may have reduced the effectiveness of the applications, and the total periods covered by the various series of applications were probably also important. Random effects, leading to ineffective treatments, may also be important.Costs are discussed.

scholarly journals Differential virulence and tsetse fly transmissibility of Trypanosoma congolense and Trypanosoma brucei strains

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Purity K. Gitonga ◽  
Kariuki Ndung’u ◽  
Grace A. Murilla ◽  
Paul C. Thande ◽  
Florence N. Wamwiri ◽  
...  
Keyword(s):  
Survival Time ◽  
Trypanosoma Brucei ◽  
Acute Infection ◽  
Glossina Pallidipes ◽  
Trypanosoma Congolense ◽  
Tsetse Fly ◽  
Economic Losses ◽  
Entire Group ◽  
Tsetse Flies ◽  
African Countries

African animal trypanosomiasis causes significant economic losses in sub-Saharan African countries because of livestock mortalities and reduced productivity. Trypanosomes, the causative agents, are transmitted by tsetse flies (Glossina spp.). In the current study, we compared and contrasted the virulence characteristics of five Trypanosoma congolense and Trypanosoma brucei isolates using groups of Swiss white mice (n = 6). We further determined the vectorial capacity of Glossina pallidipes, for each of the trypanosome isolates. Results showed that the overall pre-patent (PP) periods were 8.4 ± 0.9 (range, 4–11) and 4.5 ± 0.2 (range, 4–6) for T. congolense and T. brucei isolates, respectively (p < 0.01). Despite the longer mean PP, T. congolense–infected mice exhibited a significantly (p < 0.05) shorter survival time than T. brucei–infected mice, indicating greater virulence. Differences were also noted among the individual isolates with T. congolense KETRI 2909 causing the most acute infection of the entire group with a mean ± standard error survival time of 9 ± 2.1 days. Survival time of infected tsetse flies and the proportion with mature infections at 30 days post-exposure to the infective blood meals varied among isolates, with subacute infection–causing T. congolense EATRO 1829 and chronic infection–causing T. brucei EATRO 2267 isolates showing the highest mature infection rates of 38.5% and 23.1%, respectively. Therefore, our study provides further evidence of occurrence of differences in virulence and transmissibility of eastern African trypanosome strains and has identified two, T. congolense EATRO 1829 and T. brucei EATRO 2267, as suitable for tsetse infectivity and transmissibility experiments.

scholarly journals Responses of Glossina pallidipes and Glossina morsitans morsitans tsetse flies to analogues of δ-octalactone and selected blends

Acta Tropica ◽  
2016 ◽  
Vol 160 ◽  
pp. 53-57 ◽  
Author(s):  
Benson M. Wachira ◽  
Paul O. Mireji ◽  
Sylvance Okoth ◽  
Margaret M. Ng’ang’a ◽  
Julius M. William ◽  
...  
Keyword(s):  
Glossina Pallidipes ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Glossina Morsitans

Upwind flight responses of tsetse flies (Glossina spp.) (Diptera: Glossinidae) to acetone, octenol and phenols in nature: a video study

1993 ◽  
Vol 83 (3) ◽  
pp. 329-333 ◽  
Author(s):  
John Brady ◽  
Nigel Griffiths
Keyword(s):  
Glossina Pallidipes ◽  
Flight Speed ◽  
Tsetse Flies ◽  
Similar Response ◽  
Visual Responses ◽  
Video Study ◽  
Upwind Flight ◽  
Odour Source ◽  
Video Observations ◽  
Odour Plumes

AbstractVideo observations were made of tsetse flies (mainly Glossina pallidipes Austen) as they approached, responded to and left a vertical (1 m square) black target in odour plumes of acetone, or a 4:1:8 mixture of octenol:propylphenol: methylphenol, or acetone plus this “4:1:8” mixture, or in no odour. No differences in mean flight speed or turn size in any of these situations were detected. With the odour source 5 m upwind of the target, the flight tracks of tsetse arriving at and leaving the target were significantly biased towards upwind, highly so when 4:1:8 was present, marginally so in acetone alone. With the source 10 m upwind, the same biases were still present but weaker. Circling flights around the black target were more frequent in acetone plus 4:1:8 than in no odour (26% vs 15%), but in either odour alone were only just significantly more than in no odour. Upwind turning at the target was more frequent (25% vs 17%) in acetone alone that in no odour (though not in 4:1:8 alone). It is concluded that 4:1:8 elicits an upwind anemotactic response comparable in strength to that in CO2, and that acetone elicits a similar response more weakly, but may be more involved in potentiating visual responses.

The ‘White-clubbed’ form of Syntomosphyrum (Hym., Eulophidae) parasitic on tsetse flies

1960 ◽  
Vol 51 (1) ◽  
pp. 17-20 ◽  
Author(s):  
D. S. Saunders
Keyword(s):  
Glossina Pallidipes ◽  
Distinct Species ◽  
Tsetse Flies ◽  
Northern Nigeria ◽  
Male Progeny ◽  
Physiological Barrier

Cross-mating experiments are reported between adults of the typical, darkclubbed form of Syntomosphyrum glossinae Wtstn., obtained from pupae of Glossina pallidipes Aust. from Kenya and of G. palpalis (R.-D.) and G. morsitans submorsitans Newst. from Northern Nigeria, and the ‘white-clubbed’ form of Syntomosphyrum, originally reported by Waterston from Nyasaland, obtained from pupae of G. morsitans Westw. from Tanganyika.Fertilised eggs, giving rise to offspring of both sexes, were produced only by crosses between the strains of typical S. glossinae. Crosses in either direction between the ‘white-clubbed’ form and typical S. glossinae resulted in all-male progeny, presumed to develop from unfertilised eggs. It is considered that this is evidence of a physiological barrier to reproduction between the two forms. The ‘white-clubbed’ form is therefore regarded as a distinct species.

Age determination for female tsetse flies and the age compositions of samples ofGlossina pallidipesAust.,G. palpalis fuscipesNewst. andG. brevipalpisNewst.

1962 ◽  
Vol 53 (3) ◽  
pp. 579-595 ◽  
Author(s):  
D. S. Saunders
Keyword(s):  
Age Structure ◽  
Blood Meal ◽  
Reproductive System ◽  
Age Determination ◽  
Glossina Pallidipes ◽  
Tsetse Flies ◽  
Third Instar Larvae

The age compositions of samples of females ofGlossina pallidipesAust.,G. palpalis fuscipesNewst. andG. brevipalpisNewst., are analysed by means of a method of age determination based upon the changes occurring in the reproductive system during successive gonotrophic cycles. This method of age determination is described in detail.Females were sampled by three main methods: in traps, by catching on a bait-animal, and on a fly-round. Some flies were also found as resting flies in the undergrowth.Trap-caught samples ofG. pallidipeswere older (i.e.), contained a larger proportion of old flies (and a smaller proportion of young flies) than the hand-caught samples. The bait-caught samples were intermediate in age structure. Correlated with the increasing mean age in the hand-caught—bait-caught—trap-caught series was an increase in the proportion of females carrying third-instar larvae and a decrease in the proportion of those carrying eggs. Results with samples ofG. palpalis fuscipesandG. brevipalpiswere not so well defined.The results of dissecting teneral and non-teneral nullipars ofG. pallidipesandG. palpalis fuscipesindicate that females of the latter are inseminated some time before they take their first blood-meal, but teneral females ofG. pallidipesare inseminated when they come to the host to feed or after they have fed.The relation of the ovarian method of age determination to Jackson's (1946) wing-fray categories in females ofG. pallidipes, and the probable epidemiological importance of the samples, are also discussed.

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