Diversity and altitudinal distribution of phlebotomine sand flies (Diptera: Psychodidae) in visceral leishmaniasis endemic areas of northwest Ethiopia

Yared, Solomon; Gebresilassie, Araya; Akililu, Essayas; Deribe, Kebede; Balkew, Meshesha; Warburg, Alon; Hailu, Asrat; Gebre-Michael, Teshome

doi:10.1016/j.actatropica.2017.07.008

Cited by 27 publications

(21 citation statements)

References 42 publications

(74 reference statements)

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“…As observed in prior studies [6,7,9,16,17,32], males represented most of the P. orientalis individuals captured on the sticky traps, in the present study. Moncaz et al [16], addressed this phenomenon in more detail.…”

Section: Discussionsupporting

confidence: 87%

Understanding sand fly sampling methods: sticky traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

et al. 2020

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Background: Sticky traps are generally viewed as interceptive sand fly sampling methods; although no previous experimental evidence has supported this assumption. In this study, we tested this assumption experimentally for Phlebotomus orientalis, the principal vector of visceral leishmaniasis in East Africa, and propose an explanation for the highly male-biased collection of sticky traps. Methods: A number of field experiments were carried out in March-June 2016-2019, in Gedarif state, eastern Sudan. In the first experiment, we compared numbers of P. orientalis caught on sticky traps made of black, red, transparent, white, yellow, green and blue A4 size papers set simultaneously at different lunar light conditions. In the second and third experiments, we compared numbers of P. orientalis captured on sticky traps placed side-by-side horizontally or vertically on the ground, or horizontally on a 15 cm height stool. We also witnessed mating behaviour of sand flies following their landing on un-sticky papers placed on the ground. Results: Phlebotomus orientalis showed significant attraction to white, yellow and transparent traps, with negligible numbers caught on the black and the red traps. Similarly, significantly higher numbers of P. orientalis were attracted to the horizontal traps, resulting in an 8-fold increase in sand fly trapping efficacy as compared to the vertical traps. Placing the traps on the stools resulted in significant reduction in this attraction. In contrast to the sticky traps that captured only very few females; we found that when male sand flies land on un-sticky white paper they successfully lure females and copulate with them. Conclusions: We demonstrate that, for P. orientalis, sticky traps are more attractant-based than interception-based sampling tools. Further, our findings support the notion that males of this sand fly species likely utilize the bright surface of the trap papers to perform mating rituals that attract the females for copulation. However, premature death in the sticky oil hampers the completion of these rituals, and thus results in failure to attract the females. These findings inform our understanding of P. orientalis behaviour and have important implications for optimization of sticky trap design for vector surveillance purposes.

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Section: Discussionsupporting

confidence: 87%

Understanding sand fly sampling methods: sticky traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

et al. 2020

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“…The environmental conditions that favor the vector are very suitable in some parts of Ethiopia ( Gebre-Michael et al., 2007 ; Hailu et al., 1995 ). Determining, the composition and distribution patterns of sand flies can indicate the possible presence of autochthonous transmission and/or can aid in the incrimination of the vector species ( Yared et al., 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Leishmaniasis in Ethiopia: A systematic review and meta-analysis of prevalence in animals and humans

Assefa

2018

Heliyon

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Leishmaniasis is a neglected tropical disease caused by obligate intracellular protozoa of the genus Leishmania. Ethiopia does not have an overall estimation of prevalence of leishmaniasis infection at a country level. The objective of this systematic review and meta-analysis was to summarize and pool estimates of studies that report the prevalence of leishmaniasis in Ethiopia. The literature search was conducted to identify all published studies reporting the prevalence of leishmaniasis with clearly designed inclusion and exclusion criteria. From all screened articles, 30 studies were eligible for final meta-analysis and systematic review. Because substantial heterogeneity was expected, random-effects meta-analyses were carried out using the total sample size and number of positives to estimate the prevalence of the disease at a country level. Between-study variability was high (τ2 = 0.02; heterogeneity I2 = 99.72% with Heterogeneity chi-square = 11985.41, a degree of freedom = 33 and P = 0.001). The overall random pooled prevalence of leishmaniasis was 19% (95% CI 14%–24%). Meta-regression analysis showed that diagnosis method used have contributed to the heterogeneity of studies. Molecular diagnosis has significantly lower prevalence than microscopic examination with a coefficient of −0.32, a p-value of 0.024, and CI (−0.6–0.05). The result of effect estimates against its standard error showed there was no publication bias with a P value of 0.084. This review indicated that there is still a higher prevalence of Leishmaniasis in the country. Reporting on risk factors like sex and age affected, species of Leishmania involved and many more other risk factors reviewing was not possible in this study due to lack of completeness in articles included. However, this report is an indication that the country needs nationally coordinated extensive prevention and control plan to reduce public health and socio-economic impact of the disease.

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“…Remarkably, most P. orientalis individuals captured on the sticky traps during the current study were males. This is a common observation, which has been reported in most previous studies on this vector [6,7,9,16,17,31]. Moncaz et al, 2013 addressed this phenomenon in more detail and reported that although baiting LHT's with CO 2 , emanating from Yeast Sugar extract, increased the number of females 8-fold and the number of males by 0.4-fold, the number of females captured on LHT's remained extremely low as compared to number of males [16].…”

Section: Discussionmentioning

confidence: 77%

“…In addition to the advantages of being inexpensive and easy to set up, no electrical power supply is needed to operate these traps and therefore, unlike the CDC traps, they hardly fail during operation. On the other hand, the sticky traps suffer the important disadvantage of sandfly male-biased collection, which has been observed with a number of species, including P. orientalis [6,7,9,16,17].…”

mentioning

confidence: 99%

Understanding Sandfly Sampling Methods: The Sticky Traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

Elnaiem

Khogali

Basheer

et al. 2020

Preprint

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Background : It is generally assumed that sticky traps are interceptive sandfly sampling methods, although no previous experimental evidence has supported this assumption. In this study, we test this assumption experimentally for Phlebotomus orientalis , the principal vector of visceral leishmaniasis in East Africa, and provide an explanation for why their collection is highly male-biased. Methods: Three field experiments were carried out in March 2016-June 2019, in Gedarif state, eastern Sudan. In a first experiment, we compared numbers of P. orientalis caught with sticky traps made of black, red, transparent, white, yellow, green and blue A4 size papers that were set simultaneously at different lunar light conditions. In a second and a third experiments, we compared numbers of P. orientalis captured on sticky traps placed side by side horizontally or vertically on the ground or horizontally on a stool. We also made observations on mating behaviour of sandflies following their landing on un-sticky papers placed on the ground. Results: Phlebotomus orientalis showed significant attraction to white, yellow and transparent traps; with negligible numbers caught on the black and the red traps. Similarly, significantly higher numbers of P. orientalis were attracted to the horizontal traps, resulting in 8-fold increase in their yield as compared to the vertical traps. Placing the traps on the stools resulted in significant reduction of this attraction. In contrast to the sticky traps that captured only very few females, our observations indicated that when male sandflies land on un-sticky white paper they successfully lure females and copulate with them. Conclusion: The study demonstrated that for P. orientalis, sticky traps are more attractant-based than interception-based sampling tools and supports the notion that males of this sandfly species probably utilize the bright surface of the papers of the traps to perform mating rituals to attract the females for copulation. However, their pre-mature death in the sticky oil hampers the completion of these rituals and thus the result in failure of the attraction of the females. The findings of the study have important implications for optimization of the ST design for vector surveillance purpose and understanding the behaviour of P. orientalis .

show abstract

Diversity and altitudinal distribution of phlebotomine sand flies (Diptera: Psychodidae) in visceral leishmaniasis endemic areas of northwest Ethiopia

Cited by 27 publications

References 42 publications

Understanding sand fly sampling methods: sticky traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

Understanding sand fly sampling methods: sticky traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

Leishmaniasis in Ethiopia: A systematic review and meta-analysis of prevalence in animals and humans

Understanding Sandfly Sampling Methods: The Sticky Traps are attraction-based and not interceptive sampling tools of Phlebotomus orientalis

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