Detection of high rates of in-village transmission of Leishmania donovani in eastern Sudan

Hassan, Mohammed Mahgoub; Elraba’a, F.M.A.; Ward, R. D.; Maingón, R.; Elnaiem, Dia-Eldin A.

doi:10.1016/j.actatropica.2004.06.001

Cited by 29 publications

(33 citation statements)

References 14 publications

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“…Natural infections of P. orientalis with L. donovani were repeatedly reported from various foci in East Africa [1], [4], [11], [29], but only once in the south-west Ethiopia [30]. In Sudan, the susceptibility of P. orientalis to L. donovani has also been demonstrated by feeding on patients with kala-azar [10], [31] or by feeding infected blood through mouse-skin membranes [11].…”

Section: Discussionmentioning

confidence: 99%

Phlebotomus orientalis Sand Flies from Two Geographically Distant Ethiopian Localities: Biology, Genetic Analyses and Susceptibility to Leishmania donovani

et al. 2013

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Background Phlebotomus orientalis Parrot (Diptera: Psychodidae) is the main vector of visceral leishmaniasis (VL) caused by Leishmania donovani in East Africa. Here we report on life cycle parameters and susceptibility to L. donovani of two P. orientalis colonies originating from different sites in Ethiopia: a non-endemic site in the lowlands - Melka Werer (MW), and an endemic focus of human VL in the highlands - Addis Zemen (AZ).Methodology/Principal FindingsMarked differences in life-cycle parameters between the two colonies included distinct requirements for larval food and humidity during pupation. However, analyses using Random Amplified Polymorphic DNA (RAPD) PCR and DNA sequencing of cytB and COI mitochondrial genes did not reveal any genetic differences. F1 hybrids developed successfully with higher fecundity than the parental colonies. Susceptibility of P. orientalis to L. donovani was studied by experimental infections. Even the lowest infective dose tested (2×103 per ml) was sufficient for successful establishment of L. donovani infections in about 50% of the P. orientalis females. Using higher infective doses, the infection rates were around 90% for both colonies. Leishmania development in P. orientalis was fast, the presence of metacyclic promastigotes in the thoracic midgut and the colonization of the stomodeal valve by haptomonads were recorded in most P. orientalis females by day five post-blood feeding.ConclusionsBoth MW and AZ colonies of P. orientalis were highly susceptible to Ethiopian L. donovani strains. As the average volume of blood-meals taken by P. orientalis females are about 0.7 µl, the infective dose at the lowest concentration was one or two L. donovani promastigotes per sand fly blood-meal. The development of L. donovani was similar in both P. orientalis colonies; hence, the absence of visceral leishmaniasis in non-endemic area Melka Werer cannot be attributed to different susceptibility of local P. orientalis populations to L. donovani.

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Section: Discussionmentioning

confidence: 99%

Phlebotomus orientalis Sand Flies from Two Geographically Distant Ethiopian Localities: Biology, Genetic Analyses and Susceptibility to Leishmania donovani

et al. 2013

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“…and Balanites aegyptiaca woodlands, 162 and where activities such as wood cutting and shepherding expose people to sandflies. and Balanites aegyptiaca woodlands, 162 and where activities such as wood cutting and shepherding expose people to sandflies.…”

Section: Insecticide Sprayingmentioning

confidence: 99%

Leishmaniasis

Boelaert¹,

Sundar²

2014

Manson's Tropical Infectious Diseases

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“…Most entomological studies, such as the trials in Iran [9]–[11], Syria [13] and Turkey [14], have singularly failed to demonstrate any effect on sand fly density through community-wide use of ITNs. The only evidence we are aware of is an Iranian trial which detected a reduction in sand fly ( P. sergenti ) density in the ITN villages [15] and a Sudanese trial in which infections caused by P. orientalis may have been reduced in villages using ITNs although the results were non-statistically significant [21]. It appears that community-wide ITN usage is more likely to reduce sand fly density and infection rate if a large proportion of sand flies feed on humans and if the leishmania is anthroponotic.…”

Section: Introductionmentioning

confidence: 96%

Effect of Village-wide Use of Long-Lasting Insecticidal Nets on Visceral Leishmaniasis Vectors in India and Nepal: A Cluster Randomized Trial

et al. 2010

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BackgroundVisceral leishmaniasis (VL) control in the Indian subcontinent is currently based on case detection and treatment, and on vector control using indoor residual spraying (IRS). The use of long-lasting insecticidal nets (LN) has been postulated as an alternative or complement to IRS. Here we tested the impact of comprehensive distribution of LN on the density of Phlebotomus argentipes in VL-endemic villages.MethodsA cluster-randomized controlled trial with household P. argentipes density as outcome was designed. Twelve clusters from an ongoing LN clinical trial—three intervention and three control clusters in both India and Nepal—were selected on the basis of accessibility and VL incidence. Ten houses per cluster selected on the basis of high pre-intervention P. argentipes density were monitored monthly for 12 months after distribution of LN using CDC light traps (LT) and mouth aspiration methods. Ten cattle sheds per cluster were also monitored by aspiration.FindingsA random effect linear regression model showed that the cluster-wide distribution of LNs significantly reduced the P. argentipes density/house by 24.9% (95% CI 1.80%–42.5%) as measured by means of LTs.InterpretationThe ongoing clinical trial, designed to measure the impact of LNs on VL incidence, will confirm whether LNs should be adopted as a control strategy in the regional VL elimination programs. The entomological evidence described here provides some evidence that LNs could be usefully deployed as part of the VL control program.Trial registrationClinicalTrials.gov CT-2005-015374

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Detection of high rates of in-village transmission of Leishmania donovani in eastern Sudan

Cited by 29 publications

References 14 publications

Phlebotomus orientalis Sand Flies from Two Geographically Distant Ethiopian Localities: Biology, Genetic Analyses and Susceptibility to Leishmania donovani

Phlebotomus orientalis Sand Flies from Two Geographically Distant Ethiopian Localities: Biology, Genetic Analyses and Susceptibility to Leishmania donovani

Leishmaniasis

Effect of Village-wide Use of Long-Lasting Insecticidal Nets on Visceral Leishmaniasis Vectors in India and Nepal: A Cluster Randomized Trial

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