Habitat preference and seasonal dynamics of Phlebotomus orientalis in urban and semi-urban areas of kala-azar endemic district of Kafta Humera, northwest Ethiopia

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

doi:10.1016/j.actatropica.2016.10.011

Cited by 13 publications

(19 citation statements)

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“…The collective studies in Sudan and NW Ethiopia lead to the consensus that P . orientalis has a low propensity to enter household buildings [ 17 , 21 , 25 , 26 , 27 , 28 , 53 , 54 ], which is corroborated by the current data showing that comparatively few P . orientalis were captured inside sleeping huts as measured by chemical knockdown (KD) methods.…”

Section: Discussionsupporting

confidence: 89%

“…In East Africa, the prominent VL vector is Phlebotomus orientalis , which thrives in remote woodlands, villages, and peridomestic habitats, characterized by the presence of black cotton soil and Acacia seyal and Balanites aegyptiaca trees [ 13 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The vector is highly exophilic and exophagic, rarely captured inside household buildings [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] with villagers being exposed outdoors in the household compound and in the peridomestic surroundings. Phlebotomus orientalis is a highly seasonal species.…”

Section: Introductionmentioning

confidence: 99%

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Outdoor Residual Insecticide Spraying (ODRS), a New Approach for the Control of the Exophilic Vectors of Human Visceral Leishmaniasis: Phlebotomus orientalis in East Africa

et al. 2020

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Visceral Leishmaniasis (VL) due to Leishmania donovani is a neglected protozoan parasitic disease in humans, which is usually fatal if untreated. Phlebotomus orientalis , the predominant VL vector in East Africa, is a highly exophilic/exophagic species that poses a major challenge to current Integrated Vector Management (IVM). Here we report results of pilot studies conducted in rural villages in Gedarif state, Sudan, to evaluate outdoor residual spraying of 20mg active ingredient (a.i.) /m 2 deltamethrin insecticide applied to the characteristic household compound boundary reed fence and to the outside of household buildings (Outdoor Residual Insecticide Spraying, ODRS), and as an alternative, spraying restricted to the boundary fence only (Restricted Outdoor Residual Insecticide Spraying, RODRS). Four to six clusters of 20 households were assigned to insecticide treatments or control in three experiments. Changes in sand fly numbers were monitored over 2,033 trap-nights over 43–76 days follow-up in four sentinel houses per cluster relative to unsprayed control clusters. Sand fly numbers were monitored by sticky traps placed on the ground on the inside (“outdoor”) and the outside (“peridomestic”) of the boundary fence, and by CDC light traps suspended outdoors in the household compound. The effects of ODRS on sand fly numbers inside sleeping huts were monitored by insecticide knockdown. After a single application, ODRS reduced P . orientalis abundance by 83%-99% in outdoor and peridomestic trap locations. ODRS also reduced numbers of P . orientalis found resting inside sleeping huts. RODRS reduced outdoor and peridomestic P . orientalis by 60%-88%. By direct comparison, RODRS was 58%-100% as effective as ODRS depending on the trapping method. These impacts were immediate on intervention and persisted during follow-up, representing a large fraction of the P . orientalis activity season. Relative costs of ODRS and RODRS delivery were $5.76 and $3.48 per household, respectively. The study demonstrates the feasibility and high entomological efficacy of ODRS and RODRS, and the expected low costs relative to current IVM practises. These methods represent novel sand fly vector control tools against predominantly exophilic/exophagic sand fly vectors, aimed to lower VL burdens in Sudan, with potential application in other endemic regions in East Africa.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Outdoor Residual Insecticide Spraying (ODRS), a New Approach for the Control of the Exophilic Vectors of Human Visceral Leishmaniasis: Phlebotomus orientalis in East Africa

et al. 2020

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“…orientalis collected from an area nearby Tabarakallah village with a similar environment revealed that 8.3% of meals from a human host [17], other studies showed that Ph. orientalis prefer feeding on humans and bovines [17,27,64,67,68,69], these findings supported the fact that Ph. orientalis is a vector of VL in the area.…”

Section: Discussionsupporting

confidence: 71%

Studies of host preferences of wild-caught Phlebotomus orientalis and Ph. papatasi vectors of leishmaniasis in Sudan

et al. 2020

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orientalis (N = 15, 48.4%). Blood meal analysis revealed human DNA in two Ph. orientalis (6.4%), hence, the anthropophilic index was 13.3%. Conclusions Multiplex PCR protocol described here allowed the identification of blood meal sources of many vertebrate species simultaneously. The results indicate that wild-caught Ph. orientalis are anthropophilic in the study areas. Further studies on larger blood-fed sample size are required to validate the potential applications of this technique in designing, monitoring and evaluating control programs, particularly in investigating the potential non-human hosts of leishmaniasis.

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“…In Sudan and other parts of the old world, most sand fly species including P. orientalis , show seasonal abundance with an increasing abundance during the dry season (January-May), reaching the peak in the early rainy season (April) and drastically drop in numbers during the wet season (August-November) [ 13 , 18 , 25 ]. Unfortunately, the authors were unable to access the study area during the rainy season and made collections so as to confirm such observations on seasonality of sand fly species in this far part of Sudan.…”

Section: Discussionmentioning

confidence: 99%

Kala-azar in Darfur: Evidence for indigenous transmission in Al-Malha Locality, North Darfur, western Sudan

Mohammed

Khalid²,

Aboud

2018

Parasites Vectors

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BackgroundRecent reports showed high numbers of visceral leishmaniasis cases in North Darfur, western Sudan. Due to a lack of previous studies, no information is available on local transmission of the disease in these areas. Therefore, a pilot entomological and epidemiological study was conducted in Al-Malha Locality during the year 2013, to investigate possibility of local transmission and places and times of the year where and when people contract the infection.MethodsKala-azar incidence data were obtained from records of Ministry of Health, North Darfur; Al-Malha rural hospital; and the Federal Ministry of Health, Division of Communicable and Non-communicable Diseases. Sand flies were collected using sticky paper and rodent burrow traps from five different microhabitats during three different phases of the year. Species identification was undertaken using appropriate taxonomic keys. Data were statistically analyzed to determine the distribution of kala-azar among different age groups and between sexes, and to compare the species richness and distribution of different sandfly species between the different microhabitats.ResultsThe most affected age groups with kala-azar during the period 2013–2016 were children between one and five years old and those under one year. Females were found to be more affected than males. A total of 918 sand fly specimens were collected using sticky paper and rodent burrow traps from five microhabitats. Identified specimens belong to 13 species; 5 Phlebotomus and 8 Sergentomyia. Phlebotomus orientalis, the principal vector of visceral leishmaniasis (VL) in Sudan and other East African countries, was found for the first time in the area. No other known vector of VL was found in the collection. The highest number of sand flies was recorded during the summer season (63%), with S. antennata (48%) and S. schwetzi (24.1%) being the most abundant species. Among Phlebotomus species, P. orientalis showed relatively high density (8.6%). A dry seasonal water course (called “Khor”) seems to be the most preferred habitat for most of the sand fly species since most of the collections (41.2%) were made from this site, followed by the rodent burrows.ConclusionsThe presence of P. orientalis and the high prevalence of VL in infants in the Al-Malha area provide the first evidence for local transmission of the parasite causing kala-azar in Darfur. Transmission is probably occurring during summer near the woodland where a high density of the vector was recorded. As a pre-requisite for designing effective control of VL in North Darfur, large scale entomological and epidemiological studies are recommended.

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Habitat preference and seasonal dynamics of Phlebotomus orientalis in urban and semi-urban areas of kala-azar endemic district of Kafta Humera, northwest Ethiopia

Cited by 13 publications

References 35 publications

Outdoor Residual Insecticide Spraying (ODRS), a New Approach for the Control of the Exophilic Vectors of Human Visceral Leishmaniasis: Phlebotomus orientalis in East Africa

Outdoor Residual Insecticide Spraying (ODRS), a New Approach for the Control of the Exophilic Vectors of Human Visceral Leishmaniasis: Phlebotomus orientalis in East Africa

Studies of host preferences of wild-caught Phlebotomus orientalis and Ph. papatasi vectors of leishmaniasis in Sudan

Kala-azar in Darfur: Evidence for indigenous transmission in Al-Malha Locality, North Darfur, western Sudan

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