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Habte Tekie

Bio: Habte Tekie is an academic researcher from Addis Ababa University. The author has contributed to research in topics: Anopheles & Malaria. The author has an hindex of 20, co-authored 56 publications receiving 939 citations. Previous affiliations of Habte Tekie include UPRRP College of Natural Sciences.


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Journal ArticleDOI
TL;DR: Aedes aegypti is breeding in a wide range of artificial containers and to control these mosquitoes, the integration of different methods should be taken into consideration.
Abstract: Background and Objectives. Entomological survey was carried out from May-June to September-October 2014 to investigate the presence of dengue vectors in discarded tires and artificial water containers in houses and peridomestic areas. Methods. A cross-sectional immature stage survey was done indoors and outdoors in 301 houses. Mosquito larval sampling was conducted using pipette or dipper depending on container types. Larvae were identified morphologically and larval indices were also calculated. Results. A total of 750 containers were inspected, and of these 405 were positive for mosquito larvae. A total of 1,873 larvae were collected and morphologically identified as Aedes aegypti (n = 1580: 84.4%) and Culex (n = 293: 15.6%). The larval indices, house index, container index, and breteau index, varied from 33.3 to 86.2, from 23.2 to 73.9, and from 56.5 to 188.9, respectively. Conclusion. Aedes aegypti is breeding in a wide range of artificial containers. To control these mosquitoes, the integration of different methods should be taken into consideration.

109 citations

Journal ArticleDOI
TL;DR: To assess the impact of a small‐scale irrigation scheme in Ziway area, a semi‐arid area in the Central Ethiopian Rift Valley, on malaria transmission, a large number of cases of malaria are reported.
Abstract: Summary Objective To assess the impact of a small-scale irrigation scheme in Ziway area, a semi-arid area in the Central Ethiopian Rift Valley, on malaria transmission. Method Parasitological, entomological and socio-economic studies were conducted in a village with and a village without irrigation. Blood smear samples were taken from individuals during the dry and wet seasons of 2005/2006. Socio-economic data were collected from household heads and key agricultural and health informants through interviews and questionnaires. Larval and adult mosquitoes were sampled during the dry and short wet seasons of 2006. Female anopheline mosquitoes were tested by enzyme-linked immunosorbent assay for blood meal sources and sporozoite infections. Results Malaria prevalence was higher in the irrigated village (19%, P < 0.05) than the non-irrigated village (16%). In the irrigated village, malaria prevalence was higher in the dry season than in the wet season while the reverse occurred in the non-irrigated village. Households with access to irrigation had larger farm land sizes and higher incomes, but also higher prevalence of malaria. Larval and adult abundance of the malaria vectors, Anopheles arabiensis and Anopheles pharoensis, was higher in the irrigated than in the non-irrigated village throughout the study period. Furthermore, the abundance of An. pharoensis was significantly higher than that of An. arabiensis during the dry irrigated period of the year. Canal leakage pools, irrigated fields and irrigation canals were the major breeding habitats of the two vector mosquitoes. Plasmodium falciparum sporozoite infection rates of 1.18% and 0.66% were determined for An. arabiensis and An. pharoensis in the irrigated village. Peak biting activities of the vectors occurred before 22:00 h, which is a source of concern that the effectiveness of ITNs may be compromised as the mosquitoes feed on blood before people go to bed. Conclusion Irrigation schemes along the Ethiopian Rift Valley may intensify malaria by increasing the level of prevalence during the dry season. To reduce the intensity of malaria transmission in the small-scale irrigation schemes currently in operation in Ethiopia, year-round source reduction by using proper irrigation water management, coupled with health education, needs to be incorporated into the existing malaria control strategies. Objectif: Evaluer l’impact d’un regime d’irrigation a petite echelle dans la region de Ziway, une zone semi-aride dans la vallee du Rift dans le centre de l’Ethiopie, sur la transmission de la malaria. Methode: Des etudes parasitologiques, entomologiques et socio-economiques ont ete conduites dans un village avec et un village sans irrigation. Des frottis d’echantillons de sang ont ete obtenus des personnes pendant les saisons seches et humides de 2005/2006. Les donnees socio-economiques ont ete recueillies aupres des chefs de menage et des informateurs cles agricoles et de la sante au moyen d’interviews et de questionnaires. Des larves et des moustiques adultes ont eteechantillonnes au cours de la saison seche et de la courte saison humide de 2006. Les moustiques anopheles femelles ont ete testes par ELISA pour les sources d’origine du sang et pour les infections a sporozoaires. Resultats: La prevalence de la malaria etait plus elevee dans le village irrigue (19,2%; P < 0,05) que dans le village non-irrigue (16,0%). Dans le village irrigue, la prevalence de la malaria etait plus elevee pendant la saison seche que pendant la saison des pluies alors que l’inverse etait observe dans le village non-irrigue. Les menages ayant acces a l’irrigation avaient des terrains agricoles de plus grandes tailles et des revenus plus eleves, mais aussi une plus forte prevalence de malaria. Une abondance de larves et d’adultes des vecteurs de la malaria, An. arabiensis et An. pharoensisetait plus elevee dans le village irrigue que dans le non-irrigue tout au long de la periode etudiee. En outre, l’abondance d’An. pharoensisetait significativement plus elevee que celle d’An. arabiensis durant la periode seche irriguee de l’annee. Les canaux de fuites des bassins, les champs irrigues et les canaux d’irrigation etaient les principaux habitats de reproduction des deux moustiques vecteurs. Des taux d’infection a sporozoites de P. falciparum de 1,18% et 0,66% ont ete determines pour An. arabiensis et An. pharoensis dans le village irrigue. Le pic des activites de piqure des vecteurs a eu lieu avant 22h00, ce qui est une source de preoccupation que l’efficacite des moustiquaires a insecticide pourrait etre compromise car les moustiques se nourrissent de sang avant l’heure de coucher des gens. Conclusion: Les systemes d’irrigation dans la vallee du Rift ethiopien pourraient intensifier la malaria en augmentant le niveau de prevalence au cours de la saison seche. Afin de reduire l’intensite de la transmission de la malaria dans les petits systemes d’irrigation a petite echelle actuellement en operation en Ethiopie, une reduction des sources tout au long de l’annee par l’utilisation d’une gestion appropriee des eaux d’irrigation, associee a l’education sanitaire, doit etre integree dans les strategies existantes de lutte contre la malaria. Objetivo: Evaluar el impacto sobre la transmision de malaria de un esquema de irrigacion a pequena escala en el area de Ziway, un area semi-arida del Gran Valle del Rift de Etiopia Central. Metodo: Se realizaron estudios parasitologicos, entomologicos y socio-economicos en un poblado con y un poblado sin irrigacion. Durante las estaciones seca y lluviosa del 2005/2006 se tomaron muestras de sangre para laminas de los individuos del estudio. Mediante entrevistas y cuestionarios a los cabeza de familia e informantes clave agricultores y sanitarios, se recolectaron los datos socio-economicos. Se muestrearon mosquitos adultos y larvas durante las estaciones seca y lluviosa del 2006. Los mosquitos anofelinos hembra fueron testados mediante un ensayo ELISA para fuentes de comida e infecciones por esporozoitos. Resultados: La prevalencia de malaria era mas alta en el poblado con irrigacion (19.2%, P < 0.05) que en el no irrigado (16.0%). En el poblado con irrigacion la prevalencia de malaria era mas alta en la estacion seca que en la lluviosa, mientras que lo contrario ocurria en el poblado no irrigado. Los hogares con acceso a irrigacion tenian terrenos cultivables mas grandes y mayores ingresos, pero tambien una mayor prevalencia de malaria. La abundancia de larvas y adultos de los vectores de malaria, An. arabiensis y An. pharoensis fue mayor en el poblado irrigado que en el no irrigado durante todo el periodo de estudio. Mas aun, la abundancia de An. pharoensis era significativamente mayor que la de An. arabiensis durante el periodo seco e irrigado del ano. Las piscinas de drenaje de los canales, los campos irrigados y los canales de irrigacion fueron los principales habitats de reproduccion de los dos mosquitos vectores. Las tasas de infeccion de esporozoitos de P. falciparum de 1.18 y 0.66% se determinaron para An. arabiensis y An. pharoensis en el poblado irrigado. Los picos de actividad de mordedura de los vectores ocurria antes de las 22:00 horas, siendo una fuente de preocupacion ya que la efectividad de las mosquiteras puede estar comprometida puesto que los mosquitos se alimentan de sangre antes de que las personas se vayan a la cama. Conclusion: Los esquemas de irrigacion a lo largo del Valle de Rift Etiope podrian intensificar la malaria al aumentar los niveles de prevalencia durante la estacion seca. Con el fin de reducir la intensidad de la transmision de malaria en los esquemas de irrigacion a pequena escala en operacion en Etiopia, se requiere incorporar a las estrategias de control de la malaria ya existentes, una reduccion de las fuentes durante todo el ano manejando adecuadamente la irrigacion apropiada, junto con una educacion sanitaria.

80 citations

Journal ArticleDOI
TL;DR: Proper canal water management could reduce vector abundance and malaria transmission in the irrigated villages, revealing that the irrigation schemes resulted in intensified malaria transmission due to poor Canal water management.
Abstract: Background: Irrigation schemes have been blamed for the increase in malaria in many parts of sub-Saharan Africa. However, proper water management could help mitigate malaria around irrigation schemes in this region. This study investigates the link between irrigation and malaria in Central Ethiopia. Methods: Larval and adult mosquitoes were collected fortnightly between November 2009 and October 2010 from two irrigated and two non-irrigated (control) villages in the Ziway area, Central Ethiopia. Daily canal water releases were recorded during the study period and bi-weekly correlation analysis was done to determine relationships between canal water releases and larval/adult vector densities. Blood meal sources (bovine vs human) and malaria sporozoite infection were tested using enzyme-linked immunosorbent assay (ELISA). Monthly malaria data were also collected from central health centre of the study villages. Results: Monthly malaria incidence was over six-fold higher in the irrigated villages than the non-irrigated villages. The number of anopheline breeding habitats was 3.6 times higher in the irrigated villages than the non-irrigated villages and the most common Anopheles mosquito breeding habitats were waterlogged field puddles, leakage pools from irrigation canals and poorly functioning irrigation canals. Larval and adult anopheline densities were seven- and nine-fold higher in the irrigated villages than in the non-irrigated villages, respectively, during the study period. Anopheles arabiensis was the predominant species in the study area. Plasmodium falciparum sporozoite rates of An. arabiensis and Anopheles pharoensis were significantly higher in the irrigated villages than the non-irrigated villages. The annual entomological inoculation rate (EIR) calculated for the irrigated and non-irrigated villages were 34.8 and 0.25 P. falciparum infective bites per person per year, respectively. A strong positive correlation was found between bi-weekly anopheline larval density and canal water releases. Similarly, there was a strong positive correlation between bi-weekly vector density and canal water releases lagged by two weeks. Furthermore, monthly malaria incidence was strongly correlated with monthly vector density lagged by a month in the irrigated villages. Conclusion: The present study revealed that the irrigation schemes resulted in intensified malaria transmission due to poor canal water management. Proper canal water management could reduce vector abundance and malaria transmission in the irrigated villages.

69 citations

Journal ArticleDOI
TL;DR: Results show much greater mosquito human-biting activities occurring outdoors than indoors and during early parts of the night, implying higher outdoor malaria transmission potential in the area, suggest high potential intervention impact of IRS and LLINs on indoor malaria transmission.
Abstract: Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are the key malaria vector control interventions in Ethiopia. The success of these interventions rely on their efficacy to repel or kill indoor feeding and resting mosquitoes. This study was undertaken to monitor human-biting patterns of Anopheles species in south-central Ethiopia. Human-biting patterns of anophelines were monitored for 40 nights in three houses using human landing catches (HLC) both indoors and outdoors between July and November 2014, in Edo Kontola village, south-central Ethiopia. This time coincides with the major malaria transmission season in Ethiopia, which is usually between September and November. Adult mosquitoes were collected from 19:00 to 06:00 h and identified to species. Comparisons of HLC data were done using incidence rate ratio (IRR) calculated by negative binomial regression. The nocturnal biting activities of each Anopheles species was expressed as mean number of mosquitoes landing per person per hour. To assess malaria infections in Anopheles mosquitoes the presence of Plasmodium falciparum and P. vivax circumsporozoite proteins (CSP) were determined by enzyme-linked immunosorbent assay (ELISA). Altogether 3,408 adult female anophelines were collected, 2,610 (76.6 %) outdoors and 798 (23.4 %) indoors. Anopheles zeimanni was the predominant species (66.5 %) followed by An. arabiensis (24.8 %), An. pharoensis (6.8 %) and An. funestus (s.l.) (1.8 %). The overall mean anopheline density was 3.3 times higher outdoors than indoors (65.3 vs 19.9/person/night, IRR: 3.3, 95 % CI: 1.1–5.1, P = 0.001). The mean density of An. zeimanni, An. pharoensis and An. funestus (s.l.) collected outdoors was significantly higher than indoors for each species (P < 0.05). However, the mean An. arabiensis density outdoors was similar to that indoors (11.8 vs 9.4/person/night, IRR: 1.3, 95 % CI: 0.8–1.9, P = 0.335). The mean hourly human-biting density of An. arabiensis was greater outdoors than indoors and peaked between 21:00 and 22:00 h. However, An. arabiensis parous population showed high indoor man biting activities during bedtimes (22:00 to 05:00 h) when the local people were indoor and potentially protected by IRS and LLINs. All mosquito samples tested for CSP antigen were found negative to malaria parasites. Results show much greater mosquito human-biting activities occurring outdoors than indoors and during early parts of the night, implying higher outdoor malaria transmission potential in the area. However, high bedtime (22:00 to 05:00 h) indoor biting activities of parous An. arabiensis suggest high potential intervention impact of IRS and LLINs on indoor malaria transmission.

58 citations

Journal ArticleDOI
TL;DR: It is shown that gravid Anopheles arabiensis are attracted and oviposit in response to the odour present in the air surrounding rice, which provides important substrates for the development of novel and cost-effective control measures that target female malaria mosquitoes, irrespective of indoor or outdoor feeding and resting patterns.
Abstract: Mosquito oviposition site selection is essential for vector population dynamics and malaria epidemiology. Irrigated rice cultivations provide ideal larval habitats for malaria mosquitoes, which has resulted in increased prevalence of the malaria vector, Anopheles arabiensis, in sub-Saharan Africa. The nature and origin of the cues regulating this behaviour are only now being elucidated. We show that gravid Anopheles arabiensis are attracted and oviposit in response to the odour present in the air surrounding rice. Furthermore, we identify a synthetic rice odour blend, using electrophysiological and chemical analyses, which elicits attraction and oviposition in laboratory assays, as well as attraction of free-flying gravid mosquitoes under semi-field conditions. This research highlights the intimate link between malaria vectors and agriculture. The identified volatile cues provide important substrates for the development of novel and cost-effective control measures that target female malaria mosquitoes, irrespective of indoor or outdoor feeding and resting patterns.

56 citations


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TL;DR: This review highlights significant regional changes in vector and pathogen distribution reported in temperate, peri‐Arctic, Arctic, and tropical highland regions during recent decades, changes that have been anticipated by scientists worldwide.
Abstract: Climate change is one of the greatest threats to human health in the 21st century. Climate directly impacts health through climatic extremes, air quality, sea-level rise, and multifaceted influences on food production systems and water resources. Climate also affects infectious diseases, which have played a significant role in human history, impacting the rise and fall of civilizations and facilitating the conquest of new territories. Our review highlights significant regional changes in vector and pathogen distribution reported in temperate, peri-Arctic, Arctic, and tropical highland regions during recent decades, changes that have been anticipated by scientists worldwide. Further future changes are likely if we fail to mitigate and adapt to climate change. Many key factors affect the spread and severity of human diseases, including mobility of people, animals, and goods; control measures in place; availability of effective drugs; quality of public health services; human behavior; and political stability and conflicts. With drug and insecticide resistance on the rise, significant funding and research efforts must to be maintained to continue the battle against existing and emerging diseases, particularly those that are vector borne.

267 citations

Journal ArticleDOI
TL;DR: Despite low quality evidence, the direction and consistency of effects indicate that housing is an important risk factor for malaria.
Abstract: Background: The global malaria burden has fallen since 2000, sometimes before large-scale vector control programmes were initiated. While long-lasting insecticide-treated nets and indoor residual spraying are highly effective interventions, this study tests the hypothesis that improved housing can reduce malaria by decreasing house entry by malaria mosquitoes. Methods: A systematic review and meta-analysis was conducted to assess whether modern housing is associated with a lower risk of malaria than traditional housing, across all age groups and malaria-endemic settings. Six electronic databases were searched to identify intervention and observational studies published from 1 January, 1900 to 13 December, 2013, measuring the association between house design and malaria. The primary outcome measures were parasite prevalence and incidence of clinical malaria. Crude and adjusted effects were combined in fixed- and random-effects meta-analyses, with sub-group analyses for: overall house type (traditional versus modern housing); screening; main wall, roof and floor mater ials; eave type; ceilings and elevation. Results: Of 15,526 studies screened, 90 were included in a qualitative synthesis and 53 reported epidemiological outcomes, included in a meta-analysis. Of these, 39 (74 %) showed trends towards a lower risk of epidemiological outcomes associated with improved house features. Of studies assessing the relationship between modern housing and malaria infection (n=11) and clinical malaria (n=5), all were observational, with very low to low quality evidence. Residents of modern houses had 47 % lower odds of malaria infection compared to traditional houses (adjusted odds ratio (OR) 0°53, 95 % confidence intervals (CI) 0°42–0°67, p<0°001, five studies) and a 45–65 % lower odds of clinical malaria (case–control studies: adjusted OR 0°35, 95 % CI 0°20–0°62, p <0°001, one study; cohort studies: adjusted rate ratio 0°55, 95 % CI 0°36–0°84, p=0°005, three studies). Evidence of a high risk of bias was found within studies. Conclusions: Despite low quality evidence, the direction and consistency of effects indicate that housing is an important risk factor for malaria. Future research should evaluate the protective effect of specific house features and incremental housing improvements associated with socio-economic development.

239 citations

Journal ArticleDOI
TL;DR: It is shown, through a review of contemporary modelling studies, that no consensus on how future changes in climatic conditions will impact mosquito-borne diseases exists and research should not focus solely on the role of climate change but instead consider growing evidence for additional factors that modulate disease risk.
Abstract: More than 80% of the global population is at risk of a vector-borne disease, with mosquito-borne diseases being the largest contributor to human vector-borne disease burden. Although many global processes, such as land-use and socioeconomic change, are thought to affect mosquito-borne disease dynamics, research to date has strongly focused on the role of climate change. Here, we show, through a review of contemporary modelling studies, that no consensus on how future changes in climatic conditions will impact mosquito-borne diseases exists, possibly due to interacting effects of other global change processes, which are often excluded from analyses. We conclude that research should not focus solely on the role of climate change but instead consider growing evidence for additional factors that modulate disease risk. Furthermore, future research should adopt new technologies, including developments in remote sensing and system dynamics modelling techniques, to enable a better understanding and mitigation of mosquito-borne diseases in a changing world.

223 citations

Journal ArticleDOI
TL;DR: Despite annual variations, multiple collections performed over consecutive years provided homogeneous patterns of the potential behavior of leishmaniasis vectors in selected sites, which it is proposed may represent sentinel areas for future monitoring.
Abstract: Background The recent geographical expansion of phlebotomine vectors of Leishmania infantum in the Mediterranean subregion has been attributed to ongoing climate changes. At these latitudes, the activity of sand flies is typically seasonal; because seasonal phenomena are also sensitive to general variations in climate, current phenological data sets can provide a baseline for continuing investigations on sand fly population dynamics that may impact on future scenarios of leishmaniasis transmission. With this aim, in 2011–2013 a consortium of partners from eight Mediterranean countries carried out entomological investigations in sites where L. infantum transmission was recently reported. Methods/Principal Findings A common protocol for sand fly collection included monthly captures by CDC light traps, complemented by sticky traps in most of the sites. Collections were replicated for more than one season in order to reduce the effects of local weather events. In each site, the trapping effort was left unchanged throughout the survey to legitimate inter-seasonal comparisons. Data from 99,000 collected specimens were analyzed, resulting in the description of seasonal dynamics of 56,000 sand flies belonging to L. infantum vector species throughout a wide geographical area, namely P. perniciosus (Portugal, Spain and Italy), P. ariasi (France), P. neglectus (Greece), P. tobbi (Cyprus and Turkey), P. balcanicus and P. kandelakii (Georgia). Time of sand fly appearance/disappearance in collections differed between sites, and seasonal densities showed variations in each site. Significant correlations were found between latitude/mean annual temperature of sites and i) the first month of sand fly appearance, that ranged from early April to the first half of June; ii) the type of density trend, varying from a single peak in July/August to multiple peaks increasing in magnitude from May through September. A 3-modal trend, recorded for P. tobbi in Cyprus, represents a novel finding for a L. infantum vector. Adults ended the activity starting from mid September through November, without significant correlation with latitude/mean annual temperature of sites. The period of potential exposure to L.infantum in the Mediterranean subregion, as inferred by adult densities calculated from 3 years, 37 sites and 6 competent vector species, was associated to a regular bell-shaped density curve having a wide peak center encompassing the July-September period, and falling between early May to late October for more than 99% of values. Apparently no risk for leishmaniasis transmission took place from December through March in the years considered. We found a common pattern of nocturnal females activity, whose density peaked between 11 pm and 2 am. Conclusions Despite annual variations, multiple collections performed over consecutive years provided homogeneous patterns of the potential behavior of leishmaniasis vectors in selected sites, which we propose may represent sentinel areas for future monitoring. In the investigated years, higher potential risk for L. infantum transmission in the Mediterranean was identified in the June-October period (97% relative vector density), however such risk was not equally distributed throughout the region, since density waves of adults occurred earlier and were more frequent in southern territories.

156 citations

Journal ArticleDOI
TL;DR: Traditional medicine, mainly involving the use of medicinal plants, is playing a significant role in meeting the primary healthcare needs of the three ethnic groups and will be used to support the country’s human and livestock health care system and improve lives and livelihoods.
Abstract: Plants have traditionally been used for treatment of human and livestock ailments in Ethiopia by different ethnic and social groups. However, this valuable source of knowledge is not adequately documented, which impedes their widespread use, evaluation and validation. Here, we recorded indigenous knowledge and standard practices for human and livestock disease control, of three ethnic groups (Aari, Maale and Bena-Tsemay) in South Omo Zone of Southern Nations, Nationalities and Peoples Regional State, Ethiopia. A cross-sectional study was carried out using a semi-structured questionnaire to document knowledge of 50 traditional healers (40 male and 10 female) in medicinal plant use for treatment of human and livestock ailments. Descriptive statistics were used to analyze and summarize the ethno-botanical data. Ninety-one plants, with claimed medicinal properties against a total of 34 human and livestock ailments, were reported and botanically identified as belonging to 57 genera and 33 plant families. Most of the plant species reported belonged to one of seven major families: Lamiaceae, Solanaceae, Menispermiaceae, Fabaceae, Asteraceae, Plumbaginaceae and Geraniaceae. Woody plants (shrubs 21% and trees 29%) were the major growth form used, whilst roots (40%) and leaves (35%) were the major plant parts used in the study areas. Healers mostly practice oral administration of plant preparations (65%). Multiple medicinal plants were cited against particular ailments, and mixing of two or more different medicinal plants (14.3%) against a single ailment was also commonly reported. This study showed that traditional medicine, mainly involving the use of medicinal plants, is playing a significant role in meeting the primary healthcare needs of the three ethnic groups. Acceptance of traditional medicine and limited access to modern healthcare facilities could be considered as the main factors for the continuation of the practice. Documented knowledge of the traditional healers can be used to support the country’s human and livestock health care system and improve lives and livelihoods. Information generated will be used in future studies to validate bioactivity of selected medicinal plants used by traditional healers, so to increase their acceptability in health care systems both nationally and internationally.

144 citations