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Background Ethiopia has shown notable progress in reducing the burden of malaria over the past two decades. Because of this progress, the country has shifted efforts from control to elimination of malaria. This study was conducted to analyse the malaria epidemiology and stratification of incidence in the malaria elimination setting in eastern Ethiopia. Methods A retrospective study was conducted to analyse the epidemiology of malaria by reviewing the district health office data from 2013 to 2019 in Harari Region. In addition, three years of sub-district level malaria data were used to stratify the malaria transmission intensity. Malaria interventions (Long-lasting insecticidal nets [LLIN] and indoor residual spraying [IRS]) employed were reviewed to analyse the intervention coverage at the Regional level. Descriptive statistics were used to show the malaria transmission in terms of years, season and species of the malaria parasite. Incidence rate per 1000 population and death rate per 1 000 000 population at risk were computed using the total population of each year. Results In the Harari Region, malaria incidence showed a more pronounced declining trend from 2017 to 2019. Plasmodium falciparum, P. vivax and mixed infections accounted for 69.2%, 30.6% and 0.2% of the cases, respectively. There was an increment in malaria intervention coverage and improved malaria diagnosis. In the year 2019 the coverage of LLIN and IRS in the Region were 93.4% and 85.1% respectively. The annual malaria incidence rate dropped from 42.9 cases per 1000 population in 2013 to 6.7 cases per 1000 population in 2019. Malaria-related deaths decreased from 4.7 deaths per 1 000 000 people annually in 2013 to zero, and there have been no deaths reported since 2015. The malaria risk appears to be heterogeneous and varies between districts. A higher number of malaria cases were recorded in Erer and Jenella districts, which constitute 62% of the cases in the Region. According to the sub-district level malaria stratification, there was shrinkage in the malaria transmission map and about 70% of the sub-districts have achieved elimination targets. Conclusions In the Harari Region, malaria morbidity and mortality have been significantly declined. Thus, if this achievement is sustained and scaling-up of the existing malaria prevention and control strategies by focusing on those populations living in the higher malaria transmission districts and sub-districts, planning of malaria elimination from the study area might be feasible.

Abstract Background: Ethiopia has shown a notable progress in reducing the burden of malaria over the last two decades. Based on the progress, the country shifted from control to elimination of malaria. This study was conducted to analyse trends in malaria cases and stratification of malaria incidence in the malaria elimination setting in eastern Ethiopia. Methods: A retrospective malaria data recorded from 2013 to 2019 were reviewed from Harari Region, eastern Ethiopia. In addition, three years malaria data were used to assess the sub-district ( kebele ) level stratification of malaria incidence. Results: A total of 44,882 (46.9%) malaria cases were detected from 95,629 malaria-suspected outpatient diagnosed in Harari Region from 2013 to 2019. Of these, 41,046 were confirmed malaria cases (microscopically and rapid diagnostic test) while 3,836 were reported as clinical cases. In the region, malaria trend was fluctuating year to year, the high peak was reported in 2016 but malaria cases showed decreasing trend in number of malaria cases from 2017 to 2019. Plasmodium falciparum , P. vivax and mixed infections were accounted for 69.2%, 30.6% and 0.2% of the cases, respectively. The malaria risk appears to be heterogeneous and varies between districts, higher number of malaria cases were recorded in Jenella, Erer and Amir Nur districts, and about 80% of the cases were from these districts. According to the latest (2019) sub-district ( kebele ) level epidemiological data of malaria stratification, 8.3% of the sub-districts in the Harari region reported no malaria and a majority (61.1%) of sub-districts reported fewer than five cases per thousand population. Furthermore, there were no high malaria strata in the Region. The highest peak of malaria cases in the Region was reported from September to November followed by from April to May. Conclusions: In the Harari Region, the retrospective malaria data showed a significant declining trend. Thus, if this achievement is sustained and scaling-up of the existing malaria prevention and control strategies by focusing on those populations living in the higher malaria transmission districts and sub-districts, planning of malaria elimination from the study area might be feasible. Key words: Elimination, Harari region, Ethiopia, Incidence, Malaria, Sub-district, Stratification

Background: Ethiopia has shown a notable progress in reducing the burden of malaria over the last two decades. Based on the progress, the country shifted from control to elimination of malaria. This study was conducted to analyse trends in malaria cases and stratification of malaria incidence in the malaria elimination setting in eastern Ethiopia.Methods: A retrospective malaria data recorded from 2013 to 2019 were reviewed from Harari Region, eastern Ethiopia. In addition, three years malaria data were used to assess the sub-district (kebele) level stratification of malaria incidence.Results: A total of 44,882 (46.9%) malaria cases were detected from 95,629 malaria-suspected outpatient diagnosed in Harari Region from 2013 to 2019. Of these, 41,046 were confirmed malaria cases (microscopically and rapid diagnostic test) while 3,836 were reported as clinical cases. In the region, malaria trend was fluctuating year to year, the high peak was reported in 2016 but malaria cases showed decreasing trend in number of malaria cases from 2017 to 2019. Plasmodium falciparum, P. vivax and mixed infections were accounted for 69.2%, 30.6% and 0.2% of the cases, respectively. The malaria risk appears to be heterogeneous and varies between districts, higher number of malaria cases were recorded in Jenella, Erer and Amir Nur districts, and about 80% of the cases were from these districts. According to the latest (2019) sub-district (kebele) level epidemiological data of malaria stratification, 8.3% of the sub-districts in the Harari region reported no malaria and a majority (61.1%) of sub-districts reported fewer than five cases per thousand population. Furthermore, there were no high malaria strata in the Region. The highest peak of malaria cases in the Region was reported from September to November followed by from April to May.Conclusions: In the Harari Region, the retrospective malaria data showed a significant declining trend. Thus, if this achievement is sustained and scaling-up of the existing malaria prevention and control strategies by focusing on those populations living in the higher malaria transmission districts and sub-districts, planning of malaria elimination from the study area might be feasible.

Anopheles stephensi, an efficient Asian malaria vector, recently spread into the Horn of Africa and may increase malaria receptivity in African urban areas. We assessed occurrence, genetic complexity, blood meal source and infection status of An. stephensi in Awash Sebat Kilo town, Ethiopia. We used membrane feeding assays to assess competence of local An. stephensi to P. vivax and P. falciparum isolates from clinical patients. 75.3% of the examined waterbodies were infested with An. stephensi developmental stages that were genetically closely related to isolates from Djibouti and Pakistan. Both P. vivax and P. falciparum were detected in wild-caught adult An. stephensi. Local An. stephensi was more receptive to P. vivax compared to a colony of An. arabiensis. We conclude that An. stephensi is an established vector in this part of Ethiopia, highly permissive for local P. vivax and P. falciparum isolates and presents an important new challenge for malaria control.Summary of the articleAn. stephensi, a metropolitan malaria vector that recently expanded to the Horn of African, was highly susceptible to local P. falciparum and P. vivax isolates from Ethiopia and may increase malariogenic potential of rapidly expanding urban settings in Africa.