A retrospective analysis on the transmission of Plasmodium falciparum and Plasmodium vivax: the case of Adama City, East Shoa Zone, Oromia, Ethiopia

BACKGROUND: Malaria is more often considered a problem of the rural poor and the disease has been overlooked in urban settings for centuries due to the assumption that economic development in urban areas results in better life conditions, such as improved housing, drainage system and environmental changes that makes urban areas not conducive for breeding of the malaria vector. But, for many African countries, including Ethiopia, in most urban areas, although there are rapid developments, they are characterized by poor housing, lack of sanitation and drainage of surface water that would provide favourable conditions for vector breeding. Limited studies have been conducted as far as urban malaria is concerned in Ethiopia. The purpose of this study was to assess the status of falciparum and vivax malaria transmission in Adama City, Eastern Shoa Zone, Oromia, Ethiopia. Understanding the local epidemiology of malaria will help policy makers and other stakeholders to design and implement tailored cost effective and efficient intervention strategies targeting urban malaria. METHODS: The study was designed to analyse 5-year trends of malaria burden by two co-endemic species in Ethiopia (Plasmodium falciparum and Plasmodium vivax) and its annual and seasonal transmission pattern in the city, by using retrospective data on malaria burden by species, malaria related inpatient department (IPD) and outpatient department (OPD) consultations from 2013/14 to 2017/18. RESULTS: OPD retrospective data analysis indicated that adolescents and adults (≥ 15 years of age) were most affected by P. vivax 43.5% (2986/6862) and P. falciparum 31.7% (2179/6862). Plasmodium vivax was found to be a predominant species in causing malaria burden in the city exhibiting less seasonal occurrence, and the relative burden of P. vivax is gradually increasing from year to year over P. falciparum. CONCLUSION: Malaria is endemic to the city showing a public health problem. The productive group of the community, adolescents and adults, were most affected exacerbating poverty. Plasmodium vivax was found to be the highest malaria burden in the city and the observed epidemiological shift from P. falciparum to P. vivax calls for additional tailored intervention strategies to reduce the associated burden.