In Ethiopia, 75% of the areas are malarious and an estimated 68% of the population lives in these areas [3,4,5]. The peak malaria transmission season in the country is from September to December, following the main rainy season from June/July to September. Although the malaria prevalence was not studied before, Ataye town is one of the malarious areas in Amhara region. In the present study microscopically confirmed cases were 2670 (8.4%) in Ataye hospital from 2013 to 2017. The minimum and maximum number of cases was recorded in 2013 and 2017, respectively. In this study, the confirmed malaria cases was higher than reported from other similar retrospective studies conducted in Bahirdar city 740 (5.0%) and Kombolcha town (2066, 7.52%), Ethiopia [3, 11]. However, the observed number of malaria cases was lower than reported [12, 13]. The observed variation might be due to difference in climate, altitude variation, laboratory personel skill in malaria parasite detection and community awareness about malaria transmission and control. In the study area, P. falciparum was the dominant Plasmodium species which accounted for 2087 (78.2%) of the reported cases in 5 years. This was slightly higher than a result reported from a retrospective study reported in Kola Diba health centre (75%) [13].
Malaria prevalence trend in the present study seems non-fluctuating as microscopically confirmed cases showed a steady increase from 2013 to 2016 for 4 consecutive years. However, the number of malaria cases was decreased in 2017. This was not in agreement with similar retrospective studies in Ethiopia [3, 11, 13]. With the exception of the year 2017 when the number of recorded P. vivax cases was higher 179/358 (50.0%) than P. falciparum cases, in other reviewed years P. falciparum cases dominated. This was more or less in agreement with previous studies [3, 11, 13]. This showed the life-threatening Plasmodium species; P. falciparum is the dominant species in the study area and other parts of the country. The finding was also in line with Ethiopian Ministry of Health report [5].
The maximum number of malaria cases in 2016 might be due to in consistent implementation of malaria prevention and control strategies in the study area. Compared to other reviewed years, the number of malaria-suspected patients and microscopically confirmed was the peak in this year which seems epidemic. The radical decrease of cases in 2017 might show there were collective action of stakeholder on awareness creation, budget increment and implementation of malaria prevention and control strategies.
In the present study, Plasmodium species infections were higher in males than females. Since the study area is a rural town main agriculture is the main livelihood. Therefore, due to the fact that males are mainly engaged in agricultural activities and other large projects. They may spend the night outside with their properties and agricultural products. This can make them easily exposed to malaria vector.
Malaria cases were high in age group 15–45 years old and the distribution of mixed infection was almost similar in all age groups. This might be due to the fact that these age groups are active and productive forces they involved in agricultural and other activities which need to travel exposing places and spending the night while keeping their products. This was in agreement with reports from Kola Diba and Kombolcha [3, 13].
Among the factors that affect malaria transmission, seasonal variation has direct role. In the present study, malaria cases were increased from September to December. This period is considered as the major malaria transmission period in Ethiopia after the heavy rain in July and August. Similarly, there was an increment of malaria cases from May to July.