In terms of geographical proximity, South Gonder District is located 666 km away from Addis Ababa, the capital city of Ethiopia. All confirmed malaria patients who seek treatment in public health facilities were considered as the source population. The final sample size was calculated by using the assumption of "presence of side effect' with the odds ratio of 4.96, the percent of controls exposed at 2.6%, the percentage of cases exposed at 11.7% with a 95% confidence interval.