Abstract
Fuzzy inference systems (FIS) have been widely used in medical diagnosis. FIS uses fuzzy reasoning in order to represent the knowledge of experts about certain problem in a systematic manner. In the last decade, Dengue fever has been considered as a severe disease in the western area of Saudi Arabia, where millions of pilgrims come from all over the world to perform their Hajj. FIS can be used to early diagnose this disease and reduce its severity. However, because of many number of factors associated with Dengue, using traditional FIS causes generating huge number of fuzzy rules, which leads to high complexity. In order to tackle this issue, this paper proposes a Hierarchical Fuzzy Inference system (HFIS) that can be used to diagnose Dengue fever. The proposed model is compared to one from the literature and shows more promising results from the perspective of simplicity and extendibility.