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Volume 50, Number 1, February 2017

Identification of factors for physicians to facilitate early differential diagnosis of scrub typhus, murine typhus, and Q fever from dengue fever in Taiwan 

Ko Chang, Nan-Yao Lee, Wen-Chien Ko, Jih-Jin Tsai, Wei-Ru Lin, Tun-Chieh Chen, Po-Liang Lu, Yen-Hsu Chen


Corresponding author:

Po-Liang Lu, Corresponding author. Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Number 100 Tzyou 1st Road, Kaohsiung, Taiwan. 


Background and purpose: 

Dengue fever, rickettsial diseases, and Q fever are acute febrile illnesses with similar manifestations in tropical areas. Early differential diagnosis of scrub typhus, murine typhus, and Q fever from dengue fever may be made by understanding the distinguishing clinical characteristics and the significance of demographic and weather factors. 



We conducted a retrospective study to identify clinical, demographic, and meteorological characteristics of 454 dengue fever, 178 scrub typhus, 143 Q fever, and 81 murine typhus cases in three Taiwan hospitals. 



Case numbers of murine typhus and Q fever correlated significantly with temperature and rainfall; the scrub typhus case number was only significantly related with temperature. Neither temperature nor rainfall correlated with the case number of dengue fever. The rarity of dengue fever cases from January to June in Taiwan may be a helpful clue for diagnosis in the area. A male predominance was observed, as the male-to-female rate was 2.1 for murine typhus and 7.4 for Q fever. Multivariate analysis revealed the following six important factors for differentiating the rickettsial diseases and Q fever group from the dengue fever group: fever ≥8 days, alanine aminotransferase > aspartate aminotransferase, platelets >63,000/mL, C-reactive protein >31.9 mg/L, absence of bone pain, and absence of a bleeding syndrome. 



Understanding the rarity of dengue in the first half of a year in Taiwan and the six differentiating factors may help facilitate the early differential diagnosis of rickettsial diseases and Q fever from dengue fever, permitting early antibiotic treatment. 


Key words:

dengue fever, murine typhus, Q fever, rainfall, scrub typhus, temperature