Prospective case-control analysis of the aetiologies of acute undifferentiated fever in Vietnam

Le-Viet, Nhiem; Le, Viet-Nho; Chung, Hai; Phan, Duc-Tuan; Phan, Quang-Duong; Cao, Thanh-Van; Abat, Cédric; Raoult, Didier; Parola, Philippe

Attributing a detected pathogen to clinical diagnosis or to the cause of AUF is a major issue. Compared with the few similar studies in the literature, the inclusion of local afebrile controls in our study was essential for our interpretation and discussion of the results [8] . Our study allowed a final causative diagnosis to be made in over half (216/378; 57.1%) of the patients. A total of 185 patients were diagnosed with causes, and 31 patients were diagnosed with probable causes (Table 5) . Indeed, rickettsial agents, Leptospira, dengue virus, influenza virus, adenovirus and enterovirus were considered causes of AUF because these pathogens are known as infectious agents of acute febrile illness, and their frequencies were significantly greater in AUFs than in Controls in this study. It was more difficult to conclude whether other respiratory pathogens that were present in similar proportions in AUFs and Controls could be causes of AUF. Thus, in AUF patients with these pathogens, the pathogen was considered a probable cause if the patient presented with cough, breathlessness or sore throat. During the study period, the clinicians did not make a causative diagnosis for these cases due to the lack of diagnostic tools and because the patients presented with sporadic symptoms that did not link to physical examination results associated with a syndrome.