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

Diagnosis of rickettsial infections may be difficult in clinical practice due to the diversity of manifestations, particularly in developing countries where diagnostic tests are usually lacking. Typical clinical signs, including eschar and skin rash, were rarely observed in a patient with dual genotype of O. tsutsugamushi infection [25] . In most cases, typical clinical signs of rickettsial infections might be absent or missed, resulting in the misdiagnosis of patients as having AUF. A finding of skin rash or eschar can increase the accuracy of the diagnosis of rickettsial infections. Here, among 16 AUF patients with rash, four patients had rickettsial infections (three cases of murine typhus and one case of scrub typhus), one had leptospirosis, one was coinfected with scrub typhus and leptospirosis, and 10 patients had an undetected cause. The appearance of rash in scrub typhus varies depending on the O. tsutsugamushi genotype and might be less frequent in Vietnamese patients with scrub typhus [25, 26] . Among the patients with scrub typhus, eschar was present in 47.4% of patients, similar to the proportion observed in our previous study [26] .