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

Of the 378 AUFs, 168 patients (44.4%) were farmers, 41 patients (11.1%) performed forest-related activities, and 38 patients (10.1%) had a chronic disease or comorbid condition (Table 1) . Patients with AUF usually had high fever and a short course of illness, with a mean peak temperature of 39.2°C (95% CI: 39.1-39.3) and a median febrile duration of 5 (4) (5) (6) days. The most common accompanying symptom was headache (81.0%), followed by disappetite (54.5%), muscle pain (44.3%), dizziness (37.5%), cough (30.4%), back pain (28%) and other less frequent symptoms. A small proportion of AUFs also presented some clinical signs, such as rash (4.3%), lymphadenopathy (4.0%), eschar (3.2%), haemorrhage (2.4%), hepatomegaly (0.8%) and splenomegaly (0.5%). Shock, altered mental status, and seizures were not observed in our patients. The overall median (IQR) white blood cell count (WBC) was 6.9 (5-9.1) × 10 9 / L, and approximately one-fifth of the patients presented with an abnormal WBC classified as either leukocytosis (WBC > 12 × 10 9 /L; 35 [9.3%] patients) or leukopenia (WBC < 4 × 10 9 /L; 50 [13. 2%] patients). The overall median (IQR) platelet count (PLT) was 176.5 (133-223) × 10 9 /L, and one-third of the patients (129 patients; 34.1%) exhibited thrombocytopenia (PLT < 150 × 10 9 /L). The median (IQR) values of the aspartate aminotransferase level (AST) and alanine aminotransferase level (ALT) were 31.5 (23-61.5) and 26.5 (15.5-49.5 ) IU/L, respectively. Abnormal aminotransferase levels were observed in 116 (30.7%) patients, which presented either an elevated level of one (elevated AST in 21 cases, elevated ALT in 6 cases) or both of the enzymes (89 cases). Abdominal ultrasound confirmed some cases presenting with hepatomegaly or splenomegaly but did not indicate other abnormal signs. The chest X-ray and urine analysis results did not indicate specific abnormalities in any cases. No patients were excluded because of being human immunodeficiency virus (HIV) positive. No specific aetiological diagnoses were made for any febrile patients during the sampling period.