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

Vietnam has been highly successful in controlling malaria, but despite the rapid decline in malaria, fever caused by nonmalarial aetiologies remains a common reason for hospital admission [4] . Although AUF is observed daily in hospitals, the precise cause is usually not known due to the lack of diagnostic tools in most hospitals in the country. In a few recent studies, dengue infection (33.6%), influenza (4.1%) and other respiratory viral infections (5.3%) were reported as common causes of AUF in southern Vietnam [5, 6] . However, these studies likely focused only on some pathogen groups of viruses or bacteria and did not include afebrile controls. In a case-control study with 1193 febrile patients and 282 afebrile individuals conducted in Cambodia, which shares a border with Vietnam, the most frequent pathogens detected were Plasmodium vivax (33.4%), Plasmodium falciparum (26.5%), Leptospira (9.4%), influenza virus (8.9%), Dengue virus (6.3%) and rickettsial agents (4.1%), but a significant proportion of malaria parasites and Leptospira were also observed in the control group [7] . Such data require careful interpretation of the role of pathogens in febrile illness, and more clinical studies are needed to verify the findings.