Dengue hemorrhagic fever in an infant after primoinfection

Background. Dengue fever is an infectious disease caused by a flavivirus and transmitted by a vector. It causes dengue fever, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). When one of these last two appears, treatment consists of intensive fluid balance control. Case report. A 4-month-old female infant presented fever. She was admitted and later showed signs and symptoms of DHF followed by DSS. Serological diagnosis was confirmed, and appropriate treatment offered. The mother does not have evidence of prior infection. Discussion. One theory proposes that DHF occurs in infants when passively transferred maternal antibodies from a previous infection cause an enhanced immune response when the infant is infected by a different type of dengue virus. This theory does not explain the occurrence of DHF in our report. Factors not dependent on the host, such as virological factors, may be responsible.