ABSTRACT
Viral hemorrhagic fevers (VHFs) can rarely be distinguished from each other or from other syndromes on clinical grounds alone; therefore laboratory diagnosis is essential for confirmation of the etiology. Specific diagnosis is made on the basis of virus isolation or demonstration of seroconversion, fourfold rise in antibody titer, or presence of specific Immunoglobulin M antibody. The most valuable specimens for diagnosis of VHF in acutely ill patients are whole blood or serum, collected as soon as possible after onset of symptoms. Specific identification of Rift Valley Fever antigen has been achieved in post-mortem human liver by immunodiffusion and in animal tissues by immunofluorescence. Marburg virus can be readily isolated from the blood, less often from urine and throat washings of acutely ill patients, and from post-mortem specimens including liver, spleen, heart, kidney, and brain. The indirect fluorescent antibody test is the preferred method for serological diagnosis of Argentinian hemorrhagic fever.
