Table 2.

Shared features of hemorrhagic viruses.

  • Most hemorrhagic viruses are transmitted by infectious agents that are arthropod-borne (mosquitoes, ticks); however, person-to-person transmission may occur with five viruses through direct contact with blood or secretions: Lassa, Marburg, Congo-Crimean, Ebola, Sabià. Animal excreta have also been implicated in transmission.

  • Asymptomatic animal reservoirs of viruses are generally rodents (Hantavirus, Lassa, Guanarito, Junin, Machupo) although monkeys and primates may perpetuate disease through a sylvatic cycle (yellow fever, dengue). Many viruses have not had reservoirs identified (Ebola, Marburg, Sabià).

  • Clinical manifestations of VHF are associated with a short incubation period (usually less than 21 days). Clinical pathology has common themes; capillary leak, thrombocytopenia, leukopenia, DIC and hepatocellular destruction are often described. Early vascular dysregulation with hypotension, flushing, and injected conjunctivae is commonly followed by hemorrhage, shock and multi-organ dysfunction. Milder undifferentiated febrile illnesses and subclinical infections with asymptomatic seroconversion and potential immunity have also been described for all of the VHF viruses.

  • Diagnosis of VHF depends upon the demonstration of the infecting virus in an acute serum sample by antigen-detection ELISA or reverse transcription and subsequent polymerase chain reaction (RT-PCR). IgM antibodies can also be helpful in making a diagnosis in early convalescence by IgM capture ELISA technique. Classical histopathology in autopsy specimens may unfortunately be the first clue.

  • Supportive therapy is the mainstay of management of most VHFs, better accomplished in countries with sophisticated technological support that is often lacking in endemic developing countries. Antiviral therapy with ribavirin is recommended for all Arenaviridae and Bunyaviridae infections (with the exception of Hantavirus pulmonary syndrome). Unfortunately, ribavirin is often difficult and expensive to obtain in an endemic setting.

  • Control measures generally involve meticulous hospital infection control efforts, strict isolation for certain agents, concurrent disinfection, and contact and source reporting to public health authorities. Vaccines can protect against some of the VHF viruses.

 

  • Most hemorrhagic viruses are transmitted by infectious agents that are arthropod-borne (mosquitoes, ticks); however, person-to-person transmission may occur with five viruses through direct contact with blood or secretions: Lassa, Marburg, Congo-Crimean, Ebola, Sabià. Animal excreta have also been implicated in transmission.

  • Asymptomatic animal reservoirs of viruses are generally rodents (Hantavirus, Lassa, Guanarito, Junin, Machupo) although monkeys and primates may perpetuate disease through a sylvatic cycle (yellow fever, dengue). Many viruses have not had reservoirs identified (Ebola, Marburg, Sabià).

  • Clinical manifestations of VHF are associated with a short incubation period (usually less than 21 days). Clinical pathology has common themes; capillary leak, thrombocytopenia, leukopenia, DIC and hepatocellular destruction are often described. Early vascular dysregulation with hypotension, flushing, and injected conjunctivae is commonly followed by hemorrhage, shock and multi-organ dysfunction. Milder undifferentiated febrile illnesses and subclinical infections with asymptomatic seroconversion and potential immunity have also been described for all of the VHF viruses.

  • Diagnosis of VHF depends upon the demonstration of the infecting virus in an acute serum sample by antigen-detection ELISA or reverse transcription and subsequent polymerase chain reaction (RT-PCR). IgM antibodies can also be helpful in making a diagnosis in early convalescence by IgM capture ELISA technique. Classical histopathology in autopsy specimens may unfortunately be the first clue.

  • Supportive therapy is the mainstay of management of most VHFs, better accomplished in countries with sophisticated technological support that is often lacking in endemic developing countries. Antiviral therapy with ribavirin is recommended for all Arenaviridae and Bunyaviridae infections (with the exception of Hantavirus pulmonary syndrome). Unfortunately, ribavirin is often difficult and expensive to obtain in an endemic setting.

  • Control measures generally involve meticulous hospital infection control efforts, strict isolation for certain agents, concurrent disinfection, and contact and source reporting to public health authorities. Vaccines can protect against some of the VHF viruses.

 
View Large
This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal