Viral hemorrhagic fevers as biological weapons
Viral hemorrhagic fevers (VHFs) are a group of serious viral diseases characterized by sudden onset, fever, and severe bleeding, primarily affecting internal organs. Due to their high morbidity and mortality rates and their potential for rapid transmission, VHFs are considered significant threats in the context of biological warfare and terrorism. The viruses responsible for these fevers belong to four main families: Arenaviridae, Filoviridae, Bunyaviridae, and Flaviviridae, with notable examples including Ebola and Lassa fever. Transmission can occur through insect bites, contact with infected rodents, and person-to-person interactions via body fluids. The symptoms of VHFs initially present as vague and mild but can quickly progress to life-threatening conditions, including shock and organ failure.
Preventive measures against VHFs include isolating infected individuals and using protective clothing for caregivers, along with sterilization of contaminated items. While vaccines are available for a limited number of hemorrhagic fevers, public health strategies focus on education, surveillance, and eradication of potential sources, such as rodents and insects. Given their potential use as biological weapons, ongoing research is essential for understanding these viruses and developing effective countermeasures. Knowledge and preparedness are crucial for minimizing the risks associated with VHFs, underlining the importance of public health initiatives in safeguarding communities.
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Viral hemorrhagic fevers as biological weapons
DEFINITION: Viral diseases characterized by sudden onset, fever, aching, and bleeding in internal organs.
SIGNIFICANCE: Because some hemorrhagic fevers can cause high rates of morbidity and mortality and are easily transmitted, the viruses that cause these diseases have great potential to be used as biological weapons. Given increasing attention to international terrorism, forensic scientists have focused awareness on the pathology and symptoms of such potential threats.
Hemorrhagic fevers, which are often transmitted by insects and rodents, are relatively rare. Symptoms of hemorrhagic fevers can progress in a few hours, and although some hemorrhagic fever viruses cause relatively mild symptoms that improve in a short period, others cause life-threatening disease. Initial signs and symptoms of infection are vague and include fever, fatigue, dizziness, muscle aches, weakness, and exhaustion. As the disease progresses, bleeding becomes more pronounced and leads to shock, coma, seizures, and organ failure. Treatment for hemorrhagic fevers includes isolation of infected persons; those who care for infected persons must wear protective clothing (gowns, gloves, and face masks); and all items used by infected persons must be sterilized.
Four families of viruses are associated with hemorrhagic fevers. Viruses of the family Arenaviridae (known as arenaviruses) cause Argentine, Bolivian, and Venezuelan hemorrhagic fevers, as well as Lassa fever and Sabia-associated hemorrhagic fever. Viruses of the family Filoviridae (filoviruses) cause Ebola and Marburg hemorrhagic fevers. Those of the family Buyaviridae (bunyaviruses) cause Crimean-Congo hemorrhagic fever, hantavirus pulmonary syndrome, and Rift Valley fever. Viruses of the family Flaviviridae (flaviviruses) cause dengue and Omsk hemorrhagic fevers, Kyasanur Forest disease, and yellow fever.
Hemorrhagic fevers can be spread by the bites of infected insects, such as mosquitoes and ticks, by human contact with the body secretions of infected rodents, and from person to person through body fluid contact. Humans can also become infected when they care for or slaughter animals that have been exposed. The viruses that cause hemorrhagic fevers and diseases occur worldwide, but in industrialized countries, the chance of contracting hemorrhagic fevers or diseases is low because the viruses usually reside in remote areas and individual viruses are spread by specific hosts that live in specific geographic areas.
Of the diseases caused by these viruses, vaccines have been developed only for yellow fever and Argentine hemorrhagic fever. Because of the possibly fatal nature of many hemorrhagic diseases, plans for the prevention of these diseases and for the control of their spread when outbreaks do occur can be important to the survival of a population. The precautions recommended by public health authorities in the United States include eradicating rodent and insect infestations, screening for early signs of disease, and educating the public about how such diseases are spread and the means that can be used to control their spread. In addition, cases of hemorrhagic disease should be reported to local and state health departments so that speedy action can be taken to secure public safety and minimize exposure. Because of the potential for hemorrhagic fever viruses to be used as bioweapons, scientists are devoting a great deal of time and effort to the investigation of the origins and behaviors of these viruses.
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