Viral hemorrhagic fevers infectivity

It is a hantavirus that produces a viral hemorrhagic fever. It is normally found in Central and Eastern Asia. The natural reservoir is the striped field mouse (Apodemus agrarius) and the virus is shed in their urine. Infection occurs after inhalation of dust contaminated with excreta from infected mice or from aerosol of animal blood or fluids. Does not produce disease in animals. This is a biosafety level 3 agent. 

It is a viral hemorrhagic fever normally found in South Asia. The natural reservoirs are ticks, monkeys, rodents, and porcupines. Ticks remain infective for life. This is a biosafety level 4 agent. 

Suggested Alternatives for Differential Diagnosis Leptospirosis, malaria, salmonella infection, lupus, typhoid fever, shigellosis, meningococcemia, yellow fever and other viral hemorrhagic fevers, rickettsial infections, thrombocytopenic purpura, acute leukemia, disseminated intravascular coagulation, hemolytic uremic syndrome. 

Differential Diagnosis Thrombocytopenia (a condition in which there is an abnormally small number of platelets in the circulating blood) and an elevated aspartate aminotransferase (AST) may provide a clue to suggest CCHF is the culprit in the febrile (denoting or relating to fever) patient seen early in the course of infection. Other viral hemorrhagic fevers, meningococcemia, rickettsial diseases, and similar conditions may resemble full-... 

Isolation Control The U.S. Centers for Disease Control and Prevention (CDC), and the World Health Organization, have produced a manual, Infection Control for Viral Hemorrhagic Fevers in the African Health Care Setting. The manual is available at the CDC Web site http //www.cdc.gov/ncidod/dvrd/spb/mnpages/vhfmanual.htm and can be downloaded. Factors covered in this lengthy manual are include ... 

Rift Valley fever is characterized by high fever and the development of hemorrhagic areas under the skin. Only a small number of cases (<1%) go on to develop the more serious viral hemorrhagic fever syndrome that causes death in 50% of those who manifest this syndrome. The syndrome is associated with mucosal bleeding or hemorrhaging, liver and kidney failure, and shock before death. Some infections can be complicated with encephalitis and a variety of ocular defects.3... 

Intravenous ribavirin decreases mortality in patients with Lassa fever and other viral hemorrhagic fevers if started early. High concentrations inhibit West Nile virus in vitro, but clinical data are lacking. Clinical benefit has been reported in cases of severe measles pneumonitis and certain encephalitides, and continuous infusion of ribavirin has decreased virus shedding in several patients with severe lower respiratory tract influenza or parainfluenza infections. At steady state, cerebrospinal fluid levels are about 70% of those in plasma. 

Clinical use and toxicity Ribavirin is used in aerosol form for respiratory syncytial virus infections. Early intravenous administration decreases mortality in Lassa fever and other viral hemorrhagic fevers. Ribavirin has recently been shown to have efficacy in treatment of hepatitis C viral infections. Aerosol ribavirin may cause conjunctival or bronchial irritation. Systemic use results in dose-dependent myelosuppression. Ribavirin is a known human teratogen. absolutely contraindicated in pregnancy. 

Yellow fever is a viral hemorrhagic fever. There are three types of transmission cycle sylvatic (or jungle), intermediate, and urban. All three cycles exist in Africa, but in South America, only sylvatic and urban yellow fever occur [46]. Sylvatic yellow fever occurs in tropical rainforests where monkeys, infected by sylvatic mosquitoes, pass the virus onto other mosquitoes that feed on them these mosquitoes, in turn, bite and infect humans entering the forest. This produces sporadic cases, the majority of which are often young men working in the forest, e.g., logging. 

Gear JHS. Clinical aspects of African viral hemorrhagic fevers. Rev Infect Dis. 1989 11 (May-Jun) S777-S782. 

Huggins JW. Prospects for treatment of viral hemorrhagic fevers with ribavirin, a broad-spectrum antiviral drug. Rev Infect Dis. 1989 1 l(4) S750 S761. 

Just how the animal host first transmits Marburg virus to humans is unknown. However, as with some other viruses which cau.se viral hemorrhagic fever, humans who become ill with Marburg hemorrhagic fever may spread the virus to other people. This may happen in several ways. Persons who have handled infected monkeys and have come in direct contact with their fluids or cell cultures, have become infected. Spread of the virus between humans has occurred in a setting of close contact, often in a hospital. Droplets of body fluids, or direct contact with persons, equipment, or ocher objects contaminated with infectious blood or tissues are all highly suspect as sources of disease. 

Altemanthera philoxeroides (Mart.) Griseb. A. sessilis (L.) R. Brown Kong Xin Lian Zi Cao Man Ti Xian (aerial part) Saponin, coumarin, tannins, falvins.33 Treat viral infections, measles, hemorrhagic fever, toxic and icteric hepatitis. 

FIGURE 3.30 Crimean-Congo hemorrhagic fever (CCHF). Localization of CCHF viral RNA as seen in a single CCHF-infected hepato-cyte. (Immunoalkaline phosphatase with naphthol fast red substrate and hematoxylin counterstain original magnification x250.)... 

Ribavirin is a synthetic guanosine analogue, with in vitro activity against a broad spectrum of DNA and RNA viruses, and retroviruses, including HIV. Ribavirin has been used for treatment of a variety of viral infections, including respiratory syncytial virus bronchiolitis and pneumonia, measles, influenza types A and B, Lassa fever, hemorrhagic fever with renal syndrome (Hantaviruses), hepatitis C, and HIV infection. It is used commonly now along with interferon alpha for treatment of hepatitis C infection. There is no known direct nephrotoxicity of ribavirin. 

In rare cases, other viral and bacterial infections can cause a hemorrhagic fever scrub typhus is a good example. 

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