|
||||||||||||
Argentinian hemorrhagic fever:
|
|
Viral weapon acting on humans |
|
Synopsis,Diagnosis, Symptoms,
|
|
|---|---|
Safety Precautions for Argentinian Hemorrhagic Fever Casualties |
Contact Precautions defined by the 1996 CDC guidelines should be adopted for handling patients.Rodent control and monitoring may be necessary.Biosafety level 3/4 practices should be adopted for handling of samples. |
| Causative organism: (Systematic name in 1997) | Junin virus |
|---|---|
| ICTV Acronym | JUNV |
| Alternative disease names: |
|
| Virus classification: | A New World Arenavirus: an enveloped spherical virus with
two subgenomic single-stranded RNAs. Click here for a detailed description of Arenaviruses |
| Vector involvement: | None. |
| Epidemiology of natural outbreaks: | The disease is limited to the area of Junin 240 km west of Buenos Aires in Argentina. The disease is carried by the local rodent Calomys laucha and C. musculinus and shows a very sharp seasonal pattern of occurrence between February and August. It is almost always seen amongst farm hands who inhale virus secreted in urine or droppings as the soil is disturbed. |
Infection has a slow onset with fever, malaise, headache and muscular pains. Petechiae (blood spots) on the upper body and bleeding from the nose and gums are observed when the disease progresses to the hemorrhagic phase.
Isolation of the virus requires Biosafety Level 4 facilities.
Differential DiagnosisOther disease or conditions that need to be eliminated | |
|---|---|
| Other infectious diseases | Other problems |
|
|
Symptoms and effects.
The disease has an incubation period of 7-16 days and the onset of symptoms is relatively slow. The first symptoms are not very specific (fever, malaise, headache, muscular pains, anorexia, nausea, vomiting). The face may be flushed and their may an enanthema ( reddening) of the throat that does not hurt. Between the third and fifth day the patient dehydrates and blood pressure, urination is infrequent and the heart slows (bradycardia). The hemorrhagic phase of the disease is signalled by the appearance of petechiae (blood spots) on the upper trunk and the oral mucosa (the moist tissues of the mouth). Bleeding begins to occur from the nose, gums, stomach, and intestine. Severe cases lose enough blood to go into hypotensive shock and have a neurological crisis. Neurological symptoms are more marked in Argentinian hemorrhagic fever and this can be used as a differential test at the early stages of the disease. Fatalities can be as low as 3% and as high as 30% of those infected.
Medical and Physical Countermeasures.
Vaccination (Immunoprophylaxis)
A safe and effective vaccine providing long-term protection (Candid-1) is available in Argentina and has the status of an Investigational New Drug in the United States. It also provides protection against Bolivian hemorrhagic fever. A US vaccine developed by the Salk Institute is no longer manufactured.
Specific Therapy
Ribavirin is effective and was made available for post-exposure prophylaxis to soldiers in Operation Desert Shield/Storm and in Korea.
The disease is endemic in Argentina and there is a standard treatment of convalescent serum (2 units) and ribavirin that is effective if begun within eight days of onset.
Supportive care
Minimize intrusive care to protect a weakened vascular bed. Attempt replacement therapy only in the case of severe hemorrhage. Fluid infusion to deal with dehydration is often counterproductive, but can be supportive if careful monitoring if accompanied by careful monitoring of serum electrolytes.
Decontamination
The virus is killed by UV radiation, drying, 1% sodium hypochlorite, or 2% glutaraldehyde.
Agent Properties and Potential Uses
The virus can be spread by aerosols and person-to-person transmission has been reported. The virus is carried by rodents, especially mice of the genus Callomys and is stable in their droppings. Typically the virus is inhaled, but it is also possible that it may entered through small abrasions or cuts in the skin.
The relatively slow onset of the disease with its unspecific symptoms that may delay diagnosis, coupled with its debilitating hemorrhagic phase make the virus a potentially serious agent.
Terrorist Acquisition and Attempted Use.
| Disease | ICD-9-CM | ICD-10 |
|---|---|---|
| Hemorrhagic fever due to Junin virus | A96.0 |
|