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Henipaviruses (Hendra and Nipah viruses) : essential data |
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Viral weapon acting on humans and livestock |
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Synopsis, Diagnosis,
Symptoms,
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Safety Precautions for Henipavirus Casualties |
Droplet Precautions defined by the 1996 CDC guidelines should be adopted for handling patients.Strict quarantine should be imposed on all possible contacts.Biosafety level 4 practices should be adopted for handling of samples. |
| Causative organism: (Systematic name in 2005) |
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| ICTV Acronym | HeV (for Hendra virus) |
| Alternative disease names: |
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| Properties: |
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| Vector involvement: | Primary carriers are fruit bats of the genus Pteropus. |
| Epidemiology of normal outbreaks: | The natural reservoirs for these viruses are the four species of Australian fruit bats. The bats appear to infect horses and it is secretions from horses that have been responsible for infections of humans. The disease not appear to be highly communicable. |
These are emerging diseases and diagnosis would be indicated after exclusion of other likely causes and identification of risk factors. Laboratories that have dealt with the virus have developed a number of tests. These include detecting a marked cytopathic effect of Hendra virus in cultured cells. Molecular and immunological methods have been developed have been developed.
Symptoms and effects.
The incubation period is unknown but may be of the order of a week. Preliminary symptoms derived from only three human cases are a respiratory disease with influenza-like symptoms. This includes fever and headache lasting 3-14 days. This developed into an encephalitis with central nervous system involvement, including fever, drowsiness, coma and seizures. Fatality in henipavirus infection humans is >50% and somewhat greater in horses.
Symptoms in horses include fever, anorexia (loss of apettite), depression and nervous behavior, and ataxia (unsteady and irregular movement). Breathing is labored and mucus membranes may show jaundice-like signs. The disease progresses rapidly and horses may die within 3 days of the appearance of symptoms.
Medical and Physical Countermeasures.
Vaccination (Immunoprophylaxis)
None known
Specific Therapy
Ribavirin is effective against the virus in experimental systems, but has not been tested in humans.
Supportive care
Paramyxoviruses are resistant to common phenolic disinfectants, but can be killed with polar, lipophilic solvents such as chloroform or by treating with steam or autoclaving of smaller objects.
Agent Properties and Potential Uses
These viruses are classed as emerging pathogens. Realtively little is known about them and the primary concern is that they could be quickly turned around into a rough-and-ready biological weapon that would be effective because of general lack of knowledge about them.
Terrorist Acquisition and Attempted Use.
The first outbreak of one of these viruses was in a stable in the Brisbane suburb of Hendra in 1994. Twenty-one horses were destroyed and two humans were infected with one of them dying. The virus identified as the causative agent was named Equine Morbillivirus. The second outbreak was in October 1995. A farmer who had assisted in the necropsies of two horses in northern Queensland appears to have died from neurological complications from equine morbillivirus infection. An earlier outbreak, in August 1994, was identified after the virus had been identified. The most recent outbreak was in 1999.
| Disease | ICD-9-CM | ICD-10 |
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| Hendra virus infection | ||
| Nipah virus ihfection |
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