Nipah аnd Hendra Virus

NIPAH VIRUS INFECTION :
The Nipah virus (NiV) is a type of RNA virus in the genus Henipavirus. The virus normally circulates among some fruit bats.
It can both spread between people and from other animals to people. Spread typically requires direct contact with an infected source.
It is also called as Barking Pig Syndrome , Poricine Respiratory and Encephalitis Syndrome , Poricine Respiratory and Neurologic Syndrome

NIPAH VIRUS STRUCTURE
Single –stranded negative sense RNA
18,246 NUCLEOTIDES in Length

HISTORY :
1998-1999 Peninsular Malaysia,
Human febrile encephalitis ,high mortality
New virus discovered
1999- Singapore
Outbreak in abattoir workers
Pigs imported from Malaysia
Since 2001 - Bangladesh ,India

EPIDEMIOLOGY
1998-1999 Malaysia 265 persons hospitalized ,105 deaths
Primarily adults males with swine contact .
India has reported 2 outbreaks of NIPAH virus encephalitis in the ester state of west bengal bordering Bangladesh in 2001 and 2007.
An outbreak in Siliguri, west Bengal ,india in 2001 was linked to nosocomial transmission in hospitals and ended after effective barrier nursing precautions were put in place.

REPLICATION OF VIRUS

Transmission

DISEASE IN HUMAN :
Incubation period : Between 4 & 18 days .In many cases infection is mild or unapparent (sub-clinical).
In symptomatic cases: Onset is usually with “influenza-like” symptoms, with higher fever and muscular pain.
Disease may progress to : Inflammation of brain (encephalitis) with drowsiness ,disorientation ,convulsions and coma.
It also causes a diffuse vasculitis, the virus is commonly identified in lungs and kidneys
Complications: Septicemia , GI bleeding , Renal impairment
Asymptomatic : Relapse or late onset deficits and Residual neurological deficits

DISEASE IN ANIMALS :
DOGS : Distemper like signs
Fever , respiratory distress
ocular & nasal discharge
CAT: Fever
depression
Severe respiratory signs
HORESE : Encephalitis

DIAGNOSIS:
Differentials for swine : Classical swine fever ,PRRS, pseudorabies, swine enzootic pneumonia ,porcine pleuropneumonia
Diagnostic test: ELISA ,Immunohistochemistry ,PCR, Virus isolation
After recovery, IgG and IgM antibody detection can confirm a prior Nipah virus infection.

TREATMENT AND PREVENTION:
Rabavirin –reduces mortality
Soluble version of the G Glycoprotein and Ephrin B2 shown to inhibit Niv envelope –mediated infection.
Recombinant vaccine : virus recombinants expressing the Nipah virus G or F glycoprotein
PREVENTION:
Keep fruit bats away from pigs
Do not drink unpasteurized fruit juices
Wash peel fruit thoroughly before eating.

HENDRA VIRUS :
Family Paramyxoviridae
Genus Henipavirus
Closely related to Nipah virus
Its is large ,pleomorphic enveloped
Single-stranded RNA virus
Family includes
Mumps and measles
Rinderpest virus
Human parainfluenza virus
Canine distemper virus

EPIDEMILOGY :
Hendra virus was first described in September 1994 in Hendra, a suburb of Brisbane, Australia following an investigation of an outbreak of severe acute respiratory disease and high fever in 14 of the 20 horses on a single property.
Two people with a history of close contact with the affected horses were infected; one died within a week of infection, and the other recovered .
A similar event occurred in Mackay, Queensland, Australia involving two horses and a human the month prior (August 1994)
Overall, the current approximate case fatality rate in horses and humans is 80% and 60% respectively

HENDRA VIRUS STRUCTURE:
Single-stranded Negative-sense RNA

REPLICATION CYCLE

PATHOGENESIS
Hendra virus has a specific tropism for vascular tissues, regardless of route of challenge.
In early infection, the vascular lesions may include edema and haemorrhage of vessel walls, fibrinoid degeneration with pyknotic nuclei in endothelial and tunica media cells, and numerous giant cells (syncytia) in the endothelium.
The virus becomes more widely distributed in various tissues throughout the body as infection progresses, presumably as a result of a leukocyte-associated viremia.
Respiratory signs can include:
pulmonary edema and congestion
respiratory distress (increased respiratory rate)
terminal nasal discharge, which may be clear initially and progress to stable white or blood-stained froth
Neurologic signs can include:
“wobbly gait” progressing to ataxia
altered consciousness (apparent loss of vision in one or both eyes, aimless walking in a dazed state)

HUMAN DISEASE:
Incubation period 4-18 days ,may be up to a year
Flu-like symptoms
Fever
Myalgia
Headaches
Vertigo
Pneumonitis : Rapid progression to respiratory failure
Meningoencephalitis

TRANSMISSION:

DIAGNOSIS:
ELISA
Immunoperoxidase: Formuline fixed tissues
Virus isolation
Virus neutralization : Detect antibodies
PCR

TREATMENT:
There is no specific antiviral treatment
Intensive supportive care
Ribavirin
Prognosis uncertain due to lack of cases
PREVENTION:
Prevention focuses on minimizing contact with fruit bat body fluids.
Control is based on euthanasia and deep burial of infected cases; monitoring, isolating, and restricting movement of in-contact animals; and disinfection of potentially contaminated surfaces.
A vaccine, containing a noninfectious protein component (G protein) of the virus, has been developed.