Nipah virus

Résumé du document

A previously unknown virus was named Nipah after the area where it was identified. Nipah virus is part of the family of viruses called Paramyxoviridae; but researchers have found many characteristics in common to another virus, Hendra, and give them their own genus: Henipavirus. Nipah virus (NiV) has a negative single stranded RNA. The virion is helical and enveloped with specific surface projections. In 1999 in Malaysia, most people infected (90%) by NiV were involved in pig farming or pork production activities (Rodriguez JJ 2002). The disease was highly contagious and one million pigs were destroyed. Nowadays, although person-to-person transmission has not been reported, the outbreaks cause concern. Among victims, all were in close contact with infected animals. Therefore, it cannot be ruled that infected people passed Nipah virus to other people.

Extraits

[...] Nipah virus (NiV) has a negative single stranded RNA. The virion is helical and enveloped with specific surface projections. Animal transmission In 1999 in Malaysia, most people infected by NiV were involved in pig farming or pork production activities (Rodriguez JJ 2002). The disease was highly contagious and one million pigs were destroyed. Transmission is thought to have occurred by respiratory droplets or contact with secretions of sick animals. Dogs, cats, ferrets, pigs and horses were also animals infected. Humans became ill through close contact with infected pigs. [...]

[...] Neither vaccine nor medicines are nowadays in the market. Viral proteins V and W The NiV P gene encodes three proteins, and W (Wang 2001), (Harcourt K. 2001). The P protein is an essential cofactor for the viral RNA polymerase. Nipah virus V and W proteins have interferon (IFN) antagonist activity which blocks the inflammatory responses of the cell. Inflammatory response pathway Figure Inflammatory response pathway When the Nipah virus infects a cell, it releases its own single stranded RNA which leads to the Interferon (IFN) production by the phosphorylation of the transcription factor IRF-3 (Fig. [...]

[...] The Nipah virus (NiV) P gene encodes three proteins, V and W. They all block the cellular response to IFN by binding to and preventing the tyrosine phosphorylation of STAT1. To determine whether a specific region is essential to the function of the gene in viral RNA synthesis, a NiV minireplicon was developed. This minigenome was constructed to encode NiV RNA containing the gene for GFP- chloramphanicol acetyltransferas (CAT). CAT protein is detected only when plasmids encoding the NiV minigenome, nucleocapsid protein phosphoprotein and polymerase protein reconstitute the viral RNA polymerase complex (Halpin K 2004). [...]

[...] Therefore, it cannot be ruled that infected people passed Nipah virus to other people. Disease and symptoms Illness with NiV begins with 3 to 14 days of fever, muscles pain, vomiting, sore throat and headache (inluenza-like symptoms) by infecting wall blood vessels (Fig. 1). It is followed by dizziness, drowsiness and disorientation that indicate acute encephalitis. Some people can also have pneumonia and respiratory problems. These symptoms can progress within 24 to 48 hours to coma. The incubation period (from infection to onset of symptoms) varies from four to 45 days (WHO 2009). [...]

[...] “Molecular characterization of th epolymerase gene and genomic termini of nipah virus.” Virology 287 (2001): 192-201. Kugler R.N. “Nipah virus, emerging infectious disease.” Medical Review Board Rodriguez JJ, Parisien JP, Horvath CM. «Nipah virus V protein evades alpha and gamma interferons by preventing STAT1 and STAT2 activation and nuclear accumulation.» Journal of virology, 2002: 11476-11483. Wang, L.F., Harcourt M., Yu M., Tamin A., Rota P.A., Bellini W.J., Eaton B.T. “Molecular biology of Hendra and Nipah viruses.” Microbes Infect (2001): 279-287. WHO. “Nipah virus.” 2009: Fact sheet N°262. [...]