Chandipura virus

Chandipura virus
Virus classification
Group:	Group V ((-)ssRNA)
Order:	Mononegavirales
Family:	Rhabdoviridae
Genus:	Vesiculovirus
Species:	Chandipura virus

Chandipura virus is a member of the Rhabdoviridae family that is associated with an encephalitic illness in humans. It was first identified in 1965 after isolation from the blood of two patients from Chandipura village in Maharashtra state, India (Bhatt et al.,1967) and has been associated with a number of otherwise unexplained outbreaks of encephalitic illness in central India. The most recent occurred in Andhra Pradesh and Maharashtra in June-August 2003 with 329 children affected and 183 deaths (Rao et al, 2004). Further sporadic cases and deaths in children were observed in Gujarat state in 2004 (Chadha et al, 2005).

Chandipura virus has been isolated from sandflies in India and West Africa (Fontenille et al., 1994) and is probably spread through its bite. The presence of the virus in Africa indicates a wide distribution although no human cases have been observed outside of India.

The significance of Chandipura virus as a human pathogen is unresolved due to doubts over its role in the 2003 and 2004 outbreaks.

Virology

Chandipura virus is an enveloped RNA virus with an approximate genome length of ~11 kb. Viral genome codes for five polypeptides, namely, Nucleocapsid protein N, Phosphoprotein P, Matrix protein M, Glycoprotein G and Large protein L in five monocistronic mRNAs. N protein encapsidates genome RNA into a nuclease resistant form to protect in from cellular RNAse function. L and P protein together forms viral RNA dependent RNA polymerase; where catalytic functions for RNA polymerization, Capping and Poly-A polymerase resides within the L protein and P acts as a transcriptional activator. Matrix protein glues the encapsidated genome RNA, also known as nucleocapsid, with the outer membrane envelop. G protein spikes out of the membrane and acts as a major antigenic determinant (Basak et al, 2007).

Viral life cycle is cytosolic. During transcription, viral polymerase synthesizes five discrete mRNAs and obeys to stop signals that are present at the gene boundaries. Accumulation of adequate amounts of viral proteins within infected cells through viral transcription and subsequent translation potentiate the onset of viral replicative cycle. In this phase, same L protein acts as a replicase and ignore the gene junctions to generate a polycistronic anti-genomic analogue that acts as a template for further rounds of replication to generate many more copies of the genome RNA. This progeny genome RNA upon packaging by viral proteins bud out as mature virus particles. The precise mechanism underlying the switch in polymerase function during viral replication remains unknown (Basak et al, 2007).

Recent outbreaks

An outbreak in Gujurat in Kheda District, Vadodara District, and Panchmahal District has killed 17 people in 2010 (DNA correspondent, 2010), sandflies bites are blamed as they inhabit cracks in walls or parts of homes made of sand or mud.

References

• Basak S, Mondal A, Polley S, Mukhopadhyay S, Chattopadhyay D. Reviewing Chandipura: a vesiculovirus in human epidemics. Biosci Rep. 2007 Oct;27(4-5):275-98. Review. PMID 17610154.
• Bhatt PN, Rodrigues FM. Chandipura: a new Arbovirus isolated in India from patients with febrile illness. Indian J Med Res. 1967 Dec;55(12):1295-305. PMID 4970067.
• Chadha MS, Arankalle VA, Jadi RS, Joshi MV, Thakare JP, Mahadev PV, Mishra AC. An outbreak of Chandipura virus encephalitis in the eastern districts of Gujarat state, India. Am J Trop Med Hyg. 2005 Sep;73(3):566-70. PubMed PMID 16172482.
• DNA correspondent, "Chandipura virus kills 17 in Gujarat" 05 August 2010.
• Fontenille D, Traore-Lamizana M, Trouillet J, Leclerc A, Mondo M, Ba Y, Digoutte JP, HG. First isolations of arboviruses from phlebotomine sand flies in West Africa. Am J Trop Med Hyg. 1994 May;50(5):570-4. PubMed PMID 8203705.
• Rao BL, Basu A, Wairagkar NS, Gore MM, Arankalle VA, Thakare JP, Jadi RS, Rao KA, Mishra AC. A large outbreak of acute encephalitis with high fatality rate in children in Andhra Pradesh, India, in 2003, associated with Chandipura virus. Lancet. 2004 Sep 4-10;364(9437):869-74. PMID 15351194.