Research Highlight

Smallpox anti-viral for Japanese Encephalitis

Subhra Priyadarshini

doi:10.1038/nindia.2008.208 Published online 26 May 2008

The NIMHANS team: (from left) V. Ravi, Liba Sebastian & Anita Desai

A known anti-viral agent widely used in the treatment of smallpox, leukemia and HIV, has now shown promise in tackling Japanese Encephalitis Virus (JEV) and West Nile Virus (WNV) prevalent in India.

One derivative of the anti-viral compound N-methylisatin-β-Thiosemicarbazone (known as methisazone or marboran) was found to be effective against JEV and WNV in mouse models. The derivate — SCH 16 — however, did not show any effect on another important flavivirus tested along with these viruses — the dengue virus.

There is no drug available for chemotherapy or chemoprophylaxis of these two flaviviruses. Absence of a specific treatment for flavivirus infections encouraged the team to look for compounds that interfere with the replication of these viruses.

"The antiviral activity of these derivatives has not been evaluated against flaviviruses. We undertook this study to investigate if any of these derivatives could suppress common flavivirus infections encountered in South India," says lead researcher Anita Desai.

Since WNV is not as big a public health concern as JEV, the researchers focused on the latter to find that the compound required a minimum contact period of eight hours after administration to completely inhibit virus replication.


  1. Sebastian, L. et al. N-methylisatin - β - thiosemicarbazone derivative (SCH 16) is an inhibitor of Japanese encephalitis virus infection in vitro and in vivo. Virol. J. 5. doi:10.1186/1743-422X-5-64 (2008)