A Biomolecular Approach of Chikungunya Prevention with Combination of Chimeric Eastern Equine Encephalitis Virus (EEEV)/Chikungunya Virus (CHIKV) and Internal Ribosome Entry Site (IRES)-Based Attenuation as Novel Vaccine for Chikungunya

Author : Mochamad Iskandarsyah Agung Ramadhan, Leonard Andreas Wiyadharma, Edwin Wijaya

Chikungunya fever is neglected tropical disease caused by Chikungunya Virus (CHIKV) from genus Alphavirus. It is a self-limiting disease with symptoms such as febrile illness and joint pain. Only a few reports revealed advanced and chronic stage of Chikungunya fever, which was associated with neurological disorder, severe joint pain, and hemorrhagic shock. Despite of low number in morbidity and mortality, CHIKV can trigger major outbreak in urban areas regarding to its transmission cycle. In Indonesia, Chikungunya fever epidemic that was lasted in 1982-1985 in Yogyakarta and Jambi had stroked again in Sumatera and West Java with bigger prevalence in 2001-2002, and again in West and Central Java with fewer cases in 2012-2013. Chikungunya was also predicted to be Indonesian health threat in 2014. Because of this potency, there should be an effort to prevent Chikungunya. The best strategy to reach this aim is by vaccination. Several methods of vaccination have been tested into animal and even human. The most famous trial is 181/25 by the US Army in 1986 ensued failure in phase II clinical trial. In vivo reversion might best explain the phenomenon, which was also happened in other experiments, like trial for DNA vaccine, liveattenuated vaccine and virus like protein vaccine. Another vaccine candidate, EEEV/IRES is a vaccine model that was formed by combining chimeric virus Eastern Equine Encephalitis Virus (EEEV) and CHIKV and Internal Ribosome Entry Site mechanism (IRES) on RNA translation. Experimental studies by Pandya et al showed that EEEV/IRES vaccine could give full immunity with no symptoms appeared on mice. EEEV/IRES was also giving no infectiveness to mosquito vector. Thus, EEEV/IRES can be effective, stabile, high immunogenicity, low-cost and practical vaccine for Chikungunya prevention. However, further studies are needed to prove that this vaccine is also effective in giving immunity of Chikungunya fever in human.

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