There are approximately 100 arboviruses are known to cause diseases in human hosts, but the severity of disease ranges from asymptomatic infection to life-threatening encephalitis or hemorrhagic fever. The most common arboviruses transmitted by mosquitoes are Dengue Virus (DENV), Yellow fever virus(YFV), Chikungunya Virus (CHIKV), Rift Valley Fever Virus (RVFV) West Nile Virus(WNV), and Japanese encephalitic Virus (JEV) 1. A recent outbreak of Zika Virus has also gained the attention of public health research community because to its involvement in the development of microcephaly in new born babies.Dengue is one of the most rapidly expanding vector-borne disease.
The causative agent of dengue is Dengue virus (serotype DENV1, DENV2, DENV3 and DENV4) that is more dominant in tropical and subtropical regions. Dengue is endemic in over 100 countries, and almost 40% of world population is at risk of dengue infection; approximately 100 million dengue cases are reported every year 1. World Health Organization reports approximately30 fold increase in dengue incident globally over the past 50 years 4. Dengue virus infection can be mild illness involving fever and body ache to the most severe and life-threatening dengue shock syndrome and dengue hemorrhagic fever 1. Another arbovirus transmitted by Aedes mosquito is Chikungunya virus (CHIKV).
Earlier Chikungunya virus was not considered as a major arboviral disease until it caused a global epidemic in 2005-2006. The epidemic was the result of and point mutational replacement of alanine to valine in E1 glycoprotein gene in Reunion Island strain, which led loss of cholesterol dependence for virus life cycle 55. The mutated CHIKV strain was more adaptive for Ae.
albopictus mosquito without losing its infectivity to Ae. aegypti females. Interestingly,Ae. albopictus was not an efficient vector and Ae.
aegypti was the major vector56. This change in vector preference has led to its global epidemic reported from around 40 countries 57. In India alone, around 1.3 million CHIKV infections were reported during 2006 outbreak 58. Chikungunya virus infection is mainly characterized by acute and chronic articular manifestations with sever polyarthralgia and fever. Although, chikungunya infection is not life-threatening, severe joint pain in fingers, knees, ankles, wrists, elbows and other proximal joints that can last for months and then, eventually leads to loss to the active participation of individuals in society. It is estimated that there was a loss of 25588 DALYs (Disability Adjusted Life Years) during 2006 CHIKV outbreak in India 59.
In some cases, like in immune-compromised patients, CHIKV infection may be life-threatening because of the occurrence of encephalopathy, encephalitis and in rare cases multi-organ failure 1. Until now there is no effective antiviral treatment available to treat arboviruses. Symptomatic or supportive care and management of medical complications are the only mean to treat arbovirus infections. Moreover, there is no FDA approved antiviral treatment available for dengue virus, the only treatment that is available relies on maintenance of body fluid volume and palliative care. The treatment of acute chikungunya infection comprised of administration of paracetamol or acetaminophen for fever and anti-inflammatory to relieve joint pain 1.