The epidemic is caused by a RNA viruses of the genus Vesiculovirus (family of Rhabdoviridaethat of the rabies virus)against which there is no medicine or vaccine. Its name is that of the village where it was first identified in 1965, in the state of Maharashtra (western India). It is transmitted by sandflies, small midges whose females feed on blood, but also, and more rarely, by mosquitoes and ticks.
The disease begins with a flu-like syndrome (headaches, myalgia, arthralgia, vomiting) and within 2 days, it can progress to cerebral edema with vascular involvement, leading to quadriparesis (or hemiparesis), aphasia, convulsions, and can lead to coma or even death, especially in children and adolescents under 15 years of age.
The pathogenicity is not completely known. The virus is probably transmitted by the saliva of the infected insect, enters the blood, multiplies in monocytes and manages to cross the blood-brain barrier. In nerve cells, it secretes a phosphoprotein, probably responsible for the rapid onset of death (less than six hours after the start of the infection).
The current epidemic is not unprecedented: in 2003, in the state ofAndhra Pradesh (central India), out of 329 children who tested positive, 183 of them died. Another one occurred in 2005, in the state of Gujaratthe site of the current epidemic, where 26 cases had been identified (including 20 deaths).
These seemingly modest figures for such a vast country should not hide serious concern about the extension of the geographical distribution of the virus. It was identified in sandflies in West Africa in 1991 and 1992 and in hedgehogs in Senegal between 1990 and 1996. Antibodies against the virus Chandipura were also detected in wild monkeys in Sri Lanka in 1993, presumably following contact with the virus.
The current epidemic resurgence may be associated with the progression of several other viral diseases spread by insects (Zika virus, dengue, Nipah virus, etc.). They are most likely linked to global warming, which favors the proliferation of these vectors. Vigilance is therefore required.
