Japanese encephalitis virus is present in Asia and Oceania, from Japan to India, Pakistan and Australia. Outbreaks are erratic and spatially and temporally limited phenomena, occurring quite unpredictably. The virus is a leading cause of viral encephalitis in Asia, with 30 000 to 50 000 cases reported annually.
West Nile virus is a mosquito-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds. Humans and horses are incidental dead-end hosts.
Sindbis virus is widely and continuously found in insects (the main vectors are Culex and Culiseta mosquitoes) and vertebrates in Eurasia, Africa, and Oceania. ECDC factsheet for health professionals
Varicella is caused by the varicella-zoster virus (VZV), which also causes shingles (herpes zoster). The virus typically affects children aged 2‒8 years.