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.
Rotaviruses are the single most important cause of severe diarrhoeal illness in infants and young children worldwide. By the age of five years most children irrespective of socioeconomic setting will have been infected at least once. While infected, many children will be in need of medical attention due to extensive fluid loss.
Rubella is a mild febrile rash illness caused by rubella virus. It is transmitted from person to person via droplets (the virus is present in throat secretions). It affects mainly, but not only, children and when pregnant women are infected, it may result in malformation of the foetus. Humans are the only reservoir of infection.
Meningococcal disease is caused by Neisseria meningitidis, a bacterium with human carriers as the only reservoir. It is carried in the nose, where it can remain for long periods without producing symptoms.