Italy: An increase in West Nile virus cases continues in northern regions through September /update 2

Event

Health officials have reported 139 additional human cases of West Nile Virus (WNV) in Italy Aug. 25-Sept. 6, bringing the total reported June 1-Sept. 6 to 440. This number compares to roughly 26 cases reported over a similar period in 2021. Disease activity has mainly occurred in northern regions, with Veneto reporting the most cases. Disease activity was also reported in Emilia-Romagna, Piedmont, Lombardy, Friuli-Venezia Giulia, Tuscany, and Sardinia. This report represents the most complete information available as of Sept. 13.

Context

Italy reported roughly 55 human WNV cases in 2021, 68 in 2020, and 54 in 2019. The vast majority of WNV in Italy are reported during the high season, which runs June-November.

West Nile virus is transmitted through the bite of an infected mosquito. Most infected people develop no symptoms. However, approximately 20 percent of infected people develop febrile illness characterized by symptoms of fever, headache, body aches, joint pains, vomiting, diarrhea, and rash. Fewer than 1 percent of infected individuals develop serious neurologic illness, which can be life-threatening. Symptoms typically appear two to six days after being bitten, but can develop up to 14 days after exposure.

Advice

Avoid mosquito bites and remove standing water to reduce the number of biting mosquitoes. Seek medical attention if symptoms develop within two weeks of being in affected areas.