In a follow-up on the West Nile virus (WNV) situation in Italy, the National Institute of Health (ISS) reports 102 additional human WNV cases in the past week, bringing the total to 275 through August 14.
Of the confirmed cases, 126 were neuroinvasive (6 in Piedmont, 7 in Lombardy, 5 in Veneto, 1 in Friuli-Venezia Giulia, 4 in Emilia-Romagna, 47 in Lazio, 50 in Campania, 1 in Basilicata, 3 in Calabria, 2 in Sardinia), 20 asymptomatic cases were identified in blood donors, 125 cases of fever, 2 asymptomatic cases, and 2 symptomatic cases.
In addition, eight more WNV deaths were recorded. The death toll now stands at 19. The case fatality rate, calculated on the neuroinvasive forms reported and confirmed so far, is 15.1%.
The 19 deaths have been reported in (1 in Piedmont, 1 in Lombardy, 8 in Lazio, 8 in Campania, 1 in Calabria).
The number of provinces with proven WNV circulation has risen to 52 (42 in last report) belonging to 15 regions : Piedmont, Lombardy, Veneto, Friuli-Venezia Giulia, Liguria, Emilia-Romagna, Lazio, Abruzzo, Molise, Campania, Puglia, Basilicata, Calabria, Sicily, and Sardinia.
"The spread of cases, which until now has mostly affected Lazio and Campania, is expanding in the endemic areas of the northern Italian regions where we record cases in humans every year," explain ISS experts from the ISS Department of Infectious Diseases. "We are also recording some sporadic cases in the southern regions. The peak of West Nile cases in humans normally occurs in August, as evidenced by data from previous years, although it is difficult to predict the exact trend in the number of infections, which can depend on numerous factors, including environmental and climatic ones."
West Nile virus in the US: 20 years ago in NYC
West Nile Fever is a disease caused by a virus (West Nile Virus - WNV) of the Flaviviridae family, first isolated in 1937 in the West Nile district of Uganda. This virus is commonly found in Africa, West Asia, Europe, Australia and the Americas.
Wild birds and mosquitoes (especially of the Culex genus) are the natural reservoirs of the virus, and mosquito bites are the main route of transmission to humans. Other routes have been documented, although much less frequent, such as organ transplant, blood transfusions and mother-to-child transmission during pregnancy. There is no evidence of human-to-human transmission of WNV through contact with an infected person. The virus is known to infect other mammals, especially equines, but also dogs, cats, rabbits and other species.