West Nile, the National Institute of Health counts 312 confirmed cases and 13 deaths
The bulletin, updated to August 19, records 156 neuro-invasive forms and a case fatality rate of 7.7%, against 13.9% in the same period of 2025. The virus is circulating in 60 provinces across sixteen regions.
The integrated surveillance bulletin coordinated by the National Institute of Health, updated to August 19, 2026 and published the following day, reports 312 confirmed human cases of West Nile virus in Italy. The breakdown of the figure is the most informative part: 156 are neuro-invasive forms, 115 are cases of West Nile fever, 40 are asymptomatic positive cases identified among blood donors, plus one symptomatic non-febrile case.
The deaths notified number 13, one of which was an imported case. The data can be consulted on the EpiCentro portal of the ISS, which publishes the periodic surveillance bulletins.
| Indicator | Value as of August 19, 2026 |
|---|---|
| Confirmed cases | 312 |
| Neuro-invasive forms | 156 |
| Deaths notified | 13 |
| Case fatality rate on neuro-invasive forms | 7.7% |
Two readings of the same data
The absolute number of cases is growing: in the previous bulletin, updated to August 12, confirmed cases stood at 226 with 7 deaths, which were themselves up 60% from the 141 recorded on August 6. The curve is the typical one for the virus’s seasonal circulation, transmitted by mosquitoes, which in Italy is concentrated in the summer months.
The indicator moving in the opposite direction is the case fatality rate calculated on neuro-invasive forms, at 7.7%: in the same period of 2025 it was 13.9%. The comparison must be handled with caution, because the denominator changes with the scope of surveillance: if more cases are identified, and among these more mild or asymptomatic forms, the ratio between deaths and cases decreases even with the same actual clinical severity. The bulletin does not provide elements to distinguish between the two explanations.
The geography
The ISS writes that “WNV is circulating steadily in almost all Regions (16 in total)”, for a total of 60 provinces affected: Piemonte, Lombardy, Veneto, Friuli-Venezia Giulia, Liguria, Emilia-Romagna, Tuscany, Umbria, Lazio, Abruzzo, Molise, Campania, Puglia, Calabria, Sicily and Sardinia. Surveillance also records 9 cases of Usutu virus, detected mainly in Lombardy.
For the 2026 season the weekly report does not provide data by sex, age group or other information based on personal data: a publication choice that reduces the epidemiological detail publicly available.
At the continental level, the European Centre for Disease Prevention and Control reported as of August 13, 2026 a total of 429 locally acquired cases in nine European countries, according to data cited by Mondo Sanità. The two surveys have different update dates — August 19 for the ISS, August 13 for the ECDC — and are not directly comparable.
What we don’t know
The bulletin does not allow us to establish whether the reduction in case fatality depends on a different capacity to identify cases or on other factors: the clinical detail that the report, for the current season, does not publish would be necessary. The distribution of the 13 deaths among the regions affected is not known.
This newspaper reports exclusively the data and assessments of the health institutions cited and does not provide any kind of guidance to readers. The next verifiable element is the ISS’s next bulletin, which will update the series beyond August 19.
Sources: EpiCentro – National Institute of Health, updates; EpiCentro – ISS periodic bulletins; Mondo Sanità, based on the ISS bulletin and ECDC data; ANSA Salute.
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