ETIDIOH - NEW

  {Summary} -- During current epidemiological week (from  23 to 29 Oct. 2025) , two new human cases of infection with West Nile Virus have been reported.  -- The cumulative number of confirmed cases this season so far rose to 773 (they were 771 last week), of these:  - 367 were West Nile Neuroinvasive Disease (WNND): 17 in Piedmont, 56 Lombardy, 35 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 30 Emilia-Romagna, 11 Tuscany, 1 Marche, 87 Latium, 2 Molise, 83 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 3 Sicily, 28 Sardinia,  - 56 were asymptomatic cases detected in blood donors ,  - 339 were West Nile Fever cases (of which: 1 imported from Kenya , 1  from Egypt and 1 from Maldives),  - 3 asymptomatic cases ,  - 8 unspecified cases.  -- Among confirmed cases, 72 fatalities have been recorded: 7 in Piedmont, 9 Lombardy, 1 Veneto, 2 Emilia-Romagna, 1 Marche, 19 Latium, 29 Campania, 2 Calabria, 1 Sicily, 1 Sardinia.  - The Case-Fatality ...

  Abstract Greece is one of the countries in Europe most affected by West Nile virus (WNV), and since 2010, when the virus caused a large outbreak with 197 human neuroinvasive cases , outbreaks occur almost every year. Mosquito surveillance is an indirect sign of virus circulation; therefore, the purpose of the study was the molecular detection of WNV in 45,988 C. pipiens s.l. mosquitoes collected during 2024 in four Regions of Greece and the genetic characterization of the virus strains. WNV was detected in 41 of 1316 ( 3.12% ) Culex spp. mosquito pools . Next-generation sequencing was applied to the WNV-positive samples that had a high viral load . All WNV sequences belong to Cluster B of the sub-lineage Europe WNV-2A presenting a temporal clustering. The WNV infection rates varied highly across the Regions, regional units and months, being higher in Thessaly and Central Macedonia Regions , especially in July and September. All mosquito pools were also tested for Usutu virus (USU...

  {Summary} -- New human cases of West Nile Virus infection continue to be reported albeit with reduced intensity.  -- During current epidemiological week (from  9 to 15 October 2025)  26 new confirmed cases have been reported.  -- The total number of cases so far is 767 (they were 740 last week), of these:  - 366 were West Nile Neuroinvasive Disease (WNND): 17 in Piedmont, 56 Lombardy, 34 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 32 Emilia-Romagna, 10 Tuscany, 1 Marche, 86 Latium, 2 Molise, 83 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 3 Sicily, 28 Sardinia,  - 57 were asymptomatic cases among blood donors ,  - 333 were West Nile Fever cases (of which 1 imported from Kenya, 1 from Egypt and 1 from Maldive),  - 3 asymptomatic cases,  - eight unspecified cases.  -- Among confirmed cases, 69 fatalities  have been reported: 7 in Piedmont, 9 Lombardy, 2 Emilia-Romagna, 18 Latium, 29 Campania, 2 Calabria, 1 Sicily, 1 Sardinia....

{Summary} -- During current epidemiological week , a rise in the West Nile Virus human cases has been observed although with reduced intensity compared most recent weeks.  -- Twenty-two new confirmed human cases have been reported during surveillance week from 2 to 8 October 2025.  -- The cumulative number of cases rose to 740  (they were 718 last week), of these:  - 354 were West Nile Neuroinvasive Disease (WNND): 16 in Piedmont, 53 Lombardy, 33 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 30 Emilia-Romagna, 11 Tuscany, 1 Marche, 84 Latium, 2 Molise, 81 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 3 Sicily, 26 Sardinia, - 57 were asymptomatic cases in blood donors ,  - 318 were West Nile Fever cases , of which 1 imported from Kenya , 1 from Egypt and 1 from Maldives ,  - 4 asymptomatic cases,  - 7 unspecified cases.  -- Among confirmed cases there were 68 fatalities : 7 in Piedmont, 9 Lombardy, 2 Emilia-Romagna, 18 Latium, 28 Campania, 2 Cal...

  {Summary} -- During current epidemiological week (from  25 September to 1rst October 2025),  38 new confirmed human infection with West Nile Virus have been reported.  -- Since the beginning of the epidemic season, 718 confirmed cases have been recorded in Italy (they were 680 in the last bulletin), of these:  - 341 were West Nile Neuroinvasive Disease (WNND): 15 in Piedmont, 51 Lombardy, 30 Veneto, 4 Friuli-Venezia Giulia, 1 Liguria, 27 Emilia-Romagna, 11 Tuscany, 1 Marche, 84 Latium, 2 Molise, 79 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 2 Sicily, 25 Sardinia,  - 57 were asymptomatic cases in blood donors ,  - 309 were West Nile Fever cases (1 imported from Kenya , 1 Egypt , and one Maldives ),  - 4 asymptomatic cases,  - 7 unspecified cases.  -- Among confirmed cases , there have been 49 fatalities : 7 in Piedmont, 5 Lombardy, 2 Emilia-Romagna, 18 Latium, 14 Campania, 2 Calabria, 1 Sardinia.  - The Case-Fatality Rate in WNN...

  {Summary} -- During current surveillance week (from 18 to 24 Sept. '25), 33 new confirmed human cases of West Nile Virus have been detected.  -- Since the beginning of the epidemic season , there have been 680 cases in total , (they were 647 last week); of these:  - 321 were West Nile Neuroinvasive Disease (WNND): 15 in Piedmont, 44 Lombardy, 27 Veneto, 2 Friuli-Venezia Giulia, 1 Liguria, 25 Emilia-Romagna, 8 Tuscany, 1 Marche, 83 Latium, 2 Molise, 79 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 1 Sicily, 24 Sardinia),  - 54 were asymptomatic cases in blood donors ,  - 296 were West Nile Fever cases (1 imported from Kenya , 1 Egypt and 1 Maldives ),  - 3 asymptomatic cases,   - 6 unspecified cases.  --  Among confirmed cases , there were 48 deaths : 7 in Piedmont, 5 Lombardy, 2 Emilia-Romagna, 17 Latium, 14 Campania, 2 Calabria, 1 Sardinia.  - The Case-Fatality Rate among WNND cases was 14.9% (it was 20% in 2018 and 14% in 2024)....

  {Summary} -- During current epidemiological week ( 11– 17 September 2025),  65 new confirmed human cases of infection with West Nile Virus have been reported.  -- The total number of confirmed cases , since the beginning of the epidemic season, has thus risen to 647 (it was 582 last week), of these:  - 300 were West Nile Neuroinvasive Disease (WNND): 15 in Piedmont, 39 Lombardy, 24 Veneto, 2 Friuli-Venezia Giulia, 1 Liguria, 23 Emilia-Romagna, 5 Tuscany, 83 Latium, 2 Molise, 77 Campania, 2 Apulia, 2 Basilicata, 5 Calabria, 1 Sicily, 19 Sardinia,  - 54 were asymptomatic cases detected among blood donors ,  - 284 were West Nile Fever cases (one imported from Kenya),  - 3 asymptomatic cases and  - 6 unspecified casese.  -- Among confirmed cases, there were 47 death cases : 7 in Piedmont, 5 Lombardy, 1 Emilia-Romagna, 16 Latium, 15 Campania, 2 Calabria, 1 Sardinia.  - The Case-Fatality Rate in WNND cases was 15.8% (it was 20% in 2018 and...

{Summary} -- During current epidemiological week (4 to 10 September), eighty new confirmed human cases of West Nile Virus infection have been reported in Italy. -- Since the beginning of the epidemic season , there have been a total of 582 confirmed cases (they were 502 last week), of these:  - 260 were West Nile Neuroinvasive Disease (WNND): 14 in Piedmont, 24 Lombardy, 22 Veneto, 1 Friuli-Venezia Giulia, 1 Liguria, 20 Emilia-Romagna, 3 Tuscany, 77 Latium, 2 Molise, 74 Campania, 1 Apulia, 2 Basilicata, 5 Calabria, 1 Sicily, 13 Sardinia,  - 48 asymptomatic cases among blood donors ,  - 262 cases of West Nile Fever (1 imported from Kenya ),  - 4 asymptomatic cases,  - 8 unspecified cases.  -- A total of 39 fatal cases have been reported so far this season: 5 in Piedmont, 2 Lombardy, 1 Emilia-Romagna, 15 Latium, 14 Campania, 2 Calabria.  - The Case-Fatality Rate among WNND cases is thus far at 15% (during 2018 season it was 20%, in 2024 14%).  -- Du...

  Abstract Background :  West Nile (WNV), Usutu (USUV), and Sindbis (SINV) virus were initially detected in the African region , and subsequently across temperate regions where they were absent. Wild birds are primary reservoirs for these arboviruses and are considered major contributors to their global spread through seasonal migration . To understand the transmission dynamics of arboviruses in wild birds and the potential of migratory birds to spread the viruses at an intercontinental scale , we investigated arboviral infections and exposures in African resident and Palearctic migratory birds at wintering locations in Nigeria.  Methodology/Principal Findings :  Oropharyngeal- and cloacal swabs , feathers and blood were collected from resident and migratory birds at two wintering locations ( Amurum and Ngel-Nyaki Forest Reserves ). Swabs and feathers were tested using RT-PCR for WNV, USUV and SINV, and blood with ELISA and FRNT90 or PRNT80 for antibodies. 573 birds ...

{Summary} -- During current surveillance week (28 August - 3 September 2025):  - 72 new confirmed human cases of West Nile Virus infection have been confirmed;  -- The total number of cases since the beginning of epidemic season has risen to 502 (they were 430 in the last bulletin); of these:  - 226 were West Nile Neuroinvasive Disease (WNND):  11 in Piedmont, 16 in Lombardy, 17 Veneto, 1 Friuli-Venezia Giulia, 1 Liguria, 15 Emilia-Romagna, 3 Tuscany, 71 Latium, 2 Molise, 72 Campania, 1 Apulia, 2 Basilicata, 5 Calabria, 1 Sicily, 8 Sardinia,  - 40 were asymptomatic cases detected in blood donors ,  - 226 were West Nile Fever cases (one of them imported from Kenya ), - 5 asymptomatic cases,  - 5 unspecified.  -- So far there have been 33 fatal cases : 3 in Piedmont, 1 Lombardy, 1 Emilia-Romagna, 14 Latium, 12 Campania, 2 Calabria.  - The Case-Fatality rate among WNND cases is thus far at 14.6% (in 2018 it was 20%, in 2024 14%).  -- During...

  Abstract Mosquito-borne diseases are deeply embedded within ecological communities, with environmental changes—particularly climate change—shaping their dynamics . Increasingly intense droughts across the globe have profound implications for the transmission of these diseases , as drought conditions can alter mosquito breeding habitats , host-seeking behaviours and mosquito–host contact rates . To quantify the effect of drought on disease transmission, we use West Nile virus as a model system and leverage a robust mosquito and virus dataset consisting of over 500 000 trap nights collected from 2010 to 2023, spanning a historic drought period followed by atmospheric rivers. We pair this surveillance dataset with a novel modelling approach that incorporates monthly changes in bird host community competence , along with drought conditions , to estimate the effect of drought severity on West Nile virus risk using panel regression models. Our results show that while drought decreases ...

  {Summary} -- During surveillance week from 21 to 27 August , 79 new confirmed human cases of West Nile Virus infection have been reported.  -- Since the beginning of the epidemic season, the total number of confirmed cases have risen to  430 (they were  351 in the last bulletin); of these: -  193 were West Nile Neuroinvasive Disease cases: 8 in Piedmont, 12 Lombardy, 14 Veneto, 1 Friuli-Venezia Giulia, 1 Liguria, 13 Emilia-Romagna, 62 Latium, 2 Molise, 64 Campania, 2 Basilicata, 5 Calabria, 1 Sicily, 8 Sardinia),  - 38 were asymptomatic cases among blood donors ,  - 193 were West Nile Fever cases,  - 3 asymptomatic and  - 3 unspecified cases.  -- Among the confirmed cases, there were 27 fatalities : 1 Piedmont, 1 Lombardy, 1 Emilia-Romagna, 11 Latium, 11 Campania, 2 Calabria).  - The Case-Fatality Rate in WNND cases is so far at 13.9% (during 2018 it was 20%, in 2024 14%).  -- One confirmed human case of Usutu virus infectio...

  Abstract Background :  Flaviviruses represent a significant worldwide threat to human health and have the potential to emerge and cause outbreaks in non-endemic geographical regions. Ongoing surveillance for these viruses in the United States–Mexican border communities such as El Paso, Texas , is lacking. As a continuing effort to better understand the prevalence and to determine which arboviruses are endemic, the aim of this study was to determine the prevalence rate of specific flavivirus antibody among 910 human umbilical cord blood samples obtained from mothers who delivered newborns in El Paso, Texas. Materials and Methods :  The samples were screened for West Nile virus (WNV) and dengue virus (DENV) IgG antibodies with an enzyme-linked immunosorbent assay and confirmed by a plaque reduction neutralization test for DENV, WNV, Zika virus (ZIKV) and Saint Louis encephalitis virus (SLEV). Results :  Among the 910 samples , 2% were positive for specific IgG antibo...

{Summary} -- During current surveillance week (14 to 20 August), seventy-six new human confirmed cases of West Nile Virus infection have been reported; -- So far this year, 351 human cases of WNV infection were confirmed (they were 275 last week); of these: - 158 were WNND (West Nile Neuroinvasive Disease): 6 in Piedmont, 8 Lombardy, 10 Veneto, 1 Friuli-Venezia Giulia, 8 Emilia-Romagna, 59 Latium, 54 Campania, 2 Basilicata, 5 Calabria, 5 Sardinia; - 27 were asymptomatic cases in blood donors ,   - 162 were West Nile Fever cases,  - 2 asymptomatic and  - 2 symptomatic (unspecified).  -- Among confirmed cases, there were 22 fatalities : 1 in Piedmont, 1 Lombardy, 10 Latium, 9 Campania, 1 Calabria).  - The Case-Fatality Rate in WNND cases is thus far at 13.9% (in 2018 it was 20%, and in 2024, 14%).  -- No confirmed cases of Usutu Virus infection have been confirmed this week. (...) Source: High Institute of Health,  https://www.epicentro.iss.it/westnile/b...

{Summary} -- Since the last update (July 31), eighty-four new confirmed cases of human infection with West Nile Virus have been reported.  -- Since the start of epidemic season, there were 173 confirmed WNV cases, of which:  - 72 were West Nile Neuroinvasive Disease (WNND): (2 in Piedmont, 2 Lombardy, 4 Veneto, 1 Friuli-Venezia Giulia, 2 Emilia-Romagna, 37 Latium, 21 Campania, 1 Basilicata, 1 Sardegna),  - 14 were asymptomatic cases in blood donors ,  - 85 were West Nile Fever cases,  - 1 was an asymptomatic case  -- Among the confirmed cases, there were eleven fatalities : 1 in Piedmont, 4 Latium, 6 .  - The case-fatality rate among WNND cases is at 15% (during 2018 season it was 20%, whereas in 2024 it was 14%).  -- No new confirmed cases of Usutu Virus human infection have been reported during current surveillance week. (...) Source: High Institute of Health,  https://www.epicentro.iss.it/westnile/bollettino/Bollettino_WND_2025_04.pdf ____...

{Excerpts} During the epidemiological week comprised between 24 and 30 July 2025, there were fifty-seven new confirmed cases of human infection with West Nile Virus . -- Since the start of the epidemic season, eighty-nine cases have been reported (there were thirty-two cases in the last week report), of which: -- forty were WNND (West Nile Neuroinvasive Disease): - 2 cases in Piedmont, 1 Lombardy, 3 Veneto, 1 Emilia-Romagna, twenty-three Latium, ten Campania); -- two cases of asymptomatic infection were detected among blood donors (one in Veneto and one in Campania); -- forty-six cases of West Nile Fever have been confirmed:  - one in Lombardy, five in Veneto, thirty-five in Latium, four in Campania, one in Sardinia; -- one asymptomatic case is from Campania; -- Among confirmed cases, eight fatalities have been recorded: one in Piedmont, two in Latium and five in Campania. The case-fatality rate among WNND so far is at 20% (during epidemic seasons 2018 it was 20% and in 2024, 14%)....

{Summary} -- During the Week 17-23 July 2025, Italy reported twenty-seven new cases of human infection with West Nile Virus. -- Since the beginning of the epidemic season, thirty-two confirmed human WNV infection cases have been reportede (there were five cases in the last update), of these: - twenty-three were West Nile Neuroinvasive Disease (WNND): 2 in Piedmont, 2 in Veneto, 1 Emilia-Romagna, 15 Latium, 3 Campania), - one asymptomatic case was detected in a blood donor (Veneto), - six cases of West Nile Fever have been reported (2 in Veneto, 4 Latium), and two asymptomatic cases (Latium), - among the cases, there were two fatalities (1 in Piedmont, 1 in Latium). -- The first confirmed case of the season was detected in Piedmont Region on March 20 2025 (sporadic case), then in Novara Province (July 3rd). -- No confirmed cases of Usutu Virus infection have been detected so far. (...) Source: Istituto Zooprofilattico Sperimentale di Teramo,  https://westnile.izs.it/j6_wnd/home ____...

Abstract Neuroinvasive arboviruses such as tick-borne encephalitis virus (TBEV), West Nile virus (WNV), Usutu virus (USUV), and Toscana virus (TOSV) have (re-)emerged with increasing incidence and geographic range . We analyzed the epidemiology of arboviral infections in Croatia during the 2024 transmission season. A total of 154 patients with neuroinvasive diseases (NID), 1596 horses , 69 dead birds , and 7726 mosquitoes were tested. Viral RNA was detected using RT-qPCR. IgM/IgG-specific antibodies were detected using commercial ELISA or IFA, with confirmation of cross-reactive samples by virus neutralization test. RT-qPCR-positive samples were Sanger sequenced. Arboviral etiology was confirmed in 33/21.42% of patients with NID. WNV was most frequently detected (17/11.03%), followed by TBEV (10/6.49%), USUV (5/3.24%), and TOSV (1/0.64%). WNV infections were reported in regions previously known as endemic, while in one continental county, WNV was recorded for the first time. USUV infec...

{Summary} Situation at a glance From 29 December 2024 and as of 26 April 2025 (with data for Ecuador updated as of 2 May 2025), a total of 212 confirmed human cases of yellow fever , including 85 deaths , have been reported to WHO by five countries in the Region of the Americas ( case fatality rate (CFR) 40% ).  The cases have been reported in the Plurinational State of Bolivia, Brazil, Colombia, Ecuador and Peru .  The 212 confirmed yellow fever cases reported so far in 2025 represent a threefold increase compared to the 61 confirmed cases reported in 2024.  WHO is supporting affected countries in implementing coordinated actions to respond to the yellow fever cases and outbreaks.  This includes:  - enhancing preventive measures,  - strengthening surveillance and case management,  - improving risk communication and community engagement, and  - implementing immunization activities.  The current yellow fever situation in the Americas is driven...

Abstract We performed serologic surveillance for selected arthropod-borne viruses (arboviruses) in bats and opossums in the Lacandona Rainforest, Chiapas, Mexico , in 2023–2024. Sera were collected from 94 bats of at least 15 species and 43 opossums of three species. The sera were assayed by the plaque reduction neutralization test (PRNT) for antibodies to eight orthoflaviviruses ( dengue viruses 1–4, St. Louis encephalitis virus , T’Ho virus, West Nile virus, and Zika virus ) and one alphavirus (chikungunya virus; CHIKV). Twelve (12.8%) bats and 15 (34.9%) opossums contained orthoflavivirus-specific antibodies . One bat (a Jamaican fruit bat) was seropositive for Zika virus , and 11 bats contained antibodies to an undetermined orthoflavivirus , as did the 15 opossums. All bats and most opossums seropositive for an undetermined orthoflavivirus had low PRNT titers, possibly because they had been infected with another (perhaps unrecognized) orthoflavivirus not included in the PRNTs. Anti...