ETIDIOH - NEW

{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 ...

  ABSTRACT Bourbon virus (BRBV) is an emerging tick-borne virus that can cause severe and fatal disease in humans . BRBV is vectored via the Amblyomma americanum tick , which is widely distributed throughout the central, eastern, and southern United States . Serosurveillance studies in Missouri and North Carolina identified BRBV-neutralizing antibodies in approximately 0.6% of tested individuals . To date, no specific antiviral therapy exists. As part of an initial screen, several nucleoside analogs were tested for their ability to inhibit BRBV replication in cell culture. Among the compounds assessed, molnupiravir , an antiviral drug with oral availability and broad spectrum antiviral activity against RNA viruses, showed antiviral activity against BRBV production in vitro. In vivo, pre-exposure administration of molnupiravir protected susceptible type I interferon receptor knockout (Ifnar1-/-) mice against lethal BRBV infection. The protection by molnupiravir was associated with l...

{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 ...

  Abstract Climate change is increasingly recognized as a major driver of emerging infectious diseases, particularly vector-borne diseases (VBDs), which are expanding in range and intensity worldwide. Europe , traditionally considered low-risk for many arboviral infections , is now experiencing autochthonous transmission of pathogens such as dengue, chikungunya, Zika virus, West Nile virus, malaria, and leishmaniasis . Rising temperatures , altered precipitation patterns , and milder winters have facilitated the establishment and spread of competent vectors , including Aedes, Anopheles, Phlebotomus, and Culex species , in previously non-endemic areas. These climatic shifts not only impact vector survival and distribution but also influence vector competence and pathogen development , ultimately increasing transmission potential. This narrative review explores the complex relationship between climate change and VBDs, with a particular focus on pediatric populations . It highlights h...

  {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 ____...

Abstract Background :  The Liao ning virus (LNV), belonging to the genus Seadornavirus within the family Sedoreoviridae , is a mosquito-borne virus . It was originally isolated from Aedes dorsalis mosquitoes in China . The original LNV strain, LNVS-NE97-31, was reported to infect several mammalian cell lines and cause hemorrhagic symptoms in mice . Subsequently, another LNV strain, LNV NSW B115745, was isolated from Australian mosquitoes ; it was reported to exhibit insect-specific infection. Materials and Methods :  Virus isolation was performed on mosquitoes collected in northern Hokkaido, Japan, in 2022 . The isolated virus was subjected to genomic and growth kinetics analyses. Results :  A LNV strain was isolated from Aedes vexans mosquitoes . Genomic sequencing and phylogenetic analysis revealed the new strain as 22WN03, and it formed a robust clade with the original Chinese strain, LNVS-NE97-31. Growth kinetics analysis did not reveal any mammalian or avian cell lin...

{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 An unprecedented outbreak of Oropouche virus (OROV) is occurring in the Americas, characterized by thousands of confirmed cases and a wide geographical spread, including areas outside the Amazon Basin. Little is known about this neglected arbovirus regarding its pathophysiological aspects and potentially different transmission modes . This study describes the clinical course of a man who returned from a trip to Cuba and presented to our hospital 4 days after the onset of febrile symptoms. The patient was diagnosed with Oropouche fever and was followed for 177 days after the onset of symptoms. We performed a longitudinal investigation of the samples collected from several body sites ( whole blood, serum, urine, and semen ) with the aim of providing further insights into OROV infection dynamics, using the detection of antigenomic RNA as a marker of active viral replication. Clinical samples that were longitudinally collected over the course of OROV infection showed consistently ...

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...

{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...

Abstract Oropouche virus (OROV), historically endemic to the Amazon, had spread to nearly all Brazil states by 2024 ; Espírito Santo emerged as a transmission hotspot in the Atlantic Forest biome . We characterized the epidemiologic factors driving OROV spread in nonendemic southeast Brazil, analyzing environmental and agricultural conditions contributing to viral transmission. We tested samples from 29,080 suspected arbovirus-infected patients quantitative reverse transcription PCR for OROV and dengue, chikungunya, Zika, and Mayaro viruses . During March‒June 2024, the state had 339 confirmed OROV cases, demonstrating successful local transmission . Spatial analysis revealed that most cases clustered in municipalities with tropical climates and intensive cacao, robusta coffee, coconut, and pepper cultivation . Phylogenetic analysis identified the Espírito Santo OROV strains as part of the 2022–2024 Amazon lineage. The rapid spread of OROV outside the Amazon highlights its adaptive pot...

{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...

Summary Background Malaysia is one of the southeast Asian countries hardest hit by dengue . We implemented a proactive integrated vector management (IVM) approach in a large non-blinded, cluster-randomised controlled trial to quantify its effectiveness on dengue incidence in urban settings. Methods In this cluster-randomised controlled trial we enrolled low-cost and medium-cost residential housing blocks in the Federal Territory of Kuala Lumpur and Putrajaya with recurrent dengue outbreaks. Of the 329 eligible sites, 139 were randomly allocated to receive IVM measures (community engagement, targeted outdoor residual spraying using K-Othrine Polyzone , and deployment of autodissemination devices to target both larval and adult mosquitoes) and 141 received routine vector control activities, stratified by block housing cost. The primary outcome was the comparison of dengue incidence between the two groups using information provided by the national e-Dengue surveillance system. Routine vec...

Abstract Determining the incubation period of Oropouche virus disease can inform clinical and public health practice . We analyzed data from 97 travel-associated cases identified by the Centers for Disease Control and Prevention (n = 74) or the GeoSentinel Network (n = 13) and 10 cases from published literature . Using log-normal interval-censored survival analysis, we estimated the median incubation period to be 3.2 (95% CI 2.5–3.9) days . Symptoms developed by 1.1 (95% CI 0.6–1.5) days for 5% of patients, 9.7 (95% CI 6.9–12.5) days for 95% of patients, and 15.4 (95% CI 9.6–21.3) days for 99% of patients . The estimated incubation period range of 1–10 days can be used to assess timing and potential source of exposure in patients with Oropouche symptoms. For patients with symptom onset >2 weeks after travel , clinicians and public health responders should consider the possibility of local vectorborne transmission or alternative modes of transmission. Source: US Centers for Disease C...