ETIDIOH - NEW

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...

Abstract {1} The 2023–24 epidemic of Oropouche fever in the Americas and the associated ongoing outbreak in Cuba suggests a potential state shift in the epidemiology of the disease , raising questions about which vectors are driving transmission. In this study, we conduct a systematic review of vector competence experiments with Oropouche virus (OROV, Orthobunyavirus ) that were published prior to the 2023–24 epidemic season. Only seven studies were published by September 2024, highlighting the chronic neglect that Oropouche virus (like many other orthobunyaviruses) has been subjected to since its discovery in 1954. Two species of midge (Culicoides paraensis and C. sonorensis) consistently demonstrate a high competence to transmit OROV (~30%), while mosquitoes (including both Aedes and Culex spp .) exhibited an infection rate consistently below ~20%, and showed limited OROV transmission . Further research is needed to establish which vectors are involved in the ongoing outbreak in Cub...

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...

Summary Background Adults older than 65 years are at increased risk for atypical presentations of chikungunya disease, as well as for severe outcomes including death. Methods In this phase 3, randomised, double-blind, placebo-controlled, parallel-group trial, adults aged 65 years and older received a single intramuscular dose of Vimkunya (previously chikungunya virus virus-like particle vaccine) or placebo at ten sites in the USA. Participants, clinical site personnel, and the sponsor were masked to individual treatment assignments until all participants had completed their involvement in the trial and the database was cleaned and locked. Baseline and postvaccination chikungunya virus serum neutralising antibody (SNA) titres (NT80) were assessed at selected timepoints. Safety was assessed up to 183 days after dose administration in all participants from the exposed population who provided safety assessment data. This trial is registered with ClinicalTrials.gov, NCT05349617, and is comp...

Summary Background Latin America has been experiencing an Oropouche virus (OROV) outbreak of unprecedented magnitude and spread since 2023–24 for unknown reasons. We aimed to identify risk predictors of and areas at risk for OROV transmission. Methods In this multidisciplinary, laboratory-based, modelling study, we retrospectively tested anonymised serum samples collected between 2001 and 2022 for studies on virus epidemiology and medical diagnostics in Bolivia, Brazil, Colombia, Costa Rica, Ecuador, and Peru with nucleoprotein-based commercial ELISAs for OROV-specific IgG and IgM antibodies. Serum samples positive for IgG from different ecological regions and sampling years were tested against Guaroa virus and two OROV glycoprotein reassortants (Iquitos virus and Madre de Dios virus) via plaque reduction neutralisation testing (PRNT) to validate IgG ELISA specificity and support antigenic cartography. Three OROV strains were included in the neutralisation testing, a Cuban OROV isolate...

Abstract Background The recent surge in incidence and geographic spread of OROV infections poses an escalating threat to global public health. However, studies exploring the clinical signs of OROV infection remains exceedingly limited. Methods We searched for OROV studies published until June 17, 2024, in several electronic databases including MEDLINE, EMBASE, SCOPUS, and the Cochrane Library. Results In total, 15 studies involving 806 patients with OROV infection were eligible for inclusion. General symptoms with fever and headache were the most common. Gastrointestinal disturbances like nausea/vomiting, anorexia , and odynophagia were also prevalent, along with ocular symptoms , mainly retro-orbital pain, photophobia, and redness . Respiratory symptoms , such as cough, sore throat and nasal congestion, are present, and skin-related issues like rash, pruritus, and pallor were also identified. Conclusion Overall, this study provides a foundational understanding of OROV’s clinical manif...

Abstract Oropouche fever is caused by the Oropouche virus (OROV; Bunyaviridae , Orthobunyavirus), one of the most frequent arboviruses that infect humans in the Brazilian Amazon . This year, an OROV outbreak was identified in Brazil , and its vertical transmission was reported, which was associated with fetal death and microcephaly. We describe the clinical manifestations identified in three cases of congenital OROV infection with confirmed serology (OROV-IgM) in the mother-newborn binomial . One of the newborns died , and post-mortem molecular analysis using real-time RT-qPCR identified the OROV genome in several tissues . All three newborns were born in the Amazon region in Brazil , and the mothers reported fever, rash, headache, myalgia, and/or retro-orbital pain during pregnancy . The newborns presented with severe microcephaly secondary to brain damage and arthrogryposis , suggestive of an embryo/fetal disruptive process at birth . Brain and spinal images identified overlapping su...

Abstract We describe introduction of the 2022–2023 Oropouche virus lineage from Brazil , which has caused large-scale outbreaks throughout Brazil , into the Amazon Region of Peru . This lineage is co-circulating with another lineage that was circulating previously. Our findings highlight the need for continued surveillance to monitor Oropouche virus in Peru. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/4/24-1748_article ____

Summary Background Arboviruses have expanded into new regions in Europe , yet data indicate gaps in disease notifications and a risk of further spread. We aimed to report on prevalence, clinical management, and outcomes of endemic arbovirus infections in southeast Europe. Methods In this prospective observational study (MERMAIDS-ARBO), we enrolled adults (age ≥18 years) hospitalised with an arbovirus-compatible disease syndrome within 21 days of symptom onset across 21 hospitals in seven countries in southeast Europe over four arbovirus seasons (May 1–Oct 31, during 2016–19). We obtained data from case report forms completed by site investigators on admission and discharge. Participants were excluded if they had non-infectious CNS disorders, symptoms of another confirmed cause, an identified focal source of infection, or symptoms caused by recurrence of a pre-existing condition. The primary outcome was the proportion of participants with confirmed or probable acute infections with West...

Situation at a glance Between 1 January and 31 December 2024, a cumulative total of 151 Zika virus disease (ZVD) cases were reported from three states in India ( Gujarat, Karnataka, and Maharashtra states). Maharashtra State reported a cumulative total of 140 ZVD cases through the Integrated Disease Surveillance Programme (IDSP). Additionally, Karnataka and Gujarat states reported ten and one cases , respectively, in 2024. As of 31 December 2024, no cases of microcephaly and/or Guillain-Barre syndrome (GBS) associated with this outbreak have been reported. Zika virus (ZIKV) is transmitted to humans by the bite of an infected Aedes mosquito . Zika virus is also transmitted from mother to fetus during pregnancy, as well as through sexual contact, transfusion of blood and blood products, and possibly through organ transplantation. There is no specific treatment available for Zika virus infection or disease. Description of the situation Between 1 January and 31 December 2024, a cumulative ...

Abstract Bussuquara virus (BSQV) was first discovered in the Brazilian Amazon in 1956 . It is an arthropod-borne virus (arbovirus) in the genus Orthoflavivirus , family Flaviviridae . Since its discovery, BSQV has been sporadically detected across the South ( Brazil, Columbia, and Argentina ) and Central ( Panama and Mexico ) America and the Caribbean ( Grenada ), but there is minimal BSQV surveillance due to limited public health awareness and a lack of specific or sensitive diagnostics. BSQV exposure has been reported in a wide range of host and vector species , including humans . Little information is available in the literature and herein we summarize the published historical findings on BSQV and suggest a pathway for future studies to better understand its potential emergence into human populations. Source: Viruses,  https://www.mdpi.com/1999-4915/17/2/183 _____

Abstract Given recent outbreaks of Oropouche virus in Latin America and >100 confirmed travel-associated cases in the United States , we evaluated the competence of US vectors , including Aedes albopictus, Culex quinquefasciatus, Culex pipiens , and Anopheles quadrimaculatus mosquitoes . Results with historic and recent isolates suggest transmission potential for those species is low . Source: Emerging Infectious Diseases Journal,  https://wwwnc.cdc.gov/eid/article/31/3/24-1886_article _____

ABSTRACT Respiratory and encephalitic virus infections represent a significant risk to public health globally . Detailed investigations of immunological responses and disease outcomes during sequential virus infections are rare. Here, we define the impact of influenza virus infection on a subsequent virus encephalitis . We used a model system in which mice were given influenza A virus (IAV) infection 8 days prior to Semliki Forest virus (SFV) infection (IAV→SFV). IAV infection clearly attenuated the subsequent SFV infection with reduced titers of infectious SFV and lower levels of cytokines and chemokines in the central nervous system ( CNS ). In contrast, the SFV viremia in both IAV→SFV and SFV-only mice was comparable. Increased type I interferon (IFN) levels in the CNS after IAV infection might have contributed to some level of protection towards SFV infection in the CNS, suggesting that early control of SFV replication in the CNS during IAV→SFV infection led to reduced adaptive res...

{Extract} Since late 2023, more than 10 000 locally acquired cases of Oropouche virus have been reported in the Americas .1 Here, we describe the first cluster of Oropouche virus imported into France from Cuba , where transmission has been ongoing since at least May, 2024.2 Oropouche virus infection was documented in a group of five women (patients 1–5, confirmed cases) travelling to Cuba with two infants (patients 6–7, suspect cases) between July 28 and Aug 14, 2024. During their stay, patients 1–5 developed a dengue-like syndrome lasting 2–11 days, presenting symptoms similar to those described in the literature for Oropouche virus infection (appendix p 8).3 After recovery, patients 1, 2, and 5 experienced symptom relapse upon their return to France; the observed relapse rate aligns with recent estimates suggesting that 60% of patients with Oropouche virus experience a biphasic illness (appendix pp 7–8).4 During relapse, patient 1 sought medical advice, becoming the first diagnosed O...