#Surveillance and #control efficacy of the Bergerac, #France, 2025 #chikungunya #outbreak

 

Abstract

The spread of the highly invasive mosquito, Aedes albopictus, across Europe, combined with climate change and human travel and trade, has led to new epidemic threats from mosquito-borne viruses, most significantly dengue and chikungunya, which are increasing in frequency and magnitude. In 2025, mainland France has seen a record number of autochthonous cases and outbreaks of chikungunya, spread across multiple locations, primarily introduced by travellers from the French Overseas Territory of La Réunion which is experiencing severe chikungunya outbreaks. Here, we describe one of the largest French outbreaks and subsequent control measures in the city of Bergerac, Dordogne, which resulted in 102 cases as of 5th November 2025. We apply a climate-driven mathematical model for Ae. albopictus and chikungunya virus transmission to the Bergerac 2025 outbreaks, comparing outputs to case data. The model suggests that the initial control measures in the first four weeks after the discovery of the outbreak, limited in their intervention radius and intensity, had little effect on reducing the number of cases, given the high incidence and the wide geographic extent of viral circulation. However, subsequent more widespread and intense control efforts, combined with likely increased public awareness, substantially reduced case numbers. These findings underscore the need to tailor control measures to intensity and scale of viral circulation combined with effective preventive and proactive arbovirus surveillance. Adulticides combined with public awareness campaigns can be effective for public health protection and are an important part of mitigating against the risk of Aedes-borne arboviruses and the ongoing outbreaks in mainland France.

Source: 

Link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014184

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#Chikungunya fever: #Brazil is intensifying its response to address health emergency in Dourados (MoH, April 4 '26)

 

{Edited}

The Brazilian government has intensified its response to the emergency situation in Dourados (MS), given the increase in cases of chikungunya, with the mobilization of an interministerial task force that integrates actions in health, assistance, civil defense, and logistical support in the territory. The emergency affects the population of the municipality, with a greater impact on indigenous communities.

As a reinforcement to the response already underway, the Federal Government has guaranteed more than R$ 3.1 million in emergency resources for the municipality. 

Of this total, R$ 1.3 million , authorized by the Ministry of Integration and Regional Development (MIDR) in a decree published this Thursday (2), will be allocated to relief and humanitarian assistance actions, such as direct support to the population and local response structures. 

Also this Thursday, the National Secretariat for Civil Protection and Defense approved a work plan worth R$ 974,100 for restoration actions, including urban cleaning, waste removal and disposal in a licensed sanitary landfill, with resources to be transferred directly to the municipality.

The Ministry of Health has already transferred R$ 855,300 to the municipality to cover the costs of surveillance, assistance, and control actions related to chikungunya in the region.

The federal response has been underway since mid-March, coordinated by the Ministry of Health, which mobilized the National Health System (SUS) Task Force , reinforced healthcare teams, and intensified vector surveillance and control actions across the territory. 

The operation includes actively searching for cases, conducting home visits, eliminating [mosquitoes] breeding sites, and expanding services to the population, with special attention to the most vulnerable areas, including indigenous territories.

The National Health System Task Force has 40 mobilized professionals , with 26 currently working directly, and has already carried out 1,288 clinical consultations , 81 transfers for medium and high complexity care, and 225 home visits . 

The teams operate both in indigenous territories and in the municipalities of Dourados and Itaporã, supporting local management, together with the Mato Grosso do Sul State Health Secretariat, reorganizing care flows, expanding active case finding, and guaranteeing assistance, health education, and psychosocial care.

Fiocruz mobilized the shipment of pain medication, reinforcing its ability to meet local demand due to the epidemic.

To expand response capacity, the Ministry of Health authorized the emergency hiring of 50 Endemic Disease Control Agents (ACEs). Of these, 20 have already been trained and will enter the field this Friday (3), while another 30 will begin training to work from Monday (6).

In the field of vector control, actions were intensified with the mobilization of approximately 95 professionals , including Community Health Agents and Indigenous Sanitation Agents (AISAN). Between March 9 and 16, 4,319 properties were inspected , of which 2,173 received treatment , identifying 1,004 breeding sites of the Aedes aegypti mosquito , mainly in water storage containers, solid waste, and tires.

Actions were also taken to control the spread of insecticide using ultra-low volume (ULV) methods, including three cycles of vehicle-mounted ULV application and backpack spraying in 43 high-traffic areas, such as schools and health units. The volunteer effort to remove breeding sites mobilized approximately 100 people and resulted in the collection of four dump truckloads of waste.

Vector control will be reinforced with support from the Ministry of Defense. Currently, 40 Brazilian Army soldiers and five vehicles are already in the area , expanding the operational capacity of the mosquito control efforts.

The Ministry of Health also sent 1,000 Larvicide Dissemination Stations (LDSs). Of the first 300 units, 150 have already been installed in priority neighborhoods, with expansion planned for other regions of the municipality.

Through Funai (National Indian Foundation), actions are also underway to provide direct support to indigenous communities in Dourados, focusing on food security and access to water. 

The distribution of 6,000 food baskets is planned , in three stages between April and June, in coordination with the Ministry of Social Development (MDS), the National Supply Company (Conab), the Special Secretariat for Indigenous Health (Sesai), and Civil Defense. The expansion of the water supply system in the Jaguapiru and Bororó villages has also been authorized to guarantee access to potable water and improve the sanitary conditions of the indigenous communities.

Epidemiological scenario

The most recent epidemiological surveillance data, referring to April 2nd, indicates that the region has registered 2,812 notifications of chikungunya, with 1,198 confirmed, 430 discarded, and 1,184 still under investigation. The highest concentration of cases is in indigenous villages, where 822 cases were confirmed—68.6% of the total confirmations in the region. 

So far, five deaths have been confirmed in Dourados, all among the indigenous population of the municipality.

To strengthen the coordination of actions, the Ministry of Health established a Situation Room in Brasília on March 25th, with permanent meetings to monitor the situation and integrate decisions between technical teams and managers.

Within the indigenous territory, the work is carried out in a coordinated manner between the Ministries of Health, Indigenous Peoples, Integration and Regional Development, Defense, Social Development, Funai (National Indian Foundation), and the Special Indigenous Health District of Mato Grosso do Sul (DSEI-MS), which has 210 Indigenous Health Agents (AIS) and 150 Indigenous Sanitation Agents (Aisan), in addition to logistical support with 91 pickup trucks, 6 vans, and 1 truck.

The actions also include training for health professionals in the municipal and indigenous networks, aligning clinical protocols for diagnosis and proper management of the disease, as well as health education activities in schools and communities. There are also plans to send prevention messages via WhatsApp to more than 234,000 residents , in Portuguese and with translation into indigenous languages.

The response also includes improving the quality of care, with the implementation of the national chikungunya protocol and training of teams for early identification of severe cases and appropriate clinical management.

Source: 

Link: https://www.gov.br/saude/pt-br/assuntos/noticias/2026/abril/governo-do-brasil-intensifica-resposta-integrada-e-mobiliza-forca-tarefa-para-enfrentar-emergencia-sanitaria-em-dourados-ms-2

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Increased #Mortality Rates During the 2025 #Chikungunya #Epidemic in #Réunion Island

 

Abstract

Background: 

Chikungunya virus (CHIKV) has historically been regarded as a low-fatality infection; however, growing evidence from diverse study designs demonstrated a substantial mortality burden during large-scale epidemics. In 2025, Réunion Island experienced a major CHIKV outbreak, raising renewed concerns about its fatal impact. 

Methods: 

We conducted an ecological time-series analysis of all-cause mortality during the 2025 chikungunya epidemic. Expected deaths were estimated using two complementary approaches: (i) a baseline based on age-specific mean mortality rates from the same calendar months in the post-pandemic period and (ii) long-term Poisson regression models using a log-link function and population offset, excluding the COVID-19 pandemic period. Excess mortality was calculated as the difference between observed and expected deaths during periods when observed mortality significantly exceeded the upper bound of the 95% confidence interval. 

Results: 

Observed mortality exceeded the upper 95% confidence interval (CI) limit for three consecutive months, coinciding with the epidemic curve and resulting in an estimated 208 excess deaths. These deaths were concentrated among older adults, peaking in April 2025 with a mortality rate ratio of 1.34 (95% CI: 1.22–1.47; p < 0.001). Among older adults, the age-specific excess mortality rate reached 145.3 per 100,000 (95% CI: 125.5–165.0) with a case fatality rate (CFR) of 2.4%, resulting in an overall population excess mortality rate of 23.2 per 100,000 and a total CFR of 0.4%. The number of deaths identified through routine surveillance was substantially lower than our estimates, highlighting a significant discrepancy between reported and excess chikungunya-associated mortality. 

Conclusions: 

Chikungunya epidemics are consistently associated with substantial underrecognized mortality worldwide. Routine surveillance relying solely on laboratory confirmation underestimates the true burden of the disease. Integrating excess mortality analysis, strengthening diagnostic and postmortem investigations, and implementing timely mitigation measures are essential to accurately assess and reduce preventable deaths during future CHIKV outbreaks.

Source: 

Link: https://www.mdpi.com/1999-4915/18/2/180

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Rapid #risk #assessment, acute event of potential public health concern: #Chikungunya virus disease, #Global (#WHO, Dec. 29 '25, summary)

 

Overall Risk statement

-- This RRA aims to assess the overall public health risk at the global level posed by the chikungunya virus (CHIKV) transmission during 2025, considering the criteria of potential risk for human health, the risk of geographical spread, and the risk of insufficient control capacities with available resources, and the implications for the 2026 transmission season. 

-- Chikungunya virus (CHIKV) poses a significant and growing global health risk due to large and widespread regional outbreaks in recent years, climate-driven mosquito expansion, lack of specific treatment, and increasing international travel. 

-- While mortality remains relatively low, the CHIKV infection can cause prolonged arthritis with disability as well as  severe illness in some patients. 

-- From 1 January to 10 December 2025, 502 264 CHIKV disease cases including  208 335 confirmed cases, and 186 CHIKV deaths, were reported globally. 

-- While certain WHO Regions are reporting lower case numbers compared to 2024, others are experiencing marked increases, furthermore some countries are seeing an emergence of chikungunya in previously unaffected populations. 

-- This heterogeneity in regional trends complicates the interpretation of the global situation. 

-- The data suggest localized resurgence or emergence in specific geographic areas. 

-- The region of the Americas has reported the highest number of confirmed cases followed by the European region (comprised of cases reported predominantly from French Overseas Departments in the Indian Ocean). 

-- Further, the potential for geographic spread remains substantial given that chikungunya can be introduced into new areas by infected travellers where local transmission may be established in the presence of competent Aedes mosquito, a susceptible population and favorable climatic and ecological conditions.  

-- The global public health risk posed by CHIKV transmission is assessed as moderate, driven by widespread outbreaks across multiple WHO regions during the 2025 season including areas with previously low or no transmission. 

-- The resurgence and emergence of cases in new geographic areas are facilitated by the presence of competent Aedes mosquito vectors, limited population immunity, favorable environmental conditions, and increased human mobility. 

-- The uneven distribution of cases complicates global interpretation, but highlights significant localized transmission. 

-- Control capacities remain challenged by gaps in surveillance, diagnostic access, healthcare infrastructure, and sustainable vector surveillance and control.  

-- Given the ongoing outbreaks reported globally in 2025, the potential for further spread in 2026 cannot be ruled out. 

(...)

Source: 

Link: https://www.who.int/publications/m/item/who-rapid-risk-assessment---chikungunya-virus--global-v.1

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#Safety and immunogenicity of a live-attenuated #chikungunya virus #vaccine in #adolescents: final results from a ... phase 3 trial in endemic areas of #Brazil

 

Summary

Background

Chikungunya outbreaks have recurred in Brazil since 2014. Building on earlier 28-day post-vaccination data, we now report 12-month safety and immunogenicity results of the VLA1553 vaccine in Brazilian adolescents.

Methods

In this double-blind, randomised, placebo-controlled, phase 3 trial, generally healthy adolescents aged 12–17 years were recruited at ten sites across Brazil. Individuals were excluded for immune-mediated or chronic arthritis or arthralgia, who are are immunologically compromised, or any recent live vaccines. Random allocation via simple block randomisation in a 2:1 ratio was stratified by baseline IgG and IgM serostatus by ELISA to receive a single intramuscular dose of VLA1553 or placebo. Assessed in the per-protocol population 28 days after vaccination, the primary endpoint was the proportion of baseline seronegative participants with chikungunya virus neutralising antibody levels assessed by a serum dilution achieving a 50% plaque reduction in a micro plaque reduction neutralisation test with a titre of 150 or more, an accepted surrogate of protection. Safety was assessed in all vaccinated participants and covered by several secondary trial endpoints; immunogenicity formed a prespecified subset for analysis. The trial is registered with ClinicalTrials.gov (NCT04650399) and is complete.

Findings

Between Feb 14, 2022, and Feb 16, 2024, 754 participants were vaccinated (502 [67%] with VLA1553 and 252 [33%] with placebo), with a per-protocol population of 351 participants for immunogenicity analyses (303 in the VLA1553 group and 48 in the placebo group). 406 (54%) of all participants were female and 348 (46%) participants were male; the median age was 15·0 years, and the majority of participants were White (245 [33%]), followed by 214 (28%) other and 192 (26%) multiracial. In baseline seronegative participants, VLA1553 induced seroprotective chikungunya virus neutralising antibody levels in 248 of 251 participants (98·8% [95% CI 96·5–99·8]) 28 days after vaccination, which was sustained in 232 of 236 participants (98·3% [95·7–99·5]) at 12 months post-vaccination. VLA1553 was generally well tolerated, with the vast majority (2082 [97%] of 2155) of adverse events of mild or moderate intensity. When compared with placebo, participants exposed to VLA1553 had a significantly higher frequency of related adverse events (352 [70%] of 502 vs 122 [48%] of 252; p<0·0001), mostly headache, injection site pain, myalgia, fever, and fatigue. One serious adverse event of high-grade fever was classified possibly related to VLA1553. Among 81 adverse events of special interest (ie, symptoms suggesting chikungunya-like disease), 16 were classified as related to trial vaccination (15 in the VLA1553 group and one in the placebo group), mostly early onset events usually starting during the first week after vaccination. Late onset adverse events of special interest showed no medically relevant differences between treatment groups. Nine adolescents had short-lived, usually mild recurring episodes of arthralgia (seven with VLA1553 and two with placebo) with a median duration of 1 day (cumulative range 1–7 days). One further participant with a history of chikungunya virus infection experienced recurring arthralgia followed by long-term polyarthralgia in several joints starting 148 days post-vaccination, classified unrelated to VLA1553. None of the recurring events of arthralgia was medically attended.

Interpretation

VLA1553 was generally safe and induced seroprotective titres up to 12 months in nearly all adolescents, with favourable safety data in those who were seropositive. The data support the use of VLA1553 for the prevention of disease caused by the chikungunya virus among adolescents and in endemic regions.

Funding

Coalition for Epidemic Preparedness Innovations and EU Horizon 2020.

Translation

For the Portuguese translation of the abstract see Supplementary Materials section.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00631-0/abstract?rss=yes

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The #epidemiology of #chikungunya virus in #Brazil and the potential #impact of #vaccines: a mathematical modelling study

 

Summary

Background

The first chikungunya virus (CHIKV) vaccine is now licensed in Brazil, the country that reports the most cases of CHIKV globally; however, the optimal use of the vaccine remains unclear owing to a poor understanding of CHIKV epidemiology and population immunity. We aimed to combine the distribution of cases and deaths reported since 2014 with seroprevalence studies to inform mathematical models that estimate the underlying rates of infection by state and year, and the underlying patterns of disease and death by age and sex.

Methods

We quantified the annual CHIKV infection and disease burden between 2014 and 2024 in each of the 27 federative units of Brazil using a mathematical model in a Bayesian framework that integrated serological surveys (n=12) and confirmed CHIKV disease cases (n=488 234) and CHIKV deaths (n=1719) reported between January, 2014, and September, 2024. Using this base, we estimated the potential impact of a vaccine over the period 2025–29 had the population been vaccinated before the 2025 season, evaluating different roll-out strategies.

Findings

We found that 18·3% (95% credible interval 16·5–20·3) of the Brazilian population has been infected since 2014, with the highest risk concentrated in the northeast and southeast. Overall, 1·13% (1·07–1·19) of infections were detected by surveillance systems, with an increasing probability of symptoms with age and greater risk of symptoms in females. Vaccinating 40% of the population older than 12 years (73 million doses), and assuming a vaccine efficacy of 70% against infection and 95% against disease, would avert up to 1·6 million (0·5–3) cases and 198 (61–359) deaths over the next 5 years.

Interpretation

Despite widespread circulation, most of Brazil remains susceptible to infection. CHIKV vaccination has the potential to substantially reduce disease burden.

Funding

CEPI.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00605-X/fulltext?rss=yes

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#USA, New York State Department of Health Confirms First Locally Acquired Case of #Chikungunya in #NewYork State (DoH)

 

ALBANY, N.Y. (October 14, 2025) — The New York State Department of Health today announced that a case of locally acquired chikungunya has been confirmed in New York State. Laboratory testing at the Department's Wadsworth Center confirmed the case in Nassau County on Long Island. This marks the first locally acquired case of chikungunya reported in New York State. No locally acquired cases have been reported in the U.S. states and territories since 2019.

An investigation suggests that the individual likely contracted the virus following a bite from an infected mosquito. While the case is classified as locally acquired based on current information, the precise source of exposure is not known. The Aedes albopictus mosquito, known to transmit chikungunya, is present in parts of downstate New York. Local transmission can occur when an A. albopictus mosquito bites an infected traveler, becomes infected and bites another person. The disease cannot be spread directly from one person to another.

"Our Wadsworth Center has confirmed this test result, which is the first known case of locally acquired Chikungunya in New York State. Given the much colder nighttime temperatures, the current risk in New York is very low." State Health Commissioner Dr. James McDonald said. "We urge everyone to take simple precautions to protect themselves and their families from mosquito bites."

Chikungunya is a mosquito-borne disease most common in tropical and subtropical regions. Symptoms include fever and joint pain, headache, muscle pain, joint swelling, or rash. The illness is rarely fatal and most patients recover within a week, though some may experience persistent joint pain. People at higher risk for severe disease include newborns infected around the time of birth, adults aged 65 and older, and individuals with chronic conditions such as high blood pressure, diabetes or heart disease.

In 2025, there have been three additional chikungunya cases outside New York City that were all linked to international travel to regions with active chikungunya infections. Routine mosquito testing conducted by the Department's Wadsworth Center and the New York City Department of Health and Mental Hygiene (DOHMH) has not detected chikungunya virus in any New York mosquito samples to date.

Mosquito activity in New York is declining as cooler fall temperatures begin. The Department reminds all New Yorkers to take precautions to reduce the risk of mosquito bites:

-- Use EPA-registered insect repellents

-- Wear long sleeves, long pants and socks outdoors when possible

-- Remove standing water around homes, such as in flowerpots, buckets and gutters

-- Repair or patch holes in window and door screens to keep mosquitoes out

(...)

Source: Department of Health, https://www.health.ny.gov/press/releases/2025/2025-10-14_chikungunya.htm

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Re-emergence of #chikungunya virus in #China by 2025: What we know and what to do?

 

Abstract

In July 2025, China witnessed its most significant chikungunya virus (CHIKV) outbreak since 2010. As of August 1, with over 6,000 cases reported in Foshan city, Guangdong Province. Although the clinical manifestations have been relatively mild, the rapid transmission within communities warrants our attention. In this context, we emphasize our current knowledge and the necessary actions to take. Specifically, we identify critical gaps in CHIKV control efforts and assess the effectiveness of current measures. These include vector management strategies, viral genomic surveillance, the deployment of newly approved vaccines, and the development of antiviral agents. Overall, to effectively control the epidemic of CHIKV, we require a comprehensive and multifaceted strategy for its prevention and management.

Source: PLoS Pathogens, https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013556

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#Chikungunya virus disease - #Global #situation (#WHO D.O.N., Summary, Oct. 3 '25)

 

Situation at a glance

In 2025, a resurgence of chikungunya virus (CHIKV) disease was noted in a number of countries, including some that had not reported substantial case numbers in recent years. 

Between 1 January and 30 September 2025, a total of 445 271 suspected and confirmed CHIKV disease cases and 155 deaths were reported globally from 40 countries, including autochthonous and travel imported cases. 

Some WHO Regions are experiencing significant increases in case numbers compared to 2024, although others are currently reporting lower case numbers. 

This uneven distribution of cases across regions makes it challenging to characterize the situation as a global rise, however, given the ongoing outbreaks reported globally in 2025, the potential for further spread remains significant. 

CHIKV disease can be introduced into new areas by infected travelers and local transmission may be established if there is the presence of Aedes mosquito and a susceptible population. 

The risk is heightened by limited population immunity in previously unaffected areas, favorable environmental conditions for vector breeding, gaps in surveillance and diagnostic capacity, and increased human mobility and trade. 

Strengthening disease surveillance, enhancing vector surveillance and control, and improving public health preparedness are essential to mitigate the risk of further transmission. 

Prior to 2025, current or previous autochthonous transmission of CHIKV has been reported from 119 countries and territories. 

A total of 27 countries and territories across six WHO regions have established competent populations of Aedes aegypti mosquitoes but have not yet reported autochthonous CHIKV transmission. 

Additional countries have established populations of Aedes albopictus mosquitoes, which can also transmit CHIKV, and in which transmission efficiency is enhanced for CHIKV lineages with the E1 226V mutation. 

The presence of these vectors poses a continuous threat of chikungunya introduction and spread in previously unaffected areas. 

Increased CHIKV transmission is driven by multiple factors that include: 

- the expanded geographic distribution of Aedes mosquitoes related to transportation in conveyances and 

- climate change, 

- unplanned urbanization, 

- poor water management, and 

- weakened vector surveillance and control. 

CHIKV disease typically causes high population attack rates. In smaller settings such as islands, the transmission dynamics can be temporarily interrupted once a proportion of the population becomes infected and subsequently immune. 

In larger populations however, where enough individuals remain immunologically susceptible, transmission can persist over time, leading to sustained outbreaks. 

These outbreaks often place a significant burden on healthcare systems due to the number of affected individuals. 

Countries differ in their ability to detect and report chikungunya and other vector-borne diseases, with many outbreaks identified only retrospectively, hindering effective public health responses. 

Early detection of cases, particularly in persons at risk for severe CHIKV disease, and timely access to appropriate medical care are essential for minimizing clinical complications and reducing mortality. 

The variation in distribution of cases across regions highlights the importance of continued investment in surveillance, preparedness, and response capacities to address evolving regional dynamics. 

WHO continues to call on all countries to strengthen their healthcare and laboratory systems to enable rapid detection, timely reporting, and effective response to chikungunya outbreaks.

(...)

Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON581

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#Syndromic approach for rapid #detection and differentiation of #human pathogenic #alphaviruses

 

Highlights

• Most vector-borne viruses like alphaviruses are not included in routine diagnostics

• Lack of testing results in misdiagnoses and underdetection

• A new multiplexed real-time PCR assay detects all human pathogenic alphaviruses

• The new multiplex assay is more sensitive than available tests and highly specific

• The multiplex test can be applied broadly for diagnostics and molecular surveillance

Abstract

Background

Knowledge of epidemiology, pathogenesis, and public health burden is scarce for many arthropod-borne viruses (arboviruses). Insufficient knowledge is partly due to lack of exhaustive laboratory diagnostics due to resource limitations. Among arboviruses, arthritogenic and encephalitogenic alphaviruses are globally widespread, can cause severe disease, and can co-occur regionally.

Objectives

We developed and validated a multiplexed real-time reverse transcription-PCR assay for the detection of all alphaviruses commonly causing human disease except Barmah Forest virus.

Study design

The assay combines five antigenic complex-specific assays and one Chikungunya virus-specific assay in a single parallelized reaction.

Results

Comparisons with previously published PCR-based protocols for broad alphavirus detection using 20 different human-pathogenic alphaviruses revealed a significantly higher sensitivity of the new multiplexed assay (Fisher’s exact test, p<0.0001). Detection limits with the new assay ranged from 0.83 cps/μl of extracted O’nyong-nyong virus to 33.05 cps/μl of extracted Western equine encephalitis virus. Antigenic complexes could be clearly differentiated by reactivity, Ct values (T-test, p<0.0025) and signal intensities (T-test, p<0.0001), even when testing high alphavirus concentrations potentially capable of causing false-positive PCR results. Testing of high-titred cell culture supernatants of eight important non-alphaviral arboviruses, of 4,308 serum samples collected from febrile patients in Benin and Peru, of seven CHIKV positive diagnostic samples from Brazil, and of non-targeted alphaviruses confirmed excellent diagnostic performance by the new assay, including improved detection of Mayaro and Venezuelan equine encephalitis virus in clinical specimens.

Conclusions

Short turn-around time, applicability in resource-limited settings, antigenic complex determination, and higher sensitivity compared to previously available tests make the new assay a useful tool for alphavirus surveillance and routine patient diagnostics.

Source: Journal of Clinical Virology, https://www.sciencedirect.com/science/article/pii/S1386653225001143?dgcid=rss_sd_all

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#Vectors on the Move: How #Climate Change Fuels the Spread of #Arboviruses in #Europe

 

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 how children may experience distinct clinical manifestations and complications, and how current data on pediatric burden remain limited for several emerging infections. Through an analysis of existing literature and reported outbreaks in Europe, this review underscores the urgent need for enhanced surveillance, integrated vector control strategies, and climate-adapted public health policies. Finally, it outlines research priorities to better anticipate and mitigate future disease emergence in the context of global warming. Understanding and addressing this evolving risk is essential to safeguard public health and to protect vulnerable populations, particularly children, in a rapidly changing climate.

Source: Microorganisms, https://www.mdpi.com/2076-2607/13/9/2034

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Serologic #Surveillance for #Orthoflaviviruses and #Chikungunya Virus in #Bats and #Opossums in #Chiapas, #Mexico

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. Antibodies that neutralized CHIKV were detected in three (7.0%) opossums and none of the bats. The three opossums had low CHIKV PRNT titers, and therefore, another alphavirus may have been responsible for the infections. In summary, we report serologic evidence of arbovirus infections in bats and opossums in Chiapas, Mexico.

Source: Viruses, https://www.mdpi.com/1999-4915/17/5/590

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#Chikungunya virus virus-like particle #vaccine #safety and immunogenicity in adults older than 65 years: a phase 3, randomised, double-blind, placebo-controlled trial

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 completed.

Findings

Between May 12 and Dec 2, 2022, 413 participants were recruited and randomly assigned (1:1) to receive the Vimkunya vaccine (n=206) or placebo (n=207). The coprimary endpoints of immunologic superiority of chikungunya virus SNA titres compared with placebo and geometric mean titre at day 22 were met. Vimkunya induced a protective seroresponse (SNA NT80≥100, considered the presumptive seroprotective antibody response) in 149 (82%) of 181 participants (95% CI 76·1–87·2) at day 15, in 165 (87%) of 189 participants (81·8–91·3) at day 22, and in 139 (76%) of 184 participants (68·9–81·2) at day 183. Although there was a slightly higher early immune response in the 65–74 years age group at day 15 compared with the 75 years and older age group, the seroresponse rates at day 22 and day 183 were similar. There were no notable differences in adverse event rates between groups, and most adverse events were grade 1 or 2 in severity and of short duration. No vaccine-related serious adverse events or deaths occurred.

Interpretation

We provide robust data from adults aged 65 years and older showing that Vimkunya is well tolerated and can provide a high rate of protection within 2 weeks postvaccination and during 6 months of follow-up.

Source: The Lancet, https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(25)00372-1/abstract?rss=yes

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