#Taiwan CDC: The #WMO predicts a strong #ElNiño event this year, which is conducive to spread of #arboviral diseases (July 7 '26)

 

    The latest forecast from the World Meteorological Organization (WMO) indicates that El Niño may intensify further in the coming months, potentially developing into a strong El Niño. 

    El Niño could further raise global temperatures and alter atmospheric circulation and rainfall patterns, increasing the risk of extreme weather events. 

    Some regions may face disasters such as short-duration heavy rainfall, torrential rain, and flooding due to more concentrated rainfall, while other regions may experience drought and water shortages. 

    International research shows that the high temperatures, warm winter, and abnormal rainfall brought about by El Niño may affect the growth and reproduction of disease-carrying mosquitoes, increasing the risk of dengue fever transmission. 

    Rising temperatures may shorten the growth cycle of disease-carrying mosquitoes, accelerating their reproduction rate; high temperatures may also shorten the time required for the dengue virus to multiply in mosquitoes to become infectious, increasing the chances of virus transmission. 

    On the other hand, after heavy rainfall, torrential rain, or continuous rainfall, various types of stagnant water environments easily form both indoors and outdoors, increasing the breeding opportunities for disease-carrying mosquitoes. 

    Due to the El Niño phenomenon facilitating dengue fever transmission and the ongoing international outbreaks of dengue fever and other mosquito-borne infectious diseases, coupled with the peak summer travel season, the public is urged to take mosquito prevention measures while traveling abroad and seek medical attention immediately if they experience any symptoms upon returning home, in order to jointly prevent dengue fever.

    Data from the Centers for Disease Control and Prevention (CDC) shows that as of July 6th this year, there have been a total of 83 confirmed dengue fever cases, including 7 local cases, all residing in Kaohsiung City; and 76 imported cases, all from Southeast and South Asian countries, with Indonesia (21 cases) being the most numerous, followed by the Maldives (14 cases) and Vietnam (11 cases). 

    The cumulative number of cases this year is lower than the same period last year (2025) (91 cases). 

    The global dengue fever outbreak remains severe, with over 1.44 million cases reported as of May this year. 

    The majority of cases are in the Americas, with Brazil having the highest number, followed by Bolivia and Colombia. 

    Neighboring Asian countries such as Vietnam, Malaysia, Sri Lanka, Cambodia, Bangladesh, and Laos have recently seen an increase in cases, with many exceeding the number from the same period last year, and showing a trend of co-circulation of multiple serotypes (DENV). 

    Given the current rainy season in Southeast Asia, the overall outbreak is expected to remain at its peak. 

    Health authorities are closely monitoring mosquito density in communities and strengthening patrols and prevention efforts in high-risk areas.

    The Centers for Disease Control (CDC) explained that with recent persistent high temperatures and frequent afternoon thunderstorms across Taiwan, post-rain environmental cleanup is crucial for dengue fever prevention. 

    Residents should proactively inspect their homes and surrounding areas, thoroughly removing water-collecting containers such as flowerpot saucers, discarded tires, and other stacked items. 

    Unused containers should be turned upside down or properly stored. A second inspection should be conducted after rain to ensure thorough cleaning and prevent mosquitoes from laying eggs and breeding.

    The Taiwan Centers for Disease Control (CDC) reminds the public that the current climate is suitable for mosquito breeding and activity. 

    When engaging in outdoor activities, the public is advised to wear light-colored long-sleeved clothing and use government-approved mosquito repellents containing effective ingredients such as DEET, Picaridin, or Imamectin (IR-3535). 

    If you experience symptoms resembling dengue fever, such as fever, headache, retro-orbital pain, or muscle and joint pain, please seek medical attention immediately and inform your doctor of your travel history. 

    Medical institutions are also urged to be vigilant, implement TOCC (travel, occupation, contact, and social contact) inquiries, use the dengue NS1 rapid test kit to aid diagnosis, and report cases promptly to facilitate timely prevention and control measures by health authorities. 

    Furthermore, given the ongoing international dengue fever outbreak, if you experience symptoms resembling dengue fever, such as fever, headache, muscle and joint pain, or rash upon arrival in Taiwan, please inform airport quarantine personnel. 

    For information related to dengue fever, please visit the Taiwan Centers for Disease Control website (https://www.cdc.gov.tw) or call the toll-free epidemic prevention hotline 1922 (0800-001922).

Source: 

Link: https://www.cdc.gov.tw/Bulletin/Detail/iheCGS59dCugdGfswWuh5Q?typeid=9

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Emerging and re-emerging vector-borne and other #zoonotic #RNA #viruses: #pathogenesis, #climate-driven dynamics, and strategies for global control

 

Abstract

Vector-borne and other zoonotic RNA viruses provide a significant and growing threat to global health, especially in areas where climate change, urbanization, and population growth facilitate the proliferation of arthropod vectors. This review offers an extensive examination of the biology, epidemiology, and pathogenesis of numerous important viruses, including dengue, Zika, chikungunya, yellow fever, Japanese encephalitis, Crimean–Congo hemorrhagic fever, Nipah, Ebola, and hantaviruses. We underscore how environmental and social factors, particularly increasing temperatures, modified precipitation patterns, and accelerated urbanization, transform vector habitats and spillover dynamics. The article further analyzes host–virus and virus–vector interactions, highlighting mechanisms of immune evasion, neurotropism, and vascular disease. Computational and machine learning models are examined as novel instruments for forecasting outbreaks and developing early warning systems. Finally, a summary of present and prospective control options is provided, covering integrated vector management, Wolbachia-based biological control, vaccinations, and antiviral immunotherapies.

Source: 

Link: https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1755594/full

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A #Market-Based #Sentinel #Surveillance for an Early #Detection of Viral #Outbreaks

 

Abstract

Mexico has experienced recurrent viral epidemics of substantial intensity, including hyperendemic dengue, COVID-19, and recent reports of avian influenza A (H5N1) infections in birds, which pose an ongoing risk of zoonotic transmission. Mexico was also the location for the earliest detection of the pdmH1N1 virus during the 2009 influenza A pandemic. Under a One Health framework, markets represent a unique opportunity for low-cost virus monitoring at the human-animal interface. Under the hypothesis that these represent sentinel sites for an early virus detection, we implemented a pilot surveillance program at the central market of Merida city, Yucatan, Mexico, considered a regional hotspot for multiple and recent viral outbreaks. Longitudinal sampling was carried out over 11 months at 1-to-6-week intervals from April 2022 to February 2023. We used multi-type surveillance in mosquitoes, live poultry, and wastewater. All samples were screened using RT-qPCR. Positive samples for DENV, SARS-CoV-2 and avian influenza A were further sequenced and analysed under a phylogenetic and epidemiological approach. Through our entomological surveillance, we report the earliest detection of DENV-3 III-B3.2 (genotype III American II lineage, considered a major public health concern in Latin America) in Mexico, overlapping with the resurgence of DENV-3 as the predominant serotype driving the 2023 national epidemic, which showed an increased severity. Through wastewater surveillance, we consistently detect SARS-CoV-2 RNA in wastewater samples, coinciding with the two infection waves officially recorded at a city and state level. Finally, cloacal swabs taken from two juvenile birds at the market suggest that avian influenza A viruses circulated in live poultry sold at the market. These findings show that our market-based surveillance framework is effective for an early detection and monitoring of pathogenic viruses in urban settings, and could complement official epidemiological surveillance in low- and middle-income countries to strengthen early-outbreak warning systems.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study was supported by the John Fell OUP Research Grant ATD00390 (M.E.Z and M.U.G.K), the Wellcome Infectious Disease Award ?317324/Z/24/Z (M.G.K, H.P.G and M.E.Z), the Secretaria de Ciencia, Humanidades, Tecnología e Inovación award (SECIHTI, Mexico) through the PRONACES Health grant (PRONAII project number 303002, G.S) and the Ciencia Básica y de Frontera programme (CBF2023-2024-3184, M.G.K), and the UKRI Innovation BSRC/EPSRC/NIHR 971557 grant (A.R.S). M.G.K is funded through a Sanger International Fellowship award. M.E.Z is funded by a UCL Rosetrees Excellence Fellowship UCL2024\2. P.M.D was funded through the doctoral program at ‘Posgrado en Ciencias de la Produccion y de la Salud Animal-UNAM’ through the SECIHTI doctoral scholarship. M.U.G.K. acknowledges funding from The Rockefeller Foundation (PC-2022-POP-005), Health AI Programme from Google.org, the Oxford Martin School Programmes in Pandemic Genomics & Digital Pandemic Preparedness, European Union's Horizon Europe programme projects MOOD (#874850) and E4Warning (#101086640), Wellcome Trust grants 303666/Z/23/Z, 226052/Z/22/Z & 228186/Z/23/Z, the United Kingdom Research and Innovation (#APP8583), the Medical Research Foundation (MRF- RG-ICCH-2022-100069), UK International Development (301542-403), the Bill & Melinda Gates Foundation (INV-063472) and Novo Nordisk Foundation (NNF24OC0094346). B.G is further funded by Wellcome Trust grants 303666/Z/23/Z, 226052/Z/22/Z & 228186/Z/23/Z. The contents of this publication are the sole responsibility of the authors and do not necessarily reflect the views of the European Commission or the other funders. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2025.12.22.25342882v1

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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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Serological #Evidence of #Flavivirus #Infection Among #Mothers of #Newborns in El Paso, #Texas

 

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 antibody to DENV, 4.4% to WNV, 0.1% to SLEV, and 0.0% for ZIKV antibody. The results confirmed the local transmission of WNV and supported a low prevalence rate for DENV, and this was the first reported serological evidence of SLEV infection in the El Paso community.

Conclusion: 

The interpretation of the public health significance of these observations supported previous findings of ongoing transmission of WNV and suggested the possibility of DENV transmission and re-emergence of SLEV in the community. Therefore, prospective studies are needed to obtain a more conclusive understanding of the prevalence of flaviviruses in the El Paso community.

Source: Vector-Borne and Zoonotic Diseases, https://www.liebertpub.com/doi/abs/10.1177/15303667251367518

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Effectiveness of integrated #vector #management on the incidence of #dengue in urban #Malaysia: a cluster-randomised controlled trial

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 vector control activities continued in both control and intervention sites. The trial was retrospectively registered (ISRCTN81915073).

Findings

Between Feb 10, 2020, and Sept 30, 2022, we carried out our IVM approach in the 139 randomly selected intervention sites. 903 834 individuals (447 149 intervention, 456 685 control) were living in the study areas. Dengue was reported in 1434 individuals in the intervention group (mean incidence per 100 person-years of 0·16 [SD 0·18]) compared with 1663 in the control group (0·18 [0·19; risk ratio 0·86, 95% CI 0·70–1·06; p=0·17). No adverse effects were reported.

Interpretation

Our study did not show an effect on the primary endpoint of the overall dengue incidence. Several factors such as substantial decrease in dengue incidence during the COVID-19 pandemic could have reduced the statistical power to detect significant differences between the two groups. Preventive and long-lasting approaches such as our IVM should be further tested to see if targeted interventions could help limit the number of cases in high-risk transmission areas.

Source: The Lancet Infectious Diseases, https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(25)00086-6/abstract?rss=yes

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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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