Current Trends in Arbovirus Outbreaks and Research

Dear Colleagues,

Arboviruses continue to represent an urgent and expanding global health challenge. In recent years, we have witnessed unprecedented outbreaks, geographic expansions, and shifts in transmission dynamics involving a wide range of arboviral pathogens. These changes are driven by a convergence of viral evolution, climate variability, anthropogenic environmental change, and increasing global connectivity.

After 20 years, chikungunya virus (CHIKV) has re-emerged in Réunion Island (2024–2025), causing a major outbreak associated with a viral clade harboring mutations such as E1-A226V, known to enhance transmission via Aedes albopictus. Similar mutations were responsible for the large-scale outbreaks that began in the Indian Ocean in 2005 and were followed by autochthonous transmission events in Europe.

This adaptation may also be contributing to the current chikungunya outbreaks in Europe and China. In 2025, Europe is experiencing both the earliest seasonal onset and the widest geographic spread of local chikungunya transmission ever recorded, while China is undergoing its largest epidemic to date. Notably, the European summer of 2025 has broken historical temperature records, creating increasingly favorable conditions for arboviral transmission in temperate regions via Aedes albopictus, a vector with expanding distribution.

These developments underscore the growing global risk of sustained arbovirus transmission beyond the tropics and raise concerns about future outbreaks in previously unaffected areas across Europe, Asia, and North America.

At the same time, the Americas are experiencing the largest arbovirus epidemics ever recorded, with explosive outbreaks of dengue, chikungunya, and yellow fever in several Latin American countries. These crises are straining surveillance systems and health services, exposing gaps in early detection, clinical management, and public health response.

Compounding this complex scenario is the rapid and unprecedented geographic expansion of Oropouche virus (OROV), a peribunyavirus historically restricted to the Amazon basin. In recent years, OROV has been detected in urban areas across Brazil, including bordering regions and signaling potential spread into the Caribbean. Despite its epidemic potential, OROV remains under-recognized and frequently misdiagnosed, presenting a silent but growing public health threat.

Topics of Interest

We invite submissions in the form of original research articles, reviews, short communications, case reports, viewpoints, and modeling studies related to the following topics:

• Arbovirus surveillance systems and outbreak investigations;
• Molecular epidemiology, viral evolution, and genomic signatures of adaptation;
• Vector competence, adaptation, and ecology in urban and temperate settings;
• Climate change and environmental drivers of arboviral transmission;
• Spillover risk and zoonotic interfaces;
• Emerging and neglected arboviruses (e.g., Oropouche, Mayaro): detection, expansion, and under-recognition;
• Diagnostic innovations and challenges in differential diagnosis;
• Arbovirus-related complications and mortality (neurological, congenital, chronic);
• Immunopathogenesis and host response to infection;
• Vaccine and antiviral development, and evaluation of public health applications;
• Health system preparedness, clinical management, and risk communication;
• Comparative studies across geographic regions, arbovirus species, or outbreak contexts.

Prof. Dr. André Ricardo Ribas Freitas
Guest Editor

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• arboviral infections
• Dengue
• Chikungunya
• Zika
• Oropouche
• West Nile
• Usutu
• Tick borne encephalitis
• Toscana
• Sandfly Fever Sicilian
• Flaviviridae
• Bunyavirales
• Togaviridae
• viral evolution
• vector ecology
• climate change
• emerging arboviruses
• surveillance
• public health preparedness