Introduction: Highly pathogenic avian influenza (HPAI) H5N1, a zoonotic virus primarily affecting birds, has shown increasing cross-species transmission, including to domestic animals such as cats. Recent reports of cat infections, often associated with contact with infected birds or the consumption of raw milk from H5N1-positive cattle, raise concerns about their role in viral adaptation and zoonotic transmission. Objective: To assess the global prevalence and characteristics of H5N1 infections in cats (Felis catus) through a systematic review and meta-analysis. Methods: Following PRISMA guidelines, we conducted a systematic search across PubMed, Scopus, and Web of Science up to 1 March 2025. Observational studies reporting the prevalence or seroprevalence of H5N1 in cats (Felis catus) were included. Data extraction and quality assessment were performed independently by four reviewers. Meta-analyses were conducted using a random-effects model, and heterogeneity was assessed via I² statistics. Results: Twenty-one studies met the inclusion criteria, of which eight were included in the meta-analysis (n = 3586 cats). The pooled global prevalence of Felis catus infections due to H5N1 influenza was 0.7% (95%CI: 0.3–1.1%), with high heterogeneity (I² = 86.5%). The prevalence varied by the diagnostic method, region, cat type, and time. Domestic cats and those in Africa had higher infection rates (20.0% and 32.0%, respectively). Case reports (n = 35) revealed a high mortality (74%), predominantly from clade 2.3.4.4b, with neurological and respiratory manifestations. Conclusions: Although the overall prevalence is low, H5N1 infection in cats is increasing, particularly in clade 2.3.4.4b. Their close contact with humans and other animals highlights the need for enhanced surveillance, diagnostics, and One Health strategies to mitigate zoonotic risks.

Yellow fever, a mosquito-borne viral hemorrhagic disease, remains a significant public health concern in endemic regions of Africa and South America. The development of the yellow fever vaccine marked a milestone in virology and immunization. In the 1930s, Max Theiler created the 17D live-attenuated vaccine, a breakthrough that has achieved global recognition and continues to underpin prevention strategies. This review outlines the historical evolution of the yellow fever vaccine, highlighting pivotal scientific advances, technological innovations, and global eradication initiatives. It examines the current landscape of immunization, focusing on the World Health Organization’s Eliminate Yellow Fever Epidemics (EYE) strategy, ongoing efforts to address vaccine supply constraints, and persistent surveillance gaps. Future directions in vaccine development, including next-generation platforms and improved delivery systems, are also discussed, alongside the need for sustained research investment and international collaboration. As yellow fever emerges in previously non-endemic areas due to climate change and globalization, strengthening vaccination programs remains critical to preventing outbreaks and ensuring effective disease control.

Thelaziasis is an emerging vector-borne zoonotic disease caused by Thelazia spp., which primarily affects animals but is increasingly recognised in humans, where it causes ocular infections. Human thelaziasis remains underreported and poorly understood in many regions despite its growing relevance. This systematic review analyzed epidemiological, clinical, diagnostic, and therapeutic data from 134 documented human cases of thelaziasis reported across 18 countries. Data sources included peer-reviewed publications and case reports, focusing on identifying trends in geographic distribution, clinical presentation, diagnostic techniques, and treatment approaches. Most cases (82.8%) were reported in Asia, particularly in South Korea, China, India, and Japan. The most common symptoms were foreign body sensation (53%), conjunctival hyperemia (39.6%), and epiphora (33.6%). Infestation was unilateral in 90.3% of cases. Diagnosis was primarily made through direct visual identification of the parasite, while molecular confirmation was used in a limited number of cases. Thelazia callipaeda was the predominant species identified (88.8%). Manual extraction was the mainstay of treatment (88.8%), with antiparasitic agents used in selected instances. Reinfection occurred in 6% of cases. This review underscores the growing recognition of human thelaziasis, particularly in Asia, and highlights the potential underdiagnosis in non-endemic regions. Environmental changes, globalization, and increasing human-animal interactions may facilitate the spread of the disease. Strengthening awareness, surveillance, and control measures is essential. Adopting a One Health approach, integrating human, animal, and environmental health perspectives, is critical for effective prevention and mitigation strategies.

Highly pathogenic avian influenza (HPAI) H5N1, particularly clade 2.3.4.4b, has demonstrated an unprecedented capacity for cross-species transmission, with recent reports confirming its presence in dairy cattle in the United States of America (USA) in 2024. This unexpected spillover challenges traditional understanding of the virus’s host range and raises serious public health and veterinary concerns. Infected cattle presented with clinical signs such as decreased milk production, thickened or discolored milk, respiratory issues, and lethargy. Pathological findings revealed inflammation of the mammary glands and the detection of a virus in nasal secretions and raw milk, suggesting a potential for both intra- and interspecies transmission. While the current risk of human-to-human transmission remains low, the detection of H5N1 in a human exposed to infected cattle highlights the need for heightened surveillance and protective measures. Moreover, the presence of infectious viruses in the food chain, particularly in unpasteurized milk, introduces a new dimension of zoonotic risk. This review synthesizes emerging evidence on the epidemiology, pathology, diagnostic findings, and zoonotic implications of HPAI H5N1 infection in cattle. It also highlights the importance of genomic surveillance, intersectoral collaboration, and One Health approaches in managing this evolving threat. As the virus continues to circulate and adapt across diverse hosts, including wild birds, domestic poultry, and now mammals, the potential for reassortment and emergence of novel strains remains a significant concern. Immediate actions to strengthen biosecurity, monitor viral evolution, and protect both animal and human populations are critical to mitigate the global risk posed by this expanding panzootic.