Aerobiology, Volume 3, Issue 3 (September 2025) – 3 articles

In many regions, the El Niño Southern Oscillation (ENSO) cycle is a key factor in modulating climate processes that can influence seasonal variability in the production and dispersal of allergy-triggering pollen. However, the impacts on allergy health are not well known. We compare grass pollen seasons between the major modes of the ENSO cycle in Auckland, New Zealand’s largest city, within a region that is highly sensitive to quasi-predictable meteorological oscillations of the ENSO cycle. We find no clear difference in the timing of onset of the pollen seasons, but season length was shorter, by >30 days, and less severe during the La Niña phase than for the other phases. The difference in pollen season length may be explained by the greater summer rainfall typically experienced in Auckland and elsewhere in northern New Zealand during La Niña phases, which tend to suppress grass pollen abundance when excessive. As grass pollen is the principal source of allergenic pollen in New Zealand and in many other countries, these results have wider implications for allergy management. With ENSO forecasting offering the prospect of several month’s lead time, there is potential for improving community preparedness and resilience to inter-annual dynamics of the grass pollen season. This work points to the need to better understand the influence of short-term climate cycles on seasonal variability in pollen allergy, while we also emphasise that the strong geographical heterogeneity in ENSO cycle climate impacts necessitates a region-specific approach. This work also further underscores the need for standardised, local–regional pollen monitoring in NZ and the risk of relying upon static, nationwide pollen calendars for informing allergy treatment. Full article

Since the emergence of SARS-CoV-2, the interplay of human behavior, environmental factors, viral evolution, and public health interventions has resulted in unexpected changes in the timing, intensity, and geography of respiratory virus outbreaks. For example, respiratory syncytial viruses (RSV) exhibited a surge during atypical summer months in several countries. Influenza, on the other hand, nearly vanished in the early years of the pandemic, but returned with unusual strength and altered seasonal patterns. Concurrently, new variants of concern in coronaviruses have demonstrated increased airborne transmissibility, greater resilience to environmental conditions, and the ability to evade both natural and vaccine-induced immunity. In this review article, we have synthesized the current understanding of the aerobiology of respiratory infectious viruses, with a particular emphasis on the paradoxical trends observed in recent years. We examined various aspects, including viral morphology and environmental survivability, shifts in seasonality, the drivers of mutation and resistance, and the impact of environmental and climatic factors. Key issues we explored include viral morphology adaptation in response to airborne selective pressures and climate variability influence on the ecology of airborne viruses. Lastly, we investigated future risks and proposed an interdisciplinary framework for monitoring and mitigating airborne viral threats in an ever-changing world. Full article

Bacterial genera present in several areas of a pig farm were analyzed using high-throughput sequencing techniques. Samples were collected from the skin and feces of animals, as well as from surfaces, water, and air. The analyses revealed a strong correlation between air and skin samples, supporting the idea that bacterial growth on skin is potentially a mechanism of aerosolization and airborne transport. A water–air transmission route also appears to be present, although the direction of the transport mechanism cannot yet be determined. Other potential routes, such as contact with surfaces or feces, seem to be less efficient. Full article