Biology subjects

Walsh, M. G.

Publications and source records attributed to Walsh, M. G..

3 recordsLinked to original sources

bioRxiv2022

Little pig, little pig, let me come in: The influence of landscape structure and La Nina climatic anomalies on the emergence of Japanese encephalitis virus in Australian piggeries in 2022

The widespread activity of Japanese encephalitis virus (JEV) in previously unaffected regions of eastern and southern Australia in 2022 represents the most significant local arbovirus emergency in almost 50 years. Japanese encephalitis virus is transmitted by mosquitoes and maintained in wild ardeid birds and amplified in pigs, the latter of which suffer significant reproductive losses as a result of infection. The landscape of JEV outbreak risk in mainland Australia is almost entirely unknown, particularly in the eastern and southern parts of the country where the virus has not been previously documented. Although other areas with endemic JEV circulation in the Indo-Pacific region have demonstrated the importance of wild waterbird-livestock interface in agricultural-wetland mosaics, no such investigation has yet determined the configuration of pathogenic landscapes for Australia. Moreover, the recent emergence in Australia has followed substantial precipitation and temperature anomalies associated with the La Nina phase of the El Nino Southern Oscillation. This study investigated the landscape epidemiology of JEV outbreaks in Australian piggeries recorded between January and April of 2022 to determine the influence of ardeid habitat suitability, hydrogeography, hydrology, land cover and La Nina-associated climate anomalies in demarcating risk. Outbreaks of JEV in domestic pigs were associated with ardeid species richness, agricultural and riparian landscape mosaics, hydrological flow accumulation, and grasslands. This study has identified the composition and configuration of landscape features that delineated risk for piggeries during the 2022 emergence of JEV in Australia. Although preliminary, these findings can inform actionable strategies for the development of new One Health JEV surveillance specific to the needs of Australia.

ecology↗

bioRxiv2020

Highly pathogenic avian influenza (H5N1) landscape suitability varies by wetland habitats and the degree of interface between wild waterfowl and poultry in India

Highly pathogenic avian influenza (HPAI), subtype H5N1, constitutes one of the worlds most important health and economic concerns given the catastrophic impact of epizootics on the poultry industry, the high mortality attending spillover in humans, and its potential as a source subtype for a future pandemic. Nevertheless, we still lack an adequate understanding of HPAI H5N1 epidemiology and infection ecology. The nature of the wild waterfowl-poultry interface, and the sharing of diverse wetland habitat among these birds, currently underscore important knowledge gaps. India has emerged as a global hotspot for HPAI H5N1, while also providing critical wintering habitat for many species of migratory waterfowl and year-round habitat for several resident waterfowl species. The current study sought to examine the extent to which the wild waterfowl-poultry interface, varied wetland habitat, and climate influence HPAI H5N1 epizootics in poultry in India. Using World Organisation for Animal Health reported outbreaks, this study showed that the wild waterfowl-poultry interface and lacustrine, riparian, and coastal marsh wetland systems were strongly associated with landscape suitability, and these realtionships varied by scale. Although increasing poultry density was associated with increasing risk, this was only the case in the absence of wild waterfowl habitat, and only at local scale. In landscapes increasingly shared between wild waterfowl and poultry, suitability was greater among lower density poultry, again at local scale only. These findings provide further insight into the occurrence of HPAI H5N1 in India and suggest important landscape targets for blocking the waterfowl-poultry interface to interrupt virus transmission and prevent future outbreaks.

ecology↗

bioRxiv2017

Climatic influence on the anthrax niche in warming northern latitudes

Climate change is impacting ecosystem structure and function, with potentially drastic downstream effects on human and animal health. Emerging zoonotic diseases are expected to be particularly vulnerable to climate and biodiversity disturbance. Anthrax is an archetypal zoonosis that manifests its most significant burden on vulnerable pastoralist communities. The current study sought to investigate the influence of temperature increases on the landscape suitability of anthrax in the temperate, boreal, and arctic North, where observed climate impact has been rapid. This study also explored the influence of climate relative to more traditional factors, such as livestock distribution, ungulate biodiversity, and soil-water balance, in demarcating high risk landscapes. Machine learning was used to model landscape suitability as the ecological niche of anthrax in northern latitudes. The model identified climate, livestock density and wild ungulate species richness as the most influential landscape features in predicting suitability. These findings highlight the significance of warming temperatures for anthrax ecology in northern latitudes, and suggest potential mitigating effects of interventions targeting megafauna biodiversity conservation in grassland ecosystems, and animal health promotion among small to midsize livestock herds.\n\nSignificance StatementWe present evidence that a warming climate may be associated with the current distribution of anthrax risk in the temperate, boreal, and arctic North. Moreover, projected warming over the coming decades was associated with substantive expansion of this risk. In addition, livestock distribution, ungulate biodiversity, and soil-water balance were also influential to anthrax risk. While these results are sobering for the future health of livestock and pastoralist communities in the northern latitudes, the coincident modulating effect of ungulate biodiversity may suggest targeted ecosystem conservation as a possible buffer against a growing anthrax niche.

epidemiology↗