The Geographical Spread of Avian Influenza A (H5N1): Panzootic Transmission (December 2003–May 2006), Pandemic Potential, and Implications

Abstract

The World Health Organization (WHO) believes that the advent of highly pathogenic avian influenza A (H5N1) has moved the world closer to a further global pandemic of human influenza than at any time since the Hong Kong (H3N2) pandemic of [1968][1969]. The immediacy of the perceived threat is underscored by the current classification of the world at Phase 3 of WHO's operative six-phase system of pandemic alert, with H5N1 having met all the prerequisites for the onset of a human pandemic but one: the efficient and sustained person-to-person transmission of the virus. With preparations for an anticipated pandemic now recognized as a global health priority, the purpose of this article is to provide a foundation for geographical research on avian influenza A (H5N1). The article introduces geographers to the complex nature and ecology of H5N1, the principal data sources available to analyze the global occurrence of the virus in birds and humans, and evidence regarding its geographical origins and international dispersal during the first thirty months of the ongoing panzootic in wild birds and poultry, from December 2003 through May 2006. Key epidemiological facets of the disease in humans are examined. We conclude with a review of the incurred and projected economic costs of H5N1, global plans for pandemic aversion and mitigation, and prospects for the future geographical expansion of the virus. Areas in which geographers can make an effective contribution to knowledge about the virus and the disease are considered. Key Words: avian influenza A (H5N1), diffusion, pandemic, panzootic.La Organización Mundial de la Salud (World Health Organization, WHO) cree que el advenimiento de la altamente patogénica gripe aviar A (H5N1) ha acercado al mundo hacia una pandemia de gripe humana más que en ninguna otraépoca desde la pandemia de Hong Kong (H3N2) de 1968 a 1969. La inmediatez de la amenaza percibida ha sido recalcada por la clasificación actual del mundo en la Fase 3 del sistema operativo de seis fases de alerta pandémica de la WHO, habiendo H5N1 cumplido todos los requisitos para el inicio de una pandemia humana, excepto uno: la eficiente y sostenida transmisión del virus de persona a persona. Con las preparaciones para una pandemia anticipada ahora reconocida como una prioridad global de salud, el propósito de este artículo es proporcionar una base para la investigación geográfica de la gripe aviar A (H5N1). El artículo presenta a los geógrafos la naturaleza y ecología complejas de H5N1, las principales fuentes de datos disponibles para analizar la ocurrencia global del virus en las aves y en los seres humanos, y la evidencia referente a sus orígenes geográficos y su dispersión internacional durante los primeros treinta meses transcurridos desde la panzootia en curso entre

Persistence and transmission of avian influenza A (H5N1): virus movement, risk factors and pandemic potential

“…Nascence of highly pathogenic forms of H5 and H7 or of other subtypes has never been observed in wild birds (Webster 1998). In addition, more than 90% of human H5N1 clusters have occurred among blood-related family members, suggesting possible genetic susceptibility (Smallman-Raynor and Cliff 2008;Abdel-Ghafar et al 2008). The current globalization of the poultry trade tends to homogenize the breeds used, resulting in homogeneity of existing genomes and day-old chicks globally, which may facilitate H5N1 spread among poultry.…”

“…The global spread of H5N1 has been reviewed in details elsewhere (Li et al 2011;Smallman-Raynor and Cliff 2008;Webster and Govorkova 2006). Liang et al (2010) analysed historical occurrences of H5N1 and found that a 300-km spatial lag corresponded to the average distance between major residential centres, and a 1250-km spatial lag corresponded to important staging points of wild birds, while a 55-day time lag and 80-day time lag corresponded to poultry and wild birds, respectively.…”

Economic globalization and the COVID-19 pandemic: global spread and inequalities

“…Several previous studies have used mapping to analyze the spread of epidemics by highlighting "spatial patterns". These include tuberculosis (Roth et al, 2016), cholera (Adesina, 1984;Ali et al, 2002), SARS-CoV (Lai et al, 2004;Shannon and Willoughby, 2004;Wang et al, 2008;Meade, 2014), MERS-CoV (Cotten et al, 2014), H1N1 influenza (Smallman-Raynor and Cliff, 2008;Souris et al, 2010), HIV (Wallace and Wallace, 1995;Wood et al, 2000) and dengue (Charette et al, 2017;Acharya et al, 2018;Atique et al, 2018;Zhu et al, 2019). In line with the approach of earlier studies, this paper attempts to analyze how the virus was transmitted across the globe and the underlying causes of its spread.…”

Using Knowledge Fusion to Analyze Avian Influenza H5N1 in East and Southeast Asia

“…For example, not taking into account the effects caused by geographical scale (the so-called “modifiable areal unit problem” [14]) could lead to interpretation errors when reviewing results from statistical analysis and modeling in area-based epidemiology. The predictive mapping of H5N1 risk in China, for instance, in Fang et al [15], conflicts with empirical observations [5], [16] and previous studies [17], [18]. Also, phylogenetic analysis [19] has its own limitations when genetic data are incomplete, and evolutionary models inappropriate [20].…”