The Landscape Epidemiology of Seasonal Clustering of Highly Pathogenic Avian Influenza (H5N1) in Domestic Poultry in Africa, Europe and Asia

Abstract

Highly pathogenic avian influenza subtype H5N1 (H5N1) has contributed to substantial economic loss for backyard and large-scale poultry farmers each year since 1997. While the distribution of domestic H5N1 outbreaks across Africa, Europe and Asia is extensive, those features of the landscape conferring greatest risk remain uncertain. Furthermore, the extent to which influential landscape features may vary by season has been inadequately described. The current investigation used World Organization for Animal Health surveillance data to (i) delineate areas at greatest risk of H5N1 epizootics among domestic poultry, (ii) identify those abiotic and biotic features of the landscape associated with outbreak risk and (iii) examine patterns of epizootic clustering by season. Inhomogeneous point process models were used to predict the intensity of H5N1 outbreaks and describe the spatial dependencies between them. During October through March, decreasing precipitation, increasing isothermality and the presence of H5N1 in wild birds were significantly associated with the increased risk of domestic H5N1 epizootics. Conversely, increasing precipitation and decreasing isothermality were associated with the increased risk during April through September. Increasing temperature during the coldest quarter, domestic poultry density and proximity to surface water were associated with the increased risk of domestic outbreaks throughout the year. Spatial dependencies between outbreaks appeared to vary seasonally, with substantial clustering at small and large scales identified during October through March even after accounting for inhomogeneity due to landscape factors. In contrast, during April to September, H5N1 outbreaks exhibited no clustering at small scale once accounting for landscape factors. This investigation has identified seasonal differences in risk and clustering patterns of H5N1 outbreaks in domestic poultry and may suggest strategies in high-risk areas with features amenable to intervention such as controlling domestic bird movement in areas of high poultry density or preventing contact between poultry and wild birds and/or surface water features.

Estimation of the number of exposed people during highly pathogenic avian influenza virus outbreaks in EU/EEA countries, October 2016–September 2018

“…During the outbreak period, a higher number of wild birds were affected over a longer period compared to affected commercial establishments during previous outbreaks of avian influenza in Europe (Alkhamis, Moore, & Perez, ; Walsh, Amstislavski, Greene, & Haseeb, ). Whereas traditional education has focused mainly on large poultry facilities, our findings suggest more outreach to other groups is needed, such as hunters or persons exposed to wild birds.…”

Notifiable Respiratory Infectious Diseases in China: A Spatial–Temporal Epidemiology Analysis

“…Affected by the seasonal factors, RIDs have obvious seasonality [15,16]. Seasonality analysis indicated the seasonal characteristics of RIDs.…”

Deleterious effects of viral pneumonia on cardiovascular system

“…By the end of 2014, the World Health Organization (WHO) had reported 701 cases with a mortality rate of 58%. 7 The clinical manifestations of H5N1 are similar to H1N1, expect for the obviously early gastrointestinal symptoms (diarrhoea, vomiting, and abdominal pain). In addition, leucopenia, especially lymphopenia, suggests poor prognosis upon admission.…”