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Predicting the risk of avian influenza A H7N9 infection in live-poultry markets across Asia
Marius Gilbert, Nick Golding, Hang Zhou, G. R. William Wint, Timothy P. Robinson, Andrew J. Tatem, Shengjie Lai, Sheng Zhou, Hui Jiang, Danhuai Guo, Zhi Huang, Jane P. Messina, Xiangming Xiao, Catherine Linard, Thomas P. Van Boeckel, Vincent Martin, Samir Bhatt, Peter W. Gething, Jeremy J. Farrar, Simon I. Hay et al.
Nature Communications 5, Article number: 4116 doi:10.1038/ncomms5116
Received 19 March 2014 Accepted 13 May 2014 Published 17 June 2014
Abstract
Two epidemic waves of an avian influenza A (H7N9) virus have so far affected China. Most human cases have been attributable to poultry exposure at live-poultry markets, where most positive isolates were sampled. The potential geographic extent of potential re-emerging epidemics is unknown, as are the factors associated with it. Using newly assembled data sets of the locations of 8,943 live-poultry markets in China and maps of environmental correlates, we develop a statistical model that accurately predicts the risk of H7N9 market infection across Asia. Local density of live-poultry markets is the most important predictor of H7N9 infection risk in markets, underscoring their key role in the spatial epidemiology of H7N9, alongside other poultry, land cover and anthropogenic predictor variables. Identification of areas in Asia with high suitability for H7N9 infection enhances our capacity to target biosurveillance and control, helping to restrict the spread of this important disease.
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Distribution of H7N9 predicted risk in Asia
Using the predictive map of live-poultry market density for Asia, market-level H7N9 infection risk was converted into a metric of infection risk at the pixel level (analogous to the probability that at least one infected market is present in the pixel), and extrapolated to Southeast and South Asia (Fig. 3b,c). Pixel-level infection risk (on introduction) is predicted to be limited to peri-urban and urban areas, where live-poultry market density is the highest, and which themselves are characterized by the environmental risk factors highlighted above. For example, the greatest risk beyond already-infected areas is estimated to be in the Bengal regions of Bangladesh and India, the Mekong and Red river deltas in Vietnam and isolated parts of Indonesia and Philippines.
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Bird flu scare for Bengal & Bangla
G.S. MUDUR
New Delhi, June 17: Bengal and Bangladesh are among areas in Asia predicted to be the most suitable for infections of a dangerous strain of bird flu that spreads through live poultry markets and has killed over 125 persons in China over the past year.
An international team of researchers has identified Bengal and Bangladesh, the river deltas of Vietnam, and parts of Indonesia and the Philippines as zones with conditions conducive for the spread of avian influenza H7N9 if the virus is introduced there.
The team?s vulnerability mapping exercise, published today in the research journal Nature Communications, has also found that the local density of live poultry markets is the most important predictor for the risk of H7N9 infections.
?We?re not saying we expect to see this infection emerge in these areas,? Marius Gilbert, an epidemiologist in Belgium who specialises in livestock and poultry diseases said in a media release issued by the International Livestock Research Institute. ?But the concentration of live poultry markets in these areas makes them very suitable for the infection should the virus be introduced there.?
...
Marius Gilbert, Nick Golding, Hang Zhou, G. R. William Wint, Timothy P. Robinson, Andrew J. Tatem, Shengjie Lai, Sheng Zhou, Hui Jiang, Danhuai Guo, Zhi Huang, Jane P. Messina, Xiangming Xiao, Catherine Linard, Thomas P. Van Boeckel, Vincent Martin, Samir Bhatt, Peter W. Gething, Jeremy J. Farrar, Simon I. Hay et al.
Nature Communications 5, Article number: 4116 doi:10.1038/ncomms5116
Received 19 March 2014 Accepted 13 May 2014 Published 17 June 2014
Abstract
Two epidemic waves of an avian influenza A (H7N9) virus have so far affected China. Most human cases have been attributable to poultry exposure at live-poultry markets, where most positive isolates were sampled. The potential geographic extent of potential re-emerging epidemics is unknown, as are the factors associated with it. Using newly assembled data sets of the locations of 8,943 live-poultry markets in China and maps of environmental correlates, we develop a statistical model that accurately predicts the risk of H7N9 market infection across Asia. Local density of live-poultry markets is the most important predictor of H7N9 infection risk in markets, underscoring their key role in the spatial epidemiology of H7N9, alongside other poultry, land cover and anthropogenic predictor variables. Identification of areas in Asia with high suitability for H7N9 infection enhances our capacity to target biosurveillance and control, helping to restrict the spread of this important disease.
...
Distribution of H7N9 predicted risk in Asia
Using the predictive map of live-poultry market density for Asia, market-level H7N9 infection risk was converted into a metric of infection risk at the pixel level (analogous to the probability that at least one infected market is present in the pixel), and extrapolated to Southeast and South Asia (Fig. 3b,c). Pixel-level infection risk (on introduction) is predicted to be limited to peri-urban and urban areas, where live-poultry market density is the highest, and which themselves are characterized by the environmental risk factors highlighted above. For example, the greatest risk beyond already-infected areas is estimated to be in the Bengal regions of Bangladesh and India, the Mekong and Red river deltas in Vietnam and isolated parts of Indonesia and Philippines.
...
Bird flu scare for Bengal & Bangla
G.S. MUDUR
New Delhi, June 17: Bengal and Bangladesh are among areas in Asia predicted to be the most suitable for infections of a dangerous strain of bird flu that spreads through live poultry markets and has killed over 125 persons in China over the past year.
An international team of researchers has identified Bengal and Bangladesh, the river deltas of Vietnam, and parts of Indonesia and the Philippines as zones with conditions conducive for the spread of avian influenza H7N9 if the virus is introduced there.
The team?s vulnerability mapping exercise, published today in the research journal Nature Communications, has also found that the local density of live poultry markets is the most important predictor for the risk of H7N9 infections.
?We?re not saying we expect to see this infection emerge in these areas,? Marius Gilbert, an epidemiologist in Belgium who specialises in livestock and poultry diseases said in a media release issued by the International Livestock Research Institute. ?But the concentration of live poultry markets in these areas makes them very suitable for the infection should the virus be introduced there.?
...