Quantifying transmission of highly pathogenic and low pathogenicity H7N1 avian influenza in turkeys.
Quantifying transmission of highly pathogenic and low pathogenicity H7N1 avian influenza in turkeys.
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DOI：
10.1371/journal.pone.0045059
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Gog JR
中科院分区：
文献类型：
--
作者：
Saenz RA;Essen SC;Brookes SM;Iqbal M;Wood JL;Grenfell BT;McCauley JW;Brown IH;Gog JR
禽流感在家禽中的爆发可能是毁灭性的，但许多基本流行病学参数尚未得到准确表征。 1999年至2000年，意大利北部爆发H7N1低致病性禽流感病毒（LPAI），随后又出现H7N1高致病性禽流感病毒（HPAI）。本研究在实验环境中调查了本次疫情中代表性 HPAI 和 LPAI H7N1 病毒株在火鸡中的传播动态，从而可以直接比较这两种病毒株。两种菌株的拟合传播率相似：HPAI 每天 2.04 (1.5–2.7)，LPAI 每天 2.01 (1.6–2.5)。然而，由于受感染的火鸡迅速死亡，HPAI 的平均感染期（1.47（1.3-1.7）天）比 LPAI（7.65（7.0-8.3）天）短得多。因此，HPAI 的基本繁殖率 (3.01 (2.2–4.0)) 显着低于 LPAI (15.3 (11.8–19.7))。传播率的比较对于理解 HPAI 如何从 LPAI 中产生至关重要。通过将竞争模型拟合到不同数量火鸡的实验中，测试了关于传播率如何随种群规模变化的两个相互竞争的假设。与频率相关的传输模型比密度相关的传输模型更适合实验数据。这对于从相对较少数量的家禽推断实验结果到商业家禽群规模，以及如何根据鸡群规模进行控制（包括疫苗接种）具有重要意义。
Outbreaks of avian influenza in poultry can be devastating, yet many of the basic epidemiological parameters have not been accurately characterised. In 1999–2000 in Northern Italy, outbreaks of H7N1 low pathogenicity avian influenza virus (LPAI) were followed by the emergence of H7N1 highly pathogenic avian influenza virus (HPAI). This study investigates the transmission dynamics in turkeys of representative HPAI and LPAI H7N1 virus strains from this outbreak in an experimental setting, allowing direct comparison of the two strains. The fitted transmission rates for the two strains are similar: 2.04 (1.5–2.7) per day for HPAI, 2.01 (1.6–2.5) per day for LPAI. However, the mean infectious period is far shorter for HPAI (1.47 (1.3–1.7) days) than for LPAI (7.65 (7.0–8.3) days), due to the rapid death of infected turkeys. Hence the basic reproductive ratio, is significantly lower for HPAI (3.01 (2.2–4.0)) than for LPAI (15.3 (11.8–19.7)). The comparison of transmission rates and are critically important in relation to understanding how HPAI might emerge from LPAI. Two competing hypotheses for how transmission rates vary with population size are tested by fitting competing models to experiments with differing numbers of turkeys. A model with frequency-dependent transmission gives a significantly better fit to experimental data than density-dependent transmission. This has important implications for extrapolating experimental results from relatively small numbers of birds to the commercial poultry flock size, and for how control, including vaccination, might scale with flock size.
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DOI：
10.1098/rsif.2011.0125
发表时间：
2011-12-07
期刊：
Journal of the Royal Society, Interface
影响因子：
--
作者：
Conlan AJ;Line JE;Hiett K;Coward C;Van Diemen PM;Stevens MP;Jones MA;Gog JR;Maskell DJ
通讯作者：
Maskell DJ
影响因子：
2.8
作者：
Capua, I;Mutinelli, F;Alexander, DJ
通讯作者：
Alexander, DJ
影响因子：
5.5
作者：
Bos, Marian E. H.;Nielen, Mirjam;De Jong, Mart C. M.
通讯作者：
De Jong, Mart C. M.
影响因子：
2.6
作者：
Bos, Marian E. H.;Nielen, Mirjam;Busani, Luca
通讯作者：
Busani, Luca
影响因子：
2.6
作者：
Mannelli, A.;Busani, L.;Marangon, S.
通讯作者：
Marangon, S.