Transmission dynamics of hepatitis E among swine: potential impact upon human infection.
Transmission dynamics of hepatitis E among swine: potential impact upon human infection.
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DOI：
10.1186/1746-6148-3-9
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发表时间：
2007-05-10
影响因子：
2.6
通讯作者：
Nishiura, Hiroshi
中科院分区：
文献类型：
--
作者：
Satou, Kunio;Nishiura, Hiroshi
背景：戊型肝炎病毒（HEV）感染是一种人畜共患病，猪是其宿主。在日本，这种感染是猪的地方性流行病。为了便于理解特定年龄的感染模式，特别是在屠宰前，需要澄清农场内的详细的传播机制，在这里，我们重新分析了一个大规模的血清阳性率调查数据集，从日本猪场估计的感染力。猪戊型肝炎病毒的感染力在北海道、本州和九州分别估计为3.45（95%置信区间：3.17，3.75）、2.68（2.28，3.14）和3.11（2.76，3.50）[x10-2/天]。我们的模型假设的估计表明，感染的平均年龄范围为59.0-67.3天，基本繁殖数R 0为4.02-5.17。对不同感染力下的日龄特异性发病率的敏感性分析表明，感染力的下降会提高感染日龄，并增加180日龄时的排毒猪数。尽管我们的估计意味着超过95%的猪在150日龄之前被感染，该模型显示，感染力下降可能会增加猪到人传播的风险。如果感染力开始下降，则可能需要实施根本性的对策（例如，从哺乳期结束开始将未感染的猪与感染的猪群隔离），以尽量减少肥育阶段病毒阳性猪的数量。
BACKGROUND: Hepatitis E virus (HEV) infection is a zoonosis for which pigs play a role as a reservoir. In Japan, the infection has been enzootic in swine. Clarifying the detailed mechanisms of transmission within farms is required in order to facilitate an understanding of the age-specific patterns of infection, especially just prior to slaughter.RESULTS: Here we reanalyze a large-scale seroprevalence survey dataset from Japanese pig farms to estimate the force of infection. The forces of infection of swine HEV were estimated to be 3.45 (95% confidence interval: 3.17, 3.75), 2.68 (2.28, 3.14) and 3.11 (2.76, 3.50) [x10-2 per day] in Hokkaido, Honshu and Kyushu, respectively. The estimates with our model assumptions indicated that the average ages at infection ranged from 59.0-67.3 days and that the basic reproduction number, R0, was in the order of 4.02-5.17. Sensitivity analyses of age-specific incidence at different forces of infection revealed that a decline in the force of infection would elevate the age at infection and could increase the number of virus-excreting pigs at the age of 180 days.CONCLUSION: Although our estimates imply that more than 95% of pigs are infected before the age of 150 days, the model shows that a decline in the force of infection could increase the risk of pig-to-human transmission. If the force of infection started to decline, it might be necessary to implement radical countermeasures (e.g. separation of uninfected pigs from infected herds beginning from the end of the suckling stage) to minimize the number of virus-positive pigs at the finishing stage.