Analysis of the 1999-2000 highly pathogenic avian influenza (H7N1) epidemic in the main poultry-production area in northern Italy

We evaluated the effects of risk factors and control policies following the highly pathogenic avian influenza (HPAI) epidemic that struck northern Italy's poultry industry in the winter of 1999–2000. The epidemic was caused by a type-A influenza virus of the H7N1 subtype, that originated from a low-pathogenic AI virus which spread among poultry farms in northeastern Italy in 1999 and eventually became virulent by mutation. Most infected premises (IP) were located in the regions of Lombardy and Veneto (382 out of 413, 92.5%), and the eradication measures provided for in the European legislation were enforced. In Veneto, where flock density was highest, infection-control was also accomplished by means of depopulation of susceptible flocks through a ban on restocking and pre-emptive slaughter of flocks that were in the vicinities of or that had dangerous contacts with IPs. In Lombardy, such control measures were applied to a lesser extent. Infection incidence rate (IR) was 2.6 cases per 1000 flocks per day in Lombardy and 1.1 in Veneto. After the implementation of infection-control measures, the at-risk population, the percentage of flocks ≤1.5 km from IPs, and the HPAI-IR underwent a greater reduction in Veneto than in Lombardy. Although the proximity (≤1.5 km) to IPs in the temporal risk window (TRW) was a major risk factor for HPAI at the individual flock level, its effect at the population level (population-attributable fraction) did not exceed 31.3%. Viral transmission therefore also occurred among relatively distant flocks. Turkey flocks were characterised by grerater IR of HPAI compared with other bird species such as layer hens, broilers, gamebirds, and waterfowl, even when located at distances >1.5 km from IPs. In Lombardy, IR for species other than turkeys was also relatively high.     

流行性乙型脑炎与三带喙库蚊的防控

流行性乙型脑炎(乙脑)在我国广泛流行。三带喙库蚊是主要媒介,依据如下:(1)三带喙库蚊是乙脑流行区的优势蚊种;(2)该种蚊的季节消长与乙脑的季节分布相一致;(3)该种蚊有乙脑病毒的自然感染,带菌率高;(4)该种蚊能叮刺和经卵传递乙脑病毒。防控方法:(1)环境治理;(2)管理宿主动物(猪等);(3)灭蚊降低密度;(4)做好个人防护;(5)接种疫苗。     

水稻纹枯病预测和管理模型—SIMPMRS

 SIMPMRS是一个以水稻生长发育时序为主轴，纹枯病发生、流行及其所致产量损失预测为基础， 栽培管理、药剂控制为管理措施，净收益最大为管理目标的系统模拟模型。其结构由水稻生长发育子模型、病原菌核初侵染子模型、病害流行预测子模型、菌核形成子模型、产量损失估计子模型、防治效应子模型和最优管理决策子模型组成。具预报与管理双重功能，既可进行中长期预报与远程决策，又可进行短期预报和实时决策。经有效性检验及大面积生产应用结果表明，该模型结构合理、逼真性强、应用方便，能有效地指导纹枯病大面积药剂防治和综合治理。     

夏谷锈病流行规律研究初报

近年河北省谷锈病逐年加重,给夏谷生产造成严重损失,尤其发病早的地块减产较重,甚至绝收。该病在夏价产区田间流行呈典型的“Ｓ”开曲线。病害流行与否阳决于夏谷生育期的雨量、雨次及其分布,夏谷品种抗病性和环境。防治技术为播种前处理还病谷草,大面积种植抗病品种,多雨年份在发病中心形成期喷药防治。     

Reactivity and prevalence of neutralizing antibodies against Japanese strains of bovine viral diarrhea virus subgenotypes

Bovine viral diarrhea virus (BVDV) field isolates show genetic and antigenic diversity. At least 14 subgenotypes of BVDV-1 and 4 of BVDV-2 have been identified in Artiodactyla worldwide. Of these, 6 subgenotypes of BVDV-1 and 1 of BVDV-2 have been isolated in Japan. Previously, we reported that each subgenotype virus expresses different antigenic characteristics. Here we investigated the reactivity of neutralizing antibodies against representative strains of Japanese BVDV subgenotypes using sera from 266 beef cattle to estimate the prevalence of this epidemic virus among cattle in Japan. Antibody titers at concentrations at least 4-fold higher than antibodies against other subgenotype viruses were considered subgenotype specific. Subgenotype-specific antibodies were detected from 117 (80.7%) of 145 sera samples (69.7% against BVDV-1a, 1.4% against BVDV-1b, 8.3% against BVDV-1c, and 1.4% against BVDV-2a). The results suggest that neutralization tests are useful in estimating currently epidemic subgenotypes of BVDV in the field.     

湖北省江陵县湖滩地区犬血吸虫病流行现状的调查

选择湖北省江陵县5个行政村的家犬(可在户外自由活动)和宠物犬为研究对象,用血清学诊断法、饱和盐水漂浮虫卵法、顶管毛蚴孵化法检测犬的感染情况,并采用抽样法对调查村所属的湖滩进行钉螺检查.结果,犬血吸虫病血清学检查阳性率为10.59%,饱和盐水漂浮虫卵法检查阳性率为8.24%,粪便毛蚴孵化法检查阳性率为10.77%,5个村湖滩阳性钉螺平均密度为0.445只/m2.结果显示,该县日本血吸虫病流行严重,阳性犬以重、轻度感染居多.     

松落针病的发生与防治措施

对松落针病的病原,侵染循环,流行规律,危害症状进行介绍,并总结了相应的综合防治措施。     

Using an age-structured model to simulate the recovery of the Australian pilchard (Sardinops sagax) population following epidemic mass mortality

An age-structured model of the Australian pilchard’s population has been adapted to simulate recovery from the mass mortality suffered during the herpesvirus epidemics of 1995 and 1998/1999. The model generates a vigorous recovery even when levels of mortality are very high, which accords with observations. In spite of this strong recovery, the model indicates that stock is sensitive to increased fishing pressure. Healthy stocks of juvenile pilchards play a key role in the vigorous post-epidemic recovery.     

玉溪市大棚内温室白粉虱的发生情况调查

对玉溪市农业科学研究所大棚内番茄植株上的白粉虱发生情况进行了调查。结果表明,白粉虱的发生数量在4月30日至5月30日期间形成3个高峰,分别是5月11日、5月19日以及5月21日,应在此时进行喷药防治;白粉虱成虫的发生数量出现2个高峰,分别是09:00后和17:00后,最低点则在13:30,应在该2个高峰时期进行喷药防治;白粉虱的发生情况和温度、湿度的变化有一定关系。     

种植密度和肥力对大蒜叶枯病的影响

[目的]了解种植密度和肥力对大蒜叶枯病的影响,为大蒜的优质高产提供参考.[方法]通过大田试验研究了成都温江地区种植密度和肥力对大蒜叶枯病的影响.[结果]大蒜叶枯病发生存在2个发病高峰期,分别在每年的1月和4月.病情指数随种植密度的增加而升高,平均最高病情指数为67.47,平均最低病情指数为32.07;各种植密度间病情指数差异极显著.各肥力水平下病情指数差异达极显著水平,与D9(CK)相比,最好的处理为D8(N100-K200-P100)处理,病情指数为31.10.[结论]低密度有利于减少叶枯病的发生;氮肥过多会导致病害发生偏重,而增施磷肥和钾肥有利于提高植物的抗病能力,降低病害的严重度.