对家蚕微粒子病感染规律的研究

本文研究了家蚕微粒子病的食下传染、胚种传染、蚕座传染的规律性。指出对丝茧育来说感染越早危害越大,对种茧育来说感染越晚危害越大;食下感染的次数具有累积效应,但以起蚕期和将眠期（5龄为将熟前）影响最大;在蚁蚕就有感染蚕存在的情况下,丝茧育有二个蚕座传染周期,种茧育有三个蚕座传染周期;淘汰措施无论对丝茧育还是种茧育均是有效的,但其有效性随着基数毒率的增大而降低,只有当丝茧育的基数毒率在3％以下,种茧育的基数毒率在1％以下时淘汰措施才能取得95％以上的有效性,而且淘汰得越早越彻底效果越好;微粒子病对次代蚕的遗传毒率是一个变量,母蛾的带毒程度是影响其变化的主要因素;有毒母蛾产下卵通过催青后,遗传毒率在蚁蚕期已基本达到最大值,蚁蚕经高温高湿处理后遗传毒率的增幅不大而主要是孢子密度的增加;同一有毒母蛾产下卵用不同方式保护后,越年种蚁蚕毒率显著大于即时浸酸种蚁蚕毒率,说明微孢子在蚕卵的休眠期仍在增殖中;胚种传染带毒蚕的死亡时期大部分在3龄以前,影响发病死亡早晚的主要因素是母蛾的带毒程度。     

Serological survey of Toxoplasma gondii infection in domestic cats from northeastern Portugal

Cats are very important hosts in the epidemiological cycle of Toxoplasma gondii, a zoonotic protozoan parasite that can infect humans and many other animal species worldwide. We report a serological survey of antibodies to T. gondii in domestic cats from northeastern Portugal, by means of the modified agglutination test. Three cats had titres of 20 (3.9%), 18 had titres of 40 (23.7%) and 55 animals had titres of > or =800 (72.4%). Results of three seropositive kittens with less than 4 months were not considered for determining the seroprevalence of infection, which was found to be 35.8% (73/204). Differences in the seroprevalence levels were not statistically significant between males (35.6%) and females (36.0%) or pure non-European (26.7%) and European or mixed-breed cats (39.6%). Animals aged 36-71 months and 72-180 months had the highest seroprevalences of infection, i.e. 51.7% and 51.2%, respectively, which significantly differ from the values observed in cats with 2-11 months (14.6%) and 12-35 months (26.3%). Infection levels were also significantly different between cats that lived totally indoors (7.7%) and those that had access to outdoors (45.4%), as well as between cats living alone (13.8%) and those that had contact with other cats (39.4%). Seroprevalence values in cats fed only commercial canned or dried food (22.9%) and animals whose diet included raw or undercooked viscera and/or meat (53.5%) were also significantly different. Furthermore, considering only 108 cats, differences of seropositivity to T. gondii were significant between feline immunodeficiency virus infected and non-infected animals, but this was not observed for feline leukaemia virus. Age, habitat and diet were identified as risk factors for the feline T. gondii infection by logistic regression analysis. Some control measures are suggested based on these findings.     

Concomitant infection of cattle with the vaccine strain Anaplasma marginale ss centrale and field strains of A. marginale

Bovine anaplasmosis, caused by Anaplasma marginale, the intraerythrocytic rickettsia, is controlled by vaccination with live Anaplasma marginale ss centrale (A. centrale), a subspecies of relatively low pathogenicity. We have experimentally demonstrated that an animal primarily infected with A. marginale, or with the related vaccine subspecies A. centrale can be infected with the heterologous subspecies, and carries both bacteria. The co-infection was detected in experimentally cross-infected calves for up to 3 months after the last inoculation with the heterologous subspecies. The occurrence of characteristic cyclic rickettsemia of A. centrale and A. marginale was observed by examination of Giemsa-stained blood smears, or by the presence of specific rickettsial DNA confirmed in PCR assays based on specific msp1a and msp4 for A. marginale, and on specifically designed msp3 and msp4 primers for A. centrale. Sequence analysis of msp4-specific fragments for each subspecies revealed the presence of dual infection in both calves on days 30 and 60 after cross-inoculation with the heterologous Anaplasma subspecies. The experimental cross-infection of calves clearly demonstrated that the concept of "infection exclusion" does not apply to Anaplasma infection in cattle; as there was no infection exclusion of A. marginale in A. centrale-infected cattle, and vice versa. The present results confirmed our previous findings that cattle grazing in an anaplasmosis-endemic field were subject to concomitant infection with both the vaccine A. centrale and the field A. marginale strains.     

熊蜂微孢子虫对熊蜂的危害

在室内研究了熊蜂微孢子虫对熊蜂的危害,结果得出:N.bombi对不同B.lucorum蜂群的同日龄工蜂的感染率差异显著,说明熊蜂个体间抗微孢子虫病的能力不同;微孢子虫感染的工蜂幼虫、工蜂蛹、成年工蜂以及蜂王没有呈现任何能诊断的特有外部症状.感病蜂王平均产卵力降低,比健康蜂王平均推迟2～3天产卵,被感染的子代蜂王比健康蜂王推迟2～4天产卵,产卵力也降低,感病蜂王产的卵未发现感染微孢子虫,说明熊蜂微孢子虫不是通过垂直传播的.     

Isolation of methicillin-resistant Staphylococcus aureus from the environment in a veterinary teaching hospital

After recognition of a cluster of methicillin-resistant Staphylococcus aureus (MRSA) infection in horses and humans at the Ontario Veterinary College Veterinary Teaching Hospital, environmental contamination with MRSA was evaluated. A total of 260 environmental surfaces were sampled during periods when MRSA-infected horses were hospitalized, and MRSA was isolated from 25/260 sites (9.6%). The most commonly contaminated sites were stalls housing MRSA-positive horses, but other stalls, medical equipment, personal items, and equine restraint devices also were contaminated. The role of the environment in the transmission of MRSA infection to horses or humans is unclear. However, relatively widespread contamination of the hospital environment, as apparently occurs when infected horses are hospitalized, suggests that the environment may be an important source of MRSA infection. This possibility must be taken into consideration when designing infection control and disinfection protocols.     

生物保鲜液膜对草莓常温保鲜效果的研究

生物保鲜液 fb- 2 0 3是从多种微生物菌种发酵提炼萃取的混合液产物 (品 ) ,将其稀释液对草莓果实细喷雾或浸醮凉干后 ,在常 (室 )温贮藏保鲜 ,延长草莓新鲜外观时间与减缓对灰霉病与其他病害的感染速度。试验表明 ,室内相对湿度在 90 %左右 ,气(室 )温在 2 2℃± 2℃ ,理想保鲜效果 3d,商品性保鲜效果 4～ 5 d(x=4.5 d) ;气 (室 )温在 2 4℃± 2℃ ,理想保鲜效果 2 d,商品性保鲜效果 3～ 4d(x=2 .5 d) ;气 (室 )温在 2 8℃± 2℃ ,理想保鲜效果 1d,商品性保鲜效果 1～ 1.5 d(x=1.3d)     

畜禽腹泻与空肠弯曲菌感染的相关性分析

对465只（头）健康和腹泻畜禽的直肠和泄殖腔拭子及108份腹泻死亡畜禽的脏器材料进行空肠弯曲菌培养,并分析畜禽腹泻与该菌感染的关系,腹泻死亡后备蛋鸡的带菌率（93．3％）明显高于腹泻后备蛋鸡（53．3％）（P＜0．005）,腹泻后备收鸡的带菌率又明显高于健康后备收鸡（22．0％）（P＜0．001）,表明后备蛋主其腹泻死亡与该菌感染相关,腹泻仔猪的带菌率很高（88．0％）也提示该菌感染与仔猪腹泻存在一定关系。在腹泻死亡畜禽肠道内,腔弯曲菌在大肠和小肠的检测出率分别为91．7％和39．0％,检出率差异极显著（P＜0．001）,即显示该菌主要感染部位可能为腹泻畜禽的大肠。351株不同动物来源空肠弯曲菌的生物学分型结果表明,分布在各种动物体的主为主（90．4％）,或其比例升高（48．1％）,健康鸡与腹泻鸡的生物型分布有差异（P＜0．05）,提示生物型Ⅱ在致畜腹泻中起一定作用,另外,同一动物体内可有该菌的2个生物型分布。     

邯郸地区某牛场球虫病的调查和防治

为了解邯郸地区牛球虫感染情况及种类,研究分别在2019年冬季和2020年春季检测邯郸地区某牛场采集的300份粪便样品,对球虫卵囊进行计数、培养与虫种鉴定,计算其感染率和感染强度等指标.结果显示,冬春两季奶牛的球虫总感染率分别为13.33％和16.00％,肉牛的球虫总感染率分别为12.00％和14.00％;在所有年龄段中...     

蒜薹采后致病菌种类及侵染规律研究

以金乡蒜薹和苍山蒜薹为试材,研究蒜薹采后病原菌种类、侵染和发病规律。结果表明:导致蒜薹采后贮藏过程中腐烂的病原真菌分为9个属14个种,其中主要是交链格孢属(Alternaria)占28.5%,并且,交链格孢属中,链格孢霉(A.alternate(Fr.)Keissler)最多,占17.9%;其次是葱紫斑交链孢霉(A.porri(Elliott)Cif.),占6.6%,侵染链格孢霉(A.infectoriaSimmons)占4.0%;葡萄孢属(Botrytis),占17.0%,主要是葱鳞葡萄孢霉(B.squamosaWalker)和葱腐葡萄孢霉(B.alliiMunn),占15.6%,灰葡萄孢霉(B.cinereaPers)仅为1.4%;而青霉属(Penicillium)、匐柄霉属(Stemphylium)、镰孢属(Fusarium)、芽枝霉属(Cladosporium)、腐霉属(Pythium)、疫霉属(Phytophthora)和聚端孢霉属(Trichothecium)依次占15.7%、12.6%、7.8%、6.5%、4.9%、3.8%和3.3%。其发病规律是:除青霉属外,其它12种病原菌初期主要侵染蒜薹的薹梢部位,之后再逐渐向薹梗、薹基部位蔓延。