贝氏隐孢子虫内生发育虫体的扫描电镜观察

贝氏隐孢子虫内生发育各阶段虫体寄生于气管和法氏囊的微绒毛丛中 ,鸭对贝氏隐孢子虫的易感性低于鸡和丝毛乌骨鸡。滋养体呈球形 ,平均直径 1 3μm ;typeⅠ裂殖体 ,平均直径 2 4μm～ 3 0 μm ,内含 8个裂殖子 ,呈逆时针旋涡状或呈桔瓣状排列 ;typeⅡ裂殖体内含 4个裂殖子 ,两种类型裂殖体的裂殖子之间填充着颗粒状残体并包围着一个大的球形残体。成熟裂殖子逸出的方式分为 4种类型。裂殖子大小为 3 0× 0 6 μm ,呈香蕉形。大配子体呈球形直径 3 3μm～ 4 2 μm ,小配子体直径为 3μm～ 3 6 μm。小配子呈子弹状 ,大小为 1 2 μm× 0 3μm ,并观察到成熟小配子的释放方式。带虫空泡可分为无球形残体和有球形残体两类 ,根据观察结果推测带虫空泡基部的梳状结构不具备营养器官的功能 ,营养器官应为带虫空泡的底部     

牛羊蜱传性血液原虫超微结构研究：双芽巴贝斯虫的超微结构观察

双芽巴贝斯虫电镜观察显示，红细胞内的虫体可分为裂殖子、正在分裂的裂殖子滋养体三个阶段。球形体大小与核一样，位于核与前极环之间。滋养体多形，膜为单层，虫体内有线粒体，微丝体。     

草原革蜱体内驽巴贝斯虫发育形态观察

将实验室培育的“清洁”草原革蜱（Ｄｅｒｍａｃｅｎｔｏｒｎｕｔｔａｌｌｉ）饥饿成虫，饲喂在人工感染驽巴贝斯虫（Ｂａｂｅｓｉａｃａｂａｉｌｉ）的驴体上，俟雌虫饱血脱落后，置２８℃、相对湿度约９０％的培育箱中产卵孵化；再将次代幼虫和若虫饲喂在健康驴体上，待饱血脱落后仍置培育箱中蜕化。观察了各发育阶段蜱的血淋巴、肠管、唾液腺以及卵内驽巴贝斯虫的发育形态。在饱血雌虫的血淋巴中发现２种不同类型的裂殖体，即大裂殖体和小裂殖体。成熟的游离大裂殖子大小为（５．０～１６．０）μｍ×（２．０～４．５）μｍ，平均９．８５μｍ×３．Ｏμｍ；小裂殖子的大小约１．２μｍ×０．５μｍ。在肠管中见到红细胞性虫体和直径４．０～６．μｍ的球形体。在卵巢中观察到梭形、球形体及梨籽形小裂殖子。卵内发育的驽巴贝斯虫呈多形性：卵圆形、圆形、椭圆形、梭形、梨籽形、棍棒形、逗点形、半月形以及难以形容的奇形古怪的形态。次代幼虫、饥饿若虫、饱血若虫和饥饿成虫的血淋巴及肠管中所见到的都是小裂殖子（幼虫的肠管中也见到大裂殖子），唾液腺中都有子孢子存在。     

马杜霉素对柔嫩艾美耳球虫(Eimeria tenella)超微结构的影响

将马杜霉素按 0 .0 0 0 5 %的比例混入饲料 ,作用于鸡体内柔嫩艾美耳球虫 (Eimeria tenella) ,透射电镜观察 ,发现裂殖体变小 ,内含裂殖子的数目减少 ,裂殖子膨胀变为椭圆 ,裂殖子间 (带虫空泡内 )微管结构模糊、膨胀 ,裂殖体中有髓鞘样结构出现 ;细胞膜外突和细胞质分离形成空隙 ,细胞膜有破损、结构模糊 ;细胞质出现空泡化 ,内部出现附加体和髓鞘样结构 ;少数细胞核的外膜外突和内膜分离 ,有的部位的核膜模糊、破损。裂殖子顶体结构发生异常变化 ,棒状体消失 ,微线数目减少或者消失。线粒体表现为形态改变 ,肿大变圆 ,或者变为马蹄形 ,内膜和嵴脱落 ,内部形成空泡、膜状结构、螺旋状或者髓样结构 ,线粒体的嵴与长轴平行排列 ,且贯穿线粒体。作者推测 ,抗生素类抗球虫药的作用机理可能是 ,通过使虫体结构的完整性受损 ,抑制虫体的物质代谢及能量代谢等生理机能 ,达到杀死虫体或者抑制虫体生长、发育和繁殖的目的。     

马杜霉素对不同虫株柔嫩艾美耳球虫超微结构的影响

鸡体内用5mg/kg马杜霉素作用于柔嫩艾美耳球虫（Eimeria tenella)敏感虫株和抗药虫株，比较裂殖生殖阶段超微结构的差异。敏感株型裂殖体体积变小，所生成裂殖子的数目变小，裂殖子膨胀，裂殖子间（带虫空泡内）微管膨胀，结构模糊，有髓鞘样结构出现；限制膜外突和细胞质分离形成空隙，膜结构模糊，有破损；细胞浆空泡化，出现附加体和髓鞘样结构；少数细胞核的外膜外突和内膜分离，有的部位的核膜模糊、破损。首次发现裂殖子顶体结构发生异常变化，棒状体消失，微线数目减少或者消失；线粒体表现为形态改变，嵴脱落，内部形成空泡、膜状结构和髓鞘样结构，线粒体的嵴与长辆平行排列，且贯穿线粒体。抗药虫株没有发现异常变化。推理抗生素类抗球虫药的作用机理为破坏虫体结构和抑制虫体的生理机能两个方面；球虫对该类药物产生抗药性的机制是基因突变和药物选择的结果。     

鸡卡氏住白细胞原虫各期虫体形态结构的观察研究

采取同居感染病鸡的外周血液 ,观察研究鸡卡氏住白细胞原虫 (LeucocytozoonCaulleryi)不同发育阶段的裂殖子和配子体的形态特点。光镜下 ,裂殖子呈圆点状 ,胞核圆形 ,着染紫红色 ,胞浆少量呈淡蓝色 ,位于血浆和血细胞内 ,配子体呈圆形或椭圆形 ,雌配子体 (大配子体 )虫体深蓝色 ,核较小 ,呈深粉红色 ,平均直径 16 6 5× 15 79μm ,雄配子体 (小配子体 )为淡蓝色 ,核较大 ,染色较雌配子体浅 ,平均直径为 11 2 7× 11 10 μm。电镜下 ,裂殖子呈圆形或卵圆形 ,外包有两层膜 ,外膜较薄 ,内膜较厚 ,内包一个圆形或卵圆形的核 ,位于红细胞细胞质内早期发育的配子体呈球形 ,表面隐约可见两层膜 ,细胞核大而淡染 ,位于中央 ,核膜呈双层 ,中间有明显的空隙 ,细胞质内可见数量不等的细微颗粒。     

菲莱氏温扬球虫裂体生殖的发育过程及超微结构

菲莱氏温扬球虫（ＷｅｎｙｏｎｅｌａｐｈｉｌｉｐｌｅｖｉｎｅｉＬｅｉｂｏｖｉｔｚ，１９６８）的裂体生殖过程是在具皱褶膜的纳虫空泡中进行的。发育早期的滋养体外被单层界膜，胞质中含一些退化的运动期虫体特有的细胞器（如微线体等），以及丰富的内质网、线粒体、高尔基体等。裂殖子以外出芽方式形成于裂殖体表面。裂殖子外被３层单位膜，中层和内层组成内膜复合体。裂殖子中部表膜上有１～２个微孔。类锥体由５～６圈微管组成，内有１对棒状体颈部，２根锥体内微管和若干微线体。类锥体前为Ｒ１、Ｒ２。棒状体起于顶孔，止于虫体中部，分细的颈部和膨大的体部，虫体前部有大量微线体。膜下微管为２２根。核位于虫体后部，每代成熟裂殖子均有数个致密体和大量支链淀粉粒。     

牛羊蜱传性血液原虫超微结构研究——大巴贝斯虫的超微结构观察

电镜观察显示，人工感染大巴贝斯虫的黄牛红细胞有一层绒毛外衣。虫体有双梨子形，单梨子形和形状多变的滋养体。细胞质内有前，后极地环及微丝体，棒状本，线粒体和内质网，除核外还观察到一个球形体。典型的双梨子虫体可见有双生的子细胞在末端相连，维持一段时间后分离，形成单梨子形虫体。滋养体的形态是多变的。大巴贝斯虫红内期的超微结构与双芽巴贝斯虫，卵形巴贝虫相似。     

羊焦虫病的流行及综合诊治

羊焦虫病是由莫氏巴贝丝虫和山羊泰勒虫在羊的红细胞体内寄生所引起血液原虫病的总称.临床上以高热、贫血、黄疸为主要特征,死亡率高,且以1～2岁羊发病多,由硬蜱吸血而传播,危害较重.2010年秋,我县张村史某从山东引进的小尾寒羊46只,次年4月发生焦虫病,现介绍如下. 1 病原特征 病原是巴贝斯科的莫氏巴贝斯虫和泰勒科的山羊泰勒虫.莫氏巴贝斯虫寄生于羊的红细胞中,其形态与牛双芽巴贝斯虫相似,呈梨子形、随圆形和不定型等多种形态.梨子形虫体的长度通常大于红细胞半径,每个有2团染色质团块.典型的虫体形态为双梨子形,以其尖端成锐角相连.虫体多寄生于红细胞中央,占其他形态的60％以上,一般红细胞内有1～2个虫体.山羊泰勒虫寄生于红细胞的形态不一,以圆形或卵圆形占大多数,其次为杆状,圆点状较少.一般红细胞内虫体数为1～4个,在脾脏和淋巴结的涂片中,可见淋巴结内和游离存在的裂殖体(石榴体).其中包含190个直径12微米呈紫红色的染色质颗粒.     

猪附红细胞体病诊治

正1病原特点导致本病的病原是附红细胞体,虫体呈球形、圆盘形、椭圆形或杆形等,直径为0.3～0.8μm,最大可达2.5μm,附红细胞体多寄生在红细胞表面,1个红细胞可附着1～10个虫体。2流行特点本病5～10月份多发,以2～5月龄猪发病较严重,其可通过口或损伤的皮肤、黏膜及胎盘感     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.