Family Dilepididae ( 囊宫科 ) Tapeworms of the dog, the cat and the fowl. The scolex usually has an armed rostellum ( 顶突 ) with several rows of hooks. The intermediate stage is a cysticercoid ( 似囊尾蚴 ).

Dipylidium canis ( 犬复孔绦虫 ) Host: Dog and cat; rarely man The commonest tapeworm of the domestic dog and cat.

Intermediate hosts: Fleas (Ctenocephalides canis, 犬栉首蚤, C. felis, 猫栉首蚤, and Pulex irritans, 扰 ) 蚤 and lice (Trichodectes canis, 犬毛虱 ). Predilection Site: Small intestine; cysticercoid in fleas and lice.

Distribution: Worldwide, and nationwide in China IDENTIFICATION Dipylidium is a much shorter tapeworm than Taenia, the maximum length being about 50 cm.

The proglottid ( 节片 ) is easily recognized, being elongate ( 细长的 ), like a large rice grain, and has two sets of genital organs, with a pore opening on each margin. The onchospheres are contained in egg packets or capsules, each with about 20 eggs

小肠中的犬复孔绦虫

Matured segment with genital pore on each margin

Egg packet of Dipylidium caninum

犬复孔绦虫储卵囊及其中的虫卵

LIFE CYCLE Eggs containing onchospheres were ingested by the intermediate hosts (fleas and lice) The onchospheres travel to the abdominal cavity where they develop into cysticercoids The final host is infected by ingestion of the flea or louse containing the cysticercoids and development to patency

Pathogenesis and Clinical Signs The adult is non-pathogenic and several hundreds can be tolerated without clinical effect

EPIDEMIOLOGY Dipylidium infection is very common, and is dependent on the continuous presence of ectoparasites (fleas and lice) for its local endemicity ( 地方性流行 ). The parasite is more prevalent in neglected animals, though infestations are also seen in well kept dogs and cats.

DIAGNOSIS Often the first indication of infection is the presence of a segment on the coat around the perineum （会阴） Confirmation of diagnosis is by the presence of egg packets in the segment

Treatment and control for Dipylidium infection must be instituted together, because it is useless to eliminate the adult tapeworm while leaving a reservoir in the animal’s ectoparasites (i.e., the parasite’s intermediate hosts). TREATMENT AND CONTROL

Hence, administration of anthelmintics such as nitroscanate ( 硝硫氰醚 ), and praziquantel should be accompanied by the use of insecticides ( 杀虫剂 ).

It is also imperative that the animal’s bedding and customary resting places should be treated with insecticides to eliminate the immature stages of the flea, which are many times more numerous than the adult parasites feeding on the dog or cat

中绦绦虫病 线中绦虫（ Mesocestoides lineatus ）属中绦科 （ Mesocestoididae ），寄生于犬、猫和野生 食肉动物（狐狸、浣熊、郊狼等）的小肠中， 偶寄生于人体。 Up to 3 m long. 线中绦虫的生活史尚未完全阐明，两个中间宿 主：第一中间宿主为食粪的地螨，在其体内可 找到似囊尾蚴；第二中间宿主为蛙、蛇、蜥蜴、 鸟类及小哺乳动物中的啮齿类，它们吞食了含 似囊尾蚴的地螨后可在其体内形成四槽蚴 （ Tetrathyridium ) 。

线中绦虫头端

欧、亚、非及北美等地均有分 布，在我国的北京、长春、浙江、 黑龙江、甘肃及新疆的犬体内、黑 龙江的猫及人体内均有发现。

第十一章 棘头虫病 棘头虫病是由棘头动物门 （ Acanthocephala ）的虫体寄生于动物和 人肠道内所引起的疾病。 是动物界中种类较少的一个门，寄生于人 和动物的种类亦较少，但其以坚韧的吻沟 插入宿主的肠壁，损伤肠粘膜，引起局部 出血，发炎，溃疡等，危害严重。 犬猫棘头虫病的流行具有一定的地区性。

棘头虫是一种左右对称、雌雄异 体的虫体，雄虫比雌虫小的多。 寄生于犬、猫的棘头虫为巨吻目 （ Gigantorhynchidea) 少棘科 （ Oligacanthorhynchidae) 钩吻属 (Oncicola) ，主要有两种： 犬棘头虫（ Oncicola canis ） 寄生于 犬的肠道。虫体长度小于 14mm ，国 内部分省区的犬有报道。

犬棘头虫成虫

猫棘头虫（ Oncicola pomatostomi ） 寄 生于猫的肠道。主要报道于澳大利亚北 部，对其中间宿主尚不清楚，但鸟类和 一些小的哺乳动物可能是其贮藏宿主。 蛭形巨吻棘头虫（ Macracanthorhynchus hirudinaceus ） 寄生于猪的小肠，也可 感染猪及犬猫，中间宿主为金龟子及其 它甲虫。在我国许多地区呈地方性流行。

第四篇、第十三章 小动物节肢动物病

Structure, Functions and Development of Arthropods ( 节肢 动物的结构、功能及基本生活史 The phylum Arthropoda ( 节肢动 物门 ) contains over 80% of all known animal species

The major characteristics ( 特 征 ) of arthropods are a hard chitinous exoskeleton ( 硬的几 丁质外骨胳 ), a segmented body ( 分节的躯体 ) and jointed limbs ( 有关节的足、 肢 ). The Major Characteristics

The hard exoskeleton ( 外骨胳 ) of arthropods is secreted by an underlying epidermis ( 真皮 ) and consists of numerous segments ( 分节 ) These segements are often clearly separated into three regions, the head, thorax ( 胸 ) and abdomen ( 腹 )

嗉囊 马尔皮基小管

The body cavity or coelom ( 体腔 ), the space between the gut and the body wall), is often called the haemocoele ( 血腔 ) since it contains blood or haemolymph ( 血淋巴 ) whose primary function is the transport of metabolites ( 代 谢产物 ).

The internal organs ( 内脏器官 ) are bathed in this blood which is continuously circulated by a dorsally situated, primitive, tubular heart. Blood enters through openings in the heart wall, called ostia ( 门、口 ), and is expelled through short vessels ( 短管 ) into the haemocoele ( 血腔 ).

Respiration in arthropods is simple, oxygen reaching the tissues by direct gaseous diffusion. Small circular openings in the exoskeleton called spiracles ( 气孔 ) allow air into the body. This then enters a system of branching tracheae ( 气管 ) and tracheoles ( 小气管 ) which ramify ( 分支 ) through most parts of the body. Respiration ( 呼吸 )

The nervous system consists of a ventrally situated ganglionated ( 有神经节 ) nerve cord which connects in the head region with a large supraoesophageal ( 食道上的 ) ganglion often called the ‘brain’. Associated with the nervous system are the sensory organs ( 感觉器官 ), including the eyes and various tactile ( 触觉 ) and auditory ( 听觉 ) organs. The Nervous System ( 神经系统 )

Other sensory organs include antennae ( 触角 ), palps ( 须 ) and various receptors ( 感受器 ) in the body which respond to temperature, humidity, food stimuli and host odours ( 气味 ).

In the arthropods the sexes are separate. The arrangement of male and female reproductive systems in arthropods is similar to sexually separated trematodes. Most arthropods are oviparous ( 卵 生的 ). Reproductive System ( 生殖系统 )

Development often involves three or more larval stages followed by the formation of a pupa ( 蛹 ) and a marked transformation or metamorphosis ( 变态 ) to the adult stage, as in all the flies and fleas ( 蚤 ). Development ( 发育 ) I: Holometabolous ( 全变态的 ) life cycle

In other insects development occurs from the egg through several nymphal ( 若虫 ) stages which resemble the adult, as in lice ( 虱 ), i.e. a hemimetabolous life cycle. II: Hemimetabolous life cycle ( 半变态生活史 )

Classification of Arthopodes ( 节肢动物的分类 ) Arthropoda ( 节肢动物门 ) Insecta ( 昆虫纲 ) Arachnida ( 蛛形纲 ) Crustacea, etc 甲壳纲, Mites and ticks ( 蟎及蜱 ) Flies, lice and fleas ( 蝇、虱及蚤 )