节肢动物(英文).pptVIP

Medical Entomology Jin Liqun Department of Parasitology Shantou University Medical College lqjin@stu.edu.cn Medical Entomology(Medical Arthropodology )  Arthropod : (Phylum Arthropoda节肢动物门) These organisms are characterized by having of jointed legs, body segments ,a hard outer covering or exoskeleton made of chitin（几丁质）. Three important characteristics: 1 bilaterally symmetric body with jointed appendages. 2 chitinized exoskeleton . 3 hemocele: the body cavity serves as blood cavity simultaneously. Classification Phylum Arthopoda contains the following Classes : 1 Insecta (昆虫纲、六足纲： insects), 2 Arachnida (蛛形纲，spiders, mites, ticks, scorpions, etc), 3 Chilopoda (centipedes ，唇足纲), 4 Diplopoda (milipedes，倍足纲), and 5 Crustacea (甲壳纲，crabs, shrimp, lobsters, water fleas, etc). * Arachnida （蛛形纲） * Insecta (昆虫纲、六足纲） The impairment of arthropods to humans 1 Direct impairment: 1a : harassment and blood sucking 1b: sting and inoculation of poison 1c: allergic reaction 1d: parasitism : such as myiasis, scabies, etc. Indirect impairment 1 Mechanical transmitting vector They play the role as a passive carrier of pathogens. 2 Biological transmitting vector The arthropod is used by pathogens not only as a vehicle but also as an environment for development and/or reproduction to their infective stages. How to judge an arthropod as a transmitting vector? ( four evidences) 1 Biological evidence: ( closely related with humans, dominant species, longer life span ) 2 Epidemiological evidence (closely related with distribution epidemic region and season) 3 Evidence of natural infection ( pathogen isolated from the vector) Laboratory evidence (Artificial infection) Ticks and mites Morphology: Gnathosoma (颚体、假头 ) Idiosoma (躯体) 4 pairs of legs (Adult) Life cycle Egg ----- larva---- nymph（若虫）---- adult Hard tick Note: scutum on its back Male(left) Female (right) Soft tick Without scutum Ticks A female hard tick’s body ma