Ⅱ Morphology of arthropotry, Segmentation of body and
appendages (antennae, palps and legs) Exoskeleton (外骨骼) : consists of chitin and
1 pair of antennae Example: diplopod
Ⅳ Harmful effects on human
1. Direct injury 2. Indirect injury: diseases transmission
Arbo-disease: diseases transmitted by medical arthropods • Mechanical transmission:
Medical arthropodology (entomology) a subject to study :
morphology, classification, life cycle, ecology, geographical distribution, pathogenesis, regularity of disease transmission and control strategies
Direct injury
Annoyance and sucking blood Damage by toxic substances
biting / contact / active projection / ingestion Example： Paederus fuscipus: dermatitis Allergic reaction (anaphylaxis) allergen: saliva, secretory and excretory substances Example: dust mites (allergic rhinitis and asthma) Invading tissues Example: Myiasis, scabies，Tungiasis，
the largest phylum, account for 75% of all animals
I Introduction
Medical arthropods
Arthropods with medical importance:
parasitic arthropods, or vectors of pathogens
quinone tanned protein Open circulatory system: the body cavity is
hemocoel, full of haemolymph Molting or ecdysis and Metamorphosis (变态)
Ⅲ Arthropods of medical importance
Ⅲ Arthropods of medical importance
3 Class Crustacea (甲壳纲) cephalothorax and abdomen, 2 pairs of antennae, 5 pairs of walking legs, most live in water Example: shrimp, crab, cyclops，etc
4 Class Chilopoda (唇足纲) slender, flat and segmented body, 1 pair of antennae Example: Centipede
5 Class Diplopoda (倍足纲) long pipe-shaped and multi-segmented body,
Examples of mechanical transmission
Insects
Pathogens
Diseases
house fly, cockroach Salmonella spp Salmonellosis
house fly
comma bacillus (霍乱弧菌）
cholera
house fly, cockroach E. histolytica
1 Class Insecta (昆虫纲) 3 parts (head, thorax and abdomen), 3 pairs of legs, 1 pair of antennae (触角) Example: mosquito, fly, flea, louse, etc
2 Class Arachnida (蛛形纲) 2 parts (cephalo-thorax and abdomen) or as a combined body，4 pairs of legs, no antennae Example: tick, mite, spider, etc
Medical arthropods 医学节肢动物
Assoc Prof. Dr. Lei Jiahui Department of Human Parasitology
Teaching points
• Morphology of arthropods • Classification of medical arthopods • Harmful effects on human • Criteria to judge medical arthropod • Mosquitoes and flies
not multiply or develop in the arthropod not an integral part of the life cycle of the pathogen
• Biological transmission:
either multiples, develops, or both in the vector. one part of the life cycle of the pathogen