20120330《传染病学总论》(七年制).ppt

Introduction of Communicable Diseases ;Introduce myself;1996;;传染病学科人才辈出 ;传染病学科教学工作;Why we learn?;Why we learn?;Why we learn?;Why we learn?;Why we learn?;Why we learn?;Characteristics;Infection and immunity ;Conception of infection;Infection spectrum; (1) Pathogen is eliminated or eradicated;Only make the host producing specific immune response Not having histomorphological damage — no symptoms and signs — no any biochemical changes — only discovered by immunological examinations Pathogens can be eradicated or carried;Make the host producing specific immune response Having pathological changes Immunity can be consolidated or temporary;No clinical manifestation but microorganism excreted Various forms: — virus or bacteria carrier — convalescent, healthy or incubatory carrier — acute or chronic carrier;Locates the pathogen but can not wipes it out Can latently for a long time Can occurs overt infection What is the different point between latent infection and carrier state ?;The role of pathogen in the infectious process;Invade directly — Leptospira, Filariform larva of Ancylostoma Adhere, colonize and produce enterotoxin — Vibrio cholera Promote spread — Vi antigen of Salmonella typhi ;Toxins — Exotoxin (Vibrio cholera，Corynebacterium diphtheriae, Clostridium tetani) — Endotoxin (S. typhi, Sh. dysentery) Enzymes (Entamoeba histolytica) ;Positive relation with pathogenicity Least number differ greatly;Factors: — environmental, drug and hereditary Various forms: — pathogenicity variation — antigenic variation — drug-resistant variation;The role of individual immunity in the infectious process ;Epidemic process influenced factors;Essential conditions of epidemic process;Patients — measles Persons of covert infection — poliomyelitis, epidemic cerebrospinal meningitis Pathogen carriers — typhoid fever, bacillary dysentery Infected animals — rabies