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In medicine and biology, transmission is the passing of a communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected.〔Bush, A.O. ''et al.'' (2001) Parasitism: the diversity and ecology of animal parasites. ''Cambridge University Press''. Pp 391-399.〕 The term usually refers to the transmission of microorganisms directly from one individual to another by one or more of the following means: * droplet contact – coughing or sneezing on another individual * direct physical contact – touching an infected individual, including sexual contact * indirect physical contact – usually by touching soil contamination or a contaminated surface (fomite) * airborne transmission – if the microorganism can remain in the air for long periods * fecal-oral transmission – usually from unwashed hands, contaminated food or water sources due to lack of sanitation and hygiene, an important transmission route in pediatrics, veterinary medicine and developing countries. Transmission can also be indirect, via another organism, either a vector (e.g. a mosquito or fly) or an intermediate host (e.g. tapeworm in pigs can be transmitted to humans who ingest improperly cooked pork). Indirect transmission could involve zoonoses or, more typically, larger pathogens like macroparasites with more complex life cycles. ==Definition and related terms== An infectious disease can be transmitted in two ways: as horizontal disease transmission from one individual to another in the same generation (peers in the same age group).〔(Horizontal Disease Transmission ), ''online-medical-dictionary.org''. date ?〕 by either direct contact (licking, touching, biting), or indirect contact air – cough or sneeze (vectors or fomites that allow the transmission of disease without physical contact).〔(Routes of transmission of infectious diseases agents ) from Modes of Introduction of Exotic Animal Disease Agents by Katharine M. Kurkjian & Susan E. Little of The University of Georgia College of Veterinary Medicine, date?〕 or by Vertical disease transmission, passing the disease causing agent from parent to offspring, such as in prenatal or perinatal transmission.〔(Vertical transmission ) ''(definition -- medterms.com)'' date?〕 The term ''infectivity'' describes the ability of an organism to enter, survive and multiply in the host, while the ''infectiousness'' of a disease indicates the comparative ease with which the disease is transmitted to other hosts.〔(【引用サイトリンク】 title=Glossary of Notifiable Conditions )〕 Transmission of pathogen can occur in various ways including physical contact, contaminated food, body fluids, objects, airborne inhalation, or through vector organisms. The point of the body where a pathogen enters is called the ''locus''. In droplet, contact and other airborne transmission it may be the respiratory system, but it could also be the gastrointestinal tract. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transmission (medicine)」の詳細全文を読む スポンサード リンク
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