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Parasite/pathogen
Emergence of new diseases
Question | Answer |
---|---|
What are EID's? | - diseases which are being found in new areas, new species or new populations - re-emerging infectious diseases are those being re-discovered in an area or species - mostly zoonotic |
What are zoonotic diseases? | - ones that spread between people and animals - these types are on the rise |
What is driving this emergence? | Anthropogenic and demographic changes are driving disease emergence |
Crowd infections | - denser populations & closer contact with livestock - exclusively human pathogen when human population density was high enough to maintain transmission |
Classical infections | - new infections reach distant populations - vectors allow transmission |
Empire infections | Travel expands geographically, exploration goes global bringing colonization - new populations without immunity to pathogens exposed |
Global infections | - urbanisation and globalisation Global travel is quicker, every day and population density is high = new pathogens!! |
Summary | Human populations increasingly mobile few isolated human populations Areas of habitat which affects populations of wildlife Increasing human-wildlife contact and human-human contact Quicker travel, reduced journey times - surveillance is better |
Cryptosporidium | - zoonotic protozoan parasites |
How does infection work? | Sporulated oocysts are excreted by in the faeces of an infected host Contaminated water or food are ingested and if the host is suitable Excystation occurs where the sporozoites are released and they invade the epithelial cells (intestines) and multiply |
Trypanosomiasis | - zoonotic protozoan parasites, i.e. T. cruzi causes Chagas disease |
How does infection work? | Infected tsetse fly bites a person/animal and injects trypomastigotes which travel to lymphatic system and bloodstream Inside the host the trypomastigotes change form and travel throughout body |
Protozoa multiply in the blood and body fluids and circulate the body When a person is bitten again by a tsetse fly, the fly ingests more protozoans | |
Protozoa change form within fly midgut & travel to salivary glands of the fly Protozoa multiply and change in to trypomastigotes, ready to infect a new host |