GEOG103 Chapter Notes - Chapter 19, 20, 26: Bioterrorism, Cyanosis, Cutaneous Condition
6 Mar 2018
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Document Summary
Seasonal event, in which certain species travel b/w breeding grounds and overwintering grounds to take advantage of seasonal changes in resource availability. Proportion of species that are migratory in any location increases w/ distance from tropics. Most common pattern is a northward spring migration to breeding grounds, where young are raised, followed by southward autumn migration to escape harsh northern winters. Some shifted to higher latitudes/altitudes; effects are very species specific, however. Delays and advances in timing of spring migration in response to warmer springs or depending on reproductive cycle. Act as a source of infection to humans: asymptomatic reservoir host, diseased host, through carriage of infected arthropod vectors (such as ticks) Migration may both enhance spread of pathogens and facilitate cross-species transmission. Wild birds well-recognized reservoirs for influenza a viruses, west nile virus (wnv), etc. Wild aquatic birds- natural reservoir of influenza a viruses and low pathogenic avian influenza viruses (precursors of highly pathogenic strains)
