Lecture%2015%20Community%20epidemiology%20II

Lecture%2015%20Community%20epidemiology%20II - 3/14/2009...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
3/14/2009 1 Community epidemiology II: Multi-host pathogens (cont’d) Parasites, predators and prey 1 Community epidemiology Community epidemiology : multi-host, multi- parasite interactions in a community context • Expand from one host – one parasite framework Community ecology: study of the structure, composition and dynamics of ecological communities Community: 2 or more interacting species at a particular place and time 2 Dilution effect Is biodiversity good for your health? • How does the presence of multiple host species affect the transmission of a generalist parasite? 3 Dilution effect Evidence from Lyme disease 4 White-footed mouse ( Peromyscus ) Deer tick ( Ixodes scapularis ) Lyme disease ( Borrelia burgdorferi ) Dilution effect Evidence from Lyme disease 5 Encounters between mice and immature ticks are the key to infection Tick encounters with white‐footed mice 6
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
3/14/2009 2 Dilution effect Is biodiversity good for your health? 7 Community 1 (fewer host species) Most contacts between highly competent (red) hosts Community 2 (more host species) Most contacts involve less competent hosts Lyme disease cases and mammal species diversity R. Ostfeld and F. Keesing, Conservation Biology 2000. Rick Ostfeld Felicia Keesing Loguidice et al. (2003) PNAS Trapped vertebrate animals in NY, Aug‐Sep Counted all ticks and allowed to engorge Ticks dropped off, allowed to molt Determined tick infection status Estimated nymphal infection prevalence as the number of infected nymphs (summing across each host species present) / total number of nymphs 9 Predicted NIP’ decreases with greater mammal species diversity valence Mice only Nymphal l infection pre Mouse density per hectare Mice + chimpunks, deer ___ + oppossums, skunks ___ + shrews and birds ___ + tree squirrels 10 Effect of forest patch size on Lyme disease transmission Allan et al. 2003 Cons Biol Small forest patches have many mice (fewer competitors and predators (fewer competitors and predators) Collected nymphal ticks at 14 forest patches Examined ticks for Lyme bacteria Estimated tick density and infection prevalence 11 Dragging for ticks 12
Background image of page 2
3/14/2009 3 Small forest patches supported higher tick density and infection Humans more likely to encounter Lyme disease in small vs. large forest patches; Habitat fragmentation increases human disease risk though biodiversity loss Patch area (ha) 13 Dilution effect Is biodiversity good for your health?
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/22/2009 for the course ECOL 4150 taught by Professor Prin during the Spring '08 term at University of Georgia Athens.

Page1 / 8

Lecture%2015%20Community%20epidemiology%20II - 3/14/2009...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online