Agriculture and Domestic Animals -the Evolution of Human Disease-

1. Agriculture and Domestic Animals-the Evolution of Human Disease- Pearce-Duvet, Jessica, The origin of human pathogens: evaluating the role of agriculture and domestic animals in the evolution of human disease, UK: Cambridge Philosophical Society, pp. 369-382, (2006).

2. In regards to the origin of human pathogens we must ask: • What are the roles of agriculture and domesticanimals in the evolution of human disease?

3. What is the relationship between agriculture and domestic animals? • Domestication of animals is linked to the development of agriculture • The close proximity of domesticated animals and the increase of human population densities were supported by agriculture.

4. Agriculture Agriculture has allowed population densities to become large enough to promote the persistence of “civilization pathogens.” Domestic Animals Human pathogens are linked to domestic animals--since we have close contacts with domestic animals, it is not surprising that we share common diseases.

5. Case StudiesSeveral human pathogens are evolutionarily linked to domestic animals. The following common pathogens were examined:-measles-pertussis-smallpox-tuberculosis-taenid worms-faciparal malaria

6. RESULTS

9. Role of domestic animals: • The strongest evidence for a domestic-animal origin of human pathogens exists for pertussis and measles. • However, the data for tuberculosis, taenid tapeworms, and malaria suggest that we should not yet assume that domestic animals caused these diseases in human populations.

10. Role(s) of agriculture: • May have changed the transmission ecology of pre-existing human pathogens • Increased the success of pre-existing pathogens, which also influence the interactions between humans and animals • Through the domestication of animals, provided a stable passage for human infection -in other words, animals serve as secondary sources (carriers not sources) in the transmission of pathogens.

11. What else can we conclude from this study? • Domestic animals can increase transmission of wildlife pathogens because they are in closer contacts with humans. • Due to studied-pathogens’ virulent transmission, they could not have persisted in small, pre-agricultural populations implying origination in larger, agricultural populations

12. Applying this knowledge • Knowing about these parasites and their origins can help in prevention -immunization However, if agriculture changes the ecology of pathogen transmission then this disturbance can change antibiotic and pesticide resistance (Armelagos et, al. 2005) -this costs the US 33-50 billion dollars a year *A greater cause of these disturbances is human induced -pollution -destroyed/altered/relocated habits -tying in human-chimp-malaria relationship: people we are knocking down rain forest, coming in closer contacts with chimps, perhaps this is how we got disease, or changed ecology could promote mosquito reproduction -previously only hunters were exposed to certain animals, but now that these animals are being sold there is an urban spread (contact) with different animals different pathogens, no built immunities

13. IN ADDITION! • Since majority of studied pathogens were not necessarily linked to domestic animals, then further studies should be conducted to discover other possible origins.