An apparent link has been established between human population density and vegetation cover and the spread of the Ebola virus from animal hosts to humans.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/ebola-animal-human-transmission-linked-population-density-and-habitat-degradation
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/international-business-times
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ebola-virus-disease-ebola-hemorrhagic-fever
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/infectious-diseases
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/epidemics
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/wildlife
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/viral-diseases
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/animal-diseases