We’re the Survivors Hosts and pathogens have a profound evolutionary influence on each other.

n Host > increased resistance n Pathogen >decreased virulence

Balanced Polymorphism s election that maintains a genetic disease in a population because heterozygotes resist an infectious disease Heterozygote advantage

Malaria is one of leading causes of morbidity and mortality in the developing world (along with TB, acute respiratory syndrome, diarrhea and HIV) but still not recognized in developed countries as a disaster like AIDS or EBOLA.

Each year, million people become ill with malaria.

More than 2 million people, mostly children, die from malaria each year.

Around 2.5 billion people (at least 40% of the world’s population) are at risk in over 90 countries.

Malaria kills more people today than three decades ago. Reasons include: Increasing drug resistance Increased migration and immigration People moving from countryside to cities. Tourist and business travel Decreased mosquito control Deforestation

Pathogen: Plasmodium falciparum (and 3 other plasmodium species)

Vector: female ‘Anopheles’ mosquitoes Symptoms: fever, chills, headache, muscle ache.

Every six months nets are dipped in insecticide and dried before use.

n Sickle cell anemia malaria n Cystic fibrosis cholera n Tay Sach’s disease---- tuberculosis

HH Hh hh CC Cc cc TT Tt tt

How Mutation Spreads Infectious Disease n Altered host (eg: parvovirus) n New toxin (eg: Eco 157:H7 n invasive Strep A) n New route of transmission n (eg: Ebola) n Drug resistance