Development, Health & Poverty

Anth 597.01

Epidemiological Transitions• H-G origins– low fertility + high infant mortality

• = low avg. life expectancy– Low pop. Density– High mobility– Chronic helminth infections

• 1st Epi Transition – Agr– high density sedentary pop.– High Fertility– Avg. age at death increases – Animal domestication

• Endemic infectious zoonosis• Acute & Communicable diseases• Influenza, smallpox, measles, tuberculosis, etc

2nd Epidemiological Transition

• Increased life expectancy– Sanitation & healthcare

• Chronic non-Infectious diseases– High energy & fat diet– Low PAL’s – Ex: CVD/CHD, cancers, diabetes

• Used to be– “diseases of affluence”– Western disease on the rise in developing nations

What do transitions illustrate?

• Dominant disease patterns are result of interactions between factors:– Cultural – Social– Political– Economic – Biological

• Why the early success in combating infectious diseases?

U.N. Millennium Development Goals

• 8 Goals to achieve in the new millenium:1. Eradicate extreme poverty & hunger2. achieve universal primary education3. Promote gender equality & empowerment 4. Reduce child mortality5. improve maternal health6. Combat HIV/AIDS, malaria & other diseases7. Ensure environmental sustainability8. develop a global partnership for development

Epidemiology: developed vs. developing nations

• The Good:– global life expectancy 50 yrs ago = 46 yrs– now = 64 yrs

• The Bad (inequalities in health):– global life expectancy is an aggregate average– Disability Adjusted Life Years (DALY)

• premature mortality + yrs of productive life lost owing to mortality & disease.

• 1 DALY = 1 yr of healthy life lost

– Comm. diseases account for 7% DALY in developed nations– 57% in developing nations

What is causing the disparity in DALY?1. Health care infrastructure– Europe 3.9 per 1,000– U.S. 2.7 per 1,000– Sub-Saharan Africa 0.1 per 1,000

2. Basic Research on diseases of Poor– small fraction of research papers dedicated to diseases of

importance for developing nations

3. Drug Development– Of 1,233 drugs licensed (‘95-97), 13 (1%) tropical diseases– only 4 of 13, developed specifically for Tropical diseases of humans

4. Pharmaceutical Sales – N. America, Europe & Japan = 82% of sales– Africa = 1%

Cultural Vectors• Set of cultural characteristics that allow

transmission (often from immobilized hosts to susceptibles)– care giving– irrigation, sewage & wells– boats, ships, trains & cargo

• Forces of modernization can have important consequences for disease transmission– virulence– emerging diseases & susceptibility

Technological Change• increased Transportation – economic centers– population centers

• Mixing & movement of peoples over short time– faster travel over larger areas– globalization fosters cheap air travel

• Spreads new diseases or variants– Ex: SARS, Avian Flu, West File– large monoculture raising operations • Confined Animal Feeding Operations• animal feed, hormones, & antibiotics

Culture Change & Virulence• Virulence – Magnitude of neg. effect of a parasite on host– measured by mortality & morbidity

• Insufficient time hypothesis– Not benefit of parasite to kill host• Evolve to be benign

– High virulence = insufficient time to evolve• evolutionary epidemiology model of virulence:– virulence the product of host-parasite interactions– niche – transmission vectors – behavioral practices

Virulence: host-parasite relationship

• Coevolution – Btw host-parasite/prey-predators– Resistance vs. Virulence

• Why are vectorborne diseases more virulent?– Malaria, Chagas, Schistosomiasis, sleeping sickness

• Case Study: Malaria– +ed breeding grounds (cultural)– +ed host density (social)

HIV/AIDS Epidemic in Africa• Found in OWM & Apes– Genetic evidence for 100 - 1000+ yrs of human infection

• Sexual reproduction = mode of transmission– increased promiscuity = more virulent– Less partners = less virulent

• Globalization = breakdown of traditional African culture– High Mobility in male wage workers– High levels of prostitution– Low levels of condom use

HIV/AIDS Epidemic in Africa• High levels & Virulence of HIV• Sub Saharan Africa

• 25 mil living w/ HIV • 3 mil newly infected • 2.2 mil died in 2003

• Anti-viral Drugs– AZT– virus mutates rapidly

The Downward Spiral:Infectious Disease & Poverty

• Unhealthy living conditions + likelihood of contracting diseases– Poor sanitation– Overcrowding & population growth– Poor infrastructure for prevention- malnutrition & hunger

• Infection/Malnutrition CycleInfection/parasite Load

Malnutrition/Hunger Low Production

“Medicalization of Disease”• Cultural beliefs that many of today’s diseases

can be “cured” by medicine– 20th Cent. Positivist ideals

• Hunger/Malnutrition– Nervos

• Antibiotics– Resistant strains - incomplete regiment– “cure alls” - viral infections

Rebirth of Tuberculosis• 20th Cent. antibiotics nearly eliminate TB– Few cases in Developed nations & controllable

• Social & Economic chaos of Soviet Collapse– Overcrowding & few antibiotics – Improper healthcare in Russian prisons

• Antibiotic resistant “Super Strain”– Slowly spreading from Russian Jails across world– May 2007, TB super strain patient travels from

Atlanta to Paris after being warned by U.S. Govnt

Infectious Disease & Environmental Changes

• Destruction of Environment– Logging, pasture, Dams, irrigation, etc– Bush meat trade & emerging infectious diseases

• Destruction of local ecosystems– Balance of prey/predator interactions– +es zoonoses

• Climate Change– Spread to new habitats– South moves North– West Nile, Malaria

Next Generation of Healthcare• Greater emphasis on prevention– Save more lives– Long-term = cheaper– Healthy people

• “Evolutionary Epidemiology”– Prevention over treatment– Stress more control of disease transmission– Active role in selective forces of pathogens

• Proposed Example: Influenza– Now: vaccine = most prevalent strain– Future: vaccine = only most virulent strains