Globalization & Disease Kendra L. Giamario Undergraduate Research 2005 Occidental College

“The Deity, jaded with omnipotence, seems to have posed Himself a paradoxical problem: just how deadly a disease can I create that humans will barely notice? His answer to His challenge was influenza.” Alfred Crosby America’s Forgotten Pandemic: The Influenza of 1918

The “Flu” 5-20% of population infected yearly –200,000 hospitalized & 36,000 killed in U.S. Causes “excess mortality” Vaccine imperfect

The Influenza Virus Native to waterfowl RNA Virus Contains surface proteins hemagglutinin 1-15 and neuraminidase 1-9 Pigs contain receptors for bird & human H strains

China Rapid urbanization High human-animal interaction Source of most flu pandemics of last 150 years

Global Trade & Travel 1.5 billion air travelers yearly 48 hours to anywhere Large live wildlife trade –40,000 primates yearly –640,000 reptiles yearly –4 million birds yearly –350 million fish yearly

SARS Coronavirus Incubation period 2-3 days –Defining symptoms appear up to 10 days after 8098 infected, 1707 died in countries Identified in mammals in wild animal market

“Swine Flu” Outbreak 1976 outbreak at American Legion convention –221 sickened, 34 died President Ford promoted mass immunization Campaign linked to Guillain-Barre syndrome Legionella pneumophilia identified in 1977

Legionnaire’s Disease Bacteria found in water and soil Survives between 68 & 122 degrees F 1000 cases reported yearly in U.S. –Outbreaks often caused by cooling systems Fatality rate of 5-15% –Up to 80% among immunocompromised

Antibiotic Resistance Antibiotic use provides selective pressure Failure to complete full regimen allows resistant strains to grow Subsequent exposure to another antibiotic provides new selective pressure Difficult to diagnose

Tuberculosis Nearly 2 billion infected latently 8 million active cases yearly Normally requires multi-drug regimen –6 month course of treatment –Often includes DOTS

MDRTB Approx. 273,000 new cases yearly Prisons & hospitals source of outbreaks Cure rate with standard treatment: 5-60% –Second line treatment: 48-80% cured Fatality rate: Up to 37% –Up to 89% in HIV+ individuals

Malaria 1 million deaths annually Complex life cycle –Multiplies in mosquito gut & moves to salivary glands –Mosquito bite infects human & virus reproduces –Uninfected mosquito bites infected human Restricted to the tropics

Temperature Based on IPCC impacts assessment of global temperature increases Relies on anopheles mosquito’s need for temperatures between 22 & 27 degrees C Predicts expansion north & south Does not take into account other environmental needs of mosquito

Current Malarial Distribution Sites currently endemic for malaria used to model multivariate climatic constraints Predicts little or no expansion Does not take into account regions where malaria was endemic but has been wiped out due to human control efforts

Spatiotemporally Validated Based on Hadley Center models of climate change Yearly mosquito needs determined by weather center data in endemic areas –Average & minimum temperatures seasonally –Average rainfall –Human population exposure Increase estimated in months of exposure Predicts increase in altitude but little increase north or south

Conclusions Globalization aspects which affect disease: –Urbanization –Speed and extent of trade & travel –New technologies –Antibiotic use –Climate change