ANSC440 Lecture III: Outbreaks of Zoonotic Diseases

Outbreaks of Zoonotic Diseases

Economical Consequences

  • Lecture-3, ANSC440/688J, February 04, 2025

Terminology of Disease Outbreaks

  • Sporadic: Occurring occasionally or in scattered instances.

  • Outbreak: A sudden increase in activity or disease.

  • Epidemic: A disease affecting large numbers at the same time, spreading rapidly within a population (e.g., brucellosis, leptospirosis).

  • Endemic: The normal incidence of a disease within a geographic area (e.g., salmonellosis, anthrax).

  • Pandemic: A disease occurring throughout a country or the world (e.g., plague).

Historical Outbreaks

Ten Worst Outbreaks in History

  1. Covid-19 (2019-2024): >7 million deaths globally.

  2. The Third Pandemic (1855-1950): >12 million deaths in China.

  3. The Black Death (1347-1351): Yersinia pestis, >75 million deaths worldwide, >25 million in Europe.

  4. Plague of Justinian (541-542): >5,000 deaths/day across Asia, Africa & Europe.

  5. Great Plague of London (1665-1666): 20% population loss, >75,000 deaths.

  6. American Plagues (16th Century): Measles, smallpox devastate Aztec/Inca civilizations.

  7. Great Plague of Milan (1629-1631): 280,000 deaths.

  8. Plague of Athens (430-427 BC): Typhus, smallpox, and measles outbreak, unknown death toll.

  9. Antonine Plague (165-180): >1,000 deaths/day in Milan.

  10. Great Plague of Marseille (1720-1722): >100,000 deaths.

Severe Acute Respiratory Syndrome (SARS)

  • Definition: Viral respiratory disease caused by SARS-CoV.

  • Outbreak Duration: November 2002 - July 2003.

  • Global Spread: Reached 37 countries, infected 8,098, resulting in 812 deaths (9.6% fatality rate).

  • Economic Impact: Estimated cost >$50 billion.

SARS Case Statistics (February-July 2003)

  • Total: 8,439 cases and 812 deaths across 30 countries.

  • Major affected areas included:

    • China: 5,326 cases

    • Singapore: 206 cases

    • Hong Kong: 1,755 cases

    • Taiwan: 698 cases

    • USA: 72 cases

  • No infectious disease spread as fast or broadly as SARS in 2003.

Lessons Learned from SARS

  • Importance of public health preparedness due to global threat from infectious diseases.

  • Role of air travel in disease spread.

  • Economic losses estimated between $30 - $150 billion from trade, travel, and tourism.

  • Global cooperation and rapid data sharing are vital for response.

Bovine Spongiform Encephalopathy (BSE)

  • Common Name: Mad cow disease, fatal neurodegenerative disease in cattle.

  • Incubation Period: 30 months to 8 years, peak onset at 4-5 years.

  • Impact: Over 180,000 infected in the UK; 4.4 million cattle slaughtered for eradication. Economic cost >$10 billion.

Avian Influenza (H1N1)

  • Known as bird flu, primarily affects birds but can infect humans.

  • Concern: Highly pathogenic avian influenza (HPAI) H5N1.

  • Since November 2003, affected >60 countries and resulted in over 220 million bird deaths due to culling.

  • Fatality rate >60% in humans exposed to H5N1.

New Avian Influenza Strains

  • H7N9 Virus: First infections reported in China in March 2013, mostly from contact with infected poultry.

  • Severity: Many cases result in severe respiratory illness, with one-third resulting in death. No sustained human-to-human transmission observed.

Swine Flu (H1N1)

  • Timeline of Outbreak:

    • March 18, 2009: Outbreak reported in Mexico.

    • April 15, 2009: H1N1 identified by CDC.

    • April 25, 2009: WHO declares a public health emergency.

Economic Impact of Recent Epidemics

Graphical Data Summary (Example)

  • SARS: >$50 billion (China, Hong Kong, Singapore, Canada).

  • Foot & Mouth Disease: $30 billion in the UK.

  • BSE in UK: $10-13 billion.

  • Avian Flu: $10 billion in Asia, US, Canada.

  • Swine Flu, Netherlands: $2.3 billion.

Economic Toll of Covid-19

  • Estimated cost of the COVID-19 pandemic in the USA is approximately $14 trillion.

  • Total deaths in the USA reached 1,212,505.

Foodborne Disease Impact

E. coli Outbreak (1996)

  • Details: Italian school-related outbreak leading to economic damages monitored across multiple prefectures.

  • Statistics: 9,492 symptomatic cases; 3 fatalities; economic damages quantified regarding healthcare and business interruptions.

Economic Losses and Costs Table Outline

  • Summary of various costs associated with foodborne illness:

    • Total human illness costs resulting from cases.

    • Laboratory testing and infrastructure costs.

    • Loss of income for caregivers (mothers caring for young children).

    • Facility improvements needed for prevention.

Hotspots of Zoonoses

Zoonotic Disease Vulnerability Zones

  • South Asia: India > Bangladesh > Pakistan.

  • East & Central Africa: Ethiopia > Nigeria > Congo DR > Tanzania > Sudan.

  • Southeast Asia: China > Indonesia > Myanmar > Vietnam.

  • West Africa: Burkina Faso > Mali > Ghana.

Key Zoonotic Diseases Affecting Human Health

  • Leptospirosis, Cysticercosis, Tuberculosis: Significant death tolls identified.

  • Rabies, Brucellosis, Avian Influenza: Notable impacts on livestock and human populations.

Diarrhea: A Silent Killer

  • WHO estimates 1.5 billion episodes of diarrhea with over 3 million deaths annually among children under 5, significantly associated with foodborne pathogens.

  • 70% of these diseases stem from foodborne or waterborne causes.

Economic Impact of Foodborne Illness in the US

  • 76 million cases of foodborne illness resulting in:

    • 325,000 hospitalizations and 5,000 deaths annually.

  • Economic Impact: Total estimated cost of foodborne illness is $152 billion.

FoodNet and Surveillance Initiatives

  • Established: In 1996 by CDC and various food safety agencies across the US.

  • Growth: Involves multiple sites for monitoring and reporting foodborne diseases.

Annual Disease Reporting in the US

Summary of Multistate Outbreaks Investigated

  • In 2021: 74 multistate outbreaks investigated including:

    • Salmonella, Listeria, E. coli.

Reportable Animal Diseases in the US

  • Top 10 Diseases: Include Brucellosis, Anthrax, and Rabies among others, each with various states reporting.

Livestock Losses in Sub-Saharan Africa

  • Impact: Significant livestock death losses attributed to modifiable diseases with underreported damage due to inefficient reporting systems.