Infectious Diseases and Natural Disasters

Background   Historically, infectious disease epidemics have high mortality   Disasters have potential for social disruption and death   Epidemics compounded when infrastructure breaks down   Can a natural disaster lead to an epidemic of an infectious disease?   Are there emerging infectious diseases after a natural disaster?

What is an emerging infectious disease?   In 1991, Institute of Medicine attempted to define:   – “new, re-emerging, or drug resistant infections whose incidence in humans has increased within the past 2 decades or whose incidence threatens to increase in the near future.”

Phases of Disaster   Impact Phase (0-4 days) – Extrication – Immediate soft tissue infections   Post impact Phase (4 days- 4 weeks) – Airborne, foodborne, waterborne and vector diseases   Recovery phase (after 4 weeks) – Those with long incubation and of chronic disease, vectorborne

Factors for Disease Transmission After a Disaster   Environmental considerations   Endemic organisms   Population characteristics   Pre- event structure and public health   Type and magnitude of the disaster

Environmental Considerations   Climate – Cold- airborne – Warm- waterborne   Season (USA) – Winter- influenza – Summer- enterovirus   Rainfall – El Nino years increase malaria – Drought-malnutrition-disease   Geography – Isolation from resources

Endemic organisms (exclusively native to a place)   Infectious organisms endemic to a region will be present after the disaster   Agents not endemic before the event are UNLIKELY to be present after   Rare disease may be more common   Unlikely a new or changed disease will occur   Deliberate introduction could change this factor

Population Characteristics   Density – Displaced populations – Refugee camps   Age – Increased elderly or children   Chronic Disease – Malnutrition – Heart disease – Transplantation

Population Characteristics   Education – Less responsive to disaster teams   Religion   Hygiene – Underlying health education of public   Trauma – Penetrating, blunt, burns   Stress

Pre-event resources   Sanitation   Primary health care and nutrition   Disaster preparedness   Disease surveillance   Equipment and medications   Transportation   Roads   Medical infrastructure

Type of disaster   Earthquake – Crush and penetrating injuries   Hurricane (Monsoon, Typhoon) and Flooding – Water contamination, vector borne diseases   Tornado – Crush   Volcano   – Water contamination, airway diseases   Magnitude – Bigger can mean more likelihood for epidemics

Dominican Republic, 1979   Hurricane David and Fredrick on Aug 31 and Sept 5th 1979   >2,300 dead immediately   Marked increase in all diseases measured 6 months after the hurricane – Thyphoid fever – Gastroenteritis – Measles – Viral hepatitis

Epidemics after Disasters San Francisco, 1907 Fires; Plague resulting from Quarantine failure Duluth, MN, 1918 Forest Fire; Influenza resulting from crowding and epidemic Italy, 1976 Earthquake; Salmonella Carriers due to sanitation stoppage

Summary of Factors   Many factors play a role in disease development and outbreaks   Change of disease not likely to play role – Increase in rare diseases   Change and/or closing of public health measures play a big role

What infections would we see today?   Endemic organisms   Post-impact phase   Recovery Phase

Post-Impact Phase Infections   Crush and penetrating trauma – Skin and soft tissue disruption (MRSA) – Muscle/tissue necrosis – Toxin production disease – Burns   Waterborne – Gastroenteritis – Cholera – Non-cholera dysentery – Hepatitis – Rare diseases

Post-Impact Phase Infections   Vector borne – Malaria – WNV, other viral encephalitis – Dengue and Yellow fever – Typhus   Respiratory – Viral – CAP – Rare disease   Other – Blood transfusions

Recovery Phase Infections   These agents need a longer incubation period – TB – Schistosomiasis – Lieshmaniasis – Leptospirosis – Nosocomial infections of chronic disease

General disaster reminders   Vaccinations are the mainstay of outbreak control in many situations   Dead bodies pose little to no infectious disease risk; however this is debated   Early surveillance and hygiene can prevent outbreaks

Conclusions   Infectious diseases may play a role in the post disaster period   These diseases will vary depending on many factors   If the disease is not present before the disaster, unlikely to be there after

Conclusions   Early recognition of certain diseases in disaster setting important   Halting infrastructure and response has led to most increases in infectious diseases   know where you are going and what is endemic