Communicable Diseases Following Natural Disasters: A Public Health Response

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Communicable Diseases Following Natural
DisastersA Public Health Response

• Stephen C. Waring, DVM, PhD
• Associate Director
• Center for Public Health Preparedness

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M Kokic, IFRC/RCS
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Learning Objectives

• To provide an overview of issues relevant to
  preparedness and response for emergency health
  relief workers
• To understand the underlying factors favoring
  outbreaks of high morbidity communicable diseases
• To review characteristics of diseases of greatest
  concern in disasters

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Communicable Diseases in Disasters

• Keys to minimizing morbidity and
  mortality
• Adequate preparedness
• Rapid, coordinated response
• Sustained recovery

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Communicable Diseases in Disasters

• Timely coordinated intervention efforts require
  continual review and revision of preparedness
  missions at the local, national, and
  international level
• Greatly facilitated by ongoing government,
  academic, and private organization training and
  education programs

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Factors Favoring Disease Outbreak

• rapid onset and broad impact
• compromised sources of water
• displacement of large numbers of people
• temporary sheltering in crowded conditions
• inadequate sanitation
• compromised waste management

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Factors Favoring Disease Outbreak

• potential food shortages
• malnutrition/malnourishment
• level of immunity
• ongoing outbreaks prior to disaster
• compromised infrastructure
• depleted supplies
• susceptibility of population

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Epidemiology and Surveillance

• Must establish disease surveillance system as
  soon as possible
• Identify key resources
• local physicians, nurses, health workers
• functioning hospitals/clinics
• medical supplies immediately available
• access to victims
• roads, waterways, telecommunications, etc.

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Epidemiology and Surveillance

• Pre-impact epidemiologic information
• baseline (expected) frequencies and distributions
  of disease (incidence, prevalence, and mortality)
• known risks
• immunization coverage
• awareness/education level in community

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Epidemiology and Surveillance

• Establish and distribute protocols
• laboratory procedures
• case definitions
• case management
• frequency and method of reporting
• thresholds for every disease with epidemic
  potential above which a response must be
  initiated (epidemic threshold)

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Epidemiology and Surveillance

• Rapid health assessments
• conducted as soon as possible
• purpose - assess immediate impact/health needs
• critical to directing timely decisions and
  planning
• rely on pre-impact information
• demographic, geographical, environmental, health
  facilities and services, transportation routes,
  security
• information from key informants
• visual inspection of the affected area

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Epidemiology and Surveillance

• Rapid epidemiologic assessments
• planned and completed as soon as possible
  following initial assessments
• building on the information already acquired
• provide more detailed analysis of ongoing threats
  and facilitate monitoring of response and
  recovery
• require additional resources and multiple skills
  and expertise
• a valuable tool that has been used in a number of
  post-disaster settings

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Epidemiology and Surveillance

• Surveillance and assessment systems
• need to be tailored to whatever means available
• if widespread disruption and displacement,
  information networks should include a variety of
  sources to be effective
• crucial to have the capacity to initiate field
  investigations immediately to verify potential
  outbreaks
• laboratory protocols, case definitions, and case
  management protocols must be agreed upon and
  distributed to all catchment areas

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Epidemiology and Surveillance

• Frequency and method of reporting
• usually telephone alert system
• established as a matter of protocol at the outset
• should have necessary resources and personnel in
  place to ensure effective monitoring
• establishment of thresholds for every disease
  with epidemic potential above which a response
  must be initiated (epidemic threshold) should be
  established

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Epidemiology and Surveillance

• Challenges in implementation
• must be understood and communicated to ensure
  effort will meet expectations
• considerations for planning/implementation
• compromises between what is collected and how it
  is to be analyzed
• competing priorities for same information
• limitations of resources
• lack of available information required to produce
  meaningful estimates
• lack of standardization of collection/reporting
  protocols

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Water-borne Diseases - Diarrhea

• Diarrhea can be a major contributor to overall
  morbidity and mortality in a disaster due to
• large scale disruption of infrastructure
• compromised water quality
• poor sanitation
• massive displacement of population into temporary
  crowded shelters
• common sources of food and water subject to cross
  contamination

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Water-borne Diseases - Diarrhea

• Cholera
• spreads rapidly high mortality across all age
  groups
• major global threat and epidemic threat is
  constant in developing countries throughout the
  year
• rapid recognition and response imperative during
  acute post-disaster phase to prevent epidemic
• emergence of antibiotic-resistant strains of
  Vibrio cholera complicate efforts in some regions
  and should be considered in preparedness planning

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Water-borne Diseases - Diarrhea

• Dysentery
• Bacillary dysentery caused by Shigella
• Fecal-oral transmission from contaminated
  food/water
• Suspect if bloody diarrhea present
• particular concern (along with cholera) due to
  ease of transmission, rapid spread in crowded
  conditions, and immediate life-threatening
  conditions
• guidelines on managing outbreak available from
  WHO
  (http//w3.whosea.org)

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Acute Respiratory Infections

• Increased risk for pneumonia
• overcrowding
• susceptibility
• malnourishment
• poor ventilation in temporary shelters
• Many acute infections involve upper respiratory
  system mild and self-limiting
• Lower respiratory infections (bronchitis,
  pneumonia) are generally more severe and require
  hospitalization

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Acute Respiratory Infections

• Account for up to 20 of all deaths in children
  less than 5 years of age, with majority due to
  pneumonia (WHO)
• May account for a major portion of overall
  morbidity depending on
• Region affected
• Characteristics of displaced population and
  temporary dwellings
• Early recognition and management are keys to
  avoiding an outbreak

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Measles

• Few outbreaks associated with natural disasters
  although possibility remains high
• Outbreaks prevented through
• effective early warning system
• rapid response to suspicious reports
• availability of vaccine

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Measles

• Mt Pinatubo eruption (Philippines) 1991
• measles accounted for 25 morbidity and 22 of
  mortality among 100,000 people displaced
• attributed to very low immunization coverage and
  cultural barriers of indigenous tribe that
  represented majority of displaced population
• Therefore, threat of measles epidemic remains
  high following natural disasters

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Tetanus

• Due to collapsing structures and falling debris
• Earthquakes and tsunamis inflicts numerous crash
  injuries, fractures, and serious wounds
• Tetanus expected when immunization coverage is
  low or non-existent
• Injured and non-immunized should receive
• prompt surgical and medical care of contaminated
  open wound
• tetanus immunization and/or immunoglobulin
  depending on vaccination history and seriousness
  of the wound infection

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Vector-Borne Diseases

• Risk usually higher following disasters
  (hurricane typhoon flood, or tsunami)
• Higher risk due to increase in number and range
  of vector habitats
• Initially flushed out mosquito breeding sites
  return shortly after waters begin to recede

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Vector-Borne Diseases

• Factors favoring outbreaks
• changing dynamics of vector
• displacement of large numbers of people in
  temporary crowded shelters
• Lag time of up to 8 weeks before onset

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Vector-Borne Diseases Malaria

• associated with serious public health emergencies
  with little warning
• likelihood of epidemic high when
• disaster in malaria-endemic area
• public health infrastructure is disrupted
• highly vulnerable population exists
• usually 4-8 weeks after initial impact
• several weeks duration before peak

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Vector-Borne Diseases Malaria

• Effective control possible in early stages if
  timely response in implementing control measures
• Morbidity and mortality reduced with early
  diagnosis and treatment
• If diagnosis delayed, treatment based solely on
  clinical history without demonstration of
  parasites
• important considerations for planning
• emergence of anti-malarial resistance
• increased transmission potential due to expanding
  range of vector habitats

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Vector-Borne Diseases Malaria

• vectors exclusively Anopheles - breed in stagnant
  fresh or brackish water
• transmission efficiency dependent on
• species of mosquito
• preferred breeding habits
• prevalence of parasite
• in endemic areas disruptions may change otherwise
  poor breeding conditions into favorable ones

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Vector-Borne Diseases - Dengue

• spreads rapidly, affects large numbers
• Dengue hemorrhagic fever (DHF) associated with
  high mortality (particularly children)
• dramatic increase in incidence over past 20 years
  (100 million cases annually)
• endemic throughout all tropical regions

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Vector-Borne Diseases Dengue

• transmitted by Aedes mosquitoes, primarily Ae.
  aegypti.
• vector particularly suited for an urban cycle of
  transmission
• breeds primarily in containers and other sources
  of standing water
• breeds in and around human dwellings rather than
  groundwater pools and swamps

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Vector-Borne Diseases Dengue

• Outbreaks contained only through early-warning
  and rapid response
• Effective vector control critical but challenging
  due to
• availability of adequate resources
• appropriate access to breeding habitats

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Water-borne Diseases Summary
Disease Clinical Features Incubation Period Diagnosis Treatment
Cholera profuse watery diarrhea, vomiting 2 hrs 5 days direct microscopic observation of V. cholerae in stool rehydration therapy antimicrobials
Leptospirosis sudden onset fever, headache, chills, vomiting, severe myalgia 2 - 28 days Leptospira-specific IgM serological assay penicillin, amoxi, doxyxycline, erythromycin, cephalosporins
Hepatitis jaundice, abdominal pain, nausea, diarrhea, fever, fatigue and loss of appetite 15 - 50 days Serological assay detecting anti-HAV of anti-HEV IgM antibodies supportive care hospitalize/ barrier nursing for severe cases monitoring of pregnant women
Bacillary Dysentery malaise, fever, vomiting, blood and mucous in stool 12 - 96 hrs Suspect if bloody diarrhea confirm by isolation of organism nalidixic acid, ampicillin hospitalize seriously ill or malnourished rehydration
Typhoid fever sustained fever, headache, constipation 3 - 14 days culture from blood, bone marrow, bowel fluids rapid antibody tests ampicillin, trimethoprim-sulfamethoxazole, ciprofloxacin
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Vector-borne Diseases Summary
Disease Clinical Features Incubation Period Diagnosis Treatment
Malaria fever, chills, sweats, head and body aches, nausea and vomiting 7 - 30 days parasites on blood smear observed using a microscope rapid diagnostic assays if available chloroquine, sulfadoxine-pyrimethamine
Dengue Sudden onset severe flu-like illness, high fever, severe headache, pain behind the eyes, and rash 4 - 7 days Serum antibody testing with ELISA or rapid dot-blot technique intensive supportive therapy
Japanese encephalitis quick onset, headache, high fever, neck stiffness, stupor, disorientation, tremors 5 - 15 days serological assay for JE virus IgM specific antibodies in CSF or blood (acute phase) intensive supportive therapy
Yellow fever fever, backache, headache, nausea, vomiting toxic phase-jaundice, abdominal pain, kidney failure 3 - 6 days serological assay for yellow fever virus antibodies intensive supportive therapy
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Direct Contact Diseases Summary
Disease Clinical Features Incubation Period Diagnosis Treatment
Pneumonia cough, difficulty breathing, fast breathing, chest indrawing 1 - 3 days Clinical presentation culture respiratory secretions co-trimoxazole, chloramphenicol, ampicillin,
Measles rash, high fever, cough, runny nose, red and watery eyes serious post measles complications (5-10 of cases) - diarrhea, pneumonia, croup 10 - 12 days generally made by clinical observation Supportive care nutrition/hydration vitamin A control fever antibiotics in complicated cases
Bacterial Meningitis Sudden onset fever, rash, neck stiffness altered consciousness bulging fontanelle in lt1 yrs of age 5 - 15 days Examination of CSF elevated WCC, protein gram negative diplococci Penicillin, ampicillin, chloramphenicol, ceftriaxone, cefotaxime, co-trimoxazole diazepam (seizures )
Tetanus difficulty swallowing, lockjaw, muscle rigidity, spasms 3 - 21 days entirely clinical immune globulin
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Summary

• Immediate concern is rapid detection and response
  to address existing health needs and prevent
  epidemics
• Factors that also play key roles in controlling
  communicable diseases in disaster setting

Proper placement of shelters Vaccinations
Adequate sanitation Provision of clean water
Adequate personal hygiene Adequate nutrition
Vector control Health education
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Summary

• Emergency response aimed to mitigate adverse
  health effects requires
• Multidisciplinary approach employing a broad
  range of expertise
• Identification and attention to those in need of
  immediate threat
• Multidisciplinary effort forms framework for
  recovery
• Requires ongoing preparedness planning,
  education, and training efforts

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Closing Comments

• Resilience of the local people is a key asset in
  recovering from all adversities physical,
  social, and economic
• Efforts should be made to strengthen community
  resilience in order to ensure a better future for
  those affected

Goal Translate lessons learned into better
preparedness, response, and recovery for the next
disaster certain to follow.
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References

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2. CDC. Surveillance in evacuation camps after the
   eruption of Mt. Pinatubo, Philippines. MMWR
   1992419-12
3. Connolly MA, Gayer M, Ryan MJ, Salama P, Spiegel
   P, Heymann DL. Communicable diseases in complex
   emergencies impact and challenges. Lancet
   20041974-1983
4. Connolly MA. Communicable disease control in
   emergencies A field manual. Geneva WHO, 2005.
5. Noji EK. The public health consequences of
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   200015147-157
6. Toole MJ. Communicable Diseases and Disease
   Control In Noji E, ed. The Public Health
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   University Press, 199779-100
7. World Health Organization. Tsunamis Technical
   Hazard Sheet and Natural Disaster Profile WHO,
   2005.
8. Waring SC, Brown BJ. The threat of communicable
   diseases following natural disasters, a Public
   Health Response, Disaster Manage Response
   20053(2)4-12.