Infectious Disease Issues in Natural Disasters

1
Infectious Disease Issues in Natural Disasters

• Christian Sandrock, M.D.
• UC Davis School of Medicine

2
(No Transcript)
3
Overview

• Discuss the role of infectious diseases in
  natural disasters (flood, earthquake, hurricane,
  etc)
• Look at the factors effecting the development of
  disease outbreak after a disaster
• Discuss specific diseases seen after various
  disasters
• Review efficacy of various treatment options

4
Is there a link?

• Conflicting belief among experts as to rise in
  disease after disaster
• Some studies relate direct link between disaster
  and disease outbreak (Dominican Republic-
  hurricane)
• Others offer theory but no link
• All depends on variable factors

5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
Background

• Historically, infectious disease epidemics have
  accounted for large number of deaths
• Disasters have potential for large number of
  deaths
• Epidemics are still viable and feared
• Can a natural disaster lead to an epidemic?

13
Phases of Disaster

• Impact Phase (0-4 days)
• Extrication
• Some immediate soft tissue infections
• Post impact Phase (4 days- 4 weeks)
• Airborne, foodborne, waterborne diseases
• Recovery phase (after 4 weeks)
• Those with long incubation and of chronic disease

14
Variables for Development of an Epidemic After a
Disaster

• Environmental considerations
• Endemic organisms
• Population characteristics
• Pre- event structure and public health
• Type and magnitude of the disaster

15
Endemic organisms

• The organisms are endemic to the region before
  the disaster
• If not present before the event, it will not be
  there after regardless of ecological conditions
• Deliberate introduction could change this factor

16
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

17
Endemic Organisms

• Northridge Earthquake
• Ninefold increase in coccidiomycosis (Valley
  fever) from January- March 1994
• Mount St. Helens
• Giardiasis outbreak in 1980 after increased
  runoff in Red Lodge, Montana from increased ash

18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Population Characteristics

• Density
• Displaced populations
• Refugee camps
• Age
• Increased elderly or children
• Chronic Disease
• Malnutrition
• DM, heart disease
• transplantation

22
Population Characteristics

• Education
• Less responsive to disaster teams
• Religion
• Polio in Nigeria, 2004
• Hygiene
• Underlying health education of public
• Trauma
• Penetrating, blunt, burns
• Stress

23
(No Transcript)
24
(No Transcript)
25
Pre-event resources

• Sanitation
• Primary health care and nutrition
• Disaster preparedness
• Disease surveillance
• Equipment and medications
• Transportation
• Roads
• Medical infrastructure

26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
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

32
Epidemics after Disasters
33
Epidemics after Disasters
34
Flooding

• Missouri 1993
• Increase reports if E.D. visits due to illness
• 17 GI, 20 respiratory
• Iowa 1993
• No reports of GI increase due to
  sanitationmeasure
• Florida Hurricane Andrew
• Heavy mosquito spraying lead to no change in
  encephalitis rates

35
Dominican Republic, 1979

• Hurricane David and Fredrick on Aug 31 and Sept
  5th 1979
• gt2,300 dead immediately
• Marked increase in all diseases measured 6 months
  after the hurricane
• Thyphoid fever
• Gastroenteritis
• Measles
• Viral hepatitis

36
(No Transcript)
37
(No Transcript)
38
(No Transcript)
39
(No Transcript)
40
What epidemics would predominate today?

• Endemic organisms
• Post-impact phase
• Recovery Phase

41
Post-Impact Phase Infections

• Crush and penetrating trauma
• Skin and soft tissue disruption
• Muscle/tissue necrosis
• Toxin production disease
• Burns
• Waterborne
• Cholera
• Non-cholera dysentery
• Hepatitis
• Rare diseases

42
Post-Impact Phase Infections

• Vector borne
• Malaria
• Encephalitis
• Dengue and Yellow fever
• Typhus
• Respiratory
• Viral
• CAP
• Rare disease
• Other
• Blood transfusions

43
Recovery Phase Infections

• These agents need a long incubation period
• TB
• Schistosomiasis
• Lieshmaniasis
• Leptospirosis
• Nosocomial infections of chronic disease

44
Skin and Soft Tissue Disease

• Crush and penetrating injuries
• ABCs
• Establish airway
• Circulation
• Stabilize
• BP support
• Respiratory support
• Diagnose extent of injuries
• Radiology
• Diagnostic procedures
• Corrective action
• CT, fracture stabilization, transfusion
• Surgery if necessary

45
Skin and Soft Tissue Disease

• Post-traumatic Care
• Hypoxia from pulmonary contusion, ARDS, VAP
• Coagulopathy
• Renal failure
• DVT/PE
• Ulcer disease
• Soft tissue infections
• Cellulitis
• Necrotizing fasciitis
• Post op wound infection
• Burn care

46
(No Transcript)
47
(No Transcript)
48
(No Transcript)
49
Cellulitis

• Skin infection involving the subcutaneous tissue
• Predisposing factors
• Lymphatic compromise
• Site of entry
• Obesity
• DM
• Microbiology
• Streptococci, Groups A, B, C, G
• Staphylococcus aureus
• Others

50
Cellulitis

• Pathogenicity
• Not well understood
• Venous and lymphatic compromise
• Bacterial invasion with endo/exotoxin release
• Cytokine release
• Symptoms
• Systemic- F/C/M
• Redness, swelling
• Tenderness, edema
• May have ulcer or abscess

51
(No Transcript)
52
(No Transcript)
53
Cellulitis

• Treatment
• Antibiotics
• B-lactam atnibiotics
• Clindamycin
• Vancomycin
• Other
• Limb elevation
• Systemic support
• Surgical consultation
• Abscess
• Occular
• Necrotizing fasciitis evaluation

54
Cellulitis

• Special situations
• MRSA possibility
• Water exposure
• Aeromonas
• Vibrio in liver failure
• DM
• Other gram negative rods
• Animal bites
• Pasteurella multocida

55
Necrotizing Fasciitis

• Fulminant destruction of tissue with systemic
  signs of toxicity
• Overlaps with necrotizing myositis or gangranous
  myositis
• Very high mortality
• Much larger bacterial load than cellulitis
• Travels through fascial plain
• Much less inflammation from necrosis, vessel
  thrombosis, and bacterial factors

56
Necrotizing Fasciitis

• Two types
• Type I
• Largely mixed aerobic and anaerobic infection
• Seen in post surgical patients
• DM, PVD big risk factors
• Examples
• Cervical necrotizing fasciitis (Ludwigs angina)
• Fourniers gangrene
• Type II
• Group A strep
• Large exotoxin production or M protein
• Any age group or without portal of entry

57
Diagnosis

• Pain
• May mimic post surgical changes
• Skin changes
• Thick or woody in nature
• Minimal erythema
• Bullae
• Systemic symptoms
• Fevers, chills
• Rapid sepsis

58
(No Transcript)
59
(No Transcript)
60
(No Transcript)
61
(No Transcript)
62
(No Transcript)
63
(No Transcript)
64
(No Transcript)
65
Treatment

• Surgical Debridement!!!!!!!!
• aggressive and explarative
• Wide tissue excision
• Antibiotics
• B- lactam antibiotics
• Clindamycin for toxin production
• Gram negative/anaerobic coverage
• Hyperbaric O2
• Supportive care

66
Toxin Diseases

• Tetnus
• Rare due to vaccination
• 1 Milliion die per year in developing world
• 4 clinical patterns
• Generalized
• Local
• Cephalic
• Neonatal

67
Tetnus

• Spores of C. tetani enter the tissue
• Produce metalloprotease, tetanospasmin
• Retrograde movement into CNS
• Blocks neurotransmission by cleaving protein
  responsible for neuroexocytosis
• Leads to disinhibition of motor cortex and
  extensive spasm

68
Tetnus

• Needs the right factors to produce
• Penetrating injury with spore delivery
• Co-infection with other bacteria
• Devitalized tissue
• Localized ischemia

69
(No Transcript)
70
(No Transcript)
71
Tetnus Treatment

• Wound management
• Halts toxin production
• Tetnus antitoxin and vaccine
• Neutralized unbound toxin
• Benzodiazepines and paralytics
• Treats spasms
• B-blockers
• Treats autonomic dysfunction of late disease
• Supportive care

72
Waterborne disease

• Cholera
• Gram negative bacterium Vibrio cholerae
• Severe water diarrhea with 50 mortality if
  untreated
• 190 serrotypes but only O1 and O139 cause human
  epidemics
• Bacterial model for toxin mediated disease

73
Cholera pathophysiology

• Enter the small bowel and colonize
• Pilus required
• Hemagglutanins
• Acessory colonizing factor
• Porin like proteins
• Produces toxin
• A with 5 B subunits
• A cleaves to A1, activates adenylate cyclase
• Leads to increase Cl secreation and decreased Na
  absorption

74
(No Transcript)
75
Cholera-symptoms

• Majority are asymptomatic
• Some with develop rapid diarrhea, with some
  emesis
• Diarrhea most severe days 1-2, stops by day 6
• May loose 100 body weight in 2 days
• Children, elderly at risk
• Death in 2 -48 hours (18 average)

76
Cholera Treatment

• Oral rehydration- per liter
• 3.5g NaCl
• 2.9g NaHCO3
• 1.5g KCl
• 20g glucose
• IV rehydration
• Antibiotics- not necessary
• Lessens diarrhea by one day
• Vaccine- no evidence
• Public health prevention

77
Non cholera dysentery

• Giardia
• E. Coli
• Toxin Mediate food poisoning
• Salmonella
• Shigella
• Campylobacter
• Yersinia
• Viral hepatitis
• others

78
(No Transcript)
79
(No Transcript)
80
(No Transcript)
81
(No Transcript)
82
Respiratory Illness

• Viral
• Most common cause of infectious illness after
  Midwest floods over past 20 years
• TB
• 25 mortality in camps in Africa and Asia
• Worsened by drought
• Community acquired bacterial pneumonia
• Mainly theoretical, no data

83
Vector borne disease

• Malaria
• 2nd most documented increase in disease after
  flooding
• Well controlled with mosquito abatement
• Encephalitis
• No documented increase in US but heavy abatement
  programs
• West Nile????

84
Disaster Response Teams

• Endemic diseases of the area
• CDC or WHO for health alert outbreaks
• Intense disease surveillance
• Working with public health
• Field laboratory for early diagnosis
• Antibiotics and equipment supplies
• IVF
• Multiple range of antibiotics for all people

85
Disaster Response Teams

• Record Keeping
• Therapies and syndromes known
• Restore basic medical care quickly
• Reduces disease susceptability
• Vaccinations
• May be very costly, misdirected in acute phase
  (cholera)
• Uses only proven vaccines after disease starts
  (measles, meningococcal)
• May be chance to vaccinate chronically ill when
  compared to baseline

86
Conclusions

• Infectious disease epidemics may play a role in
  the post disaster period
• These diseases will vary depending on type of
  disaster, population characteristics, endemic
  diseases, and climate and geography of the region
• If the disease if not present before the
  disaster, it will not be there after

87
Conclusions

• Early recognition of certain diseases in
  particular disaster settings may improve outcome
• Public health infrastructure, equipment,
  antibiotics, and medical infrastructure is key to
  a communitys survival and well being
• If deployed, know where you are going