This document discusses communicable diseases in humanitarian settings. It defines communicable diseases and lists examples of food- and water-borne diseases, zoonoses and vector-borne diseases, air-borne diseases, sexually transmitted diseases, and vaccine-preventable diseases. It also discusses the disease burden in low-income countries and the MDG targets related to HIV/AIDS, malaria and other diseases. Finally, it covers topics such as the disease cycle, surveillance, prevention and control measures for communicable diseases in humanitarian crises."

1. Communicable Diseases in
humanitarian settings
1

2. “communicable” diseases
Infectious diseases that
can be transmitted
from one individual to
another either directly
by contact or indirectly
by fomites and
vectors.
2

3. Communicable diseases
Food- and Zoonoses and vector borne Air-borne diseases
water-borne diseases • Brucellosis • Legionellosis
 Cholera
• Echinococcosis • Meningococcal disease
 Hepatitis
 Botulism
• Rabies • Pneumococcal infections
 Campylobacteriosis • Malaria • Tuberculosis
 Cryptosporidiosis • Plague • Viral haemorrhagic fevers
 Giardiasis Sexually transmitted diseases Diseases preventable by
 E.coli vaccination
• Chlamydia infections
 Leptospirosis
• Gonococcal infections • Diphtheria
 Listeriosis
 Salmonellosis • HIV-infection • Haemophilus influenza
 Shigellosis • Syphilis • Measles
 Toxoplasmosis Viral hepatitis • Mumps
 Trichinosis • Pertussis
• Hepatitis A
 Yersinosis
• Hepatitis B • Poliomyelitis
• Hepatitis C • Rubella

4. WHO 2004: Low income countries
leading mortality causes
Neonatal
infections Malaria
Lower
respiratory
infections
Tuberculosis
Chronic
obstructive
pulmonary
disease Diarrhoeal
diseases
Coronary heart
disease
HIV/AIDS
Stroke and
other
Prematurity and
cerebrovascular
low birth weight
diseases
4

5. MDG 6
Combat HIV/AIDS, Malaria and Other Diseases
• targets
– 1. Halt and begin to reverse, by 2015, the spread
of HIV/AIDS
– 2. Achieve, by 2010, universal access to treatment
for HIV/AIDS for all those who need it
– 3. Halt and begin to reverse, by 2015, the
incidence of malaria and other major diseases
5

6. HIV and crises
• How do crises affect HIV?
6

7. 1. Communicable disease cycle
Death
Progression Healthy
of disease State
Immunity
Clinical Risk factors
Illness Exposure factors
Biological
Susceptibility to
evidence of
infection
infection
7

8. Communicable diseases
Population Vulnerability
Individual susceptibility
Risk exposure
Individual physical and
material resources
Immunity to pathogens
Health care services
8

9. Higher incidence
Crises Higher mortality
Malnutrition
Absence /
Poor Communicable Disruption
Hygiene
Diseases of health
Wat/San
care
Poor Living Conditions Epidemics
9

10. Effects of outbreaks on health system
1. Population panic
2. Overcrowding of Health Services
I. Overwork of Health Staff
II. Health Staff at exposed risk
III. Risk to patients
3. Malfunction of Health Services
4. Increased morbidity
I. Further spread of outbreaks
5. Increased mortality
6. Economic and social consequences
10

11. 2. What can be done?
Treatment Surveillance
Death
Progression of Healthy
disease State
Containment
Immunity
Clinical Risk factors
Illness Exposure factors
Prevention
Biological
Susceptibility to
evidence of
infection
infection
11

12. Rapid assessment Surveillance Survey
Often qualitative or quantitative data quantitative data
semi-quantitative data
wide variety of data limited data Can gather wide variety
of data
data on convenience Often tries to gather data on Usually gathers data on
sample of people and every case of illness sample of population
facilities
data at a single point in data over ongoing, data at single point in
time prospective time period time
gathers data for Gathers data for numerator Gathers data for
numerator of prevalence of incidence and prevalence numerator and
and incidence; ; Denominator must come denominator, allowing
Denominator must come from separate source. calculation of
from separate source prevalence or incidence
rates

13. surveillance
• Systematic ongoing collection, collation, and
analysis of data and the timely dissemination of
information to those who need to know so that
action can be taken.
» World Health Organization
• The ongoing systematic collection, analysis, and
interpretation of health data, essential to the
planning, implementation, and evaluation of
public health practice, closely integrated with the
timely dissemination of these data to those who
need to know.
» US Centers for Disease Control and Prevention

14. Surveillance
• Passive Surveillance – uses available data or
reporting from health care provider or
regional health officer
• Active Surveillance – periodic field visits to
health care facilities to identify new cases
14

15. 15

16. Prevention
• Public level
– Vector control
– Water and sanitation systems
– Blood safety requirements
• Individual level
– Hand washing
– Condoms
• Public / Individual level
– Vaccination
• Routine or during outbreaks
16

17. Control measures
• Prevention of exposure:
– Isolation, vector control, containment
– Hygiene and education
• Prevention of infection:
– Vaccination, clean water
• Prevention of disease:
– prophylaxis
• Prevention of death:
– Case identification and management
17

18. Surveillance in emergencies
• Objectives
– identify public health priorities;
– monitor the severity of an emergency by collecting and
analyzing mortality and morbidity data;
– detect outbreaks and monitor response;
– monitor trends in incidence and case-fatality from major
diseases;
– monitor the impact of specific health interventions
– provide information for programme planning, implementation
and adaptation, and resource mobilization.
DATA ➜ INFORMATION ➜ ACTION
18

19. Disease Early Warning System (DEWS)
Pakistan
• Covered 92 districts and ~ 60% of the population.
• centralized in Islamabad, with regional hubs and
surveillance officers active at district level.
• Weekly reporting includes priority epidemic
diseases and those with high morbidity & flood
related diseases.
• Data sources include up to 2600 basic health units
and all large government hospitals,
• Data relayed using a variety of media, SMS, fax, and
telephone.
• Widespread compliance, due in part to the regular
visits of the surveillance officers to facilities.
19

20. Disease Early Warning System (DEWS)
Pakistan
• quantity of weekly data reported places very high
work burden on the surveillance officers, many of
whom cover wide geographical areas.
• A lot of data but…
– 90% of outbreaks have been detected by formal
immediate alerts.
– Only 10% were detected through data analysis.
• incompatibilities with other “vertical” surveillance
systems
• Not transitioning to integration into routine
government surveillance systems
20

21. DEWS- Film
• http://www.youtube.com/watch?v=s2Q5oQx4
dGw&feature=bf_prev&list=ULQRFpUxJxcoE&l
f=mfu_in_order
21

22. True or False
• The geographical distribution of reported cases is
indicative of where the disease is the worst.
• The case fatality rate data from health facilities is
indicative of how deadly a disease is
• In a complex emergency where systems are
disrupted it is important for the emergency
surveillance system to capture as much
information as possible
• HIV, TB and Malaria get a lot of attention and
money from global initiatives so it is not
appropriate to spend humanitarian funds
22

23. Key information for designing
surveillance systems
• What is the population under surveillance
– displaced population, local population etc
• What data should be collected and why
• Who will provide the data
• What is the period of time of the data collection?
• How will the data be transferred (data flow)?
• Who will analyse the data and how often?
• How will reports be disseminated and how often?
23

24. Questions to ask when selecting
diseases /conditions
• Does the condition result in a high disease impact
(morbidity, disability, mortality)?
• Does it have a significant epidemic potential (e.g.
cholera, meningitis, measles)?
• Is it a specific target of a national, regional or
international control programme?
(e.g.malaria, TB)
• Will the information to be collected lead to
significant and cost-effective public health
action?
24

25. Key diseases to consider
• bloody diarrhea,
• acute watery diarrhea,
• suspected cholera,
• lower respiratory tract infection,
• measles,
• meningitis.
• Other endemic /epidemic prone diseases (eg
malaria or viral haemorrhagic fevers)
25

26. Risk factors
• Diarrheal diseases
– Overcrowding
– Inadequate quantity and/or quality of water
– Poor personal hygiene
– Poor washing facilities
– Poor sanitation
– Insufficient soap
– Inadequate cooking facilities
26

27. Risk factors
• Acute respiratory infections
– Inadequate shelter with poor ventilation
– Indoor cooking, poor health care services
– Malnutrition, overcrowding
– Age group under 1 year old
– Large numbers of elderly
– Cold weather
27

28. Risk factors
• Meningococcal meningitis
– Meningitis belt (although the pattern is changing
to include eastern, southern & central Africa)
– Dry season
– Dust storms
– Overcrowding
– High rates of acute respiratory infections
28

29. Risk factors
• Malaria
– Movement of people from endemic into malaria-free
zones or from areas of low endemicity to
hyperendemic areas
– Interruption of vector control measures
– Increased population density promoting mosquito
bites
– Stagnant water
– Inadequate health care services
– Flooding
– Changes in weather patterns
29

30. Risk factors
• Measles
– Measles vaccination coverage rates below 80% in
country of origin, overcrowding,
– population displacement
• Tuberculosis
– High HIV seroprevalence rates
– Overcrowding
– Malnutrition
30

31. Key terms
• Incidence
– the number of new cases of a specified disease reported over a given
period.
– number of new cases per 1000 people
• Case-fatality rate (CFR)
– the percentage of persons diagnosed as having a specified disease who
die as a result of that disease within a given period,
– usually expressed as a percentage (cases per 100).
• Attack rate (outbreaks):
– The cumulative incidence of cases (persons meeting case definition since
onset of outbreak) in a group observed over a period during an outbreak.
• Epidemic threshold:
– level of disease above which an urgent response is required
– specific to each disease depending on infectiousness, other determinants
of transmission and local endemicity levels.
31

32. Epidemic threshold
• Diseases for which one suspected case
represents a potential outbreak and requires
immediate investigation:
– cholera
– measles
– typhus
– plague
– yellow fever
– viral haemorrhagic fever
32

33. Case classification
• Suspected case
– Clinical signs and symptoms compatible with the disease in question
but no laboratory evidence of infection (negative, pending or not
possible)
• Probable case
– Compatible clinical signs and symptoms, and additional
epidemiological (e.g.contact with a confirmed case) or laboratory (e.g.
screening test) evidence for the disease in question
• Confirmed case
– Definite laboratory evidence of current or recent infection, whether or
not clinical signs or symptoms are or have been present
– Even if clinical symptoms are not -subclinical infection is a major
source of transmission
33

34. Case definitions
• developed for each health event /disease
/syndrome.
– Use MoH or WHO definitions
• For consistency of reporting
• Used for surveillance not treatment
34

35. Case definition:
ACUTE WATERY DIARRHEA
Three or more abnormally loose or
fluid stools in the past 24 hours with or
without dehydration.
• suspect case of cholera:
– Person aged over 5 years with severe dehydration or death from
acute watery diarrhea with or without vomiting.
– Person aged over 2 years with acute watery diarrhea in an area
where there is a cholera outbreak.
• To confirm case of cholera:
– Isolation of Vibrio cholera O1 or O139 from diarrheal stool
sample.
35

36. Case definition:
MEASLES
Fever and maculopapular rash (i.e. non-
vesicular) and cough, coryza (i.e. runny nose) or
conjunctivitis (i.e. red eyes)
or
Any person in whom a clinical health worker
suspects measles infection.
• To confirm case:
– At least a fourfold increase in antibody titre or
– isolation of measles virus or
– presence of measles-specific IgM antibodies..
36

37. 37

38. Scenario: early detection & response
38

39. Scenario: delayed detection & response
39

40. 40

41. Zimbabwe Cholera
Weekly attack rates, by district. Weekly attack rates, by district.
as of 31/01/09 W4 as of 14/03/09 W11
41

42. Global system
• CDC
– International Emergency and Refugee Health Branch
• European CDC
• WHO
– DCE (disease control in humanitarian emergencies)
• Part of Global Alert and Response department
• Produce “public health risk assessment” for crises
– GOARN (global alert and response network)
http://video.who.int/streaming/eprfilms/GOARN_Wor
king_Together_in_Outbreak_Response.wmv
– Event management system
42

43. WHO SHOC
(strategic health operations center)
43

44. International Health Regulations
• Legally binding international treaty
– 194 signatory countries
– entered into force on 15 June 2007,
• Purpose: enable international community to
prevent and respond to acute public health risks
– potential to cross borders and threaten people
worldwide
• requires countries to report certain disease
outbreaks and public health events to WHO.
• requires countries to strengthen their existing
capacities for public health surveillance and
response.
44

45. Humanitarian Crises and IHR (2005)
Potential for serious public health impact:
“The population at risk is especially
vulnerable (refugees, low level of
immunization, children, elderly, low
immunity, undernourished, etc.)”
“Concomitant factors that may hinder or
delay the public health response (natural
catastrophes, armed conflicts,
unfavourable weather conditions, multiple
foci in the State Party).”

46. Humanitarian Crises and IHR (2005)
Risk of international spread:
“Event in an area of intense
international traffic with limited
capacity for sanitary control or
environmental detection or
decontamination.”