3. SPECIFIC OBJECTIVES
At the end of a lecture/ discussion students should be able to:
1. Define Ebola virus disease
2. Mention the etiology and mode of transmission
3. Explain the replication of Ebola virus
4. Describe the pathophysiology of Ebola virus disease
5. Mention the signs and symptoms of Ebola virus disease
6. Describe the management of Ebola virus disease
7. Outline the preventive measures of Ebola outbreak
8. outline disease surveillance in relation to EVD
4. DEFINITION
• Ebola virus disease (formally known as Ebola hemorrhagic
fever) is a disease caused by Ebola virus characterized by fever,
headache, nausea, tiredness, vomiting and diarrhoea.
5.
6. ETIOLOGY
•It is caused by Ebola virus.
•This virus belongs to FILOVIRIDAE family In
general, ebolavirions are 80 nanometers (nm) in
width and may be as long as 14,000 nm.
7. VIRUS STRUCTURE
•Single stranded , linear , non segmented , negative
– sense RNA virus
•Appears to have “spikes” due to glycoprotein on
outside membrane
•Therefore , spreads rapidly.
8. EBOLA SUBSPECIES
Ebola virus has 5 identical sub species
§Bundibugyo ebolavirus (BDBV)
§Zaire ebolavirus (EBOV)
§Sudan ebolavirus (SUDV)
§Tai Forest ebolavirus (TFEV)
§Reston ebolavirus (RESTV)
10. REPLICATION
The ebolavirus life cycle begins with virion attachment to specific
cell-surface receptors.
• Then fusion of the virion envelope with cellular membranes and
the concomitant release of the virus nucleocapsid into the cytosol.
• Viral RNA-dependent RNA polymerase (RdRp) partially uncoats
the nucleocapsid and transcribes the genes into positive-stranded
mRNAs.
• Then it is translated into structural and nonstructural proteins.
11. Cont..
• Ebolavirus binds to a single promoter located at the 3' end of the
genome.
• Transcription either terminates after a gene or continues to the next
gene downstream.
• Replication results in full-length, positive-stranded antigenomes that
are in turn transcribed into negative-stranded virus progeny genome
copy.
• Newly synthesized structural proteins and genomes self-assemble
and accumulate near the inside of the cell membrane.
12. Cont..
•Virions bud off from the cell, gaining their envelopes
from the cellular membrane they bud from.
•The mature progeny particles then infect other cells to
repeat the cycle.
13. PATHOPHYSIOLOGY
•Endothelial cells, mononuclear phagocytes, and
hepatocytes are the main targets of infection.
•After infection, in a secreted glycoprotein (sGP) the
Ebola virus glycoprotein (GP) is synthesized. Ebola
replication overwhelms protein synthesis of infected cells
and host immune defenses.
14. Cont..
• The GP forms a trimeric complex, which binds the virus to the
endothelial cells lining the interior surface of blood vessels.
• The sGP forms a dimeric protein which interferes with the
signalling of neutrophils, a type of white blood cell.
• This allows the virus to evade the immune system by inhibiting
early steps of neutrophil activation.
15. Cont..
These white blood cells also serve as carriers to transport the virus
throughout the entire body to places such as the lymph nodes, liver,
lungs, and spleen.
The presence of viral particles and cell damage resulting from
budding the release of cytokines result into fever and inflammation.
The cytopathic effect, from infection in the endothelial cells, results
in a loss of vascular integrity.
16. Cont..
•This loss in vascular integrity is furthered with synthesis
of GP, which reduces specific integrins.
•This is responsible for cell adhesion to the inter-cellular
structure, and damage to the liver, which leads to
coagulopathy.
17. SIGNSAND SYMPTOMS
The incubation period, that is, the time interval from infection
with the virus to onset of symptoms is 2 to 21 days.
Initial signs and symptoms
High temperature (at least 38.8c).
Muscle, joints, abdominal pain
21. Medication
There is currently no-approved specific therapy for EVD.
Treatment is primarily supportive in nature and includes;
• Minimizing invasive procedures.
• Balancing fluids and electrolytes to counter dehydration.
22. Cont..
• Administration of anticoagulants early in infection to prevent or
control disseminated intravascular coagulation.
• Administration of procoagulants late in infection to control
hemorrhaging.
• Maintaining oxygen levels
• Pain management
• Administration of antibiotics to treat secondary infections.
23. EFFECTS OF EBOLA VIRAL DISEASE
Direct Effects of Epidemics:
•EVD if not well managed, may affect large number
of individuals and can lead to complications
including disabilities and death.
24. EFFECTS OF EBOLA VIRAL DISEASE
• direct effects cont........
• There is always a possibility of existence of sufficient
number of disease carriers who may favour the
resurgence and spread of disease.
• On seeing the suffering and deaths especially within close
relatives, psychological effects are also common during
epidemics.
25. EFFECTS OF EBOLA VIRAL DISEASE
Indirect Effects of EVD outrake:
• Social and political disruption due to tension and law and
order problems.
• Economic loss arising from lack of strength of cultivates.
Scarcity of resources to manage nd contain the disease.
26. Mitigational measures:
• Investment in training more human resource who should
help in disease savaillance can reduce the frequency of
human contact with pathogenic agents.
• Building strong health systems and supporting community
volunteers in disease surveillance and epidemic
preparedness may also help in reducing the impact
• baseline levels of health, making people less susceptible
to infectious diseases.
27. Mitigational measures:
• provision of vaccines to the eligible population may also
help in lessening the impact/ the burden of sizable
outbreaks and epidemics.
• proper case management
• strict isolation of confirmed cases and sengthening
preventive measures in the public.
28. Public Health Surveillance I
• Is the ongoing systematic identification, collection, collation,
analysis, and interpretation of disease occurrence and public
health event data to take timely and robust action
• It includes the:
§ timely dissemination of resulting information for effective and
appropriate action
• Is essential for planning, implementation, and evaluation of
public health practice
29. OBJECTIVES OF SURVEILLANCE
Public health surveillance serves two main objectives:
• To m e a s u r e d i s e a s e b u r d e n , i n c l u d i n g m o n i t o r i n g
morbidity/mortality trends, in order to effectively guide control
programs and corresponding allocation of resources
• To early detect public health events requiring rapid investigation
and response, in order to ensure that events of all origins are
rapidly controlled
30. IMPORTANNCE OF SURVEILLANCE DURING AN
OUTBRAKE
• Majority of public health events occur outside the health
sector
• Communities may become aware of public health events
before the public health system captures them
• Routine reporting has a fixed frequency and may not report
events timely
• Public health emergencies require urgent action
• Delayed detection leads to delayed response
31. EVD SURVEILLANCE
TERMINOLOGIES
• A probable case of EVD is case in which a person meets clinical
criteria of the suspected case but lacks confrimatory evidence
and has never mate the criteria of any contact.
• A proven/confirmed case: is a case where the pthogen/
causative egent has been isolated with the help of a microscope.
• A possible case is where a person present with signs and
symptomes of the suspected infections and had had contact with
a probable or a proven case.
• contact: a person or animal that has been in physical association
with an infected person or animal.
32. terms cont.......
• Early Warning and Response (EWAR): Defined by the World
Health Organization (WHO) as the organized mechanism to detect
any abnormal occurrence or any divergence from the usual or
normally observed frequency of phenomena as early as possible.
• Epidemic Intelligence: The systematic collection, analysis and
communication of any information to detect, verify, assess and
investigate events and health risks with an early warning objective.
• Evaluation: The periodic assessment of the relevance,
effectiveness and impact of activities in the light of the objectives of
the surveillance and response systems.
33. terms cont.......
• Reporting: The process by which health events and health
risks are brought to the knowledge of the health authorities.
• Response: Any public health action triggered by the
detection of a public health risk (e.g. monitoring of the
event, information of the public, triggering field
investigation and/or implementation of any control or
mitigation measures).
• Reservoir: Any animal, person, plant, soil, substance - or
combination of any of these - in which a zoonotic disease
agent normally lives and multiplies, and for which it
primarily depends on for its survival.
34. terms cont.......
• Indicator-Based Surveillance (IBS):Indicator-based
surveillance (IBS) is defined as the systematic collection,
monitoring, analysis, and interpretation of structured data,
i.e. indicators, produced by a number of well-identified,
predominantly health-based formal sources.
• Event-Based Surveillance (EBS): Event-Based
Surveillance (EBS) is defined as the organized collection,
monitoring, assessment and interpretation of mainly
unstructured information regarding health events or risks,
which may represent an acute risk to human health.
35. EVD SURVAILLANCE
• Disease outbreaks threaten life, cause economic disruption, and
create a burden on society.
• Emerging and re-emerging events with the potential to cause
disease outbreaks remain a constant threat to national health
security.
• The purpose of strengthening the Public Health Surveillance
System is to provide early warning and rapid response through the
Integrated Disease Surveillance and Response (IDSR) strategy in
order to mitigate these threats.
• This strategy is implemented through Indicator-Based Surveillance
(IBS) and Event-Based Surveillance (EBS).
36. STAGES IN EBS
• Within EWAR, the collection of data (IBS and EBS) with
the aim of detecting emerging health threats is part of a
single process called epidemic intelligence (EI.).
• This process should be able to monitor all prioritized health
events and acute public health risks within Zambia, as well
as events reported from other countries that have the
potential to affect Zambia. EI, and therefore EBS, can be
organized into five main stage
38. DETECTION OF RAW DATAAND INFORMATION
• The detection stage consists of:
• Defining the modality through which data and information will be
collected; and
• Implementing the data collection and information-seeking schemes.
• Information is generally made up of raw data originating from formal
and informal sources that have been collected by a number of
mechanisms (e.g. direct communication, internet-based devices,
hotlines and literature reviews) that will be defined according to our
needs.
39. TRIAGE
• In EBS, triaging involves screening data and information that are
relevant for early detection of public health threats.
• Triage is crucial not only to ensure that acute public health events and
health risks are effectively detected, but also to avoid overwhelming
the epidemic intelligence system.
• This stage consists of sorting data and information into the categories
of “likely to be relevant” and “not likely to be relevant” for early
detection of health events requiring a rapid response.
• Regardless of the mode of acquisition of information, not all raw data
and information corresponds to genuine acute public health events.
40. Selection:
• It is the sorting out of information according to national
priority criteria, for instance involving “discard” of
information and reports concerning non-prioritized mild
diseases such as the common cold, or related to an
increase of cases consistent with the known seasonal
periodicity of a disease.
• Selection is the phase that has the greatest impact on the
capacity of EBS to provide early detection
41. VERIFICATION
• Verification is an essential step that consists of confirming
the reality (authenticity and conformity) of the signal and its
characteristics.
• This is done by actively cross-checking the validity of the
information using reliable sources, or verifying pertinence in
order to confirm and, when possible, to characterize the
nature of the event.
42. RISK ASSESSMENT
• In the context of EWAR, risk assessment is a systematic
and continuous process for gathering, assessing and
documenting information to provide the basis for taking
action to manage and reduce the negative consequences of
an acute public health event.
43. The risk management cycle
•Once a signal has been verified as an event, it then
needs to be assessed to determine the level of risk
to human health and to establish the nature of the
potential mitigation and control measures that can
be implemented.
44.
45. • It is an ongoing process as the level of risk may change
over time.
• The initial risk assessment should be carried out within 48
hours of signal detection and repeated as new information
becomes available
46. • The risk assessment will help health authorities to:
• Determine additional information and analysis required to
fully assess the event;
• Activate surveillance and other special investigations for
assessing the extent of the event;
• Estimate likelihood of spread /increase in number of cases
and the need to scale up response;
47. • Implement mitigation / control measures (including preparedness
actions in unaffected areas);
• Estimate the potential for political or media attention and define
messages of alerts for communication with the media and the
public;
• Estimate the potential consequences for travel and trade
• Determine whether the event needs to be notified through IHR
(2005), to other supranational organizations and/or to neighbours;
and
• ▪Define communication strategy.
48. EVENT BASED SURVEILLANCE AT NATIONAL
LEVEL
• At the national level, the Ministry of Health (MOH) through
Zambia National Public Health Institute (ZNPHI) is
responsible for overall national health security through
prevention, early detection, and response to public health
threats using the IDSR strategy.
• This strategy is anchored in IBS and EBS.
• At National level, ZNPHI through the Surveillance and
Disease Intelligence Cluster will be responsible for
implementing EBS through Hotline and Media Scanning.
49. Roles and Responsibilities of National Level (ZNPHI)
• Train and support EBS stakeholders at province, district,
health facility and community.
• Triage and verify reports received from signals
• Receive reports of events from provincial level and district
level
• Record events in existing surveillance data tools and
platforms.
• Conduct risk assessment of all events to inform response.
50. EVENT BASED SURVEILLANCE AT PROVINCIAL HEALTH
LEVEL
• Provincial Health Offices (PHOs) are mandated to oversee the
provision of health services in the districts including 2nd level and
3rd level hospitals.
• Their core function includes supervision, coordination, performance
assessment, technical support and capacity building to the lower
levels.
• They play a critical role in linking the districts and the National level
and ensuring that health policies are implemented at the lower level.
• PHOs are responsible for Public health security at regional level .
• Through the Provincial Surveillance Officers (PSOs), PHOs are
responsible for implementation of IDSR strategy which includes
implementation of EBS.
51. roles and responsibilities of PHOs in EBS
• Train EBS stakeholders at district levels, health facilities and
communities
• Triage and verify reports received of signals from Districts and
Media scanning
• Receive reports of events from District level
• Record events in existing surveillance data tools and
platforms(DHIS2)
• Conduct risk assessment of all events to inform response. As
needed, work with national authorities to provide data as
appropriate to WHO
52. EVENT BASED SURVEILLANCE AT DISTRICT LEVEL
• The district health office is mandated to coordinate public health
responses at the district level and collects, collates and analyzes
data from the facilities under its jurisdiction, supervises the health
facilities (Public and Private) and conveys reports to the Province.
• Furthermore, in line with the Integrated Disease Surveillance and
Response guidelines the district is the focus for integrating
surveillance functions and its subcomponents which are Indicator
Based Surveillance and Event Based Surveillance. (Technical
Guidelines for Integrated Disease Surveillance and Response in
the WHO African Region, 3rd Edition, March 2019)
53. Roles and Responsibilities
• Train EBS stakeholders at local levels, communities, and health
facilities
• Receive reports of events from Health facilities and Community EBS
(local level)
• Record events in existing surveillance data tools and EBS DHIS
platforms
• Conduct standard risk assessment of all events to inform response.
• As needed, work with Provincial authorities to provide data as
appropriate to ZNPHI (National level)
• Support Investigation and response to public health events in the
district.
54. EVENT BASED SURVEILLANCE AT HEALTH FACILITY
LEVEL
• Zambia has a well-developed public health care system which
includes both public and private sector.
• Both focus on provision of primary health care comprising of first
level hospitals, Zonal clinics, health centres and Health posts.
• 2nd and 3rd level hospitals offer specialized medical services such
as diagnostic, curative etc.
• Super specialized hospitals are also being developed in Zambia.
• Typically, clinicians and health care workers have a primary role in
patient care and management at this level. (Provide citation).
55. Steps of HEBS conducted in health facilities
Signal detection
• Signals are broad and allows for a sensitive surveillance
system with a requirement for immediate notification.
• Healthcare professionals, including clinicians, nurses, and
infection control officers, should be sensitized to recognize
signals and report them immediately.
• Healthcare professionals will directly notify designated
public health authorities or HEBS focal points (Health
facility Surveillance Focal point person) identified in their
health facilities.
56. • HF FPP will in maintain the log book and initiate the processes of triage,
filtering, verification, risk assessment and response within the facility of
community if need arise.
• All signals detected will be reported to the District surveillance officer.
• It s expected that all Hospitals should have the capacity to complete the
verification, risk assessment and response processes with little support from
the DHO. Meanwhile, Zonal Health Centres, Health Centres and Health Post
will be supported by the District Rapid Response Teams to carry out the
processes of verification, risk assessment and response.
57. List of signals for detection at health facilities
1.Severe illness requiring admission of HCW after caring for
a patient after a similar illness
2.Increase of infectious disease cases based on the
clinicians judgment
3.Two or more cases with similar symptoms within a week
from the same location
4.Any case with unexplained/unusual clinical manifestation
of a known disease
5.Any case that fails known therapy
58. COMMUNITY EVENT BASED SURVEILLANCE
• In Zambia, Community health care is essentially an integral part of
Primary Health Care (PHC) as defined in the Alma Ata Declaration
(1978):
• ”Primary health care is essential health care based on practical,
• Scientifically sound and socially acceptable methods and
technology made universally accessible to individuals and families
in the community through their full participation and at a cost that
the community and country can afford to maintain at every stage of
their development in the spirit of Self-reliance and self-
determination (Community health Strategy,2017-2021).
59. Roles and Responsibilities
• The implementation of EBS at the community level will
use the existing resources and networks to ensure its
integration into existing national public health and
surveillance platforms.
• The most critical component of CBS implementation is the
recruitment and retention of those individuals with primary
responsibility for signal notification
60. Role Responsibility
Detect Ensure the appropriate use signal off definitions to identify priority public health
events in the community
Triage Conduct triaging of signals
Record Maintain a log of all reported signals in his/her community units
Report Report events to Health facility
Verification Support CHA/EHT & RRTs in verification of signals reported
Feedback Give feedback to CBVs and community on reported signals, prevention and
control measures of events
Risk assessment Work with Health Facility Focal person to conduct rapid assessment of events
Respond Support the health facility during response
Analyze and
Interpret
Analyze EBS data and prepare and disseminate monthly reports
Support function Periodic sensitization of CBVs and provide regular positive reinforcement and
feedbackAct as a link between the health Centre and the communitySupervise
CBVsConvene quarterly review meetings for CBVs Maintain and update
database of trained CBVs
61. References
1. Leroy EM, Gonzalez JP, Baize S (2011). Ebola and Marburg haemorrhagic fever viruses:
major scientific advances, but a relatively minor public health threat for Africa. Clin
Microbiol Infect.
2. Formenty P, Hatz C, Le Guenno (2018). Human infection due to Ebola virus, subtype Côte
d'Ivoire: clinical and biologic presentation. J Infect Dis.
3. Feldmann H, Geisbert TW. (2011). Ebola haemorrhagic fever. Lancet. 5;377(9768):849-62.
4. All Answers Ltd. (November 2018). Ebola Virus Explained Essay. Retrieved from
https://nursinganswers.net/essays/ebola-virus-explained-essay-6879.php?vref=1
