Application of Epidemiology (Part 5)

Verify the diagnosis

- closely linked to verifying the existence of an outbreak

- often these two steps are addressed at the same time

Importance of verifying the diagnosis

a. to ensure that the disease has been properly identified, since control measures are often disease-specific; and

b. to rule out laboratory error as the basis for the increase in reported cases.

Steps in Verifying the diagnosis

Step 1: review the clinical findings and laboratory results

Step 2: visit patients and review laboratory results

Step 3: summarize the clinical features using frequency distributions

Establish a Case Definition

Standard set of criteria for deciding whether an individual should be classified as having the health condition of interest.

Establish a Case Definition

- clinical criteria (signs and symptoms)

- restrictions by time, place and person

- apply without bias

- note: exposure or risk factor is not included

Identify and Count Cases/Find cases systematically and record information

- Identifying information - name, address, contact number

- Demographic information - age, sex, race and occupation

- Clinical information - date of birth, date of death, hospitalization date, date of onset, duration of illness

Identify and Count Cases/Find cases systematically and record information

- Risk factor information - food and water sources, toilet facility

- Reporter information - Usually a physician, clinic, hospital, or laboratory

Find Cases Systematically and Record Information

- passive or active surveillance

- A form or questionnaire may also be distributed asking for more in about clinical symptoms and laboratory specimens could be collected.

- Persons identified as cases may also be asked to refer anyone with the same condition so they can also be asked.

Perform descriptive epidemiology

- the outbreak is characterized by time, place, and person

- Describe and orient the data in terms of time, place and person

Characterized by Time

- difference between maximum and minimum incubation period

- probable time exposure

- incubation period when probable time of exposure is known

- epidemic curve (drawing, interpreting and analyzing)

Characterized by Place

- geographic extent

- spot map

- area map

Characterized by Person

host characteristics

- age

- race

- sex

- medical status

Characterized by Person

exposures

- occupation

- leisure activities

- tobacco use

- use of medication/drugs

Develop hypotheses

- may address the source of the agent, the mode (and vehicle or vector) of transmission, and the exposures/risk factors that caused the disease

Develop hypotheses

- should be testable

- generated in a variety of ways.

Ways of generating hypothesis

- consider what you know about the disease itself (round up the usual suspects)

- talk to a few of the case-patients

Evaluation of hypothesis

done in one of two ways:

1. comparing the hypotheses with the established facts

2. using analytic epidemiology to quantify relationships and assess the role of chance (case control studies and retrospective control studies.)

Reconsider, refine, and re-evaluate hypotheses

Unrevealing analytic studies = poor hypothesis

May need more specific exposure histories

May need more specific control group

Laboratory results

confirm the findings from the analytic epidemiologic studies

Environmental studies

can explain why the outbreak occurred

combination of analytic epidemiology studies, laboratory results and environmental studies

give a complete picture of the outbreak investigation and guide appropriate public health action

Primary Goal of Outbreak Investigations

control of the outbreak and prevention of additional cases

Protect the public's health

the health department's first responsibility in the event of an outbreak

Confidentiality

an important issue in implementing control measures

Initiate or maintain Surveillance

- important to determine whether the prevention and control measures are working in terms of declining number of cases.

- Checking whether the outbreak has spread to other areas where control measures would need to be initiated

Final task of Outbreak Investigation

to summarize the investigation, its findings, and its outcome in a report, and to communicate this report in an effective manner

Communicate findings

Through: Information, Education and Communication

- meetings and discussions (oral communication, power point presentation, visual aids)

- writing and disseminating full reports

- IEC dissemination to local and mass media

Communicate findings

Addressed to:

- Local Government Unit Officials

- Local health Workers

- Concerned Authorities

- Regional Health Authorities

- Department of Health

- People/Citizenry

Public Health Surveillance

an ongoing systematic collection, analysis, interpretation and dissemination of health data

Surveillance System

often considered information loops or cycles involving health care providers, public health agencies and the public

Information Loop of Public Health Surveillance

1. begins when cases of disease occur and are reported by

health care providers to the public agencies

2. Information about cases are relayed to those responsible for disease prevention and control and others who need to know.

3. Information is shared or given to health providers, health agencies and public; government agencies (Local and National), potential or high risk exposed individuals, employers, vaccine manufacturers, NGO and NGA.

Role of the Nurse in Surveillance

- researcher

- should participate in investigative efforts to determine what is precipitating the increased disease rate and work to remedy the identified threats or risk.

Surveillance

- continuous collection and analysis of data of cases and death.

- also important in monitoring the progress of the disease, reduction initiatives and an integral part of many programs

Objectives of surveillance

1. To measure the magnitude of the problem; and

2. To measure the effect of the control program.

Disease Under Surveillance

Laboratory Diagnosed

• Cholera

• Hepatitis A and B

• Malaria

• Typhoid Fever

Disease Under Surveillance

Clinically Diagnosed

- Dengue Hemorrhagic Fever

- Diphtheria

- Measles

- Meningococcal Disease

- Neonatal Tetanus

Disease Under Surveillance

Clinically Diagnosed

- Non Neonatal Tetanus

- Pertussis

- Rabies

- Leptospirosis

- Acute Flaccid Paralysis (Poliomyelitis)

Disease Under Surveillance

Under Surveillance System

- Acute Flaccid Paralysis (Poliomyelitis)

- Measles

- Maternal and Neonatal Tetanus

Disease Under Surveillance

Under Surveillance System

- Paralytic shellfish poisoning

- Fireworks and related injury

- HIV/AIDS

Functions of the Nurse in Epidemiology

- Implement public health surveillance;

- Monitor local health personnel conducting disease surveillance;

- Conduct and/or assist other health personnel in outbreak investigation

Functions of the Nurse in Epidemiology

- Assist in the conduct of rapid surveys and surveillance during disasters;

- Assist in the conduct of surveys, program evaluations and other epidemiologic studies;

- Assist in the conduct of training course in epidemiology;

Functions of the Nurse in Epidemiology

- Assist the epidemiologist in preparing the annual report and financial plan; and

- Responsible for inventory and maintenance of epidemiology and surveillance unit (ESU) equipment.

Specific Role of the Nurse during Epidemiologic Investigations

- Maintains surveillance of the occurrence of notifiable disease;

- Coordinates with other members of the health team during the disease outbreaks;

Specific Role of the Nurse during Epidemiologic Investigations

- Participates in case findings and collection of laboratory specimens;

- Renders nursing care, teaches and supervises giving of care;

- Performs and teach household members method, concurrent and terminal disinfection;

Specific Role of the Nurse during Epidemiologic Investigations

- Gives health teachings to prevent further spreading of disease to individuals and families;

- Follow-up cases and contacts;

- Organizes, coordinates and conducts community health education campaigns/meetings;

Specific Role of the Nurse during Epidemiologic Investigations

- Refers cases when necessary;

- Coordinates with other concerned community agencies; and

- Accomplishes and keeps records and reports and submits to proper office/agency.

Functions of a Health Worker

- Collects data

- Tabulates data

- Analysis and interprets data

- Evaluates data

- Recommends redirection and strengthening of specific areas in health program as needed.

Monitoring

done while the intervention is still being implemented to provide feedback on its current status

Evaluation

done at the end of the project to assess whether or not its objectives were achieved