Case Investigation of Avian in Southeast Asia Influenza Overview - - PDF document

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Case Investigation of Avian Influenza

Rapid Response Team Training in Southeast Asia

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Overview

• Initiating an investigation
• Pre-investigation activities
• Investigation
• Recordkeeping and reporting
• Post-investigation activities

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Learning Objectives

Initiating an Investigation

• Discuss what makes an avian influenza

(AI) case investigation different from investigations of other infectious diseases

• Discuss criteria that would initiate an AI

case investigation

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What makes an AI case investigation different from other outbreak investigations?

Discussion

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What makes an AI case investigation different?

• AI is an emerging infectious disease
• Can be political
• Requires early investigation for early

control

• Requires working with other parts of

ministry or other organizations with whom we do not usually work

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What criteria would initiate an AI case investigation?

Discussion

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Case Confirmation

• Does reported case actually exist?

– Confirm the case is not a rumor – Talk with hospital, doctors, community residents

• Does reported case-patient have illness

similar to avian influenza?

– Signs, symptoms, exposures to avian influenza

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Investigating a Suspect Case

Evidence for H5N1 infection based on

– Clinical findings – Epidemiological evidence – Laboratory testing

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Case Definition

Categories of case definitions for avian influenza A/H5

• Patient under Investigation
• Possible Case
• Probable Case
• Confirmed Case

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Case Definitions for Influenza A/H5

Patient Under Investigation

• Any individual reporting:

– Fever (temperature above 38º C)

And one or more of these symptoms

– Cough – Sore throat – Shortness of breath

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Case Definitions for Influenza A/H5

Possible Case

• A “patient under investigation” who ALSO

has one or more of the following:

– Lab test for Influenza A (not including subtype) – Contact in past 7 days with confirmed case of Influenza A/H5 – Contact in past 7 days with sick birds – Worked in lab where there is processing of samples from persons/animals with Influenza A

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Case Definitions for Influenza A/H5

Probable Case

• Any “patient under investigation” or

possible case who ALSO has

–In-country laboratory evidence for influenza A/H5

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Case Definitions for Influenza A/H5

Confirmed Case

• Laboratory testing demonstrates 1 or more
• f following

– Positive viral culture for A/H5 – Positive PCR for A/H5 – IFA Test positive for A/H5 – 4-fold rise in A/H5 in paired serum samples

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Pre-Investigation Activities

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Learning Objectives

Pre-Investigation Activities

• Assemble an investigation team
• Prepare the epidemiologic, medical and

personal protective equipment and supplies required for an outbreak investigation

• Advise relevant public health personnel

that a case investigation will be conducted

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Assemble Investigation Team

• FETP:

– 2-3 Medical Epidemiologists – 1 Veterinary Epidemiologist – 1-2 Senior MOPH Epidemiologists

• In the field may be assisted by:

– Provincial rapid response team members – Village health volunteers

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Advise Relevant Personnel of Case Investigation

• Veterinary Health Authority
• Government Officials
• Health Care personnel
• Community
• Non-governmental organizations
• Laboratory

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Gather Documentation

• Information already

gathered

– Location of case, date of illness onset, clinical or exposure details

• List of contacts
• Case reporting forms
• Standardized

questionnaires

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Gather Resources

• People

– Local health workers caring for case-patient – Veterinarians, clinical and laboratory experts, support personnel

• Ministry of Health

– Advice, guidance, additional personnel

• World Health Organization (WHO)
• Avian influenza references
• Other

– Transportation – Security – Communication devices

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Gather Equipment and Supplies

• Epidemiological

– Reporting forms – Notebook (or laptop) for recording data

• Medical

– Antiviral medication (if available)

• Laboratory

– Swabs, needles, cooler, ice, viral transport media

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Gather Equipment and Supplies

• Educational

– Brochures, posters, with influenza safety information – Easy to read – Guidelines for contacts, family members

• PPE

– Masks, gloves, gown, cap, goggles

• Decontamination

– Solution for decontaminating homes or hospital rooms

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Investigation

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Learning Objectives

Investigation

• Review a case patient’s medical record
• Conduct interviews of clinical staff attending

the case patient, the case patient, and patient’s family

• Conduct environmental survey of the

household

• Conduct active case finding in the

community

• Assess possibility of human-to-human

transmission

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Practical Steps

• First visit: Hospital where patient was

admitted

– Review medical chart – Talk to doctors, nurses – Put on PPE – Meet with patient in the room for interview – Remove PPE

• Second Visit: Patient’s home

– Identify and interview contacts – Environmental assessment

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Review Patient’s Medical Chart

• Demographic information
• Medical history
• Current medical complaint / symptom history
• Physical examination findings
• Recommended treatment
• Laboratory or other test results

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Sample Patient Chart: Clinical Information

Demographic Information Date: _____ Name __________ Age ____ Gender ___ Occupation_______ Address______________________________________________________ History of Illness Chief Complaint_____________________ Date of Illness Onset _________________ Other Symptoms and symptom onset date: _______________________________________________________ _______________________________________________________ Physical Exam Findings _______________________________________________________ _______________________________________________________

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Sample Patient Chart: Clinical Information

Demographic Information Date: _Nov 1, 2006 Name _Sok Phhoung_ Age __21_ Gender:_F_ Occupation______ Address___Patang village, Rattanakiri, Cambodia_____________ History of Illness Chief Complaint___Dyspnea_________ Date of Illness Onset ___Oct 27, 2006______ Other Symptoms and symptom onset date: __Fever – onset Oct 25_________________________________ __Cough – onset Oct 25 ________________________________ Physical Exam Findings _Current fever – 39.4°C, Pulse 123 beats/min________________ _______________________________________________________

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Epidemiologic Context

• Potential exposure to H5N1

– Travel or residence in area affected by avian influenza

• utbreaks in animals

– Direct contact with dead or diseased birds or other animals in affected area – Close contact with a person with unexplained moderate or severe acute respiratory illness – Occupational exposure

Warning! Even if NO reports of ill poultry in a province, there could be disease in that area, especially if poultry influenza vaccines are used

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Sample Patient Chart:

Exposure History

Contact with ill people? (If yes, date and name, relationship to patient) ___________________________________________ ___________________________________________ Contact with diseased poultry (Live or dead)? (If yes, date and location) ___________________________________________ ___________________________________________ Recent travel? (If yes, date and location) ___________________________________________ ___________________________________________ Other close patient contacts (Household members, close coworkers) ___________________________________________

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Use All Information

• Clinical signs compatible with avian

influenza

• History compatible with exposure to

avian influenza

• 3 or more cases could indicate an

emergency

• Send samples for laboratory

confirmation

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Interviews

Gather information on exposures and

• ther possible cases

– Case-patient(s) – Household contacts – Friends and neighbors – Local health care personnel

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Interview Tips

• Collect as much information as

possible

– Unstructured interviews – Generate list of contacts

• Repeat critical questions for accuracy,

validity and additional details

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Interview Tips

• Be friendly, but professional
• Identify yourself and your institution
• Explain purpose of interview
• Stress importance of information you will collect
• Inform respondents that all information will be kept

confidential

• If appropriate, conduct interview in private

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Type of Information to Collect

• Demographic information: age, sex

contact details

• Clinical information: signs &

symptoms, physical exam, vitals, date

• f onset, hospital admission
• Exposure history: occupational

exposure, travel, animal exposure

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Contact Identification

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What is Contact Identification?

The identification and diagnosis of persons who may have come into close contact with an infected individual

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Purpose of Contact Identification

• Find new cases that meet case

definition

• Provide interventions for exposed

individuals to decrease risk of illness and interrupt further transmission

– Antivirals (Oseltamivir) – Precautionary Information

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How to Identify Contacts

• 1. Review patient’s activities for the 7

days before onset of symptoms

• 2. Based on activities, identify all close

contacts (within 1 meter)

• 3. Verify all information collected

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Key Information to Gather

• Who did case come into close contact

with?

• What activities was case doing?
• Where did this take place?
• When did case come into contact with…?
• Contact’s Address and Phone Number
• Contact’s Health Status
• Contact’s Gender, Occupation, Age

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General Guidelines for Interviewing Contacts

• Do not alarm contacts
• Communicate precautionary information
• Refer symptomatic individuals to clinic
• Consider if Personal Protective Equipment is

necessary

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Information to Gather from Contact

• Demographic and contact information

– Name, Address – Occupation, age, gender

• Exposure History

– Contact with case-patient – Other high-risk exposures

• Physical Exam and Clinical information

– Temperature – Presence of sore throat, coughing – Signs and symptoms

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Monitoring and Managing Contacts

• Monitor for signs of illness for at least 7 days

after contact with case

– Encourage self-health monitoring – Instruct to report onset of symptoms – Visit or phone daily to monitor for illness

• Request voluntary home quarantine of all

contacts for at least 7 days

• Consider antiviral prophylaxis

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Prioritize Contact Identification

• If number of contacts is large focus on:

– Contacts of laboratory confirmed cases – Contacts with extended duration and closeness to case – Contacts that are at high risk, such as those involved in unprotected care of case – Contacts from large gatherings, school that case attended

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Environmental Observation

Visit suspect areas

• Observe

– Are there chickens in or around the house? – How many chickens/other birds are there? – Do the chickens appear to be healthy? – What are conditions like? Crowded?

• Take appropriate samples

– Animal – Environmental

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Next Steps

• Active case finding in the community
• Assessing possibility of human-to-

human transmission

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Why is Active Case Finding Important?

• Ensure you have identified ALL cases
• Case finding may provide information

about human-to-human transmission

• Any cases related in time and space to

initial cluster or case

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How to Find Cases

• Consider all possible symptomatic

persons as cases at the beginning of an investigation

– Visit health facilities, homes of neighbors and adjacent communities – Public information messages in the affected communities

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Common Challenges to Case Finding

• Even with case finding, all cases may

not be identified

– Physician may not suspect avian influenza – Some infected persons may not seek medical attention

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Recordkeeping and Reporting

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Learning Objectives

Recordkeeping and Reporting

• Implement record keeping for cases

and contacts that facilitates efficient management and data analysis

• Write a report of investigation
• Inform decision-makers and other

relevant public health personnel of

• utcome of investigation

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Keeping Track of Information

• Systematically record data during an

investigation

– Patients and contacts – Location visits – Samples collected

• Helps others understand what has been done

and how

• Minimize duplication

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Data Management

• Line Listing
• Record keeping
• Validation and Cross-Checking

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Line Listing

Case # Age Sex Status Occupation Difficult breathing Date of Onset

1 5 M F 3 48 M Possible Poultry Farmer No 7 July Child Yes 7 July 2 55 Probable Caretaker of case #1 Yes 9 July Possible

Information included: An organized way to view all cases in an investigation

• Demographic
• Clinical
• Exposure

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What is an Epidemic Curve and How Can it Help in an Outbreak?

An epidemic curve (‘Epi’ curve) is a graph or picture

• f the number of

cases of illness by the date of illness onset

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Record-keeping

• Where will records be kept?
• How will records be kept?
• Who is assigned to record-keeping?
• Maintain confidentiality

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Validation and Cross-Checking

• Check line lists against medical charts

and interviews

• Validation

– Ask same question in different ways – Ask same question at different times – Ensure answers are consistent

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Assessing Human to Human Transmission

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Current Status of H5N1 Transmission

• Now

– Human-to-human transmission of Influenza A/H5 highly ineffective – Has occurred only among very close contacts

• In the future

– Virus could mutate and pass between humans – Global outbreak could occur

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Assessing Human to Human Transmission

• Cases occur close together in time and

place among individuals who had close contact with a human case

– Family members or health care workers

• Onset between two cases falls within

the incubation period

• No alternative source of exposure is

found

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When a Cluster May Exist

• 3 or more people with moderate or

severe acute respiratory illness

– Unexplained by other causes – May have died from the illness – Onset within 7-10 days of each other

AND

• History strongly suggesting exposure

to H5N1 virus

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Epidemic Curves and Transmission

Assess whether human-to-human transmission is occurring

– Epi curve pattern for infectious agent transmitted between people – Epi curve pattern for infectious agent transmitted from one source to people

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Example Epi Curve for Human to Human Transmission

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Example Epi Curve for Human Cases from Single Source

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Writing an Investigation Report

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Why communicate the findings?

• A document for action

– Control and prevention measures

• To share new insights
• Documents the investigation
• To assist other nations districts or

countries with investigation

• Inform the public

– Prevents future outbreaks

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Content of a summary report

• Summary
• Introduction and Background
• Outbreak Description
• Methods and Results
• Discussion
• Lessons Learned
• Recommendations
• Acknowledgements
• Supporting Documentation

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Reporting: Informing Those who Need to Know

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Inform Those who Need to Know

• Local Level
• National Level
• International Level

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Inform Those who Need to Know

• Insert Local and/or National Reporting

Requirements (country-specific)

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Inform Those who Need to Know

• International Health Regulations (IHR)

– Compulsory notification of highly-pathogenic strains of avian influenza – Vaccination and food safety of poultry products

• Compliance with these standards is required

to strengthen early detection, reporting, and response

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Post-Investigation Activities

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Learning Objectives

Post-Investigation Activities

• Describe the type of analytic studies

that may be conducted following or in conjunction with case investigations

• Describe questions that may be

included to further study the outbreak in animals

• Evaluate investigation performance
• Monitor investigator’s symptoms

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Other Analytic Studies

• Special epidemiologic studies
• Serosurveys
• Surveys of antiviral resistance

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What questions might an epi ask to further investigate

• utbreaks in animals?

Discussion

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Questions to ask about animal

• utbreaks?
• What are the patterns of disease in this

animal?

– What was observed with the death of the animal? – When did the symptoms start? – What were the symptoms? – How quickly did the animal die from the

• nset of symptoms?

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Questions to ask about animal

• utbreaks?
• Which species of poultry or animal is

the outbreak occurring in?

• How is the species managed (if

domestic)?

• What are the interactions between

species – as relates to susceptability to flu?

• What recent mortalities have there

been?

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Questions to ask about animal

• utbreaks?
• What are the animals movements in

and out of the environment

– Are movements recent? – Are movements on a regular basis?

• What are the produces marketing from

their livestock?

• What other population (of animals)

does this population have contact with?

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Why Evaluate the Investigation

• To summarize the events that occurred
• To learn from experience

– Make recommendations for future investigations – Take lessons from what worked well – Take lessons from mistakes

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What to Evaluate

• Timeliness of response
• Completeness of the investigation
• Accuracy of the data

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Timeliness of Deployment

• Response time

Notification Arrive at location

• Ideal: about 24 hours
• Delays

– Assembling team – Finding supplies – Getting to location

• How could response time be improved?

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Timeliness: Investigation and Initial Assessment Report

Arrival in field Deliver initial assessment report

• Initial report

– Oral or written – May receive feedback on how to proceed

• Delays

– Interviews, initial investigation – Poor communication in team – Too busy

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Timeliness: Investigation and Final Assessment Report

Arrival in field Deliver final assessment report

• Final report

– Oral or written – Summary and recommendations

• Delays

– Follow-up interviews – Containment measures – Poor data management

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Timeliness: Final Report

End of field Official investigation investigation report

• Official record of investigation
• Delays

– Back to “normal” work – Lack of motivation

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Completeness

• Necessary activities completed?

– Team assembled and worked well – Interviews – Case definitions – Data collection – Reports

• Data collected from questionnaires

complete?

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Accuracy of Data

• Data management
• Validation and cross checking
• A report based on incomplete or

inaccurate data is not informative!

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And, last but most importantly

• Observe your own symptoms for 10

days following an AI outbreak investigation

– Take temperature twice a day – Look for GI symptoms – Take Tamiflu if you have a fever