Surveillance Strategies and Sample

Collection

Muhammad Farooq TahirDisease Surveillance Officer

Poultry Research Institute

Rawalpindi

Surveillance Definition-Dictionary

“Close observation,

especially of a

Suspected spy

or criminal.”

ORIGIN: from Fr., from sur- 'over' + veiller 'watch'Source: The Concise Oxford Dictionary. Ed. Pearsall J. Oxford University Press, 2001.

Surveillance

“Surveillance is the ongoing

systematic collection,

analysis and interpretation

of data to describe

and monitor a health event;

and the dissemination of information to those who need to

know in order that action may be taken .”

Klaucke,1992

Disease Surveillance

• The continuing scrutiny of all aspects of

occurrence and spread of disease that are pertinent

to effective control.

Early warning

Presence or absence of a disease

Source: Last JM. A Dictionary of Epidemiology (Second Edition). Oxford University Press 1988, New York.

Objectives of Disease Surveillance

To monitor trend & magnitude of diseases

Epidemic (outbreak) detection and prediction

Early warning

Design/change vaccination policy

Estimate Future Disease Impact.

Evaluate interventions to improve them

Certify elimination / eradication of a disease Monitor

progress towards a control objective

Facilitate planning

Types of Surveillance

PASSIVE SURVEILLANCE

Where reports are awaited and no attempt

made to actively seek reports from

community.

ACTIVE SURVEILLANCE

Where veterinary services actively move to

the community to seek the disease reports.

Passive Surveillance

Receives data from all potential Veterinary

Dispensaries, Hospitals, Labs etc

Often minimal/incomplete.

Usually data received in irregular pattern as by thefield staff.

False Positive Results

Requires Less Resources

Active Surveillance

Usually conducted for specific disease.

Requires substantial more time and more

resources.

Often used when outbreak has begun and

is suspected to track new cases.

Usually complete and in a regular pattern until

the outbreak is controlled.

How Surveillance is Conducted

Surveillance

Disease/

Event

Data/ Samples

Information

Intervention

Sample Collection

Laboratory diagnosis is theonly tool to confirm adisease but it all depends onCorrect Sampling

Sample Types for PoultrySample Type Objective

Swabs Virus detection

Tissue Virus detection

Feces Virus detection (Less Sensitive)

Blood/ Serum Screening for pathogen

Flock monitoring

Swabs

• Two kind of swab samples Tracheal & Cloacal

• Take 2-3 ml of transport medium in the sterilized

swab

• For taking tracheal swab open the beak of bird

• Insert the swab deep to the pharynx

• Gently rub it

• Put the swab in the transport medium

• Properly label and pack it

Swabs cont….

• For taking Cloacal swab

• Locate the Cloaca of the bird

• Insert the swab deep in to Cloaca

• Rub it gently

• Put it in transport medium

• Properly label and pack it

Cont….

Transport MediumSampling tubes should be filled with 2-3ml Transport

medium with antibiotics

PBS/BHI with :▫ 10 IU/ml Penicillin▫ 10 mg/ml Streptomycin▫0.25 mg/ml Gentamycine▫ 5 IU/ml Mycostatine

After addition of the antibiotics the pH must be adjusted to pH 7.0-7.4

If not available:

Use NaCl 0.9% (Normal Saline) or MEM

Tissues

Fresh ORGANS or organ pools (2-5 birds) to be taken

Trachea, lungs

Intestine (incl. content)

Liver, spleen

Brain (especially when nervous signs)

All other organs with lesions

Use sterile and water tight containers

cover with transport medium

Pooling of Samples (Swabs & Organs)

Max 5 birds for one pool

Same species

Samples from the same unit

Separate tracheal and cloacal swabs

Separate organs

Feces

Faecal material must be fresh!

Optimum 1 g

Only to be used if no other sampling possible, as

less sensitive

Use sterile and water tight containers

Can be used for market surveillance purpose

Blood Objective

Serology

MaterialSyringe 2.5 ml

Needle: 21, 23 G

Hemolysis tubes or vacutainers

Sample sizeIdeally 1.5 ml

Min 0.5 ml

Blood

Sampling for ALP Project

• Major focus on ND, AI, IB and Salmonella

• All types of sampling required

• No fixed target or quantity but 200-300 samples

monthly appreciated.

• Proper sampling with history on prescribed

proforma.

THANKS FOR THE ATTENTION