progressive control practitioners’ network conducting an

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Progressive Control Practitioners’ Network

Conducting an NSP antibody Sero-survey

Progressive Control Practitioners’ Network

NSP sero-survey PC Practitioner Network 2

Conducting an NSP-Antibody Sero-survey

Introduction

Kees van MaanenEuFMD component manager MENA and Laboratory networs

Javad EmamiProvincial Veterinary Officer, West Azarbaijan, Iran


Chris BartelsEuFMD component

manager PCP

Wilmot ChikurunheShort-term professional Southern Africa

Objective Field

application

Design Laboratory issues

and result

interpretation

Jenny

MaudTraining ProgrammeManager

Practicing the

Network

Introduction

Practitioners’ Network

NSP sero-surveys- To understand level of infection in and

endemic situation- To understand two-stage sampling- To manage sample size calculations for

two-stage sampling- To develop a questionnaire for putative

risk factors- To manage data collection and validation- To analyse risk factors for spread of

infection

Webinar and pre-recorded presentationsToday’s webinar, prerecorded presentation and a final webinar on 9 February

Exercises or assignments- Assessing laboratory results- Estimating animal

prevalence, epi-unit andwithin epi-unit prevalence

- Confidence intervals

Invited experts- Wilmot Chikurunhe- Javad Emami- Kees van Maanen

Knowledge Bank andJob Aidshttps://eufmd.rvc.ac.uk


Discussion forum & tutoring- Publications- Propositions- News-feeds- Agenda

A new tool/job-aid- A checklist to conducting a survey- Template for questionnaire to conduct when

sampling

Programme and Practitioners’ view

Agenda for January –February

2017


Week Mon Tuesday Wed Thursday Fri

1 16 17 Online available:

exercises, job-aids,

SOP’s related to

‘Survey design’

18 19 Webinar

Introduction and

Survey design

Chris Bartels

Wilmot Chikurunhe

Javad Emami

20

2 23 24 25 26 27

3 30 31 Online available:

exercises, job-aids,

SOP’s related to

‘lab interpretation’

1 2 Pre-recorded

presentations

Laboratory

interpretation

Kees van Maanen

3

4 6 7 8 9 Closing webinar:

results and

explanation of

exercises

10


12-monthsprogrammefor the Practitioners’Network


Month 01

NSP sero-survey Complementing outbreak

reporting

Month 02

Outbreak

investigation Fit for purpose

Month 03

Economic impact

assessment From clinical disease to lost

dollars

Month 04

Month 05

Risk analysis along

value chain Understanding value chains is

the tool to mitigate widespread transmission of

FMD virus

Month 06

Stakeholder

consultation If people make livestock

move, what do we need to know about these people

Month 07

Post-vaccination

monitoring Testing the vaccine and its

performance as not all vaccines and applications are

the same

Month 08

Month 09

Risk-based

surveillance More information for less

input

Month 10

Training of

trainers Integrating capacity building

with strengthening Veterinary Services

Month 11

Review of the year

and future plans What has the Network

brought you and how did you contribute?

Month 12


ObjectiveDuring this session, we will discuss

• how sero-surveys support understanding of the epidemiology of FMD and monitoring and evaluation of FMD control plans

• Importance to define objective for the sero-survey (objective) – Prevalence estimation versus detection of disease

– Unit of interest versus unit of sampling

– Study population versus target population

– Inclusion and exclusion criteria

• Principles of survey design such as – Two-stage sampling

– Sample size calculation

– Accounting for random error and prevention of bias

– Collect accurate attribute information to be able to conduct further analysis

• Implementation and organisation of conducting a NSP-Ab sero-survey– Developing materials

– Training of staff

– Pretesting of questionnaire and data recording

– Data management

• Laboratory aspects



What does clinical disease tells us about occurrence of FMD?

Information gain– FMD serotype, strain

– Impact

– Vaccine effectiveness

– Risk factors for disease


Objective

What does clinical disease tells us about occurrence of FMD? And thus, what not?

Information gain

– FMD serotype, strain

– Impact

– Vaccine effectiveness

– Risk factors for disease


• Lack of information – Origin of infection

– Extent of spread of infection

• temporal, spatial, cross species

– Risk factors for transmission of infection

Objective

Outbreak reporting

– being lucky to see

Sero-survey: actively

searching the unseen


Objective

Question

What percentage of occurrence of FMD in livestock do you think is reported to the Veterinary Services?

1. Between 1 – 5 per cent

2. Between 6 and 10 per cent



5. More than 40 per cent


Objective

W. Azerbaijan serosurvey

80.2% of epi-units had at least 5 calves with a high titre (>75% inhibition)

18% observed clinical signs in their stock in the previous 12 months (questionnaire)


Incidence85.71 - 100.0080.71 - 85.7171.43 - 80.7166.67 - 71.4350.00 - 66.67

2011 Incidence FMD serosurvey

Incidence28.57 - 40.0027.27 - 28.5719.81 - 27.2716.67 - 19.818.57 - 16.670.00 - 8.57

Incidence FMD reports (sample)

Incidence13.77 - 32.769.97 - 13.779.18 - 9.977.81 - 9.187.37 - 7.811.52 - 7.37

16 mo prior to survey

Incidence FMD reports

District-level FMD Incidence:

Serosurvey and clinical signs (survey and official reports)

Objective

What are potential reasons for differences between serological and reported data?


Objective

What are potential reasons for differences between serological and reported data?

May be due to:1. Under-reporting

• More likely in sheep

• Non aware of reporting

• Non-confident of consequences of reporting

2. Subclinical infection• FMD signs observed by farmers on:

– 18% NSP+ epi-units in W. Azerbaijan

• May vary by FMD strain, species infected, vaccination status

3. Reflection of previous year’s cases?• Importance of limiting serosurvey to young animals

(ideally 4-12 months, possibly more practical to include 6-18/24 months)


Objective

Both approaches contribute to assessing and monitoring FMD risk and FMD control programmes

NSP serologyMeasures FMD infection

Less biased (with careful design!)

– Unit of interest, unit of sampling

Combine with questionnaire to give more information about risk factors

Resource intensive

Survey can be combined with post-vaccination monitoring (SP-Ab testing)


Objective


Any questions?





manager PCP


Objective Field

application


and result

interpretation

Jenny


Practicing the

Network

Introduction

Step 1 – What and why?

Define objective

Define focus

Prevalence estimate

Detection of disease/Disease

freedom

Comparison of prevalences

Identify target

population

Unit of interest

Unit of sampling

(primary and secondary)

Define diagnostic

tests

Antibody vsantigen

Test characteristics (Sens, Spec)


Design

Population

Research question

Sampling strategy

Sample size

Sample

measurements

Analysis


Design

Most common research questions


Prevalence Estimation

e.g prevalence of FMD infectionDifference in prevalence

e.g. between regions, countries,

case and control group

Detection of disease e.g. presence of disease

at a predefined level or

above?

Freedom of disease

e.g. confidence that disease

is absent

Design

Surveys

Determine what question is being asked... and how best to answer it

Examples of questions?– Is there FMD in my country?

– How much FMD is in my country?• What is the NSP sero-prevalence?

• What is the incidence of clinical FMD?

– Is the level of FMD higher in one area than another?

– What are risk factors for FMD? (must define factors of interest)

– Is vaccination effective?• What is the level of sero-conversion after vaccination?

• Are vaccinated animals less likely to develop disease?

– What is socio-economic impact of FMD on dairy farms?• Measure the decrease in milk production associated with FMD

• Quantify the economic loss due to an outbreak of FMD


Design

Unit of interest (unit of analysis): what are you counting?

NSP sero-survey PC Practitioner Network 22Control AI Vaccination AI & ND Vaccination

Treatment Blocks

Kulon Progo District

v

v v

v v

v

v

v

v

v

Individual animal

Nr animals sick/total nr animals

Pens

Nr Infected pens/total nr pens

Farms

Households/villages

Districts

Design

Calculate sample size

Assumptions Primary and secondary

sampling unit

Define sampling procedure

Random, Convenience, Selective,

Risk-based

Single or multiple stage

Selection procedure

Develop collection

instruments

Sampling materials

Questionnaire Recording

Pre-test and instruct

Supervision EnumeratorsLivestock owners

Define objective

Define focus

Identify target

population

Define diagnostic

tests

Step 2 – How to conduct?


Design


The concept of a sample

Measuring whole population - census

Design

Target Population


Sample

Measure and infer

results to whole

population

Design

Single-stage and 2-stage sampling?

• Based on number of animals involved

• Based on management practices and observed clustering of animals

• In most cases never a simple, single stage random sampling because the animals numbers are almost always very high and exist in some form of clustering

• Most surveys fall in the 2-stage sampling category

• Rarely do surveys involve more than 2 stages


Design

Two stage sampling

Primary sampling units (PSU)

– Herds, villages, flocks

– First level of clustering of

individual animals

– Often the unit of our primary

interest for estimation of

prevalence as FMD control

aims at epi-unit level

(livestock owner, village)

more than on individual

animal

– Bulk milk testing may help

to simplify the design

Secondary sampling unit (SSU)

– Animals, individuals

– Units required to provide

information about the

primary unit (it is just not

possible to sample the herd,

village directly to define it

infected or not)

– Thus, to qualitatively define

the disease / infection status

of the herd, village, flock

referring to detection of

‘disease’


Design

First Stage Sampling


Animal

clusters

(as the sampling frame)

Design

Second Stage Sampling (Selection of animals)


Second stage sample

Sampling frame? - Each of the epi units in the first stage sample

Design

Have you worked with a 2-stage sampling approach?

Yes

No


Design

Sample size determination at both stages

Use of software eg Winepiscope


You need:

•Design prevalence -

a hypothetical value that

is given for disease

presence in a herd or

population when planning

a survey. Herd level and

within herd

•Level of confidence

•Population size

Design

Sample surveys (bias)


There will be always a difference between the true value of the parameter (most of the times unknown) and its estimate

This error can be broadly classified into:

Random error • Sample size

Systematic error

• Selection

• Measurement

• Information

BIAS

Design

Questionnaire

When sampling livestock, it is important to collect additional information to understand association between lab result and factors (attributes)

– At animal level• Age

• Purpose

• Origin (born where sampled or introduced

newly)

• Vaccination status (if known at individual level)

– At household level• Common grazing, common drinking

• Herd structure, presence of other livestock

species

• Trading activities of owner/family

– At village level

• History of FMD

• Vaccination history

• Location near animal market, main road,

nature reserves

HOUSEHOLD – ask owner- QUESTIONNAIRE IDENTIFICATION - VV/GG/01-

X- COORDINATE ……………

Y-COORDINATE ……………

1 Are there (or have there been in the last 12 months)

sheep or goats in this household? (3)

0 No

1 Yes

2 Where did ruminants go for drinking in the last 12

months? (more than one answer possible)

0 At the house

1 Within village

2 Around village

3 In nearby village

3 Where were ruminants fed in the last 12 months?

(more than one answer possible)

0 At the house

1 Within village

2 Around village

3 In nearby village

4 Were ruminants introduced/purchased in last 12

months? (more than 1 answer is possible)

0 No

1 Yes, from this village

2 Yes, from this municipality

3 Yes, from this district

4 Yes, from this governorate

5 Yes, from –governorate-

5 For what purpose are ruminants raised?

(more than 1 answer is possible)

1 Milk production

2 Fattening

3 Other

6 How did you treat the manure in the last 12 months?

(more than 1 answer is possible)

0 Keep for himself

1 Lend to his neighbors in the

same village

2 Sold out the villages

7 Did you buy/introduce manure from other farms in

the last 12 months?

0 No

1 Yes

8 Have you sold any ruminants in the last 12 months? 0 Yes

1 No


SAMPLE SHEET QUESTIONNAIRE IDENTIFICATION - VV/GG-



Serial number Age in

months

Sex

0 = male

1 = female

Species

0 = cattle

1 = buffalo

Born at owner

0 = yes

1 = no, in village

2 = no, in municipality

3 = no, in district

4 = no, in different

governorate

Owner Coding for

household

questionnaire

VV/GG/01/01

VV/GG/01

VV/GG/01/02

VV/GG/02/03 VV/GG/02(1)

VV/GG/02/04(2)

VV/GG/03/05 VV/GG/03

VV/GG/03/06


VV/GG/04/08


VV/GG/05/010

VV/GG/06/011 VV/GG/06

VV/GG/06/012

VV/GG/07/013 VV/GG/07

VV/GG/07/014

VV/GG/07/015

VILLAGE – ask local veterinarian - QUESTIONNAIRE IDENTIFICATION - VV/GG -



1 Is there a ruminant market in this village? 0 No

(Only one answer possible) 1 No, but in same municipality

2 No, but in same district

3 Yes

2 Have there been clinical signs for FMD in the last 12

months? (Only one answer possible)

0 No

1 No, but in same municipality

2 No, but in same district

3 Yes

3 Was there vaccination against FMD in the last 12

months? (Only one answer possible)

0 No

1 Yes, 1 time, - month -

2 Yes, 2 times, - month -

4a What is the estimated number of cattle in this village? Cattle …………….

4b What is the estimated number of buffaloes in this village? Buffaloes …………….

4c What is the estimated number of sheep in this village? Sheep …………….

4d What is the estimated number of goats in this village? Goats …………….

IDENTIFICATION -Fill out yourself- QUESTIONNAIRE IDENTIFICATION - VV/GG -



Name of owner ………………………… Village ……………………..

Municipality ………………………… District ……………………..

Governorate …………………………

Location of local clinic 0 Same village

1 Different village

1 What are geocoordinates (decimal degrees) of the

village?

X …………………………..

Y …………………………..

Design

Available on our PC Practitioner site areSupporting documentation and publications


Design


Any questions?





manager PCP


Objective Field

application


and result

interpretation

Jenny


Practicing the

Network

Introduction

Calculate sample size

Define sampling

procedure

Develop collection

instruments

Pretest

Define objective

Define focus

Identify target

population

Define diagnostic

tests

Conduct survey

Monitor implementation

Support service

Collect and enter

data

Data flow field to central

Check for completeness and accuracy

Validate and

analyse

Descriptive Analytical

Interpret Follow-up actionsFeedback to participants

Step 3 – Do it and learn!


Field application

IRANIAN NSP-SEROSURVEY TO ESTIMATE

FMD INFECTION LEVEL WHERE NON-

PURIFIED FMD VACCINE IS USED

J Emami, M McLaws, A Emami, R Ghaffari,

N Sedghi, N Rasouli, C Bartels

Field application

Implementing an

NSP-Ab Sero-survey:

Experiences from West Azerbaijan province of Iran


Field application


Country

Neighboring countries

Size

Human population: 80 million

Small scale farming : 21 million

of people

Dairy farms

Beef farms

Province

Neighboring countries

FMD focus area of

3-years project (EuFMD)

FMD control program

Iran West Azerbaijan

Field application

Objectives

1. To estimate prevalence of epi-units with indication of recent FMD infection

2. To identify putative risk factors

3. To use results in

targeted FMD control

4. To monitor impact of FMD

control program over time


Field application

Animal

Infected with FMD virus

SP antibodies

NSP antibodies

Vaccinated with purified vaccine

SP antibodies only

Vaccinated with

impure Vaccine

SP antibodies

NSP antibodies?

Background: FMD structural proteins (SP) and non-structural proteins (NSP)

42

Field application

ThereforeNSP serosurvey is an accepted way to measure

previous FMD infection, even in vaccinated populations, providing the vaccine is purified However, the vaccine used in Iran is locally

produced and impure. How does this affect the interpretation of NSP sero-survey results?

43

Field application

Materials & Methods I

2-stage sampling

Assumptions: 1. 35% epi units infected (+/- 5%, 95% confidence)

300 epi-units sampled randomly from a complete list from 4 production type

– 200 villages, 40 dairy farms, 30 beef farms,

30 farms with cattle and small ruminants

2. Within epi-unit: 10% animals infected

30 head of livestock within each epi-unit sampled

Sample youngstock (6-24 mo), NSP Ab is reflection of recent infection(0-2 vaccinations)


Field application

Materials & Methods II

All 17 districts

Questionnaire survey

– Animal

– Household (villages)

– Epi-unit characteristics

Provincial laboratory with trained staff, use PrioCheck NSP-antibody ELISA


Field application

Preparing for field

First Step

- Provincial manager of sero-survey selected and trained in Iran Veterinary Organization(IVO) under FAO- EuFMD Epidemiologists to implement sero-survey

-Preparing a preliminary questionnaire from previous experiences of FAO and EuFMD in different countries (specially Egypt) for Iran

-Sharing preliminary questionnaire with provincial experienced veterinarians and improve it many times

-Sharing and pretest and improve preliminary questionnaire with farmers

-Prepare second questionnaire that was ready to use in the field in pretest district(Salmas) in north part of province

-NSP sero-survey PC Practitioner Network 46

Field application

Sampling in the field


Field application

Pretest(Questionnaire and Sampling)

Salmas district


Field application

Questionnaire– Data – 3 Level – Animal level

Animal level Informationمورد خونگیری داممشخصات

districtpoldashtنام شهرستان کد واحد

code

3216012

9

epunitنام واحد اپیدمیولوژیک

nameoroj mohamad

row numberردیف

_ نام دامدار

farmer

name

شماره گوش

گاو در

صورت وجود

ear tag

number (if

exist)

) سن دام به ماه

ط خونگیری فق

تا 6از دامهای

ماهه انجام 24

age in( شود

months

نر )جنس دام

= ماده / 0=

1)sex(ma

le=0 /

1=female

)

سن دام هنگام

از شیر گیری

ageبه ماه

at

weaning

in months

آیا دام در این روستا یا دامداری

و بلی 0=خیر )متولد شده است؟

، بلی همین شهرستان1=همین واحد

, (3=، شهرستانهای دیگر 2=

yes No=0 in this epi-unit

yes=1, in this district =2 ,

other districts = 3

)نوع استفاده از دام

گوشتی/ 0=شیری

=1 )purpose

(dairy=0/beef=

1)

آیا به تب برفکی در یک

ت؟ سال گذشته مبتلا شده اس

( 0= خیر /1= بلی )

Clinical Signs of

FMD observed

(Y=1/N=0, if yes:

when?

WA_ poldasht_1 2404310نورالدین شجاعی

WA_ poldasht_22414300نورالدین شجاعی




WA_ poldasht_61214100محمود آقازاده




WA_ poldasht_102414300یونس آقازاده




Field application

Questionnaire– Data – 3 Level – Farmer level

Farmer level informationاطلاعات دامدار Farm /Houshold informationیا خانه ای که خونگیری می شود؟ ( شیری یا گوشتی )مشخصات دامداری

نام

شهرست

ان

Name

of

district

poldasht

کد واحد

epiunit

code

32160129نام واحد اپیدمیولوژیک

epiunit name oroj mohamad

ردیف

row

numb

er

نام دامدار

_

farmer

name

تاریخ نمونه

Dateبرداری

of Sampling

تعداد گاو

و گاومیش

موجود در

زمان

خونگیری

numbe

r of

cattle,

د و تعداد گوسفن

بز موجود در

زمان خونگیری

number

of,

_other

ruminants

کود یک سال گذشته

دامهای خود را چکار

خودم استفاده)کردید؟

، می 0=می کنم

= ، هر دو 1=فروشم

2 )Manure

treatment (Own

use=0 , SELL =1,

Both =2)

خرید و فروش دام های

ماه 12دامداری در

= ا بلی در روست) گذشته

، بلی در میدان دام 1

=، بلی سایر موارد 2=

( 0= ، خیر 3

Trading of

Animals in Last 12

monthes-No=0,

YES in this

village=1, in

animal market=2 ,

yes other places ,

no=3

آیا دام دارای چرای خارج

از خانه یا دامداری است؟

grazed outdoors خیر

1=بلی در همین واحد 0=

ا ، بلی در مرتع مشترک ب

2= روستای های همجوار

، ( 3=، بلی در سایر جاها

No=0,yes in this ep

uint=1 , common

pasture=2 other

villages=3 , other

places = 4

دام معمولا در کجا نگهداشته می

شود؟ همیشه داخل دامداری یا

، گاهی خانه و گاهی 0=خانه

، در 1=در نزدیکی روستا

( 2=مناطق دور از روستا

the animal is always

kept within the

compound (0), within

the epi-unit (1), or has

been outside the epi-

unit (2)

آیا علائم بیماری تب

برفکی در دامداری یا

خانه مورد خونگیری

ماه گذشته دیده 12در

Clinicalشده است؟

FMD signsin last

12 monthes

outbreak seen

(yes=1/no=0)

آیا علاوه بر گاو ،

گوسفند و بز هم در

خانه یا دامداری

نگاهداری می شود؟

0= ، خیر 1= بلی

If there are

sheep/goats in

the same

compound

yes=1 and No

=0

1نورالدین

شجاعی1390/04/0790012200

0

1390/04/076010200محمود آقازاده21

1390/04/0751000200یونس آقازاده31

1390/04/076001200رجابر پاشاپو40


Field application

Questionnaire – Data – 3 Level – Epiunit level

Ep unit level informationاطلاعات واحد اپیدمیولوژیک

نام

شهرست

ان

distric

t

name

نام واحد

Epiunit

Name

کد واحد

Epiunit

Code

علائم تب

برفکی در

ه یکسال گذشت

این واحد

گزارش شده

= بلی)است ؟

شته.تاریخ نو

0=خیر/ شود

Clinical

FMD

outbreak

seen

(yes= Dat

e should

inter /no=0)

تاریخ آخرین مایه

در کوبی تب برفکی

Lastواحد ؟

FMD

vaccination

date

ه تاریخ مای

ل کوبی راپ

در آخرین

فاز تب

برفکی؟

Last

Booster

Vaccin

ation

Date

ه تاریخ مایه کوبی ک

قبل از آخرین مایه

کوبی انجام شده

FMDاست؟

vaccination

date before

last

vaccination

Type ofنوع واحد

Epiunit ، 1=روستا )

، 2= گاوداری شیری

گروه گاوداری پرواری

ام و پرواری با شیری تو

، گروه دامداری 3=

د های دارای گاو و گوسفن

vilage=1( 4= وبز

, dairy farm=2 ,

beef farms =3 ,

smal ruminants=4

تعداد گاو و

گاومیش در

زمان

خونگیری

Number of

cattle and

calves

فاصله از

دان نزدیکترین می

دام به کیلومتر

distance to

closest

animal

market (in

km)

ند تعداد گوسف

و بز در زمان

خونگیری

Number

of sheep

and goat

نام نوع

اده واکسن استف

شده در این

تترا ) واحد

، 0= والان

= منووالان

1)type of

vaccine

used

0=Monov

alent=1/T

etravalent

نام شرکت

سازنده

واکسن

استفاده شده

در این واحد

= رازی )

= مریال / 0

1 )

0=Merial

=1/Razi

poldashtoroj

mohamad32160129

در گوسفند دیده

1389/05/17شده1389/12/031389/10/21111225520

0

1

1


Field application

Combining Field survey data with Lab Reported Data


Field application

Implementing of survey in the field

Second Step

-A coordination session with all colleagues(provincial and district representatives) in this survey and explanation them all details

-Holding other coordination sessions in every district veterinary office among field groups

-Starting of questionnaire field survey and blood sampling in the same time in different epi-units in pre-defined dates

-All blood samples transferred to district veterinary offices and sera prepared in same day

-All sera labeled and checked very carefully due to hemolysis (often 2-4 more sera sampled)

-All samples (with questionnaires) were sent to provincial veterinary office in 24-48 under cold chain(2-8°C)

-


Field application

Lab test and combine data

Third Step

-There was a responsible man in provincial veterinary office to take over samples and questionnaires and check them

-All samples sent to laboratory of provincial veterinary office and stored in proper temperature

-All samples were tested with a trained man with NSP test kits(Priocheck)

-All lab results were sent to survey manager and combined with field data and all missed data revised with district representatives.


Field application

Providing final dataset

Fourth Step

-All epi-units data combined together in every district

-All district data combined together

-One final data(one excel file including 3 level data(epi-unit-farmer-animal) developed

-Final file was sent to FAO-EuFMD epidemiologist

-All data checked many times to delete errors and correct missed data

-Final dataset prepared and analyzed by epidemiologist

-


Field application

Descriptive results


• 281 epi units

• 1798 different owners

• 8378 animals were sampled

Po

sitiv

e

Ne

ga

tive

• Manufacturer recommended 50%

inhibition as cut off

• Graph shows distribution of titers

• 53.7% of all samples positive for

NSP-Ab

• 279 epi-units with 1 or more

seropositive cattle (˃99% positive epi-units)

• 6 epi-units with all 30 cattle

seropositive

50 % cut

off as

reference

line

Field application

540 Samples retested at lab in Brescia – ItalyIstituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna

(IZSLER): FAO collaborating laboratory for FMD NSP ELISA

Cedi test

ELISA

IZSLER ELISA

Positive Negative Total

Positive 227 61 288

Negative 18 234 252

Total 245 295 54057

Compared with IZSLER Elisa

• Agreement 85%

• Kappa 0.71

- Rel. Se. 92.6%

- Rel. Sp. 79.3%

- Higher cut off (60-75% inhibition),

higher agreement(90%)

Higher

cut off

Field application

Thank you for your

attention!


Field application


Field application

Available on our PC Practitioner site areSupporting documentation and publications


Any questions?





manager PCP


Objective Field

application


and result

interpretation

Jenny


Practicing the

Network

Introductions

IAH

FMD antibody detectionObjectives

– confirmation of infection, particularly subclinical infection– retrospective diagnosis when epithelium not available e.g. after

resolution of acute infection– import/export– during epidemiological surveys

Screening by ELISA– rapid– Sensitive

Confirmation by VNT– 'Gold standard' for international trade

Laboratory aspects

Which Antibodies can be found in animals that have been in contact with FMDV ??

Which information do they provide us ?

Which tests fit for different purposes ?

FMD virus structure : mosaic of many different antigensStructural Proteins = SP Non Structural Proteins = NSP

FMD Non-structural and Structural Proteins

Laboratory aspects

+ -

- -

+ +Serological assays Ab anti-SP Ab anti-NSP

vaccinated

naive

infected

Laboratory aspects

O A C Asia 1 SAT 1 SAT 2 SAT 3

anti-SP Antibodies serotype-specificSeven different assays, one for each FMD virus type

anti-NSP antibodies identical for 7 serotypesO / A / C / Asia 1 / SAT 1 / SAT 2 / SAT 3NSP tests A unique assay for all FMD virus types

Laboratory aspects

NSP antibody detection ELISAs1. Test principles

• Commercially available test kits

• Indirect ELISAs versus blocking versus competition ELISAs

• Advantages and disadvantages

2. Test characteristics• Test validation

• Technical information manufacturer

• Independent/peer reviewed information

• Sensitivity (in vaccinated and in non vaccinated animals)

• Specificity (in vaccinated and in non vaccinated animals)

• Repeatability and reproducibility

• Positive and negative predictive values

3. Interpretation of test results, validity of data, pitfalls


Laboratory aspects

Available on our PC Practitioners’ site areExercises


Exercises available


NSP Sero-survey

Exercise 1

Estimating individual animal prevalence, herd prevalence and within-

herd prevalence.

In the datasheet “NSP sero-survey_exercise 1” you find the result of

5000 samples collected as part of the NSP sero-survey explained by Dr

Javad Emami, Urmia, Iran.

In this dataset we have copied information on

The questions to answer are the following:

1) What is the estimated animal prevalence, and the 95%

confidence interval?

Available on our PC Practitioners’ site areExercises

Exercises available

In summary

During this session, we discussed

• NSP sero-survey complements information about outbreak notifications

• It allows for assessing the extent of virus circulation and putative risk factors for infection

• A proper design makes inference of results possible• use in developing a Risk-based strategy

• tool to monitor the impact of such strategy

• Implementation and organisation• Develop procedures in consultation with people involved in particular with

fieldstaff responsible for bleeding and questionnaire as it will not be

possible to repeat it

• Consider entry of data be performed centrally to safeguard consistency

• Perform data validation thoroughly and double check with enumerators

• Laboratory aspects


Summary





manager PCP


Objective Field

application


and result

interpretation

Jenny


Practicing the

Network


Getting started

https://eufmd.rvc.ac.uk

Look out for new

features!


Getting started

Track your progress with course completion

Complete your profile

Discussion forum:• Ask and answer questions• Notification of new

resources

Select training and resources that meet your needs

Online quizzes allow us to track your progress

Receive recognition for the training you undertake

Each network activity is associated with credits, 1 credit = 1 hour’s training time

Recognition for number of credits accumulated

– Certificate

– Bronze, Silver and Gold levels

Getting started

To get started:

E-mail [email protected] with:

Your full name

Location

Brief background

OR visit https://eufmd.rvc.ac.uk and follow links from the homepage.

Share this opportunity with your colleagues


mailto:[email protected]

https://eufmd.rvc.ac.uk

Any questions?


progressive control practitioners’ network conducting an

Documents