EuFMD OS20 open session

1. A REVIEW OF THE WRLFMD’S
PROFICIENCY TESTING SCHEME
Introduction
Each year the World Reference Laboratory for foot-and-
mouth disease (WRLFMD) invites international and
national laboratories to participate in a proficiency testing
scheme (PTS).
Virological and serological panels are accompanied by
scenarios that assess both testing algorithms and case
interpretation. The methods to be used are not specified
and need to be determined by each laboratory based on
which diagnostic tests they have available.
The latest PTSs, Phase XXXI (2018/2019) and Phase XXXII
(2019/2020) had similar formats. However, for Phase
XXXII, the Progressive Control Pathway (PCP) status of
the country was used to define the minimum expected
capability of its participating laboratories.
The PCP status was also included with retrospective data
from the last 10 years to assess if there is an association
between a laboratory’s PTS performance and its host
country PCP status.
Description of Panels
An example of testing scenarios are
highlighted below.
Virological Panel
A veterinarian has visited a dairy farm and noticed
vesicular lesions on the mouth and feet of two
cattle that have recently been introduced into the
herd. The veterinarian was able to take epithelial
tissue samples from both of these animals and
these have now been sent to your laboratory for
testing.
Serological Panel
In response to the outbreak described in Panel 1,
animals have been vaccinated, but it is unclear
whether all animals located on farms in the
vaccinated zone have been correctly vaccinated.
Four serum samples have been collected from 6-
12 months old cattle on a farm in the region where
vaccination has been used for the first time, about
a month ago.
Participants were asked to test the samples
using relevant FMD virological and serological
assays. In addition, they were asked the
following for each panel:
Panel 1: Virus Detection
If FMDV positive samples were detected define
the serotype and, if possible, further characterise
any FMD viruses that were detected.
Panel 2: Serological Testing
Determine if the animals have been vaccinated
without signs of infection. If specific antibodies are
detected, indicate whether the immune responses
are adequate (protective), and what assumptions
and further enquiries or investigations could be
made to understand this better.
Results
Phase XXXI - seventy laboratories participated
(Figure 1).
Virological Panel
There appeared to be an increase in the number
of false positives observed in both rRT-PCR and
antigen ELISA. Laboratories should review their
current methods to ensure that they address good
working practices and that proper controls are in
place to highlight possible contamination issues.
Serological Panel
The overall ability to identify samples as positive
for FMDV is improving year upon year; however,
there are still difficulties in identifying the serotype
that is present in the sample.
Laboratories are switching from in-house
serological ELISAs to commercially available kits.
In addition, more kits are being added to their
repertoire.
Phase XXXII – ongoing
75 laboratories and commercial companies
have been invited. 33 of these are funded by
EUFMD.
31 participants have received their shipment
and 22 of these have returned their results.
Additional shipments are being organised but
this has been delayed due to COVID-19 closure
and flight restrictions.
Future
Initial feedback for Phase XXXII will be
distributed in early 2021.
A new PTS (Phase XXXIII) will be initiated in
mid-2021
A more detailed analysis will be performed
within the next year on the association between
a laboratory’s PTS performance and its
country’s PCP level. It is envisaged that key
results will be integrated as part of the feedback
sent to each country regarding their proficiency
test results.
FMD Reference Laboratory
Figure 1 Countries which participated in Phase XXXI
Preliminary analysis suggests that some
countries with PCP status 1 and 2 have the
laboratory capability to be in a higher PCP
status (Figure 2).
From the laboratory requirements component,
the main limitation for most countries to
advance their PCP status is the lack of
characterising the samples beyond the
serotype (i.e. the ability to determine the
topotype/lineage of the sample).
Ag ELISA and/or rRT-PCR NSP ELISA SP ELISA
PCP1
0 2 4 6 8 10
PCP2
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
0 2 4 6 8 10
0 2 4 6 8 10
0 2 4 6 8 10
0 2 4 6 8 10
0 2 4 6 8 10
Figure 2 - Each column represents a diagnostic test, while each row is either PCP 1 or PCP 2. The x-axis is the
number of laboratories that participated in the PTS each year (y-axis). The solid purple bars are the number of
laboratories that have the assay available and the outlined purple boxes signify the laboratories without this assay
availability. The minimum requirement for a country in PCP 1 is Ag ELISA (and/or rRT-PCR) and NSP ELISA. The
minimum requirement for a country in PCP 2 is Ag ELISA (and/or rRT-PCR), NSP ELISA and SP ELISA.
Participant
Did not participate
Legend