Foot and mouth disease by dr. bishor ibrahim

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FOOT-AND-MOUTH DISEASE
IMPLEMENTING AN EFFECTIVE DISEASE CONTROL PROGRAMS IN AFRICA
AND ROLE OF RAPID POINT OF CARE TESTING
V I Bishor
CEO & Managing Director
ubio Biotechnology Systems Pvt. Ltd
Biotechnology Incubation center, Kinfra Hitech Park, Kalamassery, Kochi
2014

Proportions of FMD Virus
Serotypes Isolated by the
WRLFMD
64%
7%
23%
4% 2%
O
A
C
SAT1
SAT2
SAT3
ASIA1
(n=311)

Foot and Mouth Disease Control in
Africa
• The vaccination programs has led to significant reduction in the
occurrence of FMD.
• Continuous monitoring and re vaccinations have kept the disease away‑
from many counties for years altogether.
• Recent our breaks : factors
– Increased movement of animals
– Introduction of new dairy animals from infected areas into the non infected
area,
– Lack of continuous disease monitoring among livestock populations in the
state that slows down outbreak detection, emergency response and epidemic
prevention.
The FMD control program has to be refined by incorporating control measures that
consider these new factors, so that we sustain and improve the FMD disease status
across the state.

FMD Disease control in Africa :
Proposed measures.
1. Clinical Surveillance
2. Migration Control and Monitoring
3. Control of cross-border livestock trade
4. Early detection measures and epidemic
control

Clinical surveillance
1. Regular random sampling of serum from across
the state
2. Testing the sample for the presence of infection
3. Identification of infected carriers or new
infections
4. Quarantine and control measures including
emergency vaccination

Migration Control and Monitoring
• Purchase of new livestock animals under various
schemes from other Provinces/countries
– While this is a welcome development from a
demographical point of view, it has a serious negative
impact on disease control programs.
– Most areas adjoining one province have higher incidence
of FMD with less developed disease control systems, there
is a high chance that FMD carriers may be imported
through inter-province purchase of new dairy animals.
• A program where every new dairy animal imported
into the state under government schemes has to be
tested and certified free of FMD before the
purchase is made has to be considered.

Control of Cross-Border livestock
trade.
• Slaughter animals imported through our border check-posts is huge.
• spend just a few hours in the state before they are slaughtered: so risk of
infections from these animals lesser in a general sense.
• However, this does not hold for FMD, as the disease is so contagious that
even animals that live near the road through which infected animals are
transported are at risk of infection.
• A screening program at border check-posts to screen and exclude infected
animals has to be implemented
• Ideally, every animal should be checked for infection and the physical or
financial responsibility to dispose of the infected animal should be fixed
on the importer.
• The tagging system at the check-posts should be extended to retain test
data and associate it with individual animals.
• A good vigilance program that randomly screens animals at slaughter-
houses can then ensure accountability and assure efficacy of the
screening program by cross-checking results from the check-post.

Early detection measures and
epidemic control
• The most important step in FMD epidemic control is to
quickly establish an infection perimeter.
• All susceptible animals in infected and adjoining areas and
areas with high risk of contagion be screened to identify early
infections whenever an epidemic is reported.
• This data should be used to establish the infection perimeter
quickly and accurately.
• This perimeter should then be used to implement quarantine
measures in the infected area, and emergency vaccination
should be performed around the perimeter to block spread,
as is done today.
• Once the epidemic is over, all the animals in the area should
be screened again for the presence of carriers so that follow-
up outbreaks do not occur.

FMD control measures:
Implementation Challenges.
• A clinical surveillance scheme that aims to detect silent FMD carriers cannot rely
on clinical examination, and would require laboratory diagnosis.
– Laboratory facility is limited .
– Difficulty in sample management: need additional infrastructure and manpower
• Migration control and monitoring programs that require ‘FMD-free’ certification of
dairy animals before purchase would need a testing method, which would allow
the veterinary doctor to test the animal at the point of purchase.
• Similar challenges also exist for check-post screening.
– A typical animal carriage vehicle will spend 30-45 minutes at the check-post for animal
tagging and clearance. It is impossible to screen all the animals in the carriage within
this time using conventional methods. Serum collection and off-site lab diagnosis is not
an option here, as infected animals would have carried the infection into the state by
the time the results are available.
• In the case of disease screening to establish infection perimeters, quick results are
very important
• In all these measures, it is important to make sure that vaccinated, non-infected
animals

Rapid FMD NSP Testing
All the FMD control measures outlined above involve fast, reliable, de-centralized
screening of the disease.
Requirements for the ideal diagnostic technique
– Quick results should available in just a few minutes.
– Should require no instrumentation, instruments should be portable if present.
– Should be easy to use.
– Should allow decentralized implementation (should not require serum transport)
– Should require no, or low, capital expenditure.
– Should be able to execute the test and read result in the field itself.
– Should not require refrigerated storage.
– Should differentiate between vaccinated and infected animals.
The only diagnostic technique available today that satisfies these requirements for
FMD diagnosis is the FMD Non-structural-protein (NSP) rapid lateral flow assay.

Practical issues of NSP testing
•The 3ABC polyprotein is concluded to be the single most reliable indicator of infection
(Concerted Action CT93 0909, 1998).
•The 3ABC protein is not serotype specific. A positive result of NSP test indicates an
infection with the FMD virus, irrespective of the serotype.
• This not contain any infectious material and therefore does not, contrary to a VN test,
have to be performed in high containment.
• In case of an outbreak large numbers of samples can be processed in the field.
• Waiting time for the test is minimal, since the test provides results within minutes.
• The NSP marker-test is recommended for herd diagnosis rather than for individual
diagnosis.

EU FMD Committee Recommendation
• Using conventional diagnostic techniques
– Not possible to distinguish FMD infected animals from purely vaccinated
animals
– In vaccinated areas, have limited possibilities to monitor virus presence or
circulation
• NSP-free or NSP-reduced vaccines in combination with a NSP-test lead to a so-
called marker-system
– Polyprotein Nonstructural Protein(NSP) 3ABC is the single most reliable
indicator of infection
– Modern, state of the art-vaccines are based upon highly purified antigens,
which are free from NSP of the FMD virus.
– Animals, vaccinated with highly purified( NSP-free vaccines), produce
antibodies against the Structural Proteins (SP) but not against NSP

OIE Recommendation (2006)
Schematic representation of laboratory tests for determining evidence of
FMDV infection through or following serological surveys

Vaccine Quality control
Ideal FMD vaccine….
• Safe and efficient (FMD control)
• Fast & long lasting clinical and virological protection
• High potency (minimum number of dose to get protection)
• DIVA test (distinction between vaccinated and infected animals): means vaccine
should be free from NSP
• Storage (room temperature)
• Economical issue (cheap)
OIE and EU recommends the implementation of additional purification steps in the manufacturing process to
remove NSP.
EU allows only NSP free vaccines for effective screening and surveillance programs.(EMEA/CVMP/775/02-FINAL)

Differentiation Infected and
Vaccinated Animal
Results serology
Conventional
test(LPB,VN)
FMDV NSP
test
Vaccinated Infected + +
Vaccinated Not infected + -
Not vaccinated Infected + +
Not vaccinated Not infected - -

Immune response of infected and vaccinated animals
(cattle)
+ve
-ve
Result
Days after vaccination or infection
4 8 12 16
SP antibodies ( Infected)
SP antibodies (Vaccinated)
NSP antibodies ( Infected )
NSP antibodies (Vaccinated)

Assay Overview and Usage
• Rapid FMD NSP tests uses recombinant FMD 3ABC
antigen and to detect the disease.
• FMD 3ABC antigen on test line
• Anti-NSP antibody in serum react
with colloidal gold conjugated detection antibody on
conjugate pad
• This labeled antigen-antibody complex is captured by
the test area forming a red line.
• Test is suitable for Bovine, Ovine, Caprine and swine.

Test procedure NEGATIVE
Only control
band visible
POSITIVE
Control and
test bands
visible
INVALID
No control
line, test is
invalid
Collect whole blood or Serum
Separate serum if testing in a lab
Use whole blood if testing in Field
Take out the test card from
the aluminium foil pouch
and place it on a horizontal
surface. Add 2µl serum or
5 µl Whole Blood into
sample hole ‘S’
Take 2µl serum or
5 µl Whole Blood
Add 2 drops of buffer
provided with the kit
Read the results in 10-15
minutes
DO NOT READ RESULTS AFTER 20 MINUTES

Recommendation of Africa
• Post vaccination sero-surveillance for NSP
antibodies.
• Border control of slaughter animals.
• Screening of animals brought for dairy purpose.

Program flow chart
for Screening Dairy
Animals

Program Flow
Chart for Screening
Slaughter Animals
The practical screening scenario
40 animals/Truck
With 3 staff (veterinary doctor and/or livestock
inspectors)
the total time for one vehicle: 57 minutes.
In addition to inspection, the check-post
authority will also note animal identification
numbers on the issued certificate and on
individual animals.

Vigilance program

Thank you
ubiquitous . biology
www.ubio.in

Foot and mouth disease by dr. bishor ibrahim

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