1 Risk of rabies introduction by non-commercial movement of pets The EFSA Journal (2006) 436 1-54, ”Assessment of the risk of rabies introduction into the UK, Ireland, Sweden, Malta, as a consequence of abandoning the serological test measuring protective antibodies to rabies” P. Have, L. Alban, L.T. Berndtsson, F. Cliquet, P. Hostnik, S.C. Rodeia and M. Sanaa
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1 Risk of rabies introduction by non-commercial movement of pets The EFSA Journal (2006) 436 1-54, Assessment of the risk of rabies introduction into the.
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Risk of rabies introduction by non-commercial movement of pets
The EFSA Journal (2006) 436 1-54, ”Assessment of the risk of rabies introduction into the UK, Ireland, Sweden, Malta, as a consequence of abandoning the serological test measuring protective antibodies to rabies”
P. Have, L. Alban, L.T. Berndtsson, F. Cliquet, P. Hostnik, S.C. Rodeia and M. Sanaa
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Current legislation
• Regulation (EC) No 998/2003– valid anti-rabies vaccination– waiting time of at least 21 days (COM
2005/91/EC)– derogations for UK, Ireland, Sweden and Malta
to maintain serological test– review of derogations at the end of transitory
period of 5 years following receipt of a scientific opinion of EFSA
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EFSA mandate
• Commission requested EFSA to issue a scientific opinion on the risk assessment of rabies introduction into Ireland, the UK, Sweden and Malta, as a consequence of abandoning the serological test for antibody titration for rabies
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Mandate cont’
• To what extent the abandoning of the individual serological test for neutralising rabies-antibodies titration could be envisaged without increasing the risk
• If the need to maintain the serological test is scientifically justified, what is the regime to be considered as giving equivalent assurance
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Approach
• Quantitative risk assessment based on
– prevalence of rabies in the country of origin in pets
– distribution of incubation periods of rabies– efficiency of establishing protective immunity
by vaccination– specificity of the neutralization test for rabies
(RFFIT or FAVN)– length of the waiting period
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Model parameters
Prevalence (P)– estimated from annual incidence data by
assuming a mean incubation time of 38 days– pet population size estimated from 1.0 dog and
1.1 cats per 10 people
P = incidence*38/(population at risk*365)
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Model parameters
• distribution of incubation periods– Dogs: 1 week to several
months– Cats: 9 days to 6
months
• described by a log-normal distribution with mean 38 days
0 50 100 150 200
0.0
00
0.0
05
0.0
10
0.0
15
0.0
20
0.0
25
days
fun
ctio
n(x
) d
lno
rm(x
, me
an
log
= 3
.37
, sd
log
= 0
.75
) (x
)
Incubation period
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Model parameters
Efficiency of vaccination (Ev)– assessed indirectly by measuring the antibody
response– measured after first, single vaccination– absence of antibodies not always associated
with loss of protection – interval between vaccination and testing major
determinant– Ev of 98% used tentatively in this study
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Model parameters
Test specificity (Sp)– determines whether truly antibody-negative
individuals are correctly assigned as such or whether some individuals are classified as false positive
– FAVN test more specific than RFFIT– a tentative value of 99% is used here
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Model parameters
• Length of waiting period (t)– Measured from time of vaccination
– t will determine the residual prevalence Pa of animals incubating rabies due to pre-vaccination exposure