TY - JOUR
T1 - Quantitative genetic analysis of the bTB diagnostic single intradermal comparative cervical test (SICCT)
AU - Tsairidou, S
AU - Brotherstone, S
AU - Coffey, MP
AU - Bishop, SC
AU - Woolliams, JA
N1 - 1026356
PY - 2016/11/24
Y1 - 2016/11/24
N2 - Background: Bovine tuberculosis (bTB) is a disease of significant economic importance and is a persistent animal
health problem with implications for public health worldwide. Control of bTB in the UK has relied on diagnosis
through the single intradermal comparative cervical test (SICCT). However, limitations in the sensitivity of this test
hinder successful eradication and the control of bTB remains a major challenge. Genetic selection for cattle that are
more resistant to bTB infection can assist in bTB control. The aim of this study was to conduct a quantitative genetic
analysis of SICCT measurements collected during bTB herd testing. Genetic selection for bTB resistance will be
partially informed by SICCT-based diagnosis; therefore it is important to know whether, in addition to increasing bTB
resistance, this might also alter genetically the epidemiological characteristics of SICCT.
Results: Our main findings are that: (1) the SICCT test is robust at the genetic level, since its hierarchy and comparative
nature provide substantial protection against random genetic changes that arise from genetic drift and from
correlated responses among its components due to either natural or artificial selection; (2) the comparative nature of
SICCT provides effective control for initial skin thickness and age-dependent differences; and (3) continuous variation
in SICCT is only lowly heritable and has a weak correlation with SICCT positivity among healthy animals which was not
significantly different from zero (P > 0.05). These emerging results demonstrate that genetic selection for bTB resistance
is unlikely to change the probability of correctly identifying non-infected animals, i.e. the test’s specificity, while
reducing the overall number of cases.
Conclusions: This study cannot exclude all theoretical risks from selection on resistance to bTB infection but the role
of SICCT in disease control is unlikely to be rapidly undermined, with any adverse correlated responses expected to be
weak and slow, which allow them to be monitored and managed.
AB - Background: Bovine tuberculosis (bTB) is a disease of significant economic importance and is a persistent animal
health problem with implications for public health worldwide. Control of bTB in the UK has relied on diagnosis
through the single intradermal comparative cervical test (SICCT). However, limitations in the sensitivity of this test
hinder successful eradication and the control of bTB remains a major challenge. Genetic selection for cattle that are
more resistant to bTB infection can assist in bTB control. The aim of this study was to conduct a quantitative genetic
analysis of SICCT measurements collected during bTB herd testing. Genetic selection for bTB resistance will be
partially informed by SICCT-based diagnosis; therefore it is important to know whether, in addition to increasing bTB
resistance, this might also alter genetically the epidemiological characteristics of SICCT.
Results: Our main findings are that: (1) the SICCT test is robust at the genetic level, since its hierarchy and comparative
nature provide substantial protection against random genetic changes that arise from genetic drift and from
correlated responses among its components due to either natural or artificial selection; (2) the comparative nature of
SICCT provides effective control for initial skin thickness and age-dependent differences; and (3) continuous variation
in SICCT is only lowly heritable and has a weak correlation with SICCT positivity among healthy animals which was not
significantly different from zero (P > 0.05). These emerging results demonstrate that genetic selection for bTB resistance
is unlikely to change the probability of correctly identifying non-infected animals, i.e. the test’s specificity, while
reducing the overall number of cases.
Conclusions: This study cannot exclude all theoretical risks from selection on resistance to bTB infection but the role
of SICCT in disease control is unlikely to be rapidly undermined, with any adverse correlated responses expected to be
weak and slow, which allow them to be monitored and managed.
U2 - 10.1186/s12711-016-0264-3
DO - 10.1186/s12711-016-0264-3
M3 - Article
SN - 0999-193X
VL - 48
JO - Genetics Selection Evolution
JF - Genetics Selection Evolution
M1 - 90
ER -