Herd tuberculosis in England, Wales, and Scotland
In Wales incidence and prevalence have decreased. Incidence and prevalence are highest in the High Risk Area of England (HRA) and lowest in the Low Risk Area of England (LRA) and in Scotland.
In England both the herd incidence rate and herd prevalence have increased between the last two 12-month periods and have stayed relatively stable in Scotland. In Wales incidence and prevalence have decreased.
Incidence and prevalence are highest in the High Risk Area of England (HRA) and lowest in the Low Risk Area of England (LRA) and in Scotland.
Between the 12 months ending June 2016 and the previous 12 month period, there was a decrease in the number of new TB incidents in the HRA and Wales.
In Scotland, the Edge Risk Area of England (ERA) and the LRA there was an increase in the number of incidents.
Prevalence at end June 2016 (the percentage of herds which were not Officially TB Free (OTF) due to a TB incident) increased in the HRA and ERA of England and decreased in Wales.
In the LRA and Scotland prevalence remained unchanged from June 2015. In Scotland the number of non-OTF herds is very low and approximately 45% of cattle herds are now exempt from routine TB surveillance testing.
In Scotland and the LRA, there are proportionately more false positive results to the tuberculin skin test than elsewhere in GB. Consequently it is also important to consider the number of new TB incidents where OTF status is withdrawn (OTFW) following confirmation of TB by postmortem examination or laboratory culture of tissue samples.
During the 12 months ending June 2016 there were 43 such incidents in the LRA, the same number as for the previous 12 months.
In Scotland there were 11 OTFW incidents in the period ending June 2016 and 8 in the 12 months to end June 2015. The OTFW incidence rate in the LRA was 0.3 breakdowns per 100 herd-years at risk in both periods.
In Scotland the OTFW incidence rate of breakdowns per 100 herd-years was 0.1 in both periods. ■