Mycobacterial coinfection and persisting bovine tuberculosis—Has the time arrived for a policy review?

Bovine tuberculosis (BTb) is mainly a disease of cattle, although it continues to infect human populations across the world. Operation of a test and slaughter plan in Iran since 1981 has lowered the frequency of BTb from >5% to <0.14% at the national scale. In 2015, unusual uncontrollable epidemics of BTb were detected in two cattle farms in municipal suburbs of Qazvin and Isfahan. These farms had a tuberculin-test-certified record of BTb-free status for the past 5 consecutive years, with no new cattle registered with either of the two herds during this time period. Routine tuberculination of the bovids in 2015 resulted in the detection of tuberculin-positive animals that were subsequently removed from the herds. Serial tuberculin tests improved the situation, as new reactors were found each time. The aim of this research is based on isolation and identification of Mycobacterium from infected animals in both farms.