INTRODUCTION
Bovine tuberculosis (bTB) is a chronic disease, caused primarily byM. bovis , affecting cattle, other domesticated animals, certain
wildlife species, non-human primates, and humans.1-3Cattle can be infected at any age, but tubercle lesion development and
subsequent clinical signs may appear at a later stages. Calves can be
born with tuberculosis congenitally when infected with M. boviseither via the umbilical vein from an infected genital tract of the dam,
from the infected placenta, or from infected amniotic
fluid.4 After birth, neonates can also be infected
even at an early stages following delivery, mainly by inhaling infected
droplets and/ or by ingesting raw milk or colostrum from infected cows.
Other routes of infection such as cutaneous, though not common, are
still important in situations where the prevalence of bTB is
high.5 As the course of the disease is slow compared
to many other infectious diseases, infected animals can spread bTB to
other herd mates and newborns before it begins to manifest clinical
signs. The transmission rate may be faster at late stages of infection
as the number of organisms being shed is larger in this
stage.1
The observation of characteristic tubercle lesions in the lungs of a
three weeks old male calf led us to raise questions like ‘how the calf
could get the infection?’ and ‘how fast is the disease progression under
natural infection?’. In order to get answers to these questions, further
investigation was made and this case report was compiled from the
pathological and molecular investigations conducted for the diagnosis of
the case.