3.1 bTB history in the park
From the investigation of official records, we delineated a timeline of
all TB cases that culminated in animal deaths from 2003 to 2018 in the
safari park (Figure 2). In brief, from 2003 to 2015, at least 16
animals, from 8 different species, died or were humanely euthanized due
to TB. Except for two llamas in 2012, TB was only diagnosed based on
necropsy findings and Ziehl-Neelsen staining of tissue samples (Figure
2). It is possible to observe an increase in the number of cases
starting around 2005, which coincides with management changes in the
park (personal communication of a previous employee). These changes
resulted in overpopulation (particularly of deer) and poor feeding
practices. In 2013, due to widespread TB, other sanitary problems and
selling of deer to properties in different Brazilian states, the
official veterinary service, through a court order, demanded the closure
of the park to visitations and halting of animal trade. From 2013
onwards, many tuberculin skin tests were performed in deer, cattle and
buffalo. However, as the PNCEBT solely covers the latter two species,
only these were mandatorily culled. The deer tested positive by TST in
2013, 2014 and 2015, and recommendations to contain the outbreak were
made to the park. In 2018, after the official veterinary service noted
the park did not follow through with the recommendations, they ordered
depopulation of the park deer based on interstate trade of potentially
infected animals. Tissue from necropsy of the two llamas and the culled
deer were the only animal samples ever subjected to M. bovisculture. A more complete history of all TB cases of the park is
described in Supplementary material.