Abstract:
Taenia saginata is a zoonotic tapeworm of humans with bovines as its intermediate host (bovine cysticercosis).
Traditional meat inspection is the main measure to identify the larval stage in carcasses and prevent human
infection, but has a notoriously low sensitivity, especially in low prevalence settings. The legislation in multiple
African countries mandates an incision in both triceps brachii muscles to detect the parasite as part of the normal
post-mortem inspection, but this has an economic cost and is not universally mandated in other countries. The
primary aim of this study was to investigate the epidemiology of bovine cysticercosis at an export abattoir in
South Africa and determine the validity and cost of the triceps incision. Risk factors were investigated, and the
effect of additional heart incisions on the current inspection. Four incisions were made into the heart in addition
to the normal post-mortem inspection in 3353 carcasses. The proportion of positive animals with and without the
cardiac and triceps incisions were compared using McNemar’s chi-square tests, while risk factors were assessed
using binary logistic regression. The economic impact of the triceps incision was estimated using a stochastic
economic cost model. Thirty-three positive carcasses were identified for an apparent prevalence of 0.98 % (95 %
CI, 0.69–1.36 %), while the true prevalence was estimated at 6.6 % (95 %CI, 4.3–8.8 %). All cysts were
confirmed as T. saginata on histopathology with 70 % (95 %CI, 53–83 %) located in the heart. The additional
cardiac incisions resulted in the detection of significantly more cases compared to the normal inspection method
prevalence of 0.72 % (95 %CI, 0.47–1.05 %; P < 0.001). The apparent prevalence of T. saginata when omitting
the triceps incision was not significantly lower compared to the prevalence when included in the inspection (P =
0.480). External feedlots (OR= 4.17, 95 %CI: 2.04–8.54, P < 0.001) and older animals (OR=3.90, 95 %CI:
1.17–13.03, P = 0.027) were associated with a positive detection. The current median annual financial cost to
the food business operator from the triceps incision was estimated at $30387 (95 %CI: $0-$130696), with the
proportion of deboned meat exported identified as the most important factor affecting cost (Spearman’s
rho=0.853). The identification of risk factors could aid in the development of a more effective risk-based inspection
system. The current inspection should be modified to increase exposure of the heart and remove the
triceps incisions. The latter should especially be considered given the minimal contribution to cysticercosis
detection, the unsupported requirement for its inclusion specifically in Africa, and its economic impact, especially
as beef exports increase.
