Distribution of Taenia saginata cysts by muscle group in naturally infected cattle in Tanzania

Abstract

The distribution of Taenia saginata cysts among organs and muscle groups was determined by slicing the heart, masseters, liver and muscles of the half carcass of 21 naturally infected Zebu cattle from Morogoro abattoir, Tanzania. The carcasses harboured from 1 to 310 cysts. In the muscle groups, normally considered predilection sites, the heart and Musculus triceps brachii harboured the highest proportions of cysts (mean 17% and 12%, respectively, of the total cysts in the carcass) while lower proportions were found in the tongue, masseters and psoas muscles (3%, 2% and 5%, respectively). A relatively high proportion was found in the liver (10%). Relative cyst density was calculated for the different muscle groups by dividing the mean proportion of total weight of the muscle group into the mean proportion of cysts located in that site. The cysticerci in the examined tissues were found in the following order of relative density: heart (10.4), tongue (2.1), masseters (1.9), M. triceps brachii (1.7), liver (1.4), M. psoas (1.3), hindlimb muscles (0.71), trunk muscles (0.67), and other forelimb muscles (0.32). The proportion of cysts expected to be found at the surfaces exposed by visual examination or incision at meat inspection was calculated using an indirect method, which incorporated the area revealed by incision and visual inspection of an organ and the proportion of cysts located in the particular organ. It was estimated that 17% of the cysts would be located at an inspected site if the regulations were followed carefully. Based on cyst density, we recommend that the heart should be paid particular attention during meat inspection.