Some quantitative characters used in the identification of Taenia hydatigena, T. ovis, T. pisiformis and T. multiceps adult worms, and T. multiceps metacestodes

Abstract

AbstractMeasurements were made of gravid worm lengths, scolex diameter, rostellum diameter, sucker diameter, and large and small rostellar hooks of adult Taenia hydatigena, T. multiceps, T. ovis and T. pisiformis obtained from dogs in North Wales. Values recorded agreed closely with published values. None of these characters could be used to differentiate reliably between the species except that, of the worms examined, those with large rostellar hooks greater than 228 μim were T. pisiformis and those with large hooks less than 168 μm were T. multiceps. The range of hook lengths of the different species overlapped considerably.Reliable identification required examination of mature proglottis morphology of specimens which were relaxed before fixation. Relaxed mature proglottides often showed a characteristic shape.Lengths of rostellar hooks of scolices from T. multiceps coenuri followed the same frequency distribution as adult worm hooks. A strong correlation was shown between coenurus volume and the number of scolices on the coenurus membrane, with a poor correlation between coenurus age and volume.