Case #261 – October, 2009

A Pathology laboratory in Australia received proglottids and eggs of a cestode that were recovered from the stool of a young female patient who had been living in Africa. The only other information given was that the patient had close contact with monkeys. The laboratory had telediagnosis capabilities and sent images to DPDx for confirmation (Figures A and B, taken at 400x magnification). The objects depicted in the images measured 52-61 micrometers in diameter. What is your diagnosis? Based on what criteria?

Figure A

Figure B

This was a case of bertiellosis, most likely caused by Bertiella studeri, the most common species of Bertiella associated with human infections. Diagnostic morphologic features shown in Figures A and B were:

round to slightly oval eggs with an external membrane and a delicate, pyriform inner shell or apparatus surrounding the oncosphere.
eggs within the size range for Bertiella spp. (37-60 micrometers in diameter).

Although the life cycles of Bertiella species are not fully understood, it is believed that these parasites undergo a two-host cycle, with an arthropod intermediate host (usually a mite) and a mammalian definitive host (usually a non-human primate). Human infections, though rare, are usually in children who have had contact with monkeys.