6533b7defe1ef96bd1275f8f

RESEARCH PRODUCT

Morphology of Bertiella studeri (Blanchard, 1891) sensu Stunkard (1940) (Cestoda: Anoplocephalidae) of human origin and a proposal of criteria for the specific diagnosis of bertiellosis.

subject

description

Human material of an African specimen of Bertiella studeri (Blanchard, 1891), a typical intestinal cestode of monkeys, is described. Mature, postmature and gravid proglottides, and eggs, previously inadequately figured, are illustrated and photographed. The description of the species agrees with that provided by Stunkard (1940). A comparative study with other descriptions of the species is made in an attempt to clarify previous findings. The morphological differences reported in various earlier descriptions of the species suggest that B. studeri should be regarded as a "B. studeri species complex". Improvements are required in the descriptions of new future findings in order to clarify the specific diagnosis of human bertiellosis. Evidence suggests that a generalised diagnosis exclusively based on egg size and geographical distribution is insufficient to differentiate B. studeri and Bertiella mucronata (Meyner, 1895), or additional species may be affecting humans. Human bertiellosis, recently reviewed by Denegri and Perez-Serrano (1997), is the intestinal parasitisation by adult cestodes of the genus Bertiella Stiles et Hassall, 1902. Members of this genus are common parasites in primates, rodents, dermopterans and Australian marsupials and are the only anoplocephalids occurring in humans. Two species, Bertiella studeri (Blanchard, 1891) and Bertiella mucronata (Meyner, 1895), each with different geographic distributions, are known to parasitise humans (Denegri et al. 1998). The majority of human cases involve B. studeri, although some B. mucronata infections have also been reported (Denegri and Perez-Serrano 1997). Bertiella studeri is a parasite of monkeys in Africa and Asia. The species was described by Stunkard (1940) based on material obtained from the rhesus monkey (Macaca mulatta). Oribatid mites are the intermediate hosts of this cestode, harbouring the cysticercoid type larva. The accidental ingestion of infected mites, found in habitats associated with monkeys, results in parasitisation of the definitive host. The lack of a complete contemporary description of specimens of B. studeri, from vertebrate hosts, is the cause of the persistent controversy initially recognised by Spasskii (1951). This author believed that some of the twelve descriptions compared by him differed from each other more than the comparative descriptions of B. studeri and B. mucronata. Currently, the lack of adequate morphological detail prevents the taxonomic differentiation of these cestodes of importance to human health. The present study contributes to further knowledge of the morphology and morphometry of African mate- rial of human origin. Mature, postmature, and gravid proglottides and eggs are described, complemented by drawings and photomicrographs of the material ana- lysed. A comparative analysis of previous descriptions of B. studeri and an evaluation of the controversy over the specific diagnosis of bertiellosis is presented.