GUINEA WORM: SOCIO-CULTURAL STUDIES, MORPHOMETRY, HISTOMORPHOLOGY, VECTOR SPECIES AND DNA PROBE FOR DRACUNCULUS SPECIES.

Abstract

Dracunculiasis still remains as a disease o f public health importance in Ghana, especially in the Northern, Volta and Brong-Ahafo Regions, despite over a decade o f an Eradication Programme. In this study, attempts have been made to determine the problems associated with the eradication o f Guinea worm in the Northern Region o f Ghana, and suggestions provided to overcome them. Also investigated were the longitudinal anatomical variation of the parasite, the vector species and a DNA probe for Dracunculus species. It was found out that 43% o f the populace still got afflicted with the malady during the last transmission season, with 33% suffering from the disease for the second consecutive year. The disease appears to be sustained by the very long transmission season, spanning over six months. The knowledge index o f the local people with respect to the disease was quite high. Over 50% of respondents seem to be aware o f disease causation, prevention, and management. Unfortunately, however, apathy, lack o f motivation, and worker fatigue on the part o f G WEP staff appear to be factors in the resurgence o f the disease.

In the histomorphological part o f the study, the longitudinal anatomical variation o f the parasite was evaluated and its histomorphology illustrated. At maturity, the gut o f the female guinea worm was found to be completely atrophied and the entire worm made-up o f the larvae-filled uterus. Differences in the musculature from the anterior region, with much thicker muscles to the mid region were observed. The most important vectors of dracunculiasis in the study areas are: M. keiferi —> M. aspericornis —> T. incisus —> T. inopinus —> T. oblongatus  To probe for molecular epidemiology o f Dracunculus species, DNA sequence isolates from a number o f Guinea worms originating from 9 African countries, Pakistan and Yemen were compared with a previously assembled isolate, 1819bp (not yet submitted to the Gene Bank) from Uganda. The 18S nuclear small subunit ribosomal RNA (SSU-rRNA) gene o f Guinea worm from human and canine cases o f dracunculiasis in Africa were isolated by PCR and sequenced. Phylogenetic analysis (o f these sequences) and comparison with the sequences from Uganda revealed that Dracunculus isolates from human cases were indistinguishable from those o f the dog case. These results certainly imply that incidental infections o f Guinea worm could occur in certain domestic animals, and therefore, suggest that some domestic animals may serve as reservoirs for human Guinea worm infection.