THE ANIMAL PARASITES OF MAN 



Dracunculus medinensis, Velsch, 1674. 



Syn. : Vena medinensis, Velsch, 1674; Dracunculus persarum, Kampfer, 1694; 

 Gordius medinensis, Linne, 1758 ; Filaria dracunculus, Bremser, 1819 ; Filaria 

 cpthiopica, Valenciennes, 1856; Dracunculus medinensis, Cobbold, 1864; Guinea 

 worm, Medina 'worm. 



The females attain a length of 50 to 80 cm., or even more, and 

 average 1*5 to 17 mm. in diameter. They are whitish or yellowish 

 in colour. The anterior extremity is roundish and bears a cuticular 

 thickening or shield. The triangular mouth opening is surrounded 

 by two projections or lips, behind which on the shield there are two 

 lateral and four pub-median papillae ; the posterior end terminates in 

 a spine, ventrally directed, and about I mm. in length ; the alimentary 

 canal below the oesophagus is atrophied, but not entirely obliterated ; 

 anus absent ; the lateral lines are very flat. The greater part of the 

 body is occupied by the long uterus, in which a great number of 

 young larvae are always found. The ovaries probably lie at the ends 

 of the uterus ; the vulva lies just behind the cephalic shield. During 

 parturition the uterus is prolapsed through this opening. 



The male is almost unknown. Leiper in an experimentally in- 

 fected monkey found two males 22 mm. long, one from the psoas 

 muscle, the other from the connective tissue behind the oesophagus. 



Occurrence. Filaria medinensis has been known since the most remote 

 period. The " fiery serpents" that molested the Israelites by the Red Sea, and 

 which Moses mentioned, were probably filariae. The term Apo/c 'vnov occurs in 

 Agathai chides (140 B.C.). Galen called the disorder dracontiasis ; the Arabian 

 authors were well acquainted with the worm. It is found not only in Medina or 

 Arabia, but also in Persia, Turkestan, Hindustan. The Guinea worm is also widely 

 distributed in Africa, on the coasts as well as in the interior. It occurs in the Fiji 

 Islands. It was carried to South America by negro slaves, but is said at the present 

 time to exist in only quite a few places (British Guiana, Brazil [Bahia]) ; it is also 

 observed in mammals (ox, horse, dog, leopard, jackal [Cam's lapuster\ etc.). 



Dracunculus medinensis in its adult stage lives in superficial ulcers 

 on the body surface ; it is seen most frequently on the lower extremi- 

 ties, more especially in the region of the ankle, but it also occurs in 

 other parts of the body on the trunk, scrotum, perineum, on the 

 upper extremities, and in the eyelids and tongue. Sometimes there 

 is only one ulcer and one worm, but more commonly several. It 

 attacks man without distinction of race, age or sex. It is observed 

 most frequently during the months of June to August. 



Life history. 1 When about a year old the worm seeks the surface 



1 The larvae resemble those of Cueujlanus elegans parasitic in the perch (Perca fluviatilis). 

 The larvse of this species develop in Cyclops sp. Fedschenko in 1870, at Leuckart's suggestion, 

 succeeded in observing the invasion of Cyclops by Guinea worm larvse. They penetrate not 

 per os but through the exoskeleton. Newly hatched larvse (in bananas) will cause infection of 

 monkeys. 



