DracunculidM 



651 



Pathogenicity.- — -Lymphangitis, perilymphangitis, sometimes acute 

 and with fever, and resulting in small tumours, are their pathological 

 signs. 



Family 7. Dracunculid^ Leiper, 1912. 



Dracunculus Kniphoff, 1759. 



Nematodes with small males and long females. In the latter 

 a vagina is wholly absent ; the embryos being discharged by rupture 

 of the gravid female. 



Dracunculus medinensis (Linnaeus, 1758). 



Synonyms. — Dracunculus veterum Velsch, 1674; Vena medinensis 

 Velsch, 1674; Dracunculus persarum Kampfer, 1691; Gordius medi- 

 nensis Linnaeus, 1758; Filaria dracuncuhis Bremser, 1819; F.csthi- 

 opica Valenciennes, 1856 ; Dracunculus medinensis Cobbold, 1864. 



Dracunculus medinensis, commonly called the guinea-worm, the 

 dracunculus, Beinwurm, Brachwasserwurm, tankworm, or dragon - 

 neau, is endemic in tropical Africa, India, Persia, Turkestan, 

 Arabia, and some places in South America, to which it was imported 

 from Africa. 



Fig. 279. — Dracunculus medinensis Linn^us. 



It has been known since the most remote periods, and it was 

 probably the fiery serpent mentioned by Moses, who apparently 

 knew the method of twisting the worm out on a stick, as he appears 

 to have made a model of this method of extraction. Galen called 

 the disease caused by these worms dracontiasis. 



The anatomy of the worm was carefully studied by Bastian in 

 1863, and the infection of Cyclops with the larva was observed by 

 Fedschenko in 1870, and confirmed later by Manson. Charles 

 found a calcified guinea-worm in 1892, which he described as the 

 male. 



Leiper, 1907, has repeated these experiments, and has further 

 proved that when monkeys are fed on infected Cyclops the males 

 and females can be found. 



Morphology. — The female is a long white filiform worm 50 to 

 80 centimetres in length and 0-5 to 1-7 millimetres in diameter. 



The anterior end is bluntly rounded, and carries the small terminal 

 mouth, which has two lips and two lateral and four submedian 

 papillae. It leads into a straight alimentary canal, which atrophies 

 considerably in the fully developed condition. The large uterus, 



