FILARIA BANCROFTI 



mosquitoes, where, in a few days, as already described by Mansori 

 in 1884, they undergo considerable changes ; they grow to a 

 length of i'5 mm. and a breadth of 0-25 mm. Of course many 

 specimens perish within the intestine of the mosquito. The 

 general opinion was that the filarial larvae, after such changes, 

 attained the water at the death of the female mosquito and were 

 introduced into man with the infected water. This opinion was 

 supported by the observation that, whereas the unaltered filarice 

 are exceedingly susceptible to water, those that have come to 

 maturity within the mosquitoes can bear immersion very well. 

 Nevertheless, this view is not correct, although recently Maitland 

 has sought to revive it. It is more probable that the larvae of 

 Filaria bancrofti are transmitted by the bite of infected mosqui- 

 toes just like those of Filaria immitis. It is quite certain that 

 in the last stage of their metamorphosis the larvae leave the 

 thoracic muscles of the mosquitoes and enter the body cavity ; 

 from here they do not reach the open by way of the oesophagus, 

 but proceed to the mouth parts, or rather the labium. We may 

 therefore conclude quite positively that when the infected mosqui- 

 toes bite, the same mechanism that directs Filaria immitis into 

 the punctured wound of the dogs is likewise adopted in the 

 transmission of Filaria bancrofti to man. [The transmission of 

 Filaria bancrofti through the mouth parts of mosquitoes was sug- 

 gested by me 1 and demonstrated by Dr. G. C. Low 2 before Noe and 

 Grassi published their paper on the transmissions of Filaria immit's. 

 -L. W. S.] 



Filaria bancrofti, or Fit. sanguinis hominis, is known in nearly 

 all tropical countries. It occurs in India, China, Japan, Aus- 

 tralia, Queensland, the Islands of Polynesia (with the exception of 

 the Sandwich Islands), Egypt, Algeria, Tunis, Madagascar, Zanzi- 

 bar, Sudan, &c., the south of the United States of America, 

 Brazil, the Antilles, &c. 3 



The disease (filariasis) presents a series of very diverse symp- 



1 Journ. of Tropical Medicine, April I4th, 1900, p. 219. 



-Brit. Med. Journ., June i6th, 1900. 



3 According" to Font, indigenous filariasis also occurs in Europe ; he reports the 

 case of a man who, since his eighteenth year, had suffered from haemato-chyluria and 

 enlargement of the scrotum, and whose blood exhibited nlariae. With the exception 

 of a short time spent in San Sebastian, the patient had never left his birthplace (Canet 

 de Mar, 41 km. north of Barcelona). Two further cases of haemato-chyluria were 

 reported from the same district, but no microscopical examination of the blood and 

 urine was undertaken in these (Font, M. " De la Filariosis : expos, del primer caso 

 esporad. observ. en Europa," Riv. dene. med. de Barcelona, 1894, pp. 73 and 97 ' re *- 

 in C. f. B. u. P., xvi., p. 85). In a case of indigenous elephantiasis originating in 

 Brest, the blood examination had a negative result (Guyot, " Un cas d'elephant. tndig. 

 obs. a Brest," Arch. med. nav., 1892, Iviii., p. 192 ; " Autrc cas d'eleph. des arabes 

 en Bretane," Ibid., 1893, ^ X M P- II 5)- 



