OBSERVATIONS ON THE SPREAD OF ASIATIC SCHISTOSOMIASIS

R. T. Leiper, E. L. Atkinson
1915 BMJ (Clinical Research Edition)  
ffect ot weak acid upon a ciliated body like tie miraciditm u-ced not apply to a cerearia witli cuticula'r covering. Ini 1913 IiatsuLrada,in a suLmmary of researl Onl Japanese glbistosomiasis, abandoned his adhlesionl to time Looss hlypotliesi in favour of a relativelyy sinple -metamorrphosis a f thle miracidium prior to kin -infection. This paper, published in December,1913lias a note to the effect that hie is informed in a private letter from a colleague tlmat Mr. Miyairi of Kiutslliad
more » ... f Kiutslliad jthdjst found a reprodtictive stage of schlistosoma in a Lym?lnaeus species. Time Commission left Engaland in February. 1914, and was enguaged upon time work untill tIe outtbreak of nwar in AuguCftst, whlen the investigation liad to be abruptly concludded Oul r hlead quarters were established at. Shmangigai. partly rc; accoulnt of time ready acc6sis firom tlis large shiippinga ceiitre to bothm Ciminese and Japanese endemaic areas, anod pat-thy because the most generouns facilities were granted tlhere by time meidical officer of healtlh and tie minicipal u tlliorities In view of tlme negative results of, previous attempts Bleing a report pnblishe<d in accordance witim the reanirements tlm Wandsworth TUrnst. D mnade in London by tlhe Wandswortlh Scbholar and elsewhere by otlhers, tlhc Looss hypotlhesis of direct infection was set aside in favour of one to the effect that the, schistosome conformned in essentials to tlle life c-cle ofother digenetic trematodes. The " blunderbuss " metlhod, arlradv used for Filaiic loa and otlher investigations, was again relied on. This is, briefly, to submit all likely h-osts to an overwllelm-iinig infection. The proper lhost will slhow a marlked, even fatal, susceptibility, whiile otlher even closely allied lhosts will remain uninfected. For this purpose it was necessary, first, to obtain' an animnal witlh suchl a h-eavy infection that the eggs could be separated from the faeces with little contarnination. None of the cases of schistosomiasis in man approximated this stipulation. After a search lasting nearly three montlhs; and involving a river joutrney of over a tlhouisand miles, wve secured a dog ideal for thie work. The motions consisted almost entirelv of mtIutIs and blood, crowvded witlh eggs. Dilution with water. a slhake, thien rapid decantation, left abundant eags which lhatchled ulpon the second addition of clean water. We observed that in highly acid faeces the eggs were almost moribund, with thie cilia on thie surface of their embryos characteristically pointing ceplhaladl. Under thle mnost favourable conditions, anid in stiff stools, the enmbryosshoiwed ndvenioeht w,hen hatched by the addLtion of water up to thetetnth day. Our second necessity w-a.s to localize a small village with a fairly highi percentage of intfection amoongst tlhe inhabitants, and then study the local imolluscan fauna and wubmit the variouts species to the " bluriderbntss test. FuLrthler, by dissection of tlle variouis molluscs frorii sucl a defined area, niaturally infected specimens miglht be found, and the nature of tlle infection diagnosed: (a) By certain pectuliariities that the cercaria of tlhc sclhistosome slhould reveal: and (b) By a second"'bltunderbuss " test to infect a susceptible mammalianhost with material fronl thle suspected intermediarylhost. Altlouah tlle disease is widely sporadic, wxe failed to localize a village that Woutld meet ouir requirements in the lower Yangtse Valley. At Soochow and Kashing we saw a number of cases of sclhistosomiasis -in the variotus dispensaries, but these occurred in peasants wlho came in fromi outlying districts and villages to whiich we couild obtain no guidance or wl)icll in other w-avs proved inaccessible. Nevertlheless, througlhouit the whlole region we coblected, dissected, and compared thle molluscan fauna. Of the several developmxiental formis and cerearia found, none presented tIme one morphiological character-"; absence of plharyx "-which wouild have established in our mind aL strong presuLmlption in favour of a hypotlietical schistosome larva. We noted, too, that tllc molltuscan speces collected were alike over infected and non-infected areas-for example, Kashling. Slhaolising, an'd Henli. The up-river llospital records indicated tllat cases were few, and none attribuLtable to the present season. Examination of nurnerouts dogs gave like results, save in the oxcption wvhii-h, as noted. above, proved our sole efficient souLrce of eggs. The local explanation of tho paucity of cases WVas that thle summllier was one of the lhottest and driest on record. All species collected were,however, suibmitted to a bioloaical test-namely, each was placed in a cylindrical jk6r containing water swarming witlh miracidia, and watched witlh a lhand lens to see if the mollusc had a definite attraction for themiracidiuLm, care being talken in large forms to discouint results really due to tlhe violent inhalation of water. Wh1ile tiie experiments with the Chinese molluscs were proceeding we continued to explore newv areas ancl decided to inclade Katayamtna, wlhere FuLjinami's eartlv expetimeintal infections of animals by brief immersion inpacddy field water,had been carried out, and indicated an intense local infection. Fromii tllis visit tlic AWandsworlith Scholar brouglht back to Shlangllai large numbers of variouis species, inoludina Vivipiara and the form describedbelowv by Mr. Ilobson as Kataynauzni nosohorat n.g., n.sp. Tllhe little village of Katayama is easily reached by rickshna ruin of about three-quarters of anhotur from Fukuyama station on the mijain line from Sliimonoseki to Tokio; it is the centre of a highly infected area, and gives the name '; Katayama disease " to Asiatic sclhistosomiasis. Professor
doi:10.1136/bmj.1.2822.201 fatcat:xn3ftp4ymrbpzntqthc43nolsa