546 Distomatosis 



bile ducts, more commonly the latter. In the chronic form it 

 leads to serious loss of condition. 



Historical. The earliest records of the disease are those of Schaper 

 von Gabueinus in 1547, and of Gemma a few years later. The term, 

 "Leberegel" (fluke) was first used in 1676 by Frommann. Valuable 

 clinical and pathological studies of the disease were made by Schaffer 

 (1764), Goeze (1782), Chabert (1879), and Bilhuber (1791). The life- 

 history of the parasite was elucidated by Mehlis (1831), v. Nordmann 

 (1832), Eschericht (1841), Steenstrup (1842), and especially by 

 Leuckart (1876), who determined the metagenesis of the fluke. Among 

 veterinary surgeons the names of Gerlach (1854), Delafond (1854), 

 Davaine (1860), Fried])erger (1878), Ziindel (1880), Thomas (1881), 

 and Ziirn (1882), are closely connected with the study of distomatosis. 

 Interesting investigations were made by Schaper (1889), and Lutz 

 (1892), regarding natural infection, and also by Schaper in connection 

 with the pathogenesis, symptomatology and pathological anatomy of 

 the disease. 



Occurrence. The Distomum hepaticum is found in marshy 

 places everywhere, whereas the distribution of the D. lanceola- 

 tum appears to be more restricted, the parasite being far more 

 common in southern Europe than in northern. The geograph- 

 ical distribution of the D. hepaticum exactly coincides with that 

 of Limnseus minutus, wdiich is practically the exclusive inter- 

 mediate host of the parasite (Leuckart). After wet summers 

 the disease is very widespread and causes very heavy losses. 

 The severe form of the disease rarely occurs among adult cat- 

 tle, although they may harbor the parasite in their livers. It 

 is principally among calves that serious losses occur. Exten- 

 sive outbreaks of the disease sometimes occur among goats 

 (Romer). Swdne, buffaloes (Hungary and East Indies), cam- 

 els, wdld ruminants, hares and exceptionally horses, asses, dogs, 

 cats and rabbits are infested. 



In 1873 a third of the sheep, which were valued at more than $200,000, 

 died in Alsace-Lorraine. In England the annual loss is computed at a million 

 sheep. Great losses were caused by fluke in Hungary and especially Upper Hun- 

 gary in 1889. On two farms practically the entire flocks were wiped out. The 

 disease was also very prevalent during the years 1893-1897. According to Popow 

 in certain districts of Poland in 1891 from 50 to 90% of the sheep died. The 

 liver fluke is not known in Iceland (Krabbe). 



In 1876 the disease caused losses up to 40% of the cattle in Slavonia. 



In 1883-84 36% of all the cattle, 7% of the calves and iyo% of the pigs 

 killed at the Berlin abattoirs were found to be affected. At Budapest during 

 the period 1889-1903 the percentages of affected animals were: 4.9% of cattle, 

 39.5% of sheep and 25% of goats. In 1902-03, 474,401 pigs were slaughtered 

 and of these 1.2% were seriously infested. At Okayama (Japan) Saito found 

 the Distomum hepaticum in 16% of cattle but the lesions were confined to the 

 bile ducts. 



Etiology. The disease is caused by two varieties of dis- 

 tomes belonging to the Trematodes family of the Platyhelmin- 

 thes. These two parasites are called Distomum hepaticum 

 (Fasciola hepatica) and D. lanceolatum (F. lanceolata, Dicro- 



