L922.] 



Liver Rot in North Wales, 1920-21. 



in 5 



passes its early stages; the final hosts being infected through 

 the ingestion of infected pastures or drinking water. L. 

 truncatida is abundant and widespread, especially in shallow 

 ditches and on ill-drained pastures, and more particularly on 

 heavy lands, but is apparently very rare, or absent, on 

 peaty soils, and infrequent on sands (for reasons to be explained 

 below). The outbreak apparently commenced about August, 

 1920, on some of the w T orst infected pastures, but did not 

 become serious until about November. 



The writer carried out a preliminary survey of the Agricul- 

 tural Zoology of the Bangor district during the summer of 

 19-20, * when data were obtained regarding some 800 holdings. 

 These were almost all within a limited district, which contained 

 relatively little of the worst affected land. It was discovered, 

 however, that the Liver Fluke was endemic in the district 

 examined, and caused persistent losses on a number of farms 

 in most years : 25 such cases were recorded. In the light of 

 subsequent experience it appears evident that a similar (or 

 worse) state of affairs existed in most of the lowland districts 

 of North Wales, and that on certain of the ill-drained clay 

 soils 10 per cent, losses from this cause were not unusual; while 

 from time to time serious (though local) losses occurred, at 

 times involving an entire flock, or a number of neighbouring 

 flocks. Such being the case it will be seen that the conditions 

 favourable to an epidemic existed, which under the exceptional 

 conditions that followed, became serious. Owing to other 

 duties, no further field work was -done in connect ion with. Agri- 

 cultural Zoology until 29th December, 1920, by which time 

 the outbreak was widespread and the losses very severe. 

 During the following tw T elve months this disease occupied a 

 large part of the writer's attention. In all, 145 personal visits 

 were made during the period, and a list of 260 affected farms 

 and holdings has been made, though this is not by any mean- 

 complete. 



Localities affected. — The districts most severely affected were 

 (1) the Vale of Clwyd, from Denbigh to the sea, and from 

 Abergele to Prestatyn; (2) a narrow coastal area from Aber to 

 near Bangor; (3) wide areas around Carnarvon; (4) about Ynv> 

 and Afonwen; (5) from Sam Meyliteyra to near Dlanengan; 

 (6) the vicinity of Aberdaron: (7) a wide area in south-west 

 Anglesey extending from Llani'air to Dwyraii, thence 



° A Preliminary Note on the Agricultural Zoology of North Wales, 

 BritUh Association, Cardiff, 1920. 



