fluke of cattle was previously unknown, mineral 

 water flowing from artesian wells furnished a suit- 

 able environment for snails. This was followed by 

 fluke problems when carrier cattle were brought to 

 the pasture. The solution was to regulate the 

 artesian flow into tanks to conserve the artesian 

 pressure in the area. These measures also showed 

 that the black water of the swamps did not sup- 

 port the proper snail host. Water criteria for live- 

 stock disease control, therefore, include pH dif- 

 ferences, mineral composition of water, and other 

 biological factors measurable in water quality 

 itself. 



Tapeworms of livestock, including poultry, do 

 not commonly utilize a water pathway. A tape- 

 worm of man does utilize a copepod and fish in its 

 life cycle. 



Roundworms include numerous species which 

 may use water pathways in their life cycle. The 

 appearance of these so-called, free-living nema- 

 todes in a piped water supply is a cause for much 

 concern, but is probably of little health signifi- 

 cance. However, moisture is an important factor 

 in the life cycle of many roundworms and live- 

 stock are maintained in an environment where 

 contamination of water supplies is a possibility 

 every day. It is usually thought that roundworm 

 eggs are eaten, but water-saturated environments 

 provide ideal conditions for maintaining popula- 

 tions of these organisms and their eggs. 



Parasitic roundworms probably evolved through 

 evolutionary cycles exemplified by the behavior 

 of the genus Stwngyloides. Their life cycle is pri- 

 marily a soil-to-host phase, but serious Strongy- 

 loides problems evolve along drainageways 

 through the washdown of concrete feeding plat- 

 forms and other housing facilities for livestock, 

 although the classification of the Strongyloides 

 implies a reasonably restricted host range for each 

 species, this may be more environmental than 

 genetic. Certainly, the range of activity of Strongy- 

 loides as parasites of insects, crabs, amphibians, 

 and reptiles as well as mammals, indicates their 

 capabilities as pollutants of water. 



Most parasitic roundworms complete their life 

 cycles without entering into a water phase, but 

 mosquitoes, blackflies, and other intermediate 

 hosts which may be associated with water man- 

 agement are sometimes involved. The Guinea 

 worm, Draciincidus, is dependent upon water, as 

 the adult lays eggs only when the host comes in 

 contact with water. Man, dogs, cats, or various 

 wild mammals may harbor the adult and the larva 

 develop in Cyclops. The life cycle is thus main- 

 tained in a water environment when the Cyclops 

 is swallowed by another suitable host. 



Criteria for water concerning roundworms 

 would not be complete without mentioning "horse- 

 hair worms." Eggs are laid by the adult in water 

 or moist soil. The larva encyst and if eaten by an 

 appropriate insect will continue development to 

 the adult stage. The cycle may be interrupted and 

 if eaten again by another insect the growth to 

 adult form will be resumed. Worms do not leave 

 the insect unless they can enter water. The life 

 cycle is completed as free-living adults in water. 



The prevention of water-born parasitisms de- 

 pends on interruption of the parasite's life cycle. 

 The most obvious is to keep Hvestock out of 

 water which carries the means of perpetuating 

 the cycle. Treatment for the removal of the para- 

 site from the host and destruction of the inter- 

 mediate host are the usual measures of control. 

 Measures for the eradication of parasitic diseases 

 usually require area or regional control programs. 

 The insidious nature of parashisms, the lack of 

 spectacular mortality, or other evidence of disease 

 in livestock result in general unawareness of the 

 extent of these problems. 



Radionuclides: All radiation exposure is re- 

 garded as harmful and any unnecessary exposure 

 to ionizing radiation should be avoided. The ac- 

 ceptability of livestock water supply containing 

 radioactive materials should be based upon the 

 determination that the intake of radioactive sub- 

 stances from such water when added to that from 

 all other sources is not likely to result in exposure 

 greater than that recommended by the Federal 

 Radiation Council {56, 57). Supplies containing 

 radium-226 and strontium-90 are acceptable with- 

 out consideration of other sources of radioactivity 

 if the concentrations of these radionuclides do 

 not exceed 3 and 10 pc/1, respectively. In the 

 known absence of strontium-90 and alpha-emitting 

 radionuclides, the water supply is considered ac- 

 ceptable if the gross beta activity does not exceed 

 1,000 pc/1. If the gross beta activity is in excess of 

 this, a more complete radiochemical analysis is 

 required to determine that the sources of radiation 

 exposure are within the limits of the radiation 

 protection guides. 



Monitoring and Measurement: Chemical analy- 

 sis of ground and surface waters for minerals is 

 feasible and is an integral part of good livestock 

 management. The monitoring of surface waters for 

 other chemical toxicants (pesticides, herbicides, 

 etc.) which may occur at sporadic intervals (due 

 to usage) is very difficult. Thus, the use of fish 

 indicator ponds at the terminal watersheds is un- 

 doubtedly an economical safety precaution that 

 should be encouraged. 



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