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MISCELLANEOUS PUBLICATION NO. 1065, U.S. DEPARTMENT OF AGRICULTURE 



it is urgent that adequate research on forested 

 and agricultural watersheds be directed towards 

 gaining new technology and better information for 

 determination of optimal combination of land 

 treatment and structural measures on upstream 

 watersheds to minimize the adverse effects of low 

 flows. 



Infectious Agents and Allergens 



Through history, water contaminated with in- 

 fectious agents has caused human disasters. It can 

 still happen. In late May and early June of 1965, 

 18,000 people in Kiverside, Calif., were infected 

 with Salmonella typhimurium that by some un- 

 explained means had entered the city water 

 supply. 



Soil, water, and air may be transmittal mediums 

 for numerous organisms that afflict man as well 

 as other animals and plants. 



Those unfortunates suffering from allergies will 

 not be consoled by evidence that 1.7 million tons 

 of pollen move into the atmosphere over the 

 United States every year. 



Animal Disease Agents 



Agricultural losses caused by infectious agents 

 of livestock and poultry carried by air, water, and 

 soil have, been heavy. Some of the diseases so 

 transmitted are leptospirosis, salmonellosis, hog 

 cholera, mastitis, foot-and-mouth disease, tuber- 

 culosis, brucellosis, histoplasmosis, ornithosis, in- 

 fectious bronchitis, Newcastle disease, anthrax, 

 blackleg, f ootrot, coccidiosis, blackhead of turkeys, 

 erysipelas, and transmissible gastroenteritis. A 

 number of these may afflict humans. 



The presence of coliform bacteria in water has 

 been used as an indicator of bacteria for about 75 

 years. Although the coliform bacteria are not 

 pathological, their presence has been taken as an 

 indication that infectious bacteria might also be 

 present. 



Recent evidence suggests that more definitive 

 information on bacterial contamination of water 

 may be gained by making counts of both fecal 

 coliform and fecal streptococcal bacteria. Empiri- 

 cal observations indicate that if the bacterial con- 

 tamination of water is coming from animals, the 

 f. coliform/f. streptococci ratio is less than 0.5. 

 If the bacterial contamination is from human 

 sources, this ratio usually exceeds -i. On this basis, 



a water bacteriologist ma} T use the following as a 

 general guide : If this ratio is less than 1.0, the 

 pollution is coming from nonhuman sources; if 

 the ratio exceeds 2.5, the bacterial pollution is most 

 probably coming from human sources. Ratios be- 

 tween 1.0 and 2.5 suggest that the pollution is a 

 mixture of human and nonhuman sources. 



On the basis of the foregoing, bacterial assays 

 on water samples from the upper Potomac Basin 

 indicate that most of the bacterial pollution of this 

 river system is coming from nonhuman sources. 



Much needs to be learned about the complete 

 reliability of the f. coliform/f. streptococci ratio 

 as an indicator of the source of infectious agents in 

 river water. Comparable studies need to be made 

 on other river systems. 



Excellent progress has been made in veterinary 

 'research in the United States over the past 85 

 years. Bovine tuberculosis has been reduced to a 

 remarkably low point. Counteractive measures in- 

 volving environmental sanitation have been 

 highly successful in curbing brucellosis and hog 

 cholera. 



Even though much has been accomplished, 

 much needs to be clone. 



Research underway on parasitic diseases will 

 contribute to reduction of environmental con- 

 tamination in two distinct ways : First, by the de- 

 velopment of methods to reduce parasitism in our 

 livestock population which will, in turn, reduce 

 environmental contamination by parasite-infested 

 animal wastes; second, by reducing the opportu- 

 nity for environmental contamination by pesti- 

 cides through development of methods of reduc- 

 ing or eliminating parasitism based on biological 

 control, immunization, improved management, or 

 more efficient use of better chemicals. 



Expansion of research on developing counter- 

 active measures to animal diseases is warranted 

 fully on the basis of the huge annual losses these 

 diseases impose on agriculture. 



In view of the key objectives for clean air 

 around us and clean water in our river basins, it is 

 essential to have (a) far better information on the 

 extent to which infectious agents in our surface 

 waters come from agricultural sources; (6) pos- 

 sible procedures to curb movement of infectious 

 agents from the farm or f eedlot to the water ; and 

 (c) continued progress in eliminating animal dis- 

 eases that contaminate air. water, and soil. Some 

 animal diseases — for example, encephalitis — are 



