THIRTY-EIGHTH BIENNIAL REPORT 23 



worms occur, all causing the same general pathology and all having 

 similar direct life cycles. Most of them are common parasites of sheep 

 and cattle and were undoubtedly introduced into this country with the 

 domestic flocks and herds. 



The extreme irritation to the intestinal tract usually causes a diar- 

 rhetic condition referred to as scours. It is usually more evident in the 

 younger animals. The developing eggs of the worms jiass ont of the 

 intestinal tract with the deer's droppings and the larval worms hatch out 

 in the soil. After a period of development they become ripe for infection 

 and migrate up moist blades of grass. Deer (or cattle and sheep) become 

 infected when they eat such contaminated grass. 



Mam' factors are involved in the ultimate condition of deer as a 

 result of these parasites. Some of these are temperature, moisture, the 

 extent of use of the pasture by infected deer or livestock, and the amount 

 of grazing done by the deer on such infected areas. In point of sequence 

 this last factor seems to be the most important in the health of the deer 

 population. Where these infections are the only ones involved in reduc- 

 tions of deer, a direct proportion can be hypothesized between the amount 

 of grazing and the extent of the losses. The more browse available, the 

 less infection with these worms. It is mainly in areas Avliere deer would 

 be most likely to live chiefly on a grass diet that this condition becomes 

 severe. In areas where it has not been observed, or where the severity 

 was of little significance, the stomach contents of the deer examined 

 showed a predominance of browse. 



In March, 1944, in collaboration with the U. S. Park Service and 

 U. S. Fish and Wildlife Service, an investigation was made of deer con- 

 ditions in the Sequoia National Park. Here, again, these intestinal 

 worms were found to be of much importance. In this area, too, deer are 

 suffering from intensive eyeworm infections. All deer infected with 

 these small worms in the eye at Sequoia have upwards of 30 worms per 

 eye, whereas when we have observed the same infection in deer in other 

 parts of the State, very few worms have been present. 



Our program on the occurrence of blood parasites of quail has been 

 continued, although reduction of field personnel has greatly reduced the 

 number of samples. AVith the cooperation of the Associated Sportsmen 

 of California and other hunters, we have obtained many samples of blood 

 and hearts in an effort to determine the distribution of these diseases. 

 This program shall be continued and expanded. As a result of our 

 studies on quail we have uncovered at least three important parasites new 

 to science. As a part of this program we are studying the parasites of 

 other species of birds to determine what diseases are common to all birds 

 as well as those that occur only in our game species. 



Two winter outbreaks of botulism were observed in ducks and coots : 

 (1) Gridley, with varying intensity during winter 1943-44; (2) Mt. Eden, 

 January, 1944. 



Preliminary investigations were nuide on the source of so-called 

 "iodine" ducks in the lower San Fraiu-isco Bay area dnring the 1943 

 duck season and plans have been formulated to make an intensive investi- 

 gation of this condition during the 1944 season. 



Numerous other parasites and diseases were diagnosed in the Avild- 

 life of the State and investigations on the epidemiology of mam- of the 



