organic phosphate systemic insecticides. The 

 latter have been used extensively in field trials 

 during the past few years with encouraging 

 results. 



The future 



The National Cattle Grub Committee reports 

 as follows: "Research in grub control now un- 

 derway and recommended includes a study of 

 the ecology and life cycle of the parasite in 

 various regions, effects of movement of cattle 

 from one climate to another on the life cycle 

 of grubs, the apparent resistance of older cat- 

 tle to grubs, and the possibility of induced im- 

 munity to grubs." 



The Animal Disease Eradication Division 

 does not envision a national cattle grub eradi- 

 cation program in the immediate future. How- 

 ever, available reports on each new develop- 

 ment in research and field trials are constantly 

 examined and analyzed in light of possible ap- 

 plication to cattle grub eradication. 



HOG CHOLERA 



The cholera chronicle 



Hog cholera is reported to have been in this 

 country since the early 1830's. Some reports 

 indicate that it was here before then. During 

 the latter part of the 19th century it devastated 

 the swine population of the country. As late as 

 1913 an epidemic of this disea.se was responsi- 

 ble for killing 10 percent of the hogs in the 

 United States. 



After much trial and error, research scien- 

 tists of the former Bureau of Animal Indu.stry 

 identified a virus as the cause of hog cholera. 

 Following this, vaccination with live hog chol- 

 era virus and serum was started. This type of 

 immunization saved the swine indu.stry of the 

 country. Periodic outbreaks, however, con- 

 tinued to occur. Investigations revealed that 

 they were due to no vaccination or. in some 

 cases, were directly attributable to the virulent 

 virus used in the immunization. 



HOG CHOLERA REPORTED 



Fiscal Year 1960 



PUERTO RICO 



U S DEPARTMENT OF AGfitCUlTuBf 



■^EG 60 (n> S057 AGBICUIIUBAI SESEAHtCM SfBviCE 



32 



