AGRICULTURAL RESEARCH IN NEW HAMPSHIRE 65 



persons have entered the poultry field, thus increasing the hazards because 

 of the introduction of stock from states with a puUorum status not near- 

 ly as good as that of our state. 



Fred E. Allen 



Blue Comb 



In September 1941, we were able to isolate a filterable virus from 

 birds afi^ected with the acute form of "Blue Comb" disease. This has been 

 grown on chick embryos and a vaccine prepared from the membranes of 

 the infected embryo. This year we have used this experimental vaccine 

 in five flocks on previously infected farms. Approximately 17,000 birds 

 are under observation. 



• E. F. Waller 



Infectious Bronchitis Work 



In May 1943, we started to use egg-propagated infectious bronchitis 

 virus to immunize chicks against this disease. Up to June 30, 1943 we had 

 used this virus on 19 flocks containing 36,000 birds. The office of the 

 state veterinarian has limited the use of this virus to infected farms and 

 has specified that it be administered by one of the veterinarians from the 

 poultry laboratory. 



E. F. Waller 



Manufacture of Fowl Laryngotracheitis Vaccine 



During the year 1942-43, 50,250 doses of laryngotracheitis v'accine 

 were distributed to flock owners in the state. This quantity was used on 

 nine farms in four counties. The vaccine is used only on infected farms 

 and usually not until the disease makes its appearance in the flock. 



Disease-free, broiler-age birds are used to produce this vaccine. It 

 is made and sold under federal license and must meet the rigid purity and 

 potency tests of the U. S. Department of Agriculture, Bureau of Animal 

 Industry. 



E. F. Waller 



Manufacture of Fowl Pox Vaccine 



During the year 1942-43, 352,500 doses of fowl pox vaccine were 

 distributed to 204 poultry flock owners in the state. This was a decrease 

 of about 100,000 doses under that sold for the previous year. 



The vaccine is manufactured and sold under federal license, num- 

 ber 194, and sales have been limited to poultrymen of the state. All birds 

 used in the manufacture of the vaccine are procured from the university 

 poultry farm. They must be in perfect health, such being assured by 

 appropriate blood and laboratory tests. x\fter the vaccine is produced, it 

 must meet the rigid federal requirements as to purity and potency before 

 it can be released to the poultrymen. These tests are the poultryman's 

 insurance against introducing organisms of other diseases when vacci- 

 nating his stock for fo\\'l pox. 



