to spread because of the infected eggs laid by such birds. These infected 

 eggs are one of the most important means of transmission of the disease 

 if eaten by healthy birds. 



Because of this danger alone, it is advisable to cull as many as possible 

 of the reactors from the flock before they start to lay. Poultrymen are 

 urged to observe these suggestions and have their flocks tested as early 

 in the season as is convenient. This will allow plenty of time for retests 

 if the flock is found to be infected. 



The Efficiency of the Agglutination Test 



Because of the attempts that are being made to discredit the agglutina- 

 tion test, it may be proper to discuss here its value. Many of these at- 

 tempts are made by propagandists who have little technical knowledge of 

 the subject which they try to discuss, and therefore much harm is being 

 done. No investigator who is interested in eradication of pullorum dis- 

 ease will dispute the fact that the agglutination test can be used suc- 

 cessfully to detect carriers of the infection, and thus aid in its eradication. 



Too much emphasis has been placed on a few attempts to study the 

 efficiency of the test, by sending blood samples to various laboratories. 

 It is true that discrepencies have occurred in such tests, but it is also 

 true that there were marked discrepancies in the samples tested in some 

 of these instances. 



The only logical method of determining the efficiency of any test is 

 to study the results being obtained in the field following the application 

 of that test. Such a procedure is being used in Massachusetts and the 

 results recorded in this report are evidence that the agglutination test is 

 as reliable, if not more reliable, than many other diagnostic tests. The 

 reader is referred to the sections on "Progress in Eradication" for defi- 

 nite information of this nature. 



In Massachusetts the agglutination test is being used to locate disease- 

 free sources and also as an aid in the elimination of infection from dis- 

 eased flocks. A common mistake made is that of testing infected flocks 

 once annually in the hope of eradication of the disease. Wiiy this pro- 

 cedure has been substituted for the natural method for eradicating any 

 infectious disease, namely, that of an intensive retesting program, is not 

 known; but herein lies one of the chief reasons for failure to obtain results 

 in eliminating pullorum disease from infected premises. 



The experience in Massachusetts has been that pullorum disease can 

 be eliminated from infected flocks in a single season if the cooperation 

 of the poultryman can be secured. Furthermore, it matters little whether 

 the infection is 35 or 2 per cent. By making the original test on the 

 flock when the birds are four to five months of age, removing the reactors, 

 cleaning and disinfecting the houses, and then retesting the entire flock 

 every month or six weeks until a non-reacting test is obtained, the disease 

 can be successfully eliminated after from two to five retests. The num- 

 ber of retests will depend on the virulency of the germ infecting the flock 

 and upon the management, as much as upon the efficiency of the test, if 

 the latter is made by properly trained technicians. 



(3ne way to estimate the efficiency of the agglutination test is to deter- 

 mine the percentage of total reactors detected by the original test on 

 a flock where the disease has been eliminated bv an intensive retesting 



