THE WHOLE BLOOD AGGLUTINATION TEST FOR 

 PULLORUM DISEASE 



By H. Van Roekel, Chief of Laboratory, and M. K. Clarke, Laboratory Assistant, 

 Poultry Disease Control 1 



In the control and eradication of pullorum disease among domestic fowl the 

 macroscopic agglutination (tube) test is regarded as a reliable and indispensable 

 means of detecting infected birds. The application of the test along with effective 

 control and eradication measures has led to the establishment of flocks which are 

 free from the disease. This fact has been clearly demonstrated in certain sections 

 which at one time suffered heavy losses from the disease but later enjoyed the 

 benefits derived from pullorum-disease-clean flocks obtained through a supervised 

 and effective testing program. 



The testing of flocks for pullorum disease has not received equal encouragement 

 in all sections of this country. This may be attributed to various factors. The 

 cost of the tube method and its inadaptability to the poultry industry in certain 

 sections have been considered to be responsible for the lack of interest and initia- 

 tive taken in pullorum-disease eradication. Consequently, with a demand for a 

 less expensive method of testing, a field test was introduced by Schaffer, MacDon- 

 ald, Hall and Bunyea (7) and Coburn and Stafseth (2). 



While some investigators and regulatory testing agencies would lead one to 

 believe that this field test is effective in the control and eradication of pullorum 

 disease, others do not accept this view. It is clearly evident, as judged from the 

 investigations reported, that further research is essential to perfect and standard- 

 ize the technique of the whole blood test in order to increase its efficiency. The 

 purpose of this investigation was to gain a more thorough insight into the factors 

 which influence the effectiveness and reliability of the whole blood test in eliminat- 

 ing pullorum infection from poultry flocks. 



HISTORICAL RESUME 



Schaffer, MacDonald, Hall and Bunyea (7) report the use of a stained antigen 

 and fresh whole blood in the rapid whole blood test for pullorum disease. The 

 antigen and whole blood are placed and mixed on a glass plate, in the approximate 

 dilution of one part of blood to two or three parts of antigen. A pipette which 

 delivers a drop of antigen, approximately .05 cc, and a wire loop measuring 

 .02 cc. of blood were used. Rotating of the plate was found unnecessary to hasten 

 or bring about agglutination. Reactions which occurred within one minute were 

 regarded as definitely positive, while slower reactions were considered suspicious, 

 and slight reactions appearing after two minutes were disregarded. It was observed 

 t hal the greater the agglutinating power of the blood, the more rapid the clumping 

 and the larger the clumps. A very fine granulation which is barely visible to the 

 naked eye should be regarded as negative. 



Coburn and Stafseth (2) described a whole blood test in which they used an 

 antigen that differs slightly from that employed 1>\ Schaffer et al. Equal amounts 

 of antigen and blood measured with standardized pipettes were placed and 



'The authors wish to extend their appreciation to Prof. 0. S. Flint for taking the photographs. 



