Development of a pooled antigen for use in the macroscopic slide agglutination test (MSAT) to detect Sejroe serogroup exposure in cattle

Brucella canis is a cause of canine infertility and abortion. Veterinarians and veterinary laboratorians screen for antibodies to B. canis with serologic tests including a rapid slide agglutination test (RSAT; D-Tec CB, Zoetis, San Diego, CA). False-positive results are possible because of cross-reactivity to antibodies to some gram-negative bacteria. Cross-reactivity has been reported between antibodies of Brucella abortus and Leptospira spp. with serologic tests for bovine brucellosis; however, this has not been documented with serologic tests for canine brucellosis, to the author’s knowledge. The RSAT was evaluated with the sera from dogs experimentally challenged with 1 of 4 serovars of Leptospira spp.: L. kirschneri serovar Grippotyphosa, or L. interrogans serovars Canicola, Icterohaemorrhagiae, or Pomona. Experimental infections were confirmed through results of microscopic agglutination testing and/or lateral flow immunochromatography testing. The sera of 32 dogs collected at day 0 and days 7, 10, and 14 yielded negative results with the RSAT. Antibodies produced through experimental infections to these 4 serovars of Leptospira spp. did not cross-react with Brucella antigen with the RSAT; therefore, cross-reactivity of anti-leptospiral antibodies may not be of concern for B. canis rapid slide agglutination testing of dogs.

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A slide agglutination test for the exclusion and diagnosis of typhoid fever

Journal of Hygiene ◽

10.1017/s0022172400011931 ◽

1939 ◽

Vol 39 (3) ◽

pp. 294-297 ◽

Cited By ~ 1

Author(s):

F. M. Berger ◽

G. Brecher

Keyword(s):

Typhoid Fever ◽

Positive Result ◽

Agglutination Test ◽

Serological Diagnosis ◽

Agglutination Reaction ◽

Negative Test ◽

Slide Agglutination ◽

Peculiar Behaviour ◽

Slide Agglutination Test ◽

Agglutination Method

A sensitive antigen suspension is described for use with a simple slide agglutination method which makes possible a serological diagnosis or exclusion of typhoid fever without recourse to a laboratory. The method has been tested on 414 sera sent to our laboratory; it detected all cases with a titre of 1: 80 or more, and most of those with a titre of 1: 40. The method was further tested on 130 clinically observed cases, in which it gave satisfactory results. The S. A. method gave a positive result with 98 out of 100 sera from patients with typhoid fever, whereas the classical Widal reaction gave a positive result with 68 of them only.The intensity and rapidity of the slide agglutination reaction provide a rough measure of the titre of a serum. A quick and distinct agglutination indicates a titre of 1: 80 or more and is diagnostic of typhoid fever. A slow and indistinct result is obtained when the titre of the serum is about 1: 40. A negative test indicates with great probablity that a diagnosis of typhoid fever may be excluded.We think the method succeeds because the nature of the suspension employed and the peculiar behaviour of slide agglutinations permit the detection of O agglutinins as well as H agglutinins.

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