Intestinal spirochete infections of chickens: a review of disease associations, epidemiology and control

Abstract

AbstractThis paper presents an overview of intestinal spirochete infections of chickens. It focuses particularly on studies in Australia, where recent surveys of 136 layer and broiler breeder flocks have revealed a high rate of infection (>40%) with intestinal spirochetes. Infection was not detected in broiler flocks. Approximately 50% of isolates from infected flocks wereBrachyspira(Serpulina)intermediaorB. pilosicoli, with the other isolates beingB. innocens, B. murdochiior the proposed species ‘B. pulli’. No isolates ofB. alvinipulliwere found. Intestinal spirochetes were significantly associated with wet litter problems and/or reduced egg production. Experimental infection of point-of-lay birds with eitherB. intermediaorB. pilosicolicaused reduced egg production, and, withB. intermedia, a significant increase in fecal moisture content. Infection withB. innocenscaused no significant changes. In-water treatment of a flock with a mixed spirochete infection using lincospectin resulted in a slimy diarrhea lasting for 2–3 weeks, followed by absence of spirochetes for 3 months. Birds treated with tiamulin remained healthy, and had a reduced level of infection with intestinal spirochetes (30%) for 3 months. Trials are under way to test the efficacy of antimicrobials in point-of-lay chickens experimentally infected with eitherB. intermediaorB. pilosicoli.