OBJECTIVES: : To investigate infection and host immunity patterns in sheep with naturally occurring "broken-mouth" periodontitis.

MATERIALS AND METHODS: : Eight periodontally healthy (HS) and eight periodontally diseased ewes (PDS) were selected. Subgingival plaque and sera were collected and examined for evidence of human periodontitis-associated pathogens. Serum IgG titers were measured by ELISA to multiple strains of Porphyromonas gingivalis, Bacteroides forsythus, Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum as well as several purified antigens (cysteine proteases, LPS, K, and fimbriae).

RESULTS: : Neither the organism Aa nor antigens to Aa were found in any animal. Most animals were positive for Pg, Bf, and Pi, but DNA probes detected no difference between HS and PDS relative to amounts of pathogens in subgingival plaque. PDS had significantly higher serum IgG titers to all Pg strains, to 50% of Bf strains, to the Pi and Fn strains, and to fimbriae and the two cysteine proteases (p-values ranging from 0.05 to 0.001). Regression analysis demonstrated a significant association between number of teeth lost and serum IgG antibody titers to whole-cell sonicate antigens of P. gingivalis strains (p<0.01) and body weight (p<0.01).

CONCLUSIONS: : The presence of pathogens associated with periodontitis was reflected in differences in serum IgG titers between healthy and diseased sheep. This may have influenced animal body weight and might have systemic health and economic consequences. The data suggest that susceptible and non-susceptible sheep can be identified for periodontal research.