Spontaneous autoimmune thyroiditis in Praomys (Mastomys) natalensis

The occurrence of lymphoplasmacellular thyroiditis associated with the presence of autoantibodies to thyroid colloid in Mastomys makes it likely that there is an autoimmune thyroiditis in this animal species. Thyroiditis occurred in 16% of the males and in 23% of the females. From longitudinal studies performed in a number of the animals, it appeared that the autoantibodies occurred from the age of 13 months onward and that they persisted until the death of the animals in the majority of the cases. The serum concentration of antibodies to thyroid colloid in Mastomys correlated only roughly with the extent of thyroid infiltration. Neither differences in serum thyroxin concentration nor in proliferative thymic lesions were found between animals with and without thyroid disease.