The effects of parenteral iron dextran and/or desferrioxamine on the development of experimental pseudotuberculosis in the domestic chicken (Gallus domesticus)

Abstract

The development of disease following oral challenge with Yersinia pseudotuberculosis (serotype 11) was compared in four groups of five birds treated with a parenteral dose of 10 mg iron dextran (Imferon), 10 mg of iron dextran plus 10 mg of the chelating agent desferrioxamine (Desferal), 10 mg of desferrioxamine or 10 mg of dextran 2 days before the experiment. Four groups of two birds received the above treatment regimens but no bacterial challenge. In iron dextran treated birds, oral challenge resulted in faecal shedding for the 10 day duration of the experiment, whereas in those birds which received dextran or desferrioxamine alone, the duration of faecal shedding was significantly less. Serological titres to the lipopolysaccharide antigen of the challenge bacteria were also lower in the groups not pretreated with iron dextran. The birds pretreated with iron dextran had diarrhoea and were clinically unwell 2 days following the initial oral challenge. Birds not given iron dextran showed no clinical signs of disease. Histological examination of five selected areas in the liver, spleen and intestine of each bird indicated that birds in the groups treated with iron dextran prior to bacterial challenge had significantly more intestinal lesions than birds in the groups not treated with iron. In contrast, there were significantly more lesions in the spleens of birds not pretreated with iron dextran. There was no evidence of stainable iron in the livers of birds challenged with Y pseudotuberculosis 10 days after an injection of 10 mg of iron dextran. This is in contrast to birds given iron dextran and no bacteria. It was concluded that pretreatment of birds with iron dextran resulted in more severe clinical disease, prolonged faecal shedding with associated intestinal lesions and higher serological titres to bacterial antigen. The number of lesions in the spleen and liver was not necessarily correlated with the severity of clinical disease, and in all infected birds the hepatic iron levels were significantly lower than in the non-infected control birds 10 days after oral challenge. It seems probable that the chicken has a high requirement for iron during infection with Y pseudotuberculosis and mobilises stored and exogenously supplied iron for tissue repair and immunological function.