Effects of some immunosuppressive factors on campylobacteriosis outbreaks in poultry

Abstract

Campylobacteria are widely distributed in domestic and wild animals. Avian species are the most common host of campylobacteria, thus an important source for human infection caused by this organism. Campylobacteriosis in animals frequently proceeds without clinical symptoms, which may be due to the different virulence of the agent, as well as to the immune status of the infected animal. In this trial we investigated the effects of the vaccine against infective bursal disease (IBD) on occurrence and clinical manifestation of campylobacteriosis in conditions of controlled experimental infection with the strain Campylobacter jejuni. The immunosuppressive effects of a live attenuated vaccine against IBD on development of clinically manifest campylobacteriosis in perorally challenged chickens were assessed. The investigation was performed on 90 chickens in experimental conditions. The presence of Campylobacter jejuni was confirmed by reisolation, while identification of the organism was performed on the basis of its morphological, cultural and biochemical characteristics. Specific antibody titer and humoral immune response to C. jejuni specific antibodies were monitored using the complement fixation reaction method. Clinical symptoms of the disease were observed in chickens infected with Campylobacter jejuni and vaccinated against infective bursal disease. Pathomorphological findings revealed changes in the intestines and liver, from which Campylobacter jejuni was isolated. C. jejuni specific antibodies were detected in the infected birds in the third week post infection, with titer values ranging from 1:4 to 1:16. Results of our research strongly imply an immunosuppressive effect of the IBD vaccine on development of campylobacteriosis, which is supported by the clinical and morphological findings, i.e. isolation of the agent and detection of specific antibodies. .