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Home » Archive » 2013

TDK conference 2013

Examination of the virulence of Bordetella avium and Ornithobacterium rhinotracheale in two animal models
Horváth Anna - year 5
Insitute for Veterinary Medical Research, Centre for Agricultural Research, HAS
Supervisor: Réka Szabó DVM

Abstract:

Bordetella avium and Ornithobacterium rhinotracheale are globally occurring avian pathogen bacteria. They primarily cause respiratory diseases that have been reported in Hungarian populations at the end of the 1980’s. The considerable economic loss they cause is not due to mortality rates, but the developmental retardation and the longer maintenance of these flocks.

According to some studies O. rhinotracheale is a primary pathogen, others observed that it only causes a disease with other pathogens. During the course of our work we investigated the pathogenic potential of the two bacteria in animal experiments. We tried to determine their respective roles and to elicit any possible synergism of these bacteria in the pathogenesis of the diseases. The aim of our study was to find an appropriate animal model for the in vivo examination of the virulence of these organisms. We tested the sensitivity of two poultry species, and noted the character and severity of the clinical signs in case of individual or simultaneous infection. We evaluated the macroscopic and microscopic disorders’ character, degree and the difference between several groups by necropsy.

In one-day-old SPF chickens we couldn’t induce an infection by neither of the pathogens. In the experiment using one-day-old commercial turkeys we could recover both pathogens from the lungs and tracheas of the animals, and we observed clinical signs, pathological and histological lesions. There was no mortality in any of the groups. This and the mild clinical signs might be explained by the weaker virulence of the bacteria or the environmental factors.

The severity of post-mortem lesions seen in the group challenged with both B. avium and O. rhinotracheale, and the fact that we could recover these organisms for a longer period could indicate some sort of cooperation between the two pathogens. We plan to examine the exact mechanism and possible virulence factors in further experiments.

These findings could provide useful information about treatment and prevention of these infections for the practice. Depending on the results, development of new strategies for the preservation of health and enhancement of cost-effectiveness in poultry populations can be possible.



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