ISOLATION OF ORNITHOBACTERIUM-RHINOTRACHE ALE FROM CHICKENS, HENS ANDTURKEYS SHOWING RESPIRATORY SYMPTOMS - PRELIMINARY-REPORT

Mass incidence of respiratory disease was observed in 4 to 6 weeks old broiler flocks of the North-Eastern region of Hungary during the summ er and in autumnal months in the Southern Plain of the country in 1994 . In the affected chickens weakness, disheveled feathers, occasionally head edema, quickly developing dyspnoea progressing to asphyxia were observed. The disease developed within one to three days affecting the whole flock and lasted 5 to 7 days, causing daily 0.5 to 2% losses. T hereafter, the clinical symptoms ceased gradually, however the losses persisted for several days. Besides frequent secondary infections (E. coli), the grade of losses (8 to 60 %) was significantly influenced by the micro climate. The pathological examinations revealed rubor in th e nasal passages and trachea, partly with fibrination and haemorrhages , as well as occasionally with pneumonia. The histological examination s - besides the signs of inflammation - revealed severe destruction of the epithelium of mucosa, partly with total necrosis. During the bact eriological investigation Pasteurella-like colonies were isolated on b lood agar from quite all regions of the respiratory tract of affected animals, mainly from the trachea and nasal passages. The bacterium gro wn more intensively in carbon dioxide medium besides other bacteria (E . coli, A Proteus, Pseudomonas, Staphylococcus, Streptococcus), mainly in subacute cases. The Gramnegative, short, rod form, oxidase and ure ase positive, catalase negative strains were identified as Ornithobact erium rhinotracheale. In the epizootiology of the disease, the vertica l spreading is supposed. The day-old birds can even be infected in the incubators, however the disease develops between the age of 24 to 40 days due to the age resistance or yolk immunity. Experiences of the tr eatment are unfavorable, only medicaments effective in vitro gave mode rate results in a dose twice or three times higher than therapeutic on e. In the control of the disease, the possibility of vertical infectio ns should be minimized. In this, an important role could have the egg treatment and incubators. Disinfection of eggs should precede a thorou gh cleaning because it is possible that formalin, used widely nowadays , coagulates the contaminating proteins, and causes a protective layer for the bacteria situated in the pores of egg shell. It is proper to dissolve, eliminate the egg shell contaminants and thereafter disinfec t the egg. Diminishing of all forms of horizontal infection is also ve ry important.