Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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Chlamydiosis in Ostriches Detlef K. Onderka Animal Health Laboratories Branch Alberta Department of Agriculture In December of 1996, 235 ostriches originating from a number of farms from the three prairie provinces were assembled for an on farm quarantine in southern Alberta. They were all adult birds of breeder age to be exported as brood stock to China. Due to the severe winter conditions the birds were kept inside a heated barn and were in crowded condition. As a part of the health protocol of the Chinese import regulations, the birds were required to be serologically tester for Chlamydia sp. The compliment fixation test was carried out at Ames, Iowa in January of 1997. The results showed 37 out of 231 (16%) to be sero positive. Between the end of January and the 8th of February at least 15 birds died. Ten birds were submitted for necropsies. The history indicated no apparent symptoms other than the birds appeared to become quite thin. Some birds were euthanized prior to submission because of frostbites. No coughing was reported. On postmortem examination, the birds were in moderate body condition and some had air sacculitis and pneumonia. One bird had inflammatory exudate in the esophagus and in some the air sacs were rather extensively involved being thickened and necrotic with extension of the inflammation into the lungs. Although none of the birds submitted had tested positive for Chlamydia sp the presence of seropositive birds in the flock together with the respiratory tract lesions prompted isolation attempts of Chlamydia organisms. In all birds, Chlamydia sp was isolated on McCoy cells and identified by fluorescent antibody technique. The suggested that the seropositive birds were likely shedding the organism, infecting other birds in the group that have previously been seronegative. Because of this development, the exportation of this flock was abandoned and the birds were sent to slaughter in Alberta. There was no significant condemnation. A group of five hens and one rooster were retained in on farm isolation for research purpose. On the initial test in January these birds were seronegative, however, there was reason to treat two of the birds with antibiotics against conjunctivitis and coughing. In August of 1997 cloacal swabs were taken from these birds and from all Clamydia sp was isolated. One egg from one of the hens failed to hatch. The inner shell membrane was swabbed and cultured for Chlamydia sp. Again Chlamydia organisms were isolated. The embryo had not pipped. The yolk sac was absorbed, but no significant metabolism of the yolk sac appeared to have occurred. There was slight edema. The likely cause for the hatchability problem may have been oxygen deficiency. Upon collection and before incubation, the egg had been surface disinfected using Virkon. Chlamydiosis has rarely been reported in ostriches. A review of chlamydiosis in ratites in Texas showed rheas to be fairly susceptible to this infection, but only one adult ostrich was found to shed Chlamydia sp on cloacal swabs. One small ostrich chick that was housed with Chlamydia positive parrots became clinically ill. It appears that ostriches are relatively resistant to clinical disease although they may be shedders. In our case, the type of Chlamydia sp was not determined, but it is thought to be Chlamydia psittaci. Work in Texas suggests that it is a strain common to pigeons and that ostriches may be infected while exposed to feral pigeons. A new test developed at the National Animal Diseases Centre, Ames, Iowa uses a PCR-RFLP diagnostic test which, based on ribosomal sequences, can reliably identify nine types of Chlamydia sp. Applying this technology it may be possible to trace the origin and spread of Chlamydia sp infection in ostriches. A second shipment of ostriches was assembled in central Alberta for export to China under a similar disease protocol and again a number of birds were seropositive resulting again in cancellation of this fairly lucrative export venture. Chlamydosis is thus a fairly significant economic disease even though in most cases the clinical disease is absent. Our present research is focused on determining whether or not long term Tetracycline treatment (60 days) may result in cessation of shedding and the production of Chlamydia free eggs and chicks. |
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