This paper has been prepared as one of the four district veterinarian (DV) contributions on Chlamydial diseases at the 2011 District Veterinarians Conference. As the other speakers are likely to concentrate on the clinical disease I thought it may be of some interest to report from our computerised records which includes surveillance data since 1994.
The data presented in this paper has been recorded in three separate software systems. It includes cases investigated by DVs and private practitioner laboratory reports.
Diagnosis reports were created from our EZY software for Chlamydia, sporadic bovine encephalitis (SBE) and arthritis. It is inevitable that there were some discrepancies in the choice of the appropriate diagnosis for data entry due to a lengthy diagnosis list available and seven different DVs or locum DVs over the period from 1994 making the call as to the 'diagnosis' for data entry. In a few cases there were multiple diagnoses for the one case and one of the diagnoses was either Chlamydia or SBE. The Chlamydia and SBE reports were added together, the arthritis reports were checked against the comments and/or property records and those that deserved to be called Chlamydia were retained and added to the composite spreadsheets for sheep and cattle that form the basis for this report.
There were 27 sheep investigations recorded with 11,505 sheep at risk, 516 sheep affected (includes deaths) and 44 deaths.
|Date||At Risk||Cases||Dead||Sex||Age Category||Problem|
There were 21 cattle investigations recorded with 829 cattle at risk, 76 affected (includes deaths) and 14 deaths.
|Date||At Risk||Cases||Dead||Sex||Breed||Age Category||Problem|
|20/05/2008||12||1||0||Mixed||Hereford||Young Adult||Nervous Problem|
|17/12/2008||1||1||0||Male||Holstein Friesian||Adult||Ill thrift|
The apparent upsurge in investigations from 2003 might be related to the lengthy drought.
It is unknown whether there are real peaks in spring and late summer or whether farmers are less likely to report disease during haymaking and harvest during November and December.
Weaners and young adults made up the bulk of cases investigated.
While the presenting problem listed can reflect the veterinarian's choice of options from the computer list, it is interesting that sheep most consistently present as lameness whereas cattle most commonly present with lameness or neurological symptoms.
I was surprised by how few farms actually had Chlamydial diagnoses recorded over a 16 year period. Sometimes our impressions (of Chlamydial arthritis in sheep) are not matched by our records. However arthritis in sheep appears to be quite common when you talk to some local industry leaders. It's interesting to note however that in the MLA final report 'Assessing the economic cost of endemic disease on the profitability of Australian beef cattle and sheep producers', arthritis is eighth on the list for sheep (page 68) and it would not only include Chlamydia but also post-marking arthritis , erysipelothrix etc. Perhaps Chlamydia in sheep (apart from studs) does not hit profits hard enough for most producers to make a call for veterinary assistance.
The ability to collate the data presented in this paper highlights the necessity for disease surveillance data to be recorded and maintained on a computerised recording system. To be effective, this computerised system must allow ready access to data collected over many years and across all of NSW.