J. A. Toribio

Cross-sectional study of canine leptospirosis in animal shelter populations in mainland Australia

OBJECTIVE To measure the prevalence of canine leptospirosis in Queensland and to detect infection, if present, in New South Wales, Victoria, South Australia, Western Australia and the Northern Territory by measuring the serological titres of dogs held in animal shelters. PROCEDURE Samples were collected through stratified sampling from multiple dog shelters in Queensland and New South Wales, and from one dog shelter located in close proximity to a major urban area in Victoria, South Australia, the Northern Territory and Western Australia. All samples were analysed using the microscopic agglutination test at the WHO/FAO/OIE Collaborating Centre for Reference & Research on Leptospirosis, Queensland Health Scientific Services in Brisbane, Queensland. RESULTS Of a total of 956 samples submitted, 18 (1.9%) had positive leptospirosis titres. True prevalence measured in Queensland was estimated to be 2.5%, and the true prevalence in New South Wales, Victoria, South Australia, Western Australia and the Northern Territory was estimated to be 2.3%, 2.8%, 0%, 1% and 1.1% respectively. An association was found between seropositive status and female dogs (odds ratio (OR) 1.92) and seropositive status and the age group 1 to < 3 years (OR 1.41). Although 11 different serovars were detected, Leptospira interrogans serovar Copenhageni was the most prevalent and was found in 4 of the 18 positive dogs as a single infection. CONCLUSION Serological evidence of canine leptospirosis in five states in mainland Australia indicates that the disease is more broadly distributed than previously thought.

Are the Australian poultry industries vulnerable to large outbreaks of highly pathogenic avian influenza

OBJECTIVE To describe the structure of the Australian poultry industry and discuss the potential for highly pathogenic avian influenza (HPAI) to spread between Australian poultry farms. PROCEDURE High densities of poultry farms, frequent contacts between farms by service providers, the supply of live poultry markets (LPM) and the presence of free-range duck flocks in affected regions have been identified as risk factors for the spread of HPAI between flocks in outbreaks causing the death or destruction of over 1 million poultry overseas. Data on 1,594 commercial Australian chicken meat, chicken egg, duck and turkey farms were collected by a telephone questionnaire of farm managers to assess the risk of a HPAI outbreak in Australia. RESULTS AND DISCUSSION Five regions of Australia had farm densities comparable to overseas regions that experienced widespread HPAI. Common service providers routinely contacted different classes and types of farms over wide geographic areas. However, no responding farms supplied LPM and the majority of duck farms did not produce free-range ducks. CONCLUSION Outbreaks of HPAI have the potential to cause serious impacts on the Australian poultry industry. The risk posted by LPM and free-range ducks is limited, but the movement of genetic stock and common service providers could spread infection between companies, industries or geographical regions. Biosecurity measures are therefore considered critical to limit the secondary spread of infection should an outbreak occur.

Financial modelling of the potential cost of ovine Johne's disease and the benefit of vaccinating sheep flocks in southern New South Wales.

OBJECTIVE To develop an enterprise gross margin (GM) model that predicts the on-farm financial impact of ovine Johnes disease (OJD) for various sheep enterprises in Australia. In addition, to estimate the benefits and costs of control through the use of the Gudair vaccination, including a breakeven point. DESIGN AND POPULATION Data for the model was gained from an observational study conducted over a 3-year period from 2002 to 2004 using sheep from 12 OJD-infected flocks from southern New South Wales. Flocks ranged between 3500 and 20,000 sheep, with owner estimates of 5% or greater OJD mortality at the start of the study. PROCEDURE A GM model was developed to predict the on-farm financial impact of OJD for various sheep enterprises in Australia, comparing non-infected, infected (status quo) and infected (vaccination) disease scenarios. RESULTS Vaccination breakeven points are achieved within 2 to 3 years for breeding enterprises if OJD mortalities are high, rising towards 7 years for a Merino ewe enterprise if OJD mortalities are low. CONCLUSION The GM model demonstrates the returns to investment of vaccination for Australian sheep producers with OJD-infected flocks.

Assessment of the risks of communicable disease transmission through the movement of poultry exhibited at agricultural shows in New South Wales.

OBJECTIVE To assess biosecurity practices in the fancy poultry show sector that would influence the establishment and spread of exotic diseases in poultry in New South Wales. DESIGN A cross-sectional survey of 105 fancy poultry exhibitors at seven agricultural shows. PROCEDURE Exhibitors were interviewed about biosecurity practices on their farms and their knowledge of exotic diseases. Poultry stewards at 18 shows were interviewed about biosecurity practices at their shows. RESULTS Although many exhibitors travelled only short distances to attend shows, some exhibitors attended up to 30 shows per year and travelled interstate to exhibit poultry. A network diagram revealed extensive connections and interactions of poultry throughout the eastern half of NSW. Five of 18 shows included cash sales without any record of purchasers; 46% of exhibitors reintroduced exhibited birds back into their flocks without a quarantine period; and 16% failed to wash cages used to transport the birds. There was a general awareness that exhibition of birds posed a risk to flock health, but knowledge of avian influenza and practices that could be adopted to minimise the risk of disease introduction was limited. CONCLUSIONS The factors that could assist the establishment and spread of exotic diseases in poultry in NSW include the mixing of birds at shows, inadequate recording of exhibitor details at shows, inadequate biosecurity practices when reintroducing exhibited poultry back into flocks, cash sales associated with shows that did not include the collection of purchaser details, and inadequate identification of birds.

Challenges posed to the traceability of weaner pigs following live auction

OBJECTIVES To gather demographic data on live pig sales through a peri-urban saleyard in Camden, New South Wales, and to demonstrate the difficulties in tracing the subsequent movements of pigs, particularly weaner pigs. PROCEDURE Records of pig sales held weekly at the Camden saleyards for the 2003/2004 and 2004/2005 financial years were analysed. Saleyard data on a number of variables were entered into a purpose-designed database. Distributions of pig sales according to pig class (weaner/porker/baconer/backfatter), purchaser type (butcher/non-butcher), and transaction type (cash/account) were determined. RESULTS More weaners (3192 in 2003/2004 and 3940 in 2004/2005) were sold than any other class of pig, accounting for 45% of the total pigs sold during this period. During 2003/2004, 3802 pigs were bought by 329 non-butcher purchasers including 1631 weaners (43%) purchased by 153 non-butchers (47%). The majority of these non-butchers during the study period (86%) paid cash for their pigs and did not provide the necessary information to allow the end destination of pigs to be determined. Location data was available for all vendors but only 25% of purchasers. CONCLUSIONS This study highlights the challenges posed in tracing movement of pigs following sale by auction. A high proportion of weaners sold at this peri-urban saleyard would not have been slaughtered immediately. This study highlights the potential difficulties in tracing pig movements after sale, for disease control purposes. We recommend that legislation be amended requiring the identification of weaner pigs sold live at auction in all states of Australia and the recording of the property identification code of all vendors and purchasers of pigs sold live at auction.

Fasciola gigantica infection in large ruminants in northern Laos: smallholder knowledge and practices

High prevalence of Fasciola spp. infection in smallholder large ruminant farming systems has been confirmed in many regions of South-East Asia, yet information on trematode knowledge and any control practices of large ruminant farmers is lacking. We surveyed smallholder farmers (n = 326) in northern Laos on knowledge of liver fluke and its management in their large ruminants, identifying 93.1% of farmers had no knowledge and 6.9% minimal knowledge of the parasite and impacts on large ruminant production. The survey further confirmed anecdotal reports that control or prevention measures were lacking, with none of the surveyed producers using effective anthelminthic treatments or grazing strategies to control Fasciola spp. This was despite 20.6% of farmers having reported observing leaf-shaped parasites in the liver of their cattle or buffalo when slaughtered in the past. With increasing demand for red meat in the region, subsistence smallholder farmers are able to supply this market and increase their income. Athough the production impact of fascioliasis in large ruminants in these farming systems still needs to be quantified, farmer knowledge and control of fascioliasis in this region is likely to increase livestock productivity and improve rural livelihoods. This would help to address regional rural poverty and food insecurity, but requires improved knowledge to address the identified knowledge and practice gaps on presence, impact and control of fasciolosis. The majority (95.4%) of surveyed farmers indicated a desire to learn more about fascioliasis in large ruminants, suggesting that extension methods used in the past need adapting to result in more effective knowledge transfer and changed practices in future.

Adverse reactions in a population of Sydney pet rabbits vaccinated against rabbit calicivirus

OBJECTIVE To determine the general clinical presentation and incidence of adverse reactions to Cylap® RCD vaccinations, of a nature serious enough for veterinary attention, in a Sydney population of pet rabbits. DESIGN A retrospective survey using hospital databases. METHODS Nine veterinary hospitals in Sydney participated in a database search for the number of rabbits vaccinated within a 2-year period. The hospitals involved had an identified interest in rabbit medicine and included general, specialist and teaching hospitals. Details of the rabbit, vaccination event and any possible reaction were collected and analysed. RESULTS Of 933 events recorded in 705 rabbits, 17 (1.8%) adverse reactions were observed. Of the adverse events, local injection site reactions (alopecia, abrasions and scabbing) were most common. Other reactions, including systemic signs of gastrointestinal tract stasis, lethargy and forelimb lameness, were also documented. Overall, rabbits presented for vaccination were mostly male (57.7%) and desexed (71.3%), with an average age of 28.1 months (median 19.0, range 1.4-149.8 months) and an average weight at first vaccination of 2.12 kg (median 2.08 kg, range 0.18-5.6 kg). A significant association between increasing age and decreased incidence of adverse events was demonstrated (P value, 0.038). CONCLUSIONS The benefits of vaccination against RCV outweigh the risks of an adverse reaction occurring. Data from this study show that adverse reactions occur infrequently, are generally mild and self-resolving, and decrease in incidence with increasing age. These results are similar to previous field research on wild rabbit colonies and reports from government and industry.