Detection of Coxiella burnetii and equine herpesvirus 1, but not Leptospira spp. or Toxoplasma gondii, in cases of equine abortion in Australia - a 25 year retrospective study

Equine abortion is a cause of severe economic loss to the equine industry. Equine herpesvirus 1 is considered a primary cause of infectious abortion in horses, however other infectious agents can also cause abortion. Abortions due to zoonotic pathogens have implications for both human and animal health. We determined the prevalence of Coxiella burnetii, Leptospira spp. and Toxoplasma gondii in 600 aborted equine foetal tissues that were submitted to our diagnostic laboratories at the University of Melbourne from 1994 to 2019. Using qPCR we found that the prevalence of C. burnetii was 4%. The highest annual incidence of C. burnetii was observed between 1997-2003 and 2016-2018. The prevalence of C. burnetii in Victoria and New South Wales was 3% and 6% respectively. All the samples tested negative for Leptospira spp. and Toxoplasma gondii DNA. Equine herpesvirus 1 DNA was detected at a prevalence of 3%. This study has provided evidence for the presence of C. burnetii in equine aborted foetal tissues in Australia, but the role of C. burnetii as potential cause of abortion in Australia requires further investigation. C. burnetii is a zoonotic disease agent that causes the disease 'Q fever' in humans. We recommend that appropriate protective measures should be considered when handling material associated with equine abortions to reduce the risk of becoming infected with C. burnetii

Bovine digital dermatitis in Victoria, Australia

Aims: The objectives of this study were to estimate the prevalence of digital dermatitis (DD) in Victoria, Australia, and to investigate which organisms are consistent with typical DD lesions. The prevalence and causative pathogens of DD are not clear yet in Australia and this paper is one of the first to explore these questions in this country. Methods: Examination and sampling of limbs was undertaken at three knackeries in Victoria, Australia. Limbs were classified as normal (N), active DD-lesion (A), dried or chronic DD-lesion (D) or suspected case of DD (S). A total of 823 cows were examined. Six skin biopsies were taken at each knackery, from which DNA was extracted for diversity profiling. Histochemical staining of samples was performed on eight of the skin biopsies. Results: DD was detected in 29.8% of all cows. The prevalence of DD was significantly higher in dairy cows (32.2%) than in beef cows (10.8%). The differential abundance of Treponema-species was significantly increased in dried lesions, compared with the normal skin biopsies. Actinobacteria, Proteobacteria, Firmicutes and Tenericutes were found to be significantly different in abundance in the DD lesions compared with normal skin biopsies. Silver staining of samples showed only mild inflammation and in two samples organisms with morphology consistent with Spirochaetes were detected. Conclusions: The calculated prevalence indicates that DD is present in Victoria, Australia. The results of diversity profiling showed that the presence of Treponema-species was significantly different between the samples of DD lesions and normal skin

Bovine digital dermatitis in Victoria, Australia

Aims: The objectives of this study were to estimate the prevalence of digital dermatitis (DD) in Victoria, Australia, and to investigate which organisms are consistent with typical DD lesions. The prevalence and causative pathogens of DD are not clear yet in Australia and this paper is one of the first to explore these questions in this country. Methods: Examination and sampling of limbs was undertaken at three knackeries in Victoria, Australia. Limbs were classified as normal (N), active DD-lesion (A), dried or chronic DD-lesion (D) or suspected case of DD (S). A total of 823 cows were examined. Six skin biopsies were taken at each knackery, from which DNA was extracted for diversity profiling. Histochemical staining of samples was performed on eight of the skin biopsies. Results: DD was detected in 29.8% of all cows. The prevalence of DD was significantly higher in dairy cows (32.2%) than in beef cows (10.8%). The differential abundance of Treponema-species was significantly increased in dried lesions, compared with the normal skin biopsies. Actinobacteria, Proteobacteria, Firmicutes and Tenericutes were found to be significantly different in abundance in the DD lesions compared with normal skin biopsies. Silver staining of samples showed only mild inflammation and in two samples organisms with morphology consistent with Spirochaetes were detected. Conclusions: The calculated prevalence indicates that DD is present in Victoria, Australia. The results of diversity profiling showed that the presence of Treponema-species was significantly different between the samples of DD lesions and normal skin

Bovine digital dermatitis in Victoria, Australia

Aims: The objectives of this study were to estimate the prevalence of digital dermatitis (DD) in Victoria, Australia, and to investigate which organisms are consistent with typical DD lesions. The prevalence and causative pathogens of DD are not clear yet in Australia and this paper is one of the first to explore these questions in this country. Methods: Examination and sampling of limbs was undertaken at three knackeries in Victoria, Australia. Limbs were classified as normal (N), active DD-lesion (A), dried or chronic DD-lesion (D) or suspected case of DD (S). A total of 823 cows were examined. Six skin biopsies were taken at each knackery, from which DNA was extracted for diversity profiling. Histochemical staining of samples was performed on eight of the skin biopsies. Results: DD was detected in 29.8% of all cows. The prevalence of DD was significantly higher in dairy cows (32.2%) than in beef cows (10.8%). The differential abundance of Treponema-species was significantly increased in dried lesions, compared with the normal skin biopsies. Actinobacteria, Proteobacteria, Firmicutes and Tenericutes were found to be significantly different in abundance in the DD lesions compared with normal skin biopsies. Silver staining of samples showed only mild inflammation and in two samples organisms with morphology consistent with Spirochaetes were detected. Conclusions: The calculated prevalence indicates that DD is present in Victoria, Australia. The results of diversity profiling showed that the presence of Treponema-species was significantly different between the samples of DD lesions and normal skin

Clinical, Microbiological and Pathological Findings of <i>Mycobacterium ulcerans</i> Infection in Three Australian Possum Species

<div><p>Background</p><p>Buruli ulcer (BU) is a skin disease caused by <i>Mycobacterium ulcerans</i>, with endemicity predominantly in sub-Saharan Africa and south-eastern Australia. The mode of transmission and the environmental reservoir(s) of the bacterium and remain elusive. Real-time PCR investigations have detected <i>M. ulcerans</i> DNA in a variety of Australian environmental samples, including the faeces of native possums with and without clinical evidence of infection. This report seeks to expand on previously published findings by the authors' investigative group with regards to clinical and subclinical disease in selected wild possum species in BU-endemic areas of Victoria, Australia.</p><p>Methodology/Principal Findings</p><p>Twenty-seven clinical cases of <i>M. ulcerans</i> infection in free-ranging possums from southeastern Australia were identified retrospectively and prospectively between 1998–2011. Common ringtail possums (<i>Pseudocheirus peregrinus</i>), a common brushtail possum (<i>Trichosurus vulpecula</i>) and a mountain brushtail possum (<i>Trichosurus cunninghami</i>) were included in the clinically affected cohort. Most clinically apparent cases were adults with solitary or multiple ulcerative cutaneous lesions, generally confined to the face, limbs and/or tail. The disease was minor and self-limiting in the case of both <i>Trichosurus</i> spp. possums. In contrast, many of the common ringtail possums had cutaneous disease involving disparate anatomical sites, and in four cases there was evidence of systemic disease at post mortem examination. Where tested using real-time PCR targeted at IS<i>2404</i>, animals typically had significant levels of <i>M. ulcerans</i> DNA throughout the gut and/or faeces. A further 12 possums without cutaneous lesions were found to have PCR-positive gut contents and/or faeces (subclinical cases), and in one of these the organism was cultured from liver tissue. Comparisons were made between clinically and subclinically affected possums, and 61 PCR-negative, non-affected individuals, with regards to disease category and the categorical variables of species (common ringtail possums <i>v</i> others) and sex. Animals with clinical lesions were significantly more likely to be male common ringtail possums.</p><p>Conclusions/Significance</p><p>There is significant disease burden in common ringtail possums (especially males) in some areas of Victoria endemic for <i>M. ulcerans</i> disease. The natural history of the disease generally remains unknown, however it appears that some mildly affected common brushtail and mountain brushtail possums can spontaneously overcome the infection, whereas some severely affected animals, especially common ringtail possums, may become systemically, and potentially fatally affected. Subclinical gut carriage of <i>M. ulcerans</i> DNA in possums is quite common and in some common brushtail and mountain brushtail possums this is transient. Further work is required to determine whether <i>M. ulcerans</i> infection poses a potential threat to possum populations, and whether these animals are acting as environmental reservoirs in certain geographical areas.</p></div

Protection Induced in Broiler Chickens following Drinking-Water Delivery of Live Infectious Laryngotracheitis Vaccines against Subsequent Challenge with Recombinant Field Virus.

Infectious laryngotracheitis virus (ILTV) causes acute upper respiratory tract disease in chickens. Attenuated live ILTV vaccines are often used to help control disease, but these vaccines have well documented limitations, including retention of residual virulence, incomplete protection, transmission of vaccine virus to unvaccinated birds and reversion to high levels of virulence following bird-to-bird passage. Recently, two novel ILTV field strains (class 8 and 9 ILTV viruses) emerged in Australia due to natural recombination between two genotypically distinct commercial ILTV vaccines. These recombinant field strains became dominant field strains in important poultry producing areas. In Victoria, Australia, the recombinant class 9 virus largely displaced the previously predominant class 2 ILTV strain. The ability of ILTV vaccines to protect against challenge with the novel class 9 ILTV strain has not been studied. Here, the protection induced by direct (drinking-water) and indirect (contact) exposure to four different ILTV vaccines against challenge with class 9 ILTV in commercial broilers was studied. The vaccines significantly reduced, but did not prevent, challenge virus replication in vaccinated chickens. Only one vaccine significantly reduced the severity of tracheal pathology after direct drinking-water vaccination. The results indicate that the current vaccines can be used to help control class 9 ILTV, but also indicate that these vaccines have limitations that should be considered when designing and implementing disease control programs

Additional file 2 of Whole genome sequence analysis of equid gammaherpesvirus -2 field isolates reveals high levels of genomic diversity and recombination

Additional file 2: Table S1. Summary of sequencing metrics and assembly for EHV2 isolates. Table S2. Percentage nucleotide identity between EHV2 isolates. Table S3. Analysis of the overall selective pressure acting on EHV2 genes. Calculations of non-synonymous substitutions per non-synonymous site (Ka) to synonymous substitution per synonymous site (Ks) ratios for all EHV2 genes, along with standard errors based on 1,000 bootstrap replicates. Table S4. Details of the genes included in the study and their accession numbers. Table S5. Recombination breakpoint analysis of 20 EHV2 strains including strains 86/67 and G9/92

Data for sub-clinically affected possums.

<p>Data for sub-clinically affected possums.</p