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Tiller R.V.,Centers for Disease Control and Prevention | Gee J.E.,Centers for Disease Control and Prevention | Frace M.A.,Centers for Disease Control and Prevention | Taylor T.K.,Australian Animal Health Laboratory | And 3 more authors.
Applied and Environmental Microbiology | Year: 2010

We report on the characterization of a group of seven novel Brucella strains isolated in 1964 from three native rodent species in North Queensland, Australia, during a survey of wild animals. The strains were initially reported to be Brucella suis biovar 3 on the basis of microbiological test results. Our results indicated that the rodent strains had microbiological traits distinct from those of B. suis biovar 3 and all other Brucella spp. To reinvestigate these rodent strains, we sequenced the 16S rRNA, recA, and rpoB genes and nine housekeeping genes and also performed multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA). The rodent strains have a unique 16S rRNA gene sequence compared to the sequences of the classical Brucella spp. Sequence analysis of the recA, rpoB, and nine housekeeping genes reveals that the rodent strains are genetically identical to each other at these loci and divergent from any of the currently described Brucella sequence types. However, all seven of the rodent strains do exhibit distinctive allelic MLVA profiles, although none demonstrated an amplicon for VNTR 07, whereas the other Brucella spp. did. Phylogenetic analysis of the MLVA data reveals that the rodent strains form a distinct clade separate from the classical Brucella spp. Furthermore, whole-genome sequence comparison using the maximal unique exact matches index (MUMi) demonstrated a high degree of relatedness of one of the seven rodent Brucella strains (strain NF 2653) to another Australian rodent Brucella strain (strain 83-13). Our findings strongly suggest that this group of Brucella strains isolated from wild Australian rodents defines a new species in the Brucella genus. Copyright © 2010, American Society for Microbiology.


Windsor M.,Institute for Animal Health | Hawes P.,Institute for Animal Health | Monaghan P.,Institute for Animal Health | Monaghan P.,Australian Animal Health Laboratory | And 5 more authors.
Traffic | Year: 2012

Infection of cells with African swine fever virus (ASFV) can lead to the formation of zipper-like stacks of structural proteins attached to collapsed endoplasmic reticulum (ER) cisternae. We show that the collapse of ER cisternae observed during ASFV infection is dependent on the viral envelope protein, J13Lp. Expression of J13Lp alone in cells is sufficient to induce collapsed ER cisternae. Collapse was dependent on a cysteine residue in the N-terminal domain of J13Lp exposed to the ER lumen. Luminal collapse was also dependent on the expression of J13Lp within stacks of ER where antiparallel interactions between the cytoplasmic domains of J13Lp orientated N-terminal domains across ER cisternae. Cisternal collapse was then driven by disulphide bonds between N-terminal domains arranged in antiparallel arrays across the ER lumen. This provides a novel mechanism for biogenesis of modified stacks of ER present in cells infected with ASFV, and may also be relevant to cellular processes. © 2011 John Wiley & Sons A/S.


Samaan G.,National Center for Epidemiology and Population Health | Hendrawati F.,Disease Investigation Center | Taylor T.,Australian Animal Health Laboratory | Pitona T.,Disease Investigation Center | And 4 more authors.
Bulletin of the World Health Organization | Year: 2012

Problem The World Health Organization (WHO) developed a guideline with 10 control measures to reduce transmission of A(H5N1) avian influenza virus in markets in low-resource settings. The practical aspects of guide implementation have never been described. Approach WHO's guideline was implemented in two Indonesian markets in the city of Makassar to try to reduce transmission of the A(H5N1) virus. The guideline was operationalized using a participatory approach to introduce a combination of infrastructural and behavioural changes. Local setting Avian influenza is endemic in birds in Makassar. Two of the city's 22 dilapidated, poorly-run bird markets were chosen for the study. Before the intervention, neither market was following any of WHO's 10 recommended control measures except for batch processing. Relevant changes Market stakeholders' knowledge about the avian influenza A(H5N1) virus improved after the interventions. WHO guideline recommendations for visual inspection, cleaning and poultry-holding practices, as well as infrastructural requirements for zoning and for water supply and utilities, began to conform to the WHO guideline. Low-maintenance solutions such as installation of wastewater treatment systems and economic incentives such as composting were well received and appropriate for the low-resource setting. Lessons learnt Combining infrastructural changes with behaviour change interventions was critical to guideline implementation. Despite initial resistance to behaviour change, the participatory approach involving monthly consultations and educational sessions facilitated the adoption of safe food-handling practices and sanitation. Market authorities assumed important leadership roles during the interventions and this helped shift attitudes towards regulation and market maintenance needs. This shift may enhance the sustainability of the interventions.


Penrith M.-L.,University of Pretoria | Vosloo W.,University of Pretoria | Vosloo W.,Australian Animal Health Laboratory | Jori F.,CIRAD - Agricultural Research for Development | And 2 more authors.
Virus Research | Year: 2013

African swine fever was reported in domestic pigs in 26 African countries during the period 2009-2011. The virus exists in an ancient sylvatic cycle between warthogs (. Phacochoerus africanus) and argasid ticks of the Ornithodoros moubata complex in many of the countries reporting outbreaks and in two further countries in the region. Eradication of the virus from the countries in eastern and southern Africa where the classic sylvatic cycle occurs is clearly not an option. However, the virus has become endemic in domestic pigs in 20 countries and the great majority of outbreaks in recent decades, even in some countries where the sylvatic cycle occurs, have been associated with movement of infected pigs and pig meat. Pig production and marketing and ASF control in Africa have been examined in order to identify risk factors for the maintenance and spread of ASF. These include large pig populations, traditional free-range husbandry systems, lack of biosecurity in semi-intensive and intensive husbandry systems, lack of organisation in both pig production and pig marketing that results in lack of incentives for investment in pig farming, and ineffective management of ASF. Most of these factors are linked to poverty, yet pigs are recognised as a livestock species that can be used to improve livelihoods and contribute significantly to food security. The changes needed and how they might be implemented in order to reduce the risk of ASF to pig producers in Africa and to the rest of the world are explored. © 2012 Elsevier B.V.


Curran J.M.,Murdoch University | Robertson I.D.,Murdoch University | Ellis T.M.,30 Leonard Street | Selleck P.W.,Australian Animal Health Laboratory
Avian Diseases | Year: 2014

Evaluation of avian influenza virus (AIV) diagnostic methods, including a nucleoprotein (NP) competitive enzyme-linked immunosorbent assay (c-ELISA), hemagglutination inhibition (HI) test, type A real-time reverse transcription polymerase chain reaction (RRT-PCR), and embryonating chicken egg (ECE) virus isolation (VI), suggested validity of these tests in wild birds comparable to that reported in poultry. This was determined by analyzing the results from experimental inoculation of three species of wild birds with a low-pathogenicity AIV and from field surveillance data. The NP c-ELISA in a high-AIV prevalence setting had 100% diagnostic sensitivity (Se; 95% confidence interval [CI]: 81.5%-100%) and 91% diagnostic specificity (Sp; 95% CI: 70.8%-98.9%) in negative controls compared with the RRT-PCR. In low-AIV prevalence flocks using a >60% inhibition positivity threshold, relative to the HI test, c-ELISA performed with 90.5% Se (95% CI: 86.2%-93.8%) and 41.2% Sp (95% CI: 38.1%-44.5%). Assessment of HI suggests a titer ≥8 is a positive test result in wild-bird sera, and using this titer had 83.3% Se (95% CI: 58.6%-96.4%) in experimentally infected birds. The RRT-PCR diagnostic performance compared with VI in cloacal swabs varied over 2-6 days postinoculation, having high Se (83.3%-100%) and Sp (94.1%-100%) with substantial agreement (kappa = 0.8). The cycle thresholds (Ct) for the RRT-PCR of Ct < 37 for positivity and Ct = 37-40 as indeterminate were found to be valid for the species included in this study. In view of the interpretative diagnostic difficulties in heterogeneous populations of wild birds, this evaluation in three species of wild birds and in surveillance data should provide greater confidence in the application of these methods routinely used in poultry. © American Association of Avian Pathologists.


Wang L.-F.,Australian Animal Health Laboratory | Daniels P.,Australian Animal Health Laboratory
Current Topics in Microbiology and Immunology | Year: 2012

Since the last major review on diagnosis of henipavirus infection about a decade ago, significant progress has been made in many different areas of test development, especially in the development of molecular tests using real-time PCR and many novel serological test platforms. In addition to provide an updated review of the current test capabilities, this review also identifies key future challenges in henipavirus diagnosis. © 2012 Springer-Verlag Berlin Heidelberg.


Field H.,Biosecurity Queensland | Crameri G.,Australian Animal Health Laboratory | Kung N.Y.-H.,Biosecurity Queensland | Wang L.-F.,Australian Animal Health Laboratory
Current Topics in Microbiology and Immunology | Year: 2012

Hendra virus, a novel and fatally zoonotic member of the family Paramyxoviridae, was first described in Australia in 1994. Periodic spillover from its natural host (fruit bats) results in catastrophic disease in horses and occasionally the subsequent infection of humans. Prior to 2011, 14 equine incidents involving seven human cases (four fatal) were recorded. The year 2011 saw a dramatic departure from the sporadic incidents of the previous 16 years, with a cluster of 18 incidents in a single 3-month period. The fundamental difference in 2011 was the total number of incidents, the geographic clustering, and the expanded geographic range. The 2011 cluster more than doubled the total number of incidents previously reported, and poses the possibility of a new HeV infection paradigm. Epidemiologic evidence suggests that compelling additional host and/or environmental factors were at play. © 2012 Springer-Verlag Berlin Heidelberg.


Laurie K.L.,Collaborating Center for Reference and Research on Influenza | Carolan L.A.,Collaborating Center for Reference and Research on Influenza | Middleton D.,Australian Animal Health Laboratory | Lowther S.,Australian Animal Health Laboratory | And 2 more authors.
Journal of Infectious Diseases | Year: 2010

Background. An age bias toward children and young adults has been reported for infection and hospitalizations with pandemic H1N1 influenza (A[H1N1]pdm) in the 2009 and 2010 influenza seasons in the Southern and Northern Hemispheres. Serological analysis of prepandemic samples has shown a higher incidence of cross-reactive antibodies to A(H1N1)pdm virus in older populations; conserved T cell epitopes between viruses have been identified. The contribution of preexisting immunity to seasonal influenza to protection against A(H1N1)pdm infection was analyzed in a ferret model. Methods. Ferrets were pre-infected with influenza A viruses and/or vaccinated with inactivated influenza viruses with adjuvant. Infection after challenge was assessed by measuring shedding virus, transmission to naive animals, and seroconversion. Results. Homologous vaccination reduced the incidence of infection and delayed transmission. Pre-infection with virus induced sterilizing immunity to homologous challenge. One prior infection with seasonal influenza A virus improved clearance of A(H1N1)pdm virus. Prior infection with A(H1N1)pdm virus reduced shedding after seasonal influenza A challenge. Two infections with seasonal influenza A viruses reduced the incidence of infection, the amount and duration of virus shedding, and the frequency of transmission following A(H1N1)pdm challenge. Conclusion. These data suggest the reduced incidence and severity of infection with A(H1N1)pdm virus in the adult population during the 2009-2010 influenza season may be a result of previous exposure to seasonal influenza A viruses. © 2010 by the Infectious Diseases Society of America. All rights reserved.


Henning J.,University of Queensland | Wibawa H.,Australian Animal Health Laboratory | Morton J.,University of Queensland | Usman T.B.,Disease Investigation Center | And 2 more authors.
Emerging Infectious Diseases | Year: 2010

In Java, Indonesia, during March 2007-March 2008, 96 farms with scavenging ducks that were not vaccinated against highly pathogenic avian influenza (HPAI) were monitored bimonthly. Bird-level (prevalence among individual birds) H5 seroprevalence was 2.6% for ducks and 0.5% for chickens in contact with ducks. At least 1 seropositive bird was detected during 19.5% and 2.0% of duck- and chickenflock visits, respectively. Duck flocks were 12.4× more likely than chicken flocks to have seropositive birds. During 21.4% of farm visits, ≥1 sampled duck was H5 seropositive when all sampled in-contact chickens were seronegative. Subtype H5 virus was detected during 2.5% of duck-flock visits and 1.5% of chicken-flock visits. When deaths from HPAI infection occurred, H5 virus shedding occurred in apparently healthy birds on 68.8% of farms. Of 180 poultry deaths investigated, 43.9% were attributed to H5 virus. These longitudinal study results indicate that ducks are a source of infection for chickens and, potentially, for humans.


Curran J.M.,Murdoch University | Robertson I.D.,Murdoch University | Ellis T.M.,30 Leonard Street | Selleck P.W.,Australian Animal Health Laboratory | O'Dea M.A.,Bentley Delivery Center
Avian Diseases | Year: 2013

There is poor understanding of host responses to avian influenza virus (AIV) infection in wild birds, with most experimental studies using captive-bred birds and highly pathogenic AIVs that have an early endpoint. The objective of this study was to experimentally assess antibody responses and patterns of viral excretion in wild birds challenged with a low pathogenicity AIV. Ruddy turnstones (Arenaria interpres), silver gulls (Chroicocephalus novaehollandiae), and wandering whistling ducks (Dendrocygna arcuata) were challenged with a H6N2 virus, and blood, cloacal, and oropharyngeal (OP) swabs were analyzed from each bird over 28 days, with serology conducted on the ducks for a further 7 mo. Nineteen of 22 birds showed evidence of infection, with respiratory infection prevalent in the turnstones and gulls as mostly low titer viral excretion to 4 days postinoculation (DPI) with gastrointestinal replication detected in only one turnstone. In AIV naive ducks, there was gastrointestinal tropism with moderately high titer viral excretion via the cloaca to 6 DPI and low-grade OP viral excretion to 4 DPI. The hemagglutination inhibition antibody response was poor in the ducks, declining from 19 to 56 DPI, with higher titer responses in the gulls and turnstones. All infected birds responded with elevated nucleoprotein antibodies (in competitive enzyme-linked immunosorbent assay) by 7-10 DPI, and in the ducks these waned slowly after 42 DPI and were long-lived to at least 8 mo. The interspecies variability in response was consistent with a subtype that had adapted well in ducks, while the response of the turnstones may have been influenced by preexisting immunity to AIV. These findings provide insight into AIV infection dynamics in wild birds and highlight the need for further research. © American Association of Avian Pathologists.

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