Enhanced Biosecurity Measures Research Articles

Genomic diversity and evolutionary dynamics of Influenza A viruses in Colombian swine: implications for one health surveillance and control

ABSTRACT Influenza A viruses (IAV) impose significant respiratory disease burdens in both swine and humans worldwide, with frequent human-to-swine transmission driving viral evolution in pigs and highlighting the risk at the animal-human interface. Therefore, a comprehensive One Health approach (interconnection among human, animal, and environmental health) is needed for IAV prevention, control, and response. Animal influenza genomic surveillance remains limited in many Latin American countries, including Colombia. To address this gap, we genetically characterized 170 swine specimens from Colombia (2011–2017). Whole genome sequencing revealed a predominance of pandemic-like H1N1 lineage, with a minority belonging to H3N2 and H1N2 human seasonal-like lineage and H1N1 early classical swine lineages. Significantly, we have identified reassortant and recombinant viruses (H3N2, H1N1) not previously reported in Colombia. This suggests a broad genotypic viral diversity, likely resulting from reassortment between classical endemic viruses and new introductions established in Colombia's swine population (e.g. the 2009 H1N1 pandemic). Our study highlights the importance of a One Health approach in disease control, particularly in an ecosystem where humans are a main source of IAV to swine populations, and emphasizes the need for continued surveillance and enhanced biosecurity measures. The co-circulation of multiple subtypes in regions with high swine density facilitates viral exchange, underscoring the importance of monitoring viral evolution to inform vaccine selection and public health policies locally and globally.

Monitoring root rot in flat-leaf parsley via machine vision by unsupervised multivariate analysis of morphometric and spectral parameters

Use of vertical farms is increasing rapidly as it enables year-round crop production, made possible by fully controlled growing environments situated within supply chains. However, intensive planting and high relative humidity make such systems ideal for the proliferation of fungal pathogens. Thus, despite the use of bio-fungicides and enhanced biosecurity measures, contamination of crops does happen, leading to extensive crop loss, necessitating the use of high-throughput monitoring for early detection of infected plants. In the present study, progression of foliar symptoms caused by Pythium irregulare-induced root rot was monitored for flat-leaf parsley grown in an experimental hydroponic vertical farming setup. Structural and spectral changes in plant canopy were recorded non-invasively at regular intervals using a 3D multispectral scanner. Five morphometric and nine spectral features were selected, and different combinations of these features were subjected to multivariate data analysis via principal component analysis to identify temporal trends for early segregation of healthy and infected samples. Combining morphometric and spectral features enabled a clear distinction between healthy and diseased plants at 4–7 days post inoculation (DPI), whereas use of only morphometric or spectral features allowed this at 7–9 DPI. Minimal datasets combining the six most effective features also resulted in effective grouping of healthy and diseased plants at 4–7 DPI. This suggests that selectively combining morphometric and spectral features can enable accurate early identification of infected plants, thus creating the scope for improving high-throughput crop monitoring in vertical farms.

Marine invasive alien species in Europe: 9 years after the IAS Regulation

Biological invasions, resulting from human activities, exert substantial impacts on ecosystems worldwide. This review focuses on marine invasive alien species (IAS) in Europe, examining the current state, proposing strategies to address the problem, and offering recommendations for enhanced management. Effective management of biological invasions relies on accessible, accurate data to inform decision-making. Information systems such as the European Alien Species Information Network (EASIN), Aquatic Non-Indigenous and Cryptogenic Species (AquaNIS), and World Register of Introduced Marine Species (WriMS) provide comprehensive databases on IAS, but their sustainability requires long-term maintenance, continuous updates, and support. Most countries lack specific monitoring programs for marine IAS, and standardization and improvement of monitoring methods are needed. Port monitoring plays a vital role in the early detection of new arrivals, and recent advancements in molecular techniques show promise for effective IAS monitoring. Risk screening tools are commonly employed to rank taxa based on their invasiveness potential in European regions, but variations in protocols can yield inconsistent results. European impact assessments highlight resource competition, novel habitat creation, and predation as primary mechanisms for negative impacts on biodiversity, while the creation of novel habitats represents a key mechanism for positive impacts. Preventing IAS introductions is critical, and measures such as ballast water treatment systems are implemented to reduce the likelihood of marine introductions. However, understanding introduction pathways remains uncertain for many IAS. Eradication and control efforts for marine IAS have limited success, emphasizing the need for enhanced biosecurity measures. Climate change, especially ocean warming, can intensify IAS impacts on native species and ecosystems. In climate change hotspots, some tropical aliens may, however, compensate for the loss of thermally sensitive natives with similar traits. Therefore, it is imperative to consider the interactions between climate change and IAS in developing effective management and conservation strategies. Enhancing IAS management in Europe entails i) securing adequate funding, ii) expanding the list of IAS of Union Concern to adequately cover marine invasions, iii) learning from countries with successful biosecurity practices, iv) sustaining information systems, v) improving monitoring and early warning systems with innovative technologies, vi) enhancing prediction models, vii) conducting integrated impact assessments and mapping cumulative IAS impacts, and vii) considering the potential benefits of IAS in ecosystem functioning and services.

Factors Affecting the Spread, Diagnosis, and Control of African Swine Fever in the Philippines.

African Swine Fever (ASF) is a highly contagious disease that threatens the swine industry globally. Since its introduction into the Philippines in 2019, ASF has spread extensively in both commercial and backyard farms. Here, using a mix of qualitative and quantitative methods, including conjoint and SWOT analyses, world café discussions, and multivariable regression models, the most important factors that influence the spread, diagnosis, and control of ASF in the Philippines were identified. Research findings suggest that swill or contaminated feed, inadequate biosecurity protocols, and movement of personnel were the top risk factors favoring ASF spread among farms in general. For commercial farms, contaminated vehicles and personnel were also important, whereas for backyard farms, the introduction of new pigs, environmental contamination, and poor feeding quality were relevant risk factors. Notable clinical signs of ASF in pigs include reduced feed intake, huddled behavior, and reluctance to stand. This study highlights the need for timely reporting, trust-building initiatives, and enhanced biosecurity measures to effectively manage ASF outbreaks in the country. Results here contribute to the knowledge of factors affecting ASF spread in the Philippines and can help design prevention and control measures in ASF-infected countries while enhancing preparedness in countries free from the disease.

Natural area visitors’ potential role in preventing pathogen threats to amphibian biodiversity

SummaryThe anthropogenic spread of disease from captive to wild amphibian populations (referred to as spillover) is linked to global amphibian declines. Disinfecting procedures and protocols exist to mitigate pathogen transmission to and within natural areas, but understanding of visitor attitudes and behaviour regarding their adoption is limited. We surveyed visitors in two natural areas in a global amphibian biodiversity hotspot to assess their attitudes regarding pathogen spread in such areas and analysed the factors influencing their behavioural intentions to take specific actions to prevent pathogen spillover. Visitors’ willingness to take action was influenced by their attitudes, behavioural control and trust in wildlife/land managers, whereas socio-demographic characteristics were less influential. These findings help us to understand visitor behaviour with respect to amphibian biosecurity in natural areas and inform enhanced biosecurity measures and strategic messaging to reduce pathogen spillover.

Enhanced Biosecurity Measures May Contribute to the Reduction of Campylobacter Incidence in Slaughterhouses

Enhanced Biosecurity Measures May Contribute to the Reduction of Campylobacter Incidence in Slaughterhouses

ЭПИЗООТИЯ АФРИКАНСКОЙ ЧУМЫ СВИНЕЙ НА СЕВЕРЕ ИТАЛИИ: СТРАТЕГИЯ БОРЬБЫ

The article provides information on the ASF epizootic, and control measures taken. The most likely reason for the introduction of the disease, considering the distance from the nearest foci of the disease, is the anthropogenic factor. The unregulated growth of the wild boar population against the background of poorly controlled movement of pig products from affected areas leads to an increased risk of the virus introduction into the population of the wild susceptible animals. The control strategy adopted by the competent authorities of Italy includes a zonal principle for the selection and implementation of a set of measures. The main control approaches are depopulation of pigs in the unprotected pig sector (PSF), restriction of wild boar migration with the help of fences, as well as active search and removal of carcasses of wild boars, followed by local depopulation of wild boar in the infected zone, reduction of its density in the threatened zone along with measures aimed at early detection of the disease, and enhanced biosecurity measures.

Anti-Classical Swine Fever Virus Strategies.

Classical swine fever (CSF), caused by CSF virus (CSFV), is a highly contagious swine disease with high morbidity and mortality, which has caused significant economic losses to the pig industry worldwide. Biosecurity measures and vaccination are the main methods for prevention and control of CSF since no specific drug is available for the effective treatment of CSF. Although a series of biosecurity and vaccination strategies have been developed to curb the outbreak events, it is still difficult to eliminate CSF in CSF-endemic and re-emerging areas. Thus, in addition to implementing enhanced biosecurity measures and exploring more effective CSF vaccines, other strategies are also needed for effectively controlling CSF. Currently, more and more research about anti-CSFV strategies was carried out by scientists, because of the great prospects and value of anti-CSFV strategies in the prevention and control of CSF. Additionally, studies on anti-CSFV strategies could be used as a reference for other viruses in the Flaviviridae family, such as hepatitis C virus, dengue virus, and Zika virus. In this review, we aim to summarize the research on anti-CSFV strategies. In detail, host proteins affecting CSFV replication, drug candidates with anti-CSFV effects, and RNA interference (RNAi) targeting CSFV viral genes were mentioned and the possible mechanisms related to anti-CSFV effects were also summarized.

Isolation and characterization of low pathogenic H7N7 avian influenza virus from a red-crowned crane in a zoo in South Korea

BackgroundSouth Korea conducts annual national surveillance programs to detect avian influenza (AI) in domestic poultry, live bird markets, and wild birds. In March 2017, an AIV was isolated from fecal samples in an outdoor aviary flight cage in a zoo in Korea.ResultsNucleotide sequencing identified the isolate as low pathogenic avian influenza virus (LPAIV) H7N7, and DNA barcoding analysis identified the host species as red-crowned crane. This isolate was designated A/red-crowned crane/Korea/H1026/2017 (H7N7). Genetic analysis and gene constellation analysis revealed that A/red-crowned crane/Korea/H1026/2017 (H7N7) showed high similarity with four H7N7 LPAIVs isolated from wild bird habitats in Seoul and Gyeonggi in early 2017.ConclusionsConsidering the genetic similarity and similar collection dates of the viruses, and the fact that zoo bird cages are vulnerable to AIV, it is likely that fecal contamination from wild birds might have introduced LPAIV H7N7 into the red-crowned crane at the zoo. Therefore, our results emphasize that enhanced biosecurity measures should be employed during the wild bird migration season, and that continued surveillance should be undertaken to prevent potential threats to avian species in zoos and to humans.

Odontologia em Tempos de COVID-19: Revisão Integrativa e Proposta de Protocolo para Atendimento nas Unidades de Saúde Bucal da Polícia Militar do Estado do Rio de Janeiro - PMERJ

Objetivo: sistematizar a produção bibliográfica sobre as recomendações, práticas e cuidados adotados no atendimento odontológico em tempos de
 COVID-19, assim como, propor um protocolo de atendimento odontológico nas unidades de saúde bucal da Polícia Militar do Estado do Rio de Janeiro a partir das evidências encontradas na literatura. Material e Métodos: foi realizada uma busca bibliográfica no dia 11 de abril de 2020 em bases bibliográficas eletrônicas brasileiras e internacionais (Portal Regional da Biblioteca Virtual em Saúde, Web of Science e Pubmed), a partir da estratégia de busca (“COVID-19" AND “dentistry”), entre estudos publicadas nos anos de 2019 e 2020. Após aplicados os critérios de inclusão e exclusão dos documentos, 18 estudos foram considerados elegíveis para a realização da revisão. Resultados: a partir das evidências científicas encontradas nos estudos, foi construída uma proposta de protocolo para o atendimento odontológico nas unidades de saúde da Polícia Militar do Estado do Rio de Janeiro, assim como em qualquer outra unidade de saúde bucal. Conclusão: durante o período de surto epidêmico os atendimentos devem restringir-se às urgências e emergências odontológicas. O Cirurgião-Dentista deve redobrar a atenção à rotina de biossegurança como: lavagem rigorosa das mãos com água e sabão e/ou 'álcool gel a 70%', uso correto de todo equipamento de proteção individual e sua troca a cada paciente. Recomenda-se o tempo de 3 horas entre os atendimentos quando houver produção de aerossol, a higienização de todas as superfícies do consultório com hipoclorito de sódio a 0,1% ou 'álcool 70%', esterilização de todo instrumental e o descarte adequado dos resíduos.

Zucchini yellow mosaic virus Genomic Sequences from Papua New Guinea: Lack of Genetic Connectivity with Northern Australian or East Timorese Genomes, and New Recombination Findings.

Zucchini yellow mosaic virus (ZYMV) isolates were obtained in Papua New Guinea (PNG) from cucumber (Cucumis sativus) or pumpkin (Cucurbita spp.) plants showing mosaic symptoms growing at Kongop in the Mount Hagen District, Western Highlands Province, or Zage in the Goroka District, Eastern Highlands Province. The samples were blotted onto FTA cards, which were sent to Australia, where they were subjected to high-throughput sequencing. When the coding regions of the nine new ZYMV genomic sequences found were compared with those of 64 other ZYMV sequences from elsewhere, they grouped together, forming new minor phylogroup VII within ZYMV's major phylogroup A. Genetic connectivity was lacking between ZYMV genomic sequences from PNG and its neighboring countries, Australia and East Timor; the closest match between a PNG and any other genomic sequence was a 92.8% nucleotide identity with a sequence in major phylogroup A's minor phylogroup VI from Japan. When the RDP5.2 recombination analysis program was used to compare 66 ZYMV sequences, evidence was obtained of 30 firm recombination events involving 41 sequences, and all isolates from PNG were recombinants. There were 21 sequences without recombination events in major phylogroup A, whereas there were only 4 such sequences within major phylogroup B. ZYMV's P1, Cl, N1a-Pro, P3, CP, and NIb regions contained the highest evidence of recombination breakpoints. Following removal of recombinant sequences, seven minor phylogroups were absent (I, III, IV, V, VI, VII, and VIII), leaving only minor phylogroups II and IX. By contrast, when a phylogenetic tree was constructed using recombinant sequences with their recombinationally derived tracts removed before analysis, five previous minor phylogroups remained unchanged within major phylogroup A (II, III, IV, V, and VII) while four formed two new merged phylogroups (I/VI and VIII/IX). Absence of genetic connectivity between PNG, Australian, and East Timorese ZYMV sequences, and the 92.8% nucleotide identity between a PNG sequence and the closest sequence from elsewhere, suggest that a single introduction may have occurred followed by subsequent evolution to adapt to the PNG environment. The need for enhanced biosecurity measures to protect against potentially damaging virus movements crossing the seas separating neighboring countries in this region of the world is discussed.

Rodent eradication scaled up: clearing rats and mice from South Georgia

AbstractThe Subantarctic island of South Georgia lost most of its birds to predation by rodents introduced by people over 2 centuries. In 2011 a UK charity began to clear brown ratsRattus norvegicusand house miceMus musculusfrom the 170 km long, 3,500 km2island using helicopters to spread bait containing Brodifacoum as the active ingredient. South Georgia's larger glaciers were barriers to rodent movement, resulting in numerous independent sub-island populations. The eradication could therefore be spread over multiple seasons, giving time to evaluate results before recommencing, and also reducing the impact of non-target mortality across the island as a whole. Eradication success was achieved in the 128 km2Phase 1 trial operation. Work in 2013 (Phase 2) and early 2015 (Phase 3) covered the remaining 940 km2occupied by rodents. By July 2017, 28 months after baiting was concluded, there was no sign of surviving rodents, other than one apparently newly introduced by ship in October 2014. A survey using detection dogs and passive devices will search the Phase 2 and Phase 3 land for rodents in early 2018. Seven (of 30) species of breeding birds suffered losses from poisoning, but all populations appear to have recovered within 5 years. The endemic South Georgia pipitAnthus antarcticuswas the first bird to breed in newly rat-free areas, but there were also signs that cavity-nesting seabirds were exploring scree habitat denied them for generations. Enhanced biosecurity measures on South Georgia are needed urgently to prevent rodents being reintroduced.

“Catch 22”: Biosecurity awareness, interpretation and practice amongst poultry catchers

Campylobacter contamination of chicken on sale in the UK remains at high levels and has a substantial public health impact. This has prompted the application of many interventions in the supply chain, including enhanced biosecurity measures on-farm. Catching and thinning are acknowledged as threats to the maintenance of good biosecurity, yet the people employed to undertake this critical work (i.e. ‘catchers’) are a rarely studied group.This study uses a mixed methods approach to investigate catchers’ (n=53) understanding of the biosecurity threats posed by the catching and thinning, and the barriers to good biosecurity practice. It interrogated the role of training in both the awareness and practice of good biosecurity. Awareness of lapses in biosecurity was assessed using a Watch-&-Click hazard awareness survey (n=53). Qualitative interviews (n=49 catchers, 5 farm managers) explored the understanding, experience and practice of catching and biosecurity.All of the catchers who took part in the Watch-&-Click study identified at least one of the biosecurity threats with 40% detecting all of the hazards. Those who had undergone training were significantly more likely to identify specific biosecurity threats and have a higher awareness score overall (48% compared to 9%, p=0.03). Crucially, the individual and group interviews revealed the tensions between the high levels of biosecurity awareness evident from the survey and the reality of the routine practice of catching and thinning. Time pressures and a lack of equipment rather than a lack of knowledge appear a more fundamental cause of catcher-related biosecurity lapses. Our results reveal that catchers find themselves in a ‘catch-22′ situation in which mutually conflicting circumstances prevent simultaneous completion of their job and compliance with biosecurity standards.33catch-22 originates from the title of a novel by Joseph Heller (Heller, J., 1961. Catch-22, a novel) in which the main character is presented with conflicting difficult circumstances from which there is no escape. Hence, although education about, and enforcement of, biosecurity protocols has been recommended, our findings suggest that further reforms, including changing the context in which catching occurs by improving the equipment and other resources available to catchers and providing more time for biosecurity, will be essential for successful implementation of existing biosecurity protocols.

Urgent request on avian influenza.

Highly pathogenic avian influenza (HPAI) H5N8 is currently causing an epizootic in Europe, infecting many poultry holdings as well as captive and wild bird species in more than 10 countries. Given the clear clinical manifestation, passive surveillance is considered the most effective means of detecting infected wild and domestic birds. Testing samples from new species and non‐previously reported areas is key to determine the geographic spread of HPAIV H5N8 2016 in wild birds. Testing limited numbers of dead wild birds in previously reported areas is useful when it is relevant to know whether the virus is still present in the area or not, e.g. before restrictive measures in poultry are to be lifted. To prevent introduction of HPAIV from wild birds into poultry, strict biosecurity implemented and maintained by the poultry farmers is the most important measure. Providing holding‐specific biosecurity guidance is strongly recommended as it is expected to have a high impact on the achieved biosecurity level of the holding. This is preferably done during peace time to increase preparedness for future outbreaks. The location and size of control and in particular monitoring areas for poultry associated with positive wild bird findings are best based on knowledge of the wider habitat and flight distance of the affected wild bird species. It is recommended to increase awareness among poultry farmers in these established areas in order to enhance passive surveillance and to implement enhanced biosecurity measures including poultry confinement. There is no scientific evidence suggesting a different effectiveness of the protection measures on the introduction into poultry holdings and subsequent spread of HPAIV when applied to H5N8, H5N1 or other notifiable HPAI viruses.

Quantitative risk assessment of Campylobacter in broiler chickens – Assessing interventions to reduce the level of contamination at the end of the rearing period

The European Food Safety Authority (EFSA) has estimated that a proportion ranging from 20% to 30% of campylobacteriosis in humans may be attributed to the consumption of broiler meat and a reduction in the numbers of Campylobacter in the intestines of infected birds at slaughter by 3 log units would reduce the public health risk by at least 90%. In this study, a stochastic model was implemented to reproduce the dynamics of Campylobacter transmission in broiler flocks and explore the effects of several management conditions and/or on-farm mitigation strategies on the estimated level of contamination of infected flocks at slaughter. Results were expressed as ‘proportion of highly contaminated flocks’ (%HCFs) and estimated as a function of the proportion of infected birds in the flock the day of final depopulation and the individual level of contamination in infected birds. The effects of the mitigation strategies aimed at reducing the level of contamination in infected birds were modelled assuming that those effects are exerted on the distribution describing the bacterial load in infected birds. The impact of management conditions such as the adoption of enhanced biosecurity measures (B+) and/or partial depopulation during the production cycle (T+) were quantified using results of an extensive epidemiological study conducted in UK. A standard broiler flock was reproduced and used as baseline to make comparisons and simulate the effects of the mitigation strategies of interest. The baseline model predicted 18.8% probability of HCFs at slaughter. A positive effect ranging from −32.44% to −4.78% was attributed to B+ while T+ had negative effect ranging from +17.55% to +86.70%. When both the effects were tested simultaneously (B+T+), results were not conclusive with %HCFs ranging from −20.21% to +77.65%. When mitigation strategies operating on Campylobacter concentration in intestine were tested, a reduction of 100% and 99.6% in %HFCs were estimated following a generic treatment with bacteriocins and bacteriophages. Reduction in %HCFs as a function of immunization measures were explored and a reduction of 15% in the rate of transmission led to a %HCFs at slaughter reduced by almost 50%. The model was developed to be flexible, easily reproducible, updatable and adaptable to several baseline scenarios. The main parameters and assumptions underlying the baseline model were tested and a sensitivity analysis was performed to identify and discuss the impact that the uncertainty in the baseline information might have on the outcomes.

A Mathematical Model that Simulates Control Options for African Swine Fever Virus (ASFV).

A stochastic model designed to simulate transmission dynamics of African swine fever virus (ASFV) in a free-ranging pig population under various intervention scenarios is presented. The model was used to assess the relative impact of the timing of the implementation of different control strategies on disease-related mortality. The implementation of biosecurity measures was simulated through incorporation of a decay function on the transmission rate. The model predicts that biosecurity measures implemented within 14 days of the onset of an epidemic can avert up to 74% of pig deaths due to ASF while hypothetical vaccines that confer 70% immunity when deployed prior to day 14 of the epidemic could avert 65% of pig deaths. When the two control measures are combined, the model predicts that 91% of the pigs that would have otherwise succumbed to the disease if no intervention was implemented would be saved. However, if the combined interventions are delayed (defined as implementation from > 60 days) only 30% of ASF-related deaths would be averted. In the absence of vaccines against ASF, we recommend early implementation of enhanced biosecurity measures. Active surveillance and use of pen-side diagnostic assays, preferably linked to rapid dissemination of this data to veterinary authorities through mobile phone technology platforms are essential for rapid detection and confirmation of ASF outbreaks. This prediction, although it may seem intuitive, rationally confirms the importance of early intervention in managing ASF epidemics. The modelling approach is particularly valuable in that it determines an optimal timing for implementation of interventions in controlling ASF outbreaks.

A Simulation-Based Evaluation of Premovement Active Surveillance Protocol Options for the Managed Movement of Turkeys to Slaughter During an Outbreak of Highly Pathogenic Avian Influenza in the United States.

Risk management decisions associated with live poultry movement during a highly pathogenic avian influenza (HPAI) outbreak should be carefully considered. Live turkey movements may pose a risk for disease spread. On the other hand, interruptions in scheduled movements can disrupt business continuity. The Secure Turkey Supply (STS) Plan was developed through an industry-government-academic collaboration to address business continuity concerns that might arise during a HPAI outbreak. STS stakeholders proposed outbreak response measure options that were evaluated through risk assessment. The developed approach relies on 1) diagnostic testing of two pooled samples of swabs taken from dead turkeys immediately before movement via the influenza A matrix gene real-time reverse transcriptase polymerase chain reaction (rRT-PCR) test; 2) enhanced biosecurity measures in combination with a premovement isolation period (PMIP), restricting movement onto the premises for a few days before movement to slaughter; and 3) incorporation of a distance factor from known infected flocks such that exposure via local area spread is unlikely. Daily exposure likelihood estimates from spatial kernels from past HPAI outbreaks were coupled with simulation models of disease spread and active surveillance to evaluate active surveillance protocol options that differ with respect to the number of swabs per pooled sample and the timing of the tests in relation to movement. Simulation model results indicate that active surveillance testing, in combination with strict biosecurity, substantially increased HPAI virus detection probability. When distance from a known infected flock was considered, the overall combined likelihood of moving an infected, undetected turkey flock to slaughter was predicted to be lower at 3 and 5 km. The analysis of different active surveillance protocol options is designed to incorporate flexibility into HPAI emergency response plans.

Application of an integrated outbreak management plan for the control of leptospirosis in dairy cattle herds

Two outbreaks of Leptospira borgpetersenii serovar Hardjo infection in dairy cattle herds were managed through the application of enhanced biosecurity measures, whole-herd antibiotic treatment and vaccination. Micro-agglutination test antibody titres were determined in paired serum samples at 3 weeks (T1: n = 125, 97% seropositivity, median 800, range 100-12 800) and 24 weeks (T2: n = 110, 88% seropositivity, median 200, range 100-6400) after vaccination and studied in relation to cows' age, herd of origin and sampling time. From T1 to T2, vaccine-elicited antibody titres decreased by 84·7% (95% CI 76·2-90·1). Consistent with increasing immunocompetence in calves (aged <12 months) and immunosenescence in adult cows (aged >36 months) associated with ageing, antibody titres correlated positively with calves' age and negatively with adult cows' age. No cow had cultivable, (histo)pathologically detectable and/or PCR-detectable leptospires in urine or kidney samples after treatment and vaccination. Vaccination together with proper biosecurity measures and chemoprophylaxis are an affordable insurance to control bovine leptospirosis.

Epidemiological investigation of Renibacterium salmoninarum in three Oncorhynchus spp. in Michigan from 2001 to 2010

Bacterial kidney disease (BKD) has caused mortalities and chronic infections in wild and farm-raised salmonids throughout the world. In the Laurentian Great Lakes of North America, BKD was associated with several large-scale mortality events of Oncorhynchus spp. throughout the 1980s and 1990s. In response to these mortality events, the state of Michigan implemented several enhanced biosecurity measures to limit the occurrence of BKD in state-operated hatcheries and gamete-collection weirs. The objectives of this study were to assess if infection levels (prevalence and intensity) of Renibacterium salmoninarum, the causative agent of BKD, have changed in broodstock and pre-stocking fingerlings of three feral Oncorhynchus spp. (Chinook salmon (O. tshawytscha), coho salmon (O. kisutch), and steelhead (O. mykiss)) over a decade, following the implementation of the enhanced biosecurity measures. Between 2001 and 2010, a total of 3,530 broodstock salmonids collected from lakes Huron and Michigan tributaries during spawning runs and 4,294 propagated pre-stocking salmonid fingerlings collected from three state of Michigan fish hatcheries were tested for the presence of R. salmoninarum antigens using the enzyme-linked immunosorbent assay. Substantial declines in the overall prevalence of the bacterium were detected in each of the examined broodstocks. Most propagated pre-stocking fingerlings also exhibited substantial declines in R. salmoninarum prevalence. Prevalence was typically higher in Chinook salmon from Lake Michigan than from Lake Huron; prevalence was also generally higher in the Hinchenbrooke strain of coho salmon than in the Michigan-adapted strain. For most strains and stocks examined, intensity of R. salmoninarum infection was found to have declined. Although there were declines in the potential for shedding the bacteria for both male and female Chinook and coho salmon, overall shedding rates were generally low (<15%) except for Hinchenbrooke coho salmon strain, which had shedding prevalences in excess of 50% at the beginning of the study. This study provides evidence that enhanced biosecurity measures at culture facilities and collection sites are capable of severely curtailing disease infection in wild populations even at the scale of Lake Michigan fisheries.

Regaining Australia's equine influenza‐free status: a national perspective

The first cases of equine influenza (EI) in Australia were reported in late August 2007. By 14 March 2008, provisional freedom from EI was declared and in December 2008 Australia was officially declared EI-free, 12 months after the last reported clinical case. Containment, and ultimate eradication, of EI was achieved through a combination of movement restrictions, zoning, vaccination and enhanced biosecurity measures that drew on the resources and expertise of industry and state and federal governments. Through these measures, the EI outbreak, which peaked in October 2007, was contained to just 3% of Australia, with no new cases reported after 9 December 2007, just four months after the outbreak began.