Antimicrobial resistance and its relationship with antimicrobial use on Austrian dairy farms.

The aim of this study was to investigate the prevalence of ESBL/AmpC-producing E. coli and the resistance pattern of commensal E. coli, as well as the link between the use of antibiotics (AMU) and the occurrence of resistance in E. coli on Austrian dairy farms. AMU data from 51 farms were collected over a one-year period in 2020. Fecal samples were collected from cows, pre-weaned and weaned calves in 2020 and 2022. Samples were then analyzed using non-selective and selective agar plates, E. coli isolates were confirmed by MALDI-TOF analysis. Broth microdilution was used for antimicrobial susceptibility testing. The AMU of each farm was quantified as the number of Defined Daily Doses (nDDDvet) and Defined Course Doses (nDCDvet) per cow and year. Cephalosporins (mean 1.049; median 0.732 DDDvet/cow/year) and penicillins (mean 0.667; median 0.383 DDDvet/cow/year) were the most frequently used antibiotics on these farms, followed by tetracyclines (mean 0.275; median 0.084 DDDvet/cow/year). In 2020, 26.8% of the E. coli isolated were resistant to at least one antibiotic class and 17.7% of the isolates were classified as multidrug resistant (≥3 antibiotic classes). Out of 198 E. coli isolates, 7.6% were identified as extended-spectrum/AmpC beta-lactamase (ESBL/AmpC) producing E. coli. In 2022, 33.7% of E. coli isolates showed resistance to at least one antibiotic and 20.0% of isolates displayed multidrug resistance. Furthermore, 29.5% of the samples carried ESBL/AmpC-producing E. coli. In 2020 and 2022, the most frequently determined antibiotic resistances among commensal E. coli isolates were to tetracyclines, sulfonamides and penicillins. In addition, pre-weaned calves had the highest resistance rates in both years. Statistical analyses showed a significant association between low and high use AMU classifications for penicillins (in nDDDvet/cow/year) and their respective resistance among commensal E. coli isolates in 2020 (p = 0.044), as well as for sulfonamide/trimethoprim (p = 0.010) and tetracyclines (p = 0.042). A trend was also noted between the total amount of antibiotics used on farm in 2020 (by nDDDvet/cow/year) and multidrug resistances in commensal E. coli isolated on farm that year (p = 0.067). In conclusion, the relationship between AMU and antimicrobial resistance (AMR) on dairy farms continues to be complex and difficult to quantify.

Analysis of Antimicrobial Use and the Presence of Antimicrobial-Resistant Bacteria on Austrian Dairy Farms-A Pilot Study.

The assumed link between high levels of antimicrobial use on farms and selection for antimicrobial-resistant (AMR) bacteria on that farm remains difficult to prove. In the pilot study presented here, we analysed total antimicrobial use on 50 dairy farms in Austria and also collected environmental samples to ascertain whether specific AMR bacteria were present. Antimicrobial use (AMU) analysis was based on electronic veterinary treatment records over a one-year period. Faecal samples for the assessment of extended-spectrum beta-lactamase (ESBL)-producing E. coli were collected from cowsheds, calf pens, and youngstock housing areas, as well as dust samples from barns, to isolate methicillin-resistant Staphylococcus aureus (MRSA). Bacteriological cultures were carried out on selective agar. Farms were split into groups of 25 of the highest antimicrobial users and 25 of the lowest users. Overall, samples from 13/50 (26.0%) farms were found to be positive for the presence of ESBL-producing E. coli. Of these, eight farms were in the low user group and five were in the high user group. Only one farm was confirmed to harbour MRSA. Statistical analyses demonstrated that there was no significant difference in this study population between high or low antimicrobial use with respect to the presence of ESBL-producing E. coli on farms (p = 0.33). In conclusion, the presence of specific AMR bacteria on farms in this study population was not found to have a statistically proven relationship with their level of antimicrobial use.

Monitoring of Farm-Level Antimicrobial Use to Guide Stewardship: Overview of Existing Systems and Analysis of Key Components and Processes.

The acknowledgment of antimicrobial resistance (AMR) as a major health challenge in humans, animals and plants, has led to increased efforts to reduce antimicrobial use (AMU). To better understand factors influencing AMR and implement and evaluate stewardship measures for reducing AMU, it is important to have sufficiently detailed information on the quantity of AMU, preferably at the level of the user (farmer, veterinarian) and/or prescriber or provider (veterinarian, feed mill). Recently, several countries have established or are developing systems for monitoring AMU in animals. The aim of this publication is to provide an overview of known systems for monitoring AMU at farm-level, with a descriptive analysis of their key components and processes. As of March 2020, 38 active farm-level AMU monitoring systems from 16 countries were identified. These systems differ in many ways, including which data are collected, the type of analyses conducted and their respective output. At the same time, they share key components (data collection, analysis, benchmarking, and reporting), resulting in similar challenges to be faced with similar decisions to be made. Suggestions are provided with respect to the different components and important aspects of various data types and methods are discussed. This overview should provide support for establishing or working with such a system and could lead to a better implementation of stewardship actions and a more uniform communication about and understanding of AMU data at farm-level. Harmonization of methods and processes could lead to an improved comparability of outcomes and less confusion when interpreting results across systems. However, it is important to note that the development of systems also depends on specific local needs, resources and aims.

Comparison of Defined Course Doses (DCDvet) for Blanket and Selective Antimicrobial Dry Cow Therapy on Conventional and Organic Farms.

Antimicrobial use in livestock production is a controversial subject. While antimicrobials should be used as little as possible, it is still necessary, from both an animal health and welfare point of view, to treat infected animals. The study presented here aimed to analyse antimicrobial use on Austrian dairy farms by calculating the number of Defined Course Doses (DCDvet) administered per cow and year for dry cow therapy. Antimicrobial use was analysed by production system and whether farmers stated that they used blanket dry cow therapy (i.e., all cows in the herd were treated) or selective dry cow therapy (i.e., only cows with a positive bacteriological culture or current/recent history of udder disease were treated). A statistically significant difference (p < 0.001) was determined between antimicrobial use for blanket (median DCDvet/cow/year: 0.88) and selective dry cow therapy (median DCDvet/cow/year: 0.41). The difference between antimicrobial use on conventional and organic farms for dry cow therapy as a whole, however, was not statistically significant (p = 0.22) (median DCDvet/cow/year: 0.68 for conventional; 0.53 for organic farms). This analysis demonstrates that selective dry cow therapy leads to a lower overall use of antimicrobials and can assist in a more prudent use of antimicrobials on dairy farms.

Mapping the global prevalence of bovine viral diarrhoea virus infection and its associated mitigation programmes.

The aim of this study was to collect information on the global distribution of the prevalence of bovine viral diarrhoea virus (BVDV) and respective mitigation programmes, using a questionnaire and literature review to provide as complete a picture of the worldwide BVDV situation as possible. This study collated information on 107 countries with respect to mitigation activities and 88 countries regarding BVDV infections during the observation period (1960-2017). A heterogeneous epidemiological situation for both BVDV prevalence and the presence of mitigation programmes was observed. The results of this analysis could be used to increase the visibility of the distribution of BVDV, to provide supporting data for global animal disease databases and to assist veterinary public health authorities in the decision-making processes to establish mitigation activities.

Relationship between the probability of veterinary-diagnosed bovine mastitis occurring and farm management risk factors on small dairy farms in Austria.

Bovine mastitis is the most frequently reported disease among dairy cows worldwide. Treatment of udder disease often involves the use of antimicrobial substances, which is difficult to justify with respect to their possible effect on the development and spread of antimicrobial resistance. Prevention of udder disease is therefore always preferable to treatment. The study presented here statistically analyzed the probability of mastitis occurring during 3,049 lactation periods on 208 farms and attempted to ascertain which on-farm management factors contributed to the occurrence of this udder disease in Austria. Farm management was assessed via online surveys completed by 211 farmers (211/251; response rate = 84.1%) as well as national milk performance recorders observing milking technique and herd veterinarians evaluating farm hygiene levels. Veterinary treatment records were used as a basis for mastitis reporting. The analysis was carried out using a generalized linear mixed model. The study population was not randomized but was part of a larger observational study. More than three fourths of the study farms were run conventionally, and the remainder were organic. Freestalls (and straw yards) made up 66% of the study population, and 34% of farms had tiestalls. Herd size ranged from 8 to 94 dairy cows (mean = 26.9; median = 21), with the most common breed (74% of all cows) being dual-purpose Simmental (Austrian Fleckvieh). A mastitis risk of 14.4% was reported via veterinary treatment records. The following factors were shown to be associated with a reduction in the risk of mastitis occurring: regular access to pasture (odds ratio, OR = 0.73), automatic milking machine shut-off (OR 0.67), and access to feed immediately after milking (OR = 0.43). Detrimental effects, which were likely to increase the probability of mastitis occurring, included lactation number (OR = 1.18), farming part time (OR = 1.55), and udders on the farm being classed by herd veterinarians as medium to severely soiled (OR = 1.47). The study presented here was able to confirm several management factors recommended to reduce the probability of mastitis occurring during a cow's lactation period, with particular relevance for the small dairy herds common to Austria.

The relationship between clinical signs and microbiological species, spa type, and antimicrobial resistance in bovine mastitis cases in Austria.

Bovine mastitis, an inflammation of the udder usually caused by bacteria, is the most common disease in dairy cattle worldwide with a negative economic impact on the dairy industry. In this study 3020 quarter milk samples from 647 dairy cows on 166 Austrian farms were collected and microbial species, spa type for Staphylococcus (S.) aureus and antimicrobial susceptibility were analysed. A multinomial logistic regression model was applied to investigate the effect of possible categorical influencing covariates on the microbiological findings. Additionally, a generalized linear model was used to analyse the effects of genotype and pathogen species on the occurrence of antimicrobial resistance. Staphylococci were the most common (17% of samples) udder pathogens including 32 different S. aureus spa types. The occurrence of pathogen groups was significantly associated with the clinical mastitis score. Enterobacteriaceae isolates had a significantly higher probability of being present in severe mastitis cases compared to streptococci. Benzylpenicillin and tetracycline were the most common resistance in S. aureus including 14% and 11% resistant isolates. Whereas 16% and 13% of coagulase-negative staphylococci (CNS) isolates were resistant to tetracycline and clindamycin. Overall the proportion of Enterobacteriaceae isolates resistant to at least one antibiotic agents was high (55% of isolates), whereas only 3% benzylpenicillin resistant streptococci were detected. Associations were detected between antimicrobial resistance and particular species of Enterobacteriaceae, CNS and specific S. aureus spa types. In conclusion we present in this study data on causative udder pathogen species and their antimicrobial resistance, which are of great importance for mastitis management and prevention.

A meta-analysis of bovine viral diarrhoea virus (BVDV) prevalences in the global cattle population.

A random effect meta-analysis was performed to estimate the worldwide pooled bovine viral diarrhoea virus (BVDV) prevalences of persistently infected (PI), viraemic (VI) and antibody-positive (AB) animals and herds. The meta-analysis covered 325 studies in 73 countries that determined the presence or absence of BVDV infections in cattle from 1961 to 2016. In total, 6.5 million animals and 310,548 herds were tested for BVDV infections in the global cattle population. The worldwide pooled PI prevalences at animal level ranged from low (≤0.8% Europe, North America, Australia), medium (>0.8% to 1.6% East Asia) to high (>1.6% West Asia). The PI and AB prevalences in Europe decreased over time, while BVDV prevalence increased in North America. The highest mean pooled PI prevalences at animal level were identified in countries that had failed to implement any BVDV control and/or eradication programmes (including vaccination). Our analysis emphasizes the need for more standardised epidemiological studies to support decision-makers implementing animal health policies for non-globally-regulated animal diseases.

Antimicrobial consumption on Austrian dairy farms: an observational study of udder disease treatments based on veterinary medication records.

BACKGROUND: Antimicrobial use in livestock production is an important contemporary issue, which is of public interest worldwide. Antimicrobials are not freely available to Austrian farmers and can only be administered to livestock by veterinarians, or by farmers who are trained members of the Animal Health Service. Since 2015, veterinarians have been required by law to report antimicrobials dispensed to farmers for use in food-producing animals. The study presented here went further than the statutory framework, and collected data on antimicrobials dispensed to farmers and those administered by veterinarians. METHODS: Seventeen veterinary practices were enrolled in the study via convenience sampling. These veterinarians were asked to contact interested dairy farmers regarding participation in the study (respondent-driven sampling). Data were collected from veterinary practice software between 1st October 2015 and 30th September 2016. Electronic data (89.4%) were transferred via an online interface and paper records (10.6%) were entered by the authors. Antimicrobial treatments with respect to udder disease were analysed by number of defined daily doses per cow and year (nDDDvet/cow/year), based on the European Medicines Agency technical unit, Defined Daily Dose for animals (DDDvet). Descriptive statistics and the Wilcoxon rank sum test were used to analyse the results. RESULTS: Antimicrobial use data from a total of 248 dairy farms were collected during the study, 232 of these farms treated cows with antibiotics; dry cow therapy was excluded from the current analysis. The mean number of DDDvet/cow/year for the antimicrobial treatment of all udder disease was 1.33 DDDvet/cow/year. Of these treatments, 0.73 DDDvet/cow/year were classed as highest priority critically important antimicrobials (HPCIAs), according to the World Health Organization (WHO) definition. The Wilcoxon rank sum test determined a statistically significant difference between the median number of DDDvet/cow/year for acute and chronic mastitis treatment (W = 10,734, p < 0.001). The most commonly administered antimicrobial class for the treatment of acute mastitis was beta-lactams. Intramammary penicillin was used at a mean of 0.63 DDDvet/cow/year, followed by the third generation cephalosporin, cefoperazone, (a HPCIA) at 0.60 DDDvet/cow/year. Systemic antimicrobial treatments were used at a lower overall level than intramammary treatments for acute mastitis. DISCUSSION: This study demonstrated that Austrian dairy cows in the study population were treated with antimicrobial substances for udder diseases at a relatively low frequency, however, a substantial proportion of these treatments were with substances considered critically important for human health. While it is vital that sick cows are treated, reductions in the overall use of antimicrobials, and critically important substances in particular, are still possible.

A systematic worldwide review of the direct monetary losses in cattle due to bovine viral diarrhoea virus infection.

Bovine viral diarrhoea virus (BVDV) is an important infectious agent of cattle worldwide that affects herd productivity and reproduction. In this systematic review of the impact of BVDV, studies were analysed with a particular focus on the monetary implications and types of direct losses, the initial infection status of herds, production systems, time periods of assessment, calculation level, study types and whether or not country-specific assessments were published. A linear mixed model was applied to analyse factors that influence the level of monetary direct losses due to BVDV infection. The 44 studies included in this review covered 15 countries and assessed direct monetary losses due to BVDV incurred over the past 30 years. Direct losses between and within countries were largely heterogeneous with respect to the monetary level and types of direct losses, ranging from 0.50 to 687.80 US dollars (USD) per animal.1 Average direct losses per naïve dairy cow were USD24.85 higher than per beef cow. Country-specific assessments of direct losses due to BVDV were provided in 38/44 (86.4%) studies. Mortality, morbidity, premature culling, stillbirths, abortion, reinfection, country and study type had a significant influence on the monetary level of direct losses (r2 = 0.69). Countries recording direct losses were more likely to carry out voluntary or compulsory control and eradication programmes (odds ratio = 10.2; 95% confidence interval 1.7-81.9; P = 0.004).

A systematic review of financial and economic assessments of bovine viral diarrhea virus (BVDV) prevention and mitigation activities worldwide.

Infection with bovine viral diarrhea virus (BVDV) results in major economic losses either directly through decreased productive performance in cattle herds or indirectly, such as through expenses for control programs. The aim of this systematic review was to review financial and/or economic assessment studies of prevention and/or mitigation activities of BVDV at national, regional and farm level worldwide. Once all predefined criteria had been met, 35 articles were included for this systematic review. Studies were analyzed with particular focus on the type of financially and/or economically-assessed prevention and/or mitigation activities. Due to the wide range of possible prevention and/or mitigation activities, these activities were grouped into five categories: i) control and/or eradication programs, ii) monitoring or surveillance, iii) prevention, iv) vaccination and v) individual culling, control and testing strategies. Additionally, the studies were analyzed according to economically-related variables such as efficiency, costs or benefits of prevention and/or mitigation activities, the applied financial and/or economic and statistical methods, the payers of prevention and/or mitigation activities, the assessed production systems, and the countries for which such evaluations are available. Financial and/or economic assessments performed in Europe were dominated by those from the United Kingdom, which assessed mostly vaccination strategies, and Norway which primarily carried out assessments in the area of control and eradication programs; whereas among non-European countries the United States carried out the majority of financial and/or economic assessments in the area of individual culling, control and testing. More than half of all studies provided an efficiency calculation of prevention and/or mitigation activities and demonstrated whether the inherent costs of implemented activities were or were not justified. The dairy sector was three times more likely to be assessed by the countries than beef production systems. In addition, the dairy sector was approximately eight times more likely to be assessed economically with respect to prevention and/or mitigation activities than calf and youngstock production systems. Furthermore, the private sector was identified as the primary payer of prevention and/or mitigation activities. This systematic review demonstrated a lack of studies relating to efficiency calculations, in particular at national and regional level, and the specific production systems. Thus, we confirmed the need for more well-designed studies in animal health economics in order to demonstrate that the implementation and inherent costs of BVDV prevention and/or mitigation activities are justified.

Sustainable breeding objectives and possible selection response: Finding the balance between economics and breeders' preferences.

To optimize breeding objectives of Fleckvieh and Brown Swiss cattle, economic values were re-estimated using updated prices, costs, and population parameters. Subsequently, the expected selection responses for the total merit index (TMI) were calculated using previous and newly derived economic values. The responses were compared for alternative scenarios that consider breeders' preferences. A dairy herd with milk production, bull fattening, and rearing of replacement stock was modeled. The economic value of a trait was derived by calculating the difference in herd profit before and after genetic improvement. Economic values for each trait were derived while keeping all other traits constant. The traits considered were dairy, beef, and fitness traits, the latter including direct health traits. The calculation of the TMI and the expected selection responses was done using selection index methodology with estimated breeding values instead of phenotypic deviations. For the scenario representing the situation up to 2016, all traits included in the TMI were considered with their respective economic values before the update. Selection response was also calculated for newly derived economic values and some alternative scenarios, including the new trait vitality index (subindex comprising stillbirth and rearing losses). For Fleckvieh, the relative economic value for the trait groups milk, beef, and fitness were 38, 16, and 46%, respectively, up to 2016, and 39, 13, and 48%, respectively, for the newly derived economic values. Approximately the same selection response may be expected for the milk trait group, whereas the new weightings resulted in a substantially decreased response in beef traits. Within the fitness block, all traits, with the exception of fertility, showed a positive selection response. For Brown Swiss, the relative economic values for the main trait groups milk, beef, and fitness were 48, 5, and 47% before 2016, respectively, whereas for the newly derived scenario they were 40, 14, and 39%. For both Brown Swiss and Fleckvieh, the fertility complex was expected to further deteriorate, whereas all other expected selection responses for fitness traits were positive. Several additional and alternative scenarios were calculated as a basis for discussion with breeders. A decision was made to implement TMI with relative economic values for milk, beef, and fitness with 38, 18, and 44% for Fleckvieh and 50, 5, and 45% for Brown Swiss, respectively. In both breeds, no positive expected selection response was predicted for fertility, although this trait complex received a markedly higher weight than that derived economically. An even higher weight for fertility could not be agreed on due to the effect on selection response of other traits. Hence, breeders decided to direct more attention toward the preselection of bulls with regard to fertility.

Antimicrobial drug use on Austrian dairy farms with special consideration of the use of "highest priority critically important antimicrobials".

The use of antibiotics in livestock production is coming under growing criticism. Beside overall antimicrobial use, specific substances listed by the WHO as "highest priority critically important antimicrobials" (HPCIAs)--these include fluoroquinolones, macrolides, 3rd and 4th generation cephalosporins, as well as glycopeptides--have been placed under specific restrictions and should only be applied in particular cases according to strict indication criteria. In this study, the consumption of antimicrobial substances on Austrian dairy farms was evaluated quantitatively. The data covered 8,027 prescription records on the use of antibiotics on 465 dairy farms. Eleven veterinary practices provided data from between four to 27 months during the period from 2008 to 2010 and the total consumption of antimicrobials was estimated. The amount of active substance(s) in grams used per livestock unit (g/LU) per year and the number of product-related daily doses used per livestock unit (n PrDD(LU)/LU) per year were determined as units of measurement. These parameters were estimated by applying Monte Carlo simulation techniques, respecting variances in annual working days of the veterinary practices as well as variances in the proportion of non-treated populations. Total antimicrobial consumption in the population-at-risk was determined to be 2.59 g/LU and 1.30 PrDD(LU)/LU per year. HPCIAs were used at a proportion of 24.6% (0.31 PrDD(LU)/LU) of the total consumption of antimicrobials for systemic and intramammary use. Of these, 3rd and 4th generation cephalosporins were most frequently administered, particularly for the treatment of mastitis and foot diseases. The total consumption of antimicrobials in Austrian dairy cattle production is negligible compared to their use in pig and poultry production systems. However, the use of HPCIAs, especially 3rd and 4th generation cephalosporins, should be minimised further.

The effect of bovine viral diarrhoea virus on fertility in dairy cows: two case-control studies in the province of Styria, Austria.

Bovine viral diarrhoea (BVD) leads to substantial economic losses in beef and dairy herds worldwide. Two case-control studies were carried out using production data from 1996 to 2012 to analyse the impact of BVD virus (BVDV) on fertility in dairy herds in the province of Styria during an eradication programme. In study 1, herds in which at least one persistently BVDV-infected (PI) animal was detected (case herds) were compared to a group of control herds proven free from BVDV infection (contro herds). In study 2, within BVD infected herds the period during which P animals were present (exposed period) was compared to the period after successful BVD eradication (unexposed period). Calving interval (CAl) and the probability of a first service conception (FSC) were used as indicators in a mixed regression model to investigate the impact of BVD on reproductive performance. The model results indicated that BVD had a significant influence on CAl and FSC. Cows from control herds were 1.1 times more likely to conceive at first service compared to cows from case herds and cows served during the BVDV unexposed period were 1.3 times more likely to conceive at first service than those inseminated during the exposed period. In BVD-infected herds the CAI averaged seven days shorter in unexposed periods than in exposed periods. Besides BVD the animal breed and the parity substantially impact the analysed fertility indicators.

The use of the "highest priority critically important antimicrobials" in 75 Austrian pig farms--evaluation of on-farm drug application data.

The World Health Organization lists antimicrobial substances which are essential for the treatment of specific infections in humans as "highest priority critically important antimicrobials" (HPCIAs): macrolides, fluoroquinolones, 3rd and 4th generation cephalosporins as well as glycopeptid antibacterials. The use of these substances in livestock husbandry should be restricted in order to minimise the risk of antimicrobial resistance. To date, there is little knowledge about the amounts of HPCIAs used in animal husbandry and the different animal species and diagnoses these antimicrobials are prescribed for. In a retrospective study, drug application data recorded from 2008 until 2011 from 75 conventional pig farms were evaluated. Data were assessed directly by the farmer at farm-level. The annual antimicrobial consumption was expressed in "weight of active substance(s) in [mg]" and "number of Daily Doses". Results were referred to the animal biomass, evaluated per pig age class (piglets, weaners, fattening pigs < 60 kg biomass; fattening pigs > 60 kg biomass, sows, boars) and broken down to some variables such as the substance class and the therapy indication. The focus was especially laid on the HPCIAs. The total usage of the HPCIAs in the study population was on average 3.0 mg/ kg/year; 1.1 UDD(kg)/kg/year; 0.2 ADD(kg)/kg/year and 0.6 PrDD(kg)/kg/year. This represents about 9%, 22%, 12% and 22% of total antimicrobial consumption, respectively, depending on the unit of measurement. Fattening farms showed the highest consumption of the named substances. The main part of the HPCIAs (nADD(kg)/year) was applied to weaners, piglets and fattening pigs < 60 kg. They played an important role in the therapies of piglets (approximately 40% of the total antimicrobial consumption in piglets). Macrolides played the major role within the HPCIAs and were mainly used for digestive tract diseases. A not negligible portion of macrolides was prescribed for metaphylactic and prophylactic measures.

BVDV infection risk in the course of the voluntary BVDV eradication program in Styria/Austria.

A total of 1362 persistently BVDV-infected animals were identified in 850 herds during the first 3 years of the voluntary BVDV eradication program in Styria/Austria. Within the same period of time, the prevalence of BVDV-infected herds dropped from 7.3% to 2.2% of the 4412 herds covered by the program. The relative BVDV infection risk decreased at least four-fold in herds on common grazing and at least five-fold in herds which purchased cattle during the first 30 months of the BVD control program. Thus, the relative BVDV infection risk was reduced by between five to nine times of the initial risk following the implementation of the 3-year eradication program in all herds participating in the program.

Genetic diversity of recent bovine viral diarrhoea viruses from the southeast of Austria (Styria).

To characterise the bovine virus diarrhoea virus (BVDV) isolates circulating in the southeastern region of Austria, namely in the province of Styria, 71 blood samples collected between 1998 and 2000 from persistently infected cattle in 62 herds were subjected to genetic typing. For this, 288bp fragments from the 5' untranslated region (5'-UTR) were amplified by polymerase chain reaction after reverse transcription (RT-PCR). The products were sequenced and used for phylogenetic analysis. Seventy virus isolates were typed as BVDV species 1 (BVDV-1). Only one isolate was typed as BVDV species 2 (BVDV-2), representing the first isolate of this pestivirus genotype found in Austria. In addition, phylogenetic analysis revealed that viruses belonging to five genetic groups within BVDV-1 are circulating in Styria. Most viruses (53) were found in group BVDV-1f, nine viruses in BVDV-1h, four viruses in BVDV-1b, three viruses in BVDV-1d and one virus in BVDV-1g. No virus was found in genetic group BVDV-1a, which is dominant in the UK and widely distributed in USA. Likewise, the BVDV isolates predominating in a neighbouring country, namely Germany, belonged to different genogroups than those circulating in Styria. We conclude that in a particular region and environment certain BVDV-1 genetic groups predominate. New groups, including BVDV-2, can be introduced, e.g. by trade of animals. The low incidence of BVDV-2 in Styria is in concert with the sporadic occurrence of these viruses in other regions of Europe.