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Decreasing prevalence of Q fever in Illinois.

There were 858 (37.7 percent) Q fever-infected dairy herds among the 2,277 tested in Illinois in 1963. The percentage decreased to 19.2 percent (380 of 1,975) in 1967. Reaction rates (complement-fixation test titer of 1:8 or greater) in serum samples from veterinarians decreased from 13.3 percent in 1956 to 3.9 percent in 1964 and from 3.6 percent in 1966 to 0 percent in 1968, 1970, 1972. There were 14 (2.7 percent) reactive serum samples among 526 abattoir workers tested in 1966; reaction rates were higher among workers having contact with swine (8.2 percent) than among workers having contact with cattle (1.8 percent). Two (0.1 percent) of 1,432 serum samples collected from 1967 to 1971 during preemployment examinations at another abattoir were reactive. Only two clinical cases of Q fever were reported to the Illinois Department of Public Health in the period 1963-80. All evidence evidence points to a decreasing prevalence of Q fever in Illinois.

Abattoirs↗

Evaluation of rapid gross visual appraisal of swine lungs at slaughter as a diagnostic screen for enzootic pneumonia.

A rapid gross visual appraisal of enzootic pneumonia lesions was made of 87 lungs at a local abattoir and the lungs were then set aside and examined in more detail. A sample of pulmonary tissue was taken from each lung and submitted for bacterial and histological examination. The principal investigator who had performed the gross and detailed lung scores was then used to assess the agreement of two inspectors who were scoring lung lesions in the abattoir. The Pearson's correlation coefficient between grossly scored lungs and scores derived from a detailed examination was 0.94. Using histological examination as the gold standard, rapid gross examination had a sensitivity of 76% and a specificity of 71%. Using bacterial recovery as a gold standard yielded a sensitivity of 77% and a specificity of 51%. The sensitivity and specificity of inspectors 1 and 2 compared to the principal investigator were: sensitivity = 97.5% and specificity = 97.4% for inspector 1, and 97% and 98% for inspector 2. The kappa values for both of the inspectors compared to the principal investigator were 0.95 suggesting that designated lay inspectors consistently agreed with the principal investigator.

Abattoirs↗

Trichinella spiralis infection in pigs in eastern Bolivia.

Trichinellosis in pigs in Bolivia was first documented in 1993 following a small abattoir survey in a rural community in the Bolivian Altiplano. The present study investigated the presence of antibodies to Trichinella spiralis in pigs in the 2 largest departments in terms of pig production in Bolivia. Three geographically separate abattoir surveys were conducted to cover the major production areas in the Departments of Santa Cruz and Chuquisaca. Sera were tested using an enzyme-linked immunosorbent assay. Of the 1,327 sera analysed from the 3 areas, 13.4% overall tested positive. Results from the 3 individual surveys varied from 10.2% seropositivity to 17.1 per cent. However, within each of the 3 sample areas, highly significant variation in seropositivity was encountered, with those areas with the most extensive production systems having the highest percentage of positive sera. Such variation is probably due to differences in nutrition with foraging and household waste being important components of pig diets in extensive production systems. The results of this study were similar to those obtained from the previous survey in the Altiplano and indicate that trichinellosis is present throughout Bolivia and is a potentially important public health problem.

Abattoirs↗

Microbiological status of selected chicken carcases from a non-automated poultry processing plant.

The microbiological status of chicken carcases sampled at three different processing points in a South African Grade B poultry abattoir slaughtering ca. 750 birds per hour, was determined. Six skin samples and two meat samples were aseptically collected from different sites on each carcase. Total bacterial counts were performed at 25 degrees C, 37 degrees C and 43 degrees C and all colonies from plates showing between 30 and 300 cfu were characterised. Bacterial counts of the skin samples at 37 degrees C were consistently the highest, followed by those at 25 degrees C and then 43 degrees, but for the two meat samples the highest bacterial counts were found at 37 degrees C and the lowest at 25 degrees C. Neck skin counts were marginally higher than bacterial counts of the other skin samples. The Gram negative genera Escherichia and Acinetobacter were isolated most frequently at all three incubation temperatures and from all sampling sites, while the dominant Gram positive genera were Staphylococcus and Enterococcus. Escherichia isolates predominated on the skin sampling site cranio-dorsal to the pygostyle, whilst Staphylococcus isolates predominated on the skin sampling site caudal to the breastbone. Microbiological contamination is a major problem in the abattoir studied and further studies should therefore aim to determine points of maximum contamination in the processing line.

Animals↗

The life-cycle of the bont tick Amblyomma hebraeum in vitro.

The life-cycle of the hard tick Amblyomma hebraeum was completed in vitro by feeding all life-stages of the tick through silicone membranes on bovine blood from an abattoir. Ticks were placed in a simple feeder membranes on bovine blood from an abattoir. Ticks were placed in a simple feeder consisting of a honey jar containing the blood with a glass tube insert (o.d. 42 mm) across the end of which the membrane was stretched. This feeding unit was held in a water bath (38 degrees C). Larvae and nymphs fed on a membrane (< 90 microns thick) made of silicone reinforced with Kodak lens cleaning paper, and adults on a silicone membrane (0.5 mm thick) reinforced with Terylene netting. To control microbial growth, gentamicin (5 micrograms/ml) and nystatin (100 i.u./ml) were added to the weekly open-collected blood, which was manually defibrinated. The blood was changed twice daily for nymphs and three times for adults and larvae. Attachment of ticks was induced with combinations of host hair, tick faeces, a bovine pelage extract and a synthetic aggregation-attachment pheromone mixture. The in vitro life-cycle started with unengorged "natural" adults, which had moulted from nymphs fed on steer. The life-cycle closed with unengorged, first in vitro generation adults which had moulted from nymphs fed in vitro. Although the feeding and development of larvae and nymphs were similar to in vivo controls, females fed and developed poorly in vitro. The toxicity of the systemic acaricide Ivermectin for nymphs of A. hebraeum was confirmed using the in vitro feeding method.

Animals↗

Pregnancies and live birth from in vitro fertilization of calf oocytes collected by laparoscopic follicular aspiration.

Oocytes were recovered by laparoscopic aspiration from 3- to 8-week-old calves treated with follicle-stimulating hormone (FSH) followed by human chorionic gonadotropin (hCG) to induce follicular growth and oocyte maturation in vivo. Most of the recovered oocytes either had resumed meiotic maturation at the time of aspiration or were competent to undergo maturation during subsequent culture in vitro. Oocytes matured in vivo following FSH and hCG treatment underwent in vitro fertilization (70%) at rates not significantly different from those of control oocytes recovered from adult cow ovaries at abattoirs and matured in vitro (75%). Calf oocytes that were immature at aspiration exhibited lower fertilization rates after in vitro maturation (36%) but their rate of development to morulae and blastocysts did not differ from that of mature oocytes at aspiration. A total of 91% of the zygotes produced from calf oocytes developed to morula and 27% to blastocyst stages during 6 days of culture. The proportion developing to morulae was significantly higher (P<0.05) than that observed for zygotes resulting from in vitro maturation and fertilization of oocytes recovered from cow ovaries obtained at an abattoir and processed concomitantly (59% to morulae and 18% to blastocysts). Morulae or blastocysts developed from oocytes from 5 to 6-week-old calves, when transferred to synchronized recipient heifers, resulted in 2 confirmed pregnancies, one of which produced a single full-term live calf. The ability to produce embryos from oocytes recovered from newborn or prepubertal calves offers the potential for markedly reducing the generation interval in cattle, thereby substantially accelerating the rate of genetic gain that can be achieved through embryo transfer.

Journal Article↗

Physiology of Sporolactobacillus strains isolated from different habitats and the indication of in vitro antagonism against Bacillus species.

In an ecological study only low numbers of Sporolactobacillus were found in habitats such as the faeces of herbivores, the rumen of cattle and the final waste water of an abattoir. Their presence in the final waste water of an abattoir indicates their possible association with food, and, more specifically, with meat. Differences were found in some physiological characteristics. One isolate (L2404) differed from the authentic Sporolactobacillus ATCC 15538 by its inability to ferment inulin, its growth in presence of 6.5% NaCl and in 0.2% tellurite, by the isomer(s) of lactic acid produced and the mol% G + G in the DNA. One Sporolactobacillus isolate (L2407) showed antagonism against Bacillus cereus, Bacillus cereus var, mycoides, Bacillus megaterium and Bacillus subtilis.

Animals↗

Enhanced chemiluminescent enzyme immunoassay for the detection of trichinellosis antibodies in pigs.

A modified enhanced chemiluminescent enzyme assay (ECIA) was developed for mass screening of pigs for trichinellosis antibodies in abattoirs. Using Bionectics beads as solid support, the assay time could be reduced to 45 min. Optimal conditions for washing, blocking, incubation, concentration of serum, antigens and conjugates as well as timing of film exposure were determined. The sensitivity and specificity of the assay were found to be comparable to those of the triple antibody-IgG ELISA. The assay was tested in an abattoir and its efficacy was found to be satisfactory. However, the major disadvantage of the assay is the high cost of magnetic beads.

Animals↗

Developmental competence of equine oocytes and embryos obtained by in vitro procedures ranging from in vitro maturation and ICSI to embryo culture, cryopreservation and somatic cell nuclear transfer.

Development of assisted reproductive technologies in horses has been relatively slow compared to other domestic species, namely ruminants and pigs. The scarce availability of abattoir ovaries and the lack of interest from horse breeders and breed associations have been the main reasons for this delay. Progressively though, the technology of oocyte maturation in vitro has been established followed by the application of ICSI to achieve fertilization in vitro. Embryo culture was initially performed in vivo, in the mare oviduct or in the surrogate sheep oviduct, to achieve the highest embryo development, in the range of 18-36% of the fertilised oocytes. Subsequently, the parallel improvement of in vitro oocyte maturation conditions and embryo culture media has permitted high rates of embryo development from in vitro matured and in vitro cultured ICSI embryos, ranging from 5 to 10% in the early studies to up to 38% in the latest ones. From 2003, with the birth of the first cloned equids, the technology of somatic cell nuclear transfer has also become established due to improvement of the basic steps of embryo production in vitro, including cryopreservation. Pregnancy and foaling rates are still estimated based on a small number of in vitro produced equine embryos transferred to recipients. The largest set of data on non-surgical embryo transfer of in vitro produced embryos, from ICSI of both abattoir and in vitro-matured Ovum Pick Up (OPU) oocytes, and from somatic cell nuclear transfer, has been obtained in our laboratory. The data demonstrate that equine embryos produced by OPU and then cryopreserved can achieve up to 69% pregnancy rate with a foaling rate of 83%. These percentages are reduced to 11 and 23%, respectively, for cloned embryos. In conclusion, extensive evidence exists that in vitro matured equine oocytes can efficiently develop into viable embryos and offspring.

Animals↗

Genome-scale evolution and phylodynamics of swine influenza A viruses in China: a genomic epidemiology study.

BACKGROUND: Pigs are recognised as crucial intermediate hosts for the emergence of influenza viruses of pandemic potential. As the largest pork-producing nation, China hosts a complex ecosystem of swine influenza viruses (SIVs). We aimed to investigate the evolutionary processes, spatiotemporal dynamics, and biological characteristics of SIVs in China. METHODS: From Jan 15, 2016, to Dec 22, 2020, we collected nasal swabs from pigs at eight abattoirs and 16 swine farms in the Guangdong, Henan, and Shandong provinces of China, as part of SIV surveillance. SIVs were detected with RT-PCR. Positive samples underwent viral isolation and genome sequencing. We analysed evolution and spatiotemporal dynamics using the whole genomes of isolated SIVs, as well as genome sequences of SIV isolates from human infections worldwide retrieved from the Global Initiative on Sharing All Influenza Data and GenBank Flu databases up to April 28, 2024. Viral sequences without a sample collection area or date were excluded from the analysis. Viral receptor-binding properties and in-vitro replication of strains isolated in this study were evaluated with a solid-phase binding assay and various cell lines, including Madin-Darby canine kidney cells, porcine alveolar macrophages, primary porcine trachea epithelial cells, human bronchial epithelioid, and human lung adenocarcinoma epithelial (A549) cells. Viral replication and transmission studies were conducted in 33 guinea pigs and 13 pigs. Additionally, we collected serum samples from pig farm workers and members of the general public recruited by the Third Affiliated Hospital of Sun Yat-sen University between Feb 28 and May 11, 2023, to detect specific antibodies against Eurasian avian-like A(H1) and human-like A(H3N2) SIVs using the haemagglutination inhibition assay. FINDINGS: 23 (1&#xb7;3%) of 1818 nasal swabs collected in abattoirs had SIVs; 22 (0&#xb7;9%) of 2375 swabs from swine farms had SIVs. Further viral isolation yielded 39 strains of SIV. We identified 534 A(H1N1), 69 A(H1N2), and 92 A(H3N2) SIVs, representing 20 genotypes within the Eurasian avian-like lineage, 14 within the classical swine A(H1) lineage, and 16 within the human-like A(H3N2) lineage. The introduction of the A(H1N1)pdm/09 virus significantly influenced the internal gene pool of SIVs, enhancing genotypic diversity in China. Notably, the Eurasian avian-like A(H1), classical swine A(H1), and human-like A(H3N2) lineages showed human-mediated spread over long distances between provinces, with the Eurasian avian-like A(H1) lineage showing the most prevalent spread pathways. Eurasian avian-like A(H1) SIVs showed a preference for binding to sialic acid &#x3b1;-2,6 glycan receptors, predominantly found in humans, resulting in an increased production of progeny viruses in human airway epithelial cells, as well as effective transmission and infectivity among guinea pigs and pigs. Among 54 eligible serum samples collected from pig farm workers (24 from slaughterhouses and 30 from swine farms), 23 (43%) were seropositive for Eurasian avian-like A(H1) SIVs and 46 (85%) for human-like A(H3N2) SIVs. Among 100 eligible samples from members of the general public, 14 (14%) were seropositive for Eurasian avian-like A(H1) SIVs and 85 (85%) for human-like A(H3N2) SIVs. INTERPRETATION: This study elucidates the evolutionary processes and spatiotemporal patterns of SIVs, highlighting potential risks to public health. These findings are crucial for informing public health interventions that aim to prevent future SIV epidemics in China and other countries worldwide. FUNDING: Scientific Innovation Strategy-Construction of High-Level Academy of Agriculture Science-Distinguished Scholar (R2020PY-JC001).

Animals↗

The correlation between Salmonella serology and isolation of Salmonella in Danish pigs at slaughter.

In Denmark, a serological Salmonella surveillance programme in finishing pig herds has been in place since 1995. The programme was founded on data from experimental studies, which demonstrated a strong association between Salmonella serology and the prevalence of these bacteria. The current study was carried out in three Danish abattoirs to evaluate the correlation under field conditions. A total of 160 Danish finishing pig herds were included. Seven out of these were examined twice, yielding a total of 167 observations. The herds were selected according to their herd serology based on data from the national surveillance. From each herd, samples were taken from 10 finishers at slaughter. The prevalence of Salmonella bacteria was measured at four sites: (1) caecal-content; (2) carcass surface; (3) pharynx; and (4) caecal lymph nodes. A logistic regression model was constructed for each sampling site. Abattoir, sanitary slaughter and herd seroprevalence were used as explanatory variables. The results demonstrated that there was a strong association between herd serology and the prevalence of Salmonella bacteria measured at three of the sampling sites: caecal-content, pharynx, and carcass surface. For these sites, the odds for being culture-positive for Salmonella varied from 1.3 to 1.5 for each increase of 10% in herd serology (P < 0.0001). For caecal lymph nodes, however, no linear association was found.

Animals↗

Crimean-Congo haemorrhagic fever virus infection in the western province of Saudi Arabia.

In 1990, an outbreak of suspected viral haemorrhagic fever involving 7 individuals occurred in Mecca in the Western Province of Saudi Arabia. Congo-Crimean haemorrhagic fever (CCHF), not previously known to be present in Saudi Arabia, was incriminated. A study of the epidemiology of this virus was therefore carried out in Mecca, and in nearby Jeddah and Taif in 1991-1993; 13 species of ixodid ticks (5 Hyalomma spp., 5 Rhipicephalus spp., 2 Amblyomma spp., 1 Boophilus sp.) were collected from livestock (camels, cattle, sheep, goats), and of these 10 were capable of transmitting CCHF. Camels had the highest rate of tick infestation (97%), and H. dromedarii was the commonest tick (70%). Attempts to isolate virus from pools of H. dromedarii and H. anatolicum anatolicum were unsuccessful. The source of infection in 3 confirmed cases of CCHF was contact with fresh mutton and, in a suspected case, slaughtering sheep. An investigation in Mecca, which included a serological survey of abattoir workers, identified 40 human cases of confirmed or suspected CCHF between 1989 and 1990, with 12 fatalities. Significant risk factors included exposure to animal blood or tissue in abattoirs, but not tick bites. It is suspected that the CCHF virus may have been introduced to Saudi Arabia by infected ticks on imported sheep arriving at Jeddah seaport, and that it is now endemic in the Western Province.

Adult↗

Cadmium levels in kidneys from Swedish pigs in relation to environmental factors--temporal and spatial trends.

The kidney cadmium level in pigs slaughtered at the age of 5-7 months was analysed with respect to geographical and temporal trends. During the period 1984-1992, a total of 1051 samples of porcine kidney from 31 abattoirs were analysed for cadmium at the National Food Administration within the control programme for livestock production. The mean kidney cadmium level was 0.11 +/- 0.07 mg/kg wet wt. (mean +/- S.D.). Regression analysis showed that the cadmium concentration in pig kidney has increased by 2% per year. By using Geographic Information System (GIS), geographical trends in cadmium concentration of porcine kidney were analysed and correlated to cadmium levels in moss and pH in the mor layer of podsolized soil. These two parameters explained 60% of the random variation in cadmium levels in porcine kidney. There were significant differences between individual abattoirs, but no significant longitudinal or latitudinal trend was found. Variation in kidney cadmium levels within breeding stocks was investigated. Kidneys from eight stocks, with five pigs from each, were analysed for cadmium concentration. In spite of the homogeneous treatment of the pig within the same stock, kidney cadmium levels varied on average by a factor of two between individuals. There was a significant correlation between cadmium in feed and cadmium levels in porcine kidney (P = 0.002). The temporal increase in cadmium levels in porcine kidney should be further investigated. An increase in cadmium body burden in pig may be an indicator of an increase in human cadmium exposure.

Animal Feed↗

In vitro maturation of bovine cumulus-oocyte complexes in undiluted follicular fluid: effect on nuclear maturation, pronucleus formation and embryo development.

Since resumption of meiosis and cytoplasmic maturation of bovine oocytes takes place in close association with follicular fluid, it would be logical to assume that this might be a perfect maturation medium. To test the hypothesis, abattoir-derived cumulus-oocyte complexes (COCs) were in vitro matured in undiluted (i) mixed follicular fluid (FF) from 3 to 15 mm follicles from abattoir ovaries, (ii) preovulatory follicular fluid (POF) from the dominant follicle from a cyclic unstimulated heifer, (iii) preovulatory follicular fluid (OPU) from synchronised and superovulated heifers 60 h after prostaglandin and 20 h after GnRH treatment, and in (iv) TCM-199 with 5% serum. Subsequent to IVM, the COC were subjected to IVF and IVC, and embryo development was followed until the blastocyst stage at Day 8 after insemination. The MII rates in the TCM-199 (69%), POF (69%) and OPU (72%) groups were not different from each other but different from the FF (41%) group (P<0.05). In spite of the high MII rates, none of the follicular fluids supported embryo development: the FF, POF and OPU blastocyst rates were alike (3%, 3%, 2%) and different (P<0.05) from the rates in the TCM-199 (19%). During IVM in follicular fluids but not in TCM-199, the expanded cumulus masses became trapped in a coagulum. Although it could be prevented by the presence of heparin during IVM, it did not improve the blastocyst rates. In conclusion, undiluted preovulatory follicular fluids supported nuclear maturation but not further embryonic development as judged by the high MII and low blastocyst rates.

Animals↗

In vitro maturation of ovine oocytes in a portable incubator.

Immature ovine oocytes were collected from ovaries obtained from an abattoir and assigned to one of three treatment groups for in vitro maturation. For Treatment 1 (T1), oocytes were matured in a conventional incubator, in tissue culture wells in an atmosphere of 5% CO(2) and air. Maturation medium consisted of bicarbonate buffered Tissue Culture Medium 199 (TCM199) supplemented with fetal calf serum (FCS), follicle stimulating hormone (FSH), luteinizing hormone (LH), and penicillin/streptomycin (pen/strep). For Treatment 2 (T2), oocytes were matured in a portable incubator, in plastic tubes containing the same medium as T1. The medium was equilibrated with 5% CO(2) and overlayed with oil. For Treatment 3 (T3) oocytes were matured in the portable incubator without CO(2) equilibration, in tubes containing HEPES buffered TCM 199 supplemented as in T1. After 24 hours at 39 degrees C, the percentage of oocytes undergoing normal nuclear maturation was 72.55, 68.14 and 66.96% for T1, T2 and T3, respectively (P >0.05). In a second experiment oocytes were matured in the 3 treatments described, then fertilized in vitro using frozen-thawed ram sperm. Fertilization rates were 44.09, 58.62 and 55.69% for T1, T2 and T3, respectively. T1 and T2 were significantly different (P < 0.05). For Experiment 3, oocytes matured and fertilized as described were cultured in drops of Modified Brinster's Mouse Ova Culture (MBMOC) containing bovine oviductal cells. These were incubated at 39 degrees C in an atmosphere of 5% CO(2) and air for 7 days. T1, T2 and T3 resulted in 20.26, 16.94 and 24.43% development to morulae, and 4.01, 3.06 and 1.85% development to blastocysts, respectively (P >0.05). The results of these experiments indicate that maturation, fertilization, and developmental rates of ovine oocytes matured in the portable incubator are similar to those of oocytes matured in a conventional incubator. This technique shows promise for transportation of oocytes to laboratories where abattoirs are not in close proximity, and holds promise for transportation of oocytes from non-domestic animals collected in the field or remote locations, to facilities capable of utilizing and preserving the gametes.

Journal Article↗

Quality controls for bovine viral diarrhea virus-free IVF embryos.

Introduction of bovine viral diarrhea virus (BVDV) with cumulus-oocyte-complexes (COCs) from the abattoir is a concern in the production of bovine embryos in vitro. Further, International Embryo Transfer Society (IETS) guidelines for washing and trypsin treatment of in-vivo-derived bovine embryos ensure freedom from a variety of pathogens, but these procedures appear to be less effective when applied to IVF embryos. In this study, COCs were exposed to virus prior to IVM, IVF and IVC. Then, virus isolations from cumulus cells and washed or trypsin-treated nonfertile and degenerated ova were evaluated as quality controls for IVF embryo production. The effect of BVDV on rates of cleavage and development was also examined. All media were analyzed prior to the study for anti-BVDV antibody. Two approximately equal groups of COCs from abattoir-origin ovaries were washed and incubated for 1 h in minimum essential medium (MEM) with 10% equine serum. One group was incubated in 10(7) cell culture infective doses (50% endpoint) of BVDV for 1 h, while the other was incubated without virus. Subsequently, the groups were processed separately with cumulus cells, which were present throughout IVM, IVF and IVC. Cleavage was evaluated at 4 d and development to morulae and blastocysts at 7 d of IVC. After IVC, groups of nonfertile and degenerated ova or morulae and blastocysts were washed or trypsin-treated, sonicated and assayed for virus. Cumulus cells collected at 4 and 7 d were also assayed for virus. Anti-BVDV antibody was found in serum used in IVM and IVC but not in other media. A total of 1,656 unexposed COCs was used to produce 1,284 cleaved embryos (78%), 960 embryos > or = 5 cells (58%), and 194 morulae and blastocysts (12%). A total of 1,820 virus-exposed COCs was used to produce 1,350 cleaved embryos (74%), 987 embryos > or = 5 cells (54%), and 161 morulae and blastocysts (9%). Rates of cleavage (P = 0.021), cleavage to > or = 5 cells (P = 0.026) and development to morula and blastocyst (P = 0.005) were lower in the virus-exposed group (Chi-square test for heterogeneity). No virus was isolated from any samples from the unexposed group. For the exposed group, virus was always isolated from 4- and 7-d cumulus cells, from all washed nonfertile and degenerated ova (n = 40) and morulae and blastocysts (n = 57) and from all trypsin-treated nonfertile and degenerated ova (n = 80) and morulae and blastocysts (n = 91). Thus, virus persisted in the system despite the presence of neutralizing antibody in IVM and IVC media, and both washing and trypsin treatment were ineffective for removal of the virus. Presence of virus in 4- and 7-d cumulus cells as well as in nonfertile and degenerated ova were good indicators of virus being associated with morulae and blastocysts.

Animals↗

Virulence-associated protein characterisation of Rhodococcus equi isolated from bovine lymph nodes.

Rhodococcus equi has a low pathogenicity in cattle, but it occasionally causes lymph node granulomas, which are detected at abattoir post mortem inspection, and must be distinguished from tuberculous granulomas. Lymph node lesions were detected in 6719 cattle, from a total of 3,263,622 cattle examined post mortem in abattoirs, in the Republic of Ireland, during 1997 and 1998. Histological examination was performed on all lesions, principally for the purpose of identifying animals with tuberculosis. A total of 1122 of the lesions were cultured on blood agar and on Stonebrinks and Lowenstein-Jensen medium containing pyruvate, because the histological findings were difficult to interpret or were suggestive of R. equi infection. R. equi was isolated from 264 lesions. Almost all of the R. equi granulomas were confined to a single lymph node, and were present predominantly in the retropharyngeal, bronchial and mediastinal lymph nodes. R. equi granulomas were present in a significantly higher proportion of the lesions detected in steers and heifers compared to cows. The prevalence in the total population of 3.3 million cattle examined post mortem was 0.008%. The 15-17kDa antigens, associated with virulence in this organism, and the 20kDa antigen, associated with intermediate virulence, were not detected in isolates from 146 cattle, analysed by immunoblot assays. A PCR assay to detect the plasmid gene encoding the 15-17kDa antigens was also negative for isolates from these 146 animals. Plasmids were not detected in 30 isolates which were examined.

Actinomycetales Infections↗

Occurrence of Escherichia coli O157 in Finnish cattle.

Bovine faecal samples were collected during June-December 1997 at 14 major abattoirs slaughtering cattle in Finland. Escherichia coli O157 was isolated from 19 of the 1448 samples (1.31%) after enrichment and immunomagnetic separation (IMS). The positive faecal isolates originated from 16 farms and eight abattoirs. The occurrence of E. coli O157 was highest in July (8/204; 3.92%) and September (6/244; 2.46%). No E. coli O157 was detected in November and December, nor from the faecal samples from the northernmost region where cattle density is low. All of the isolates carried the eae gene and showed the enterohaemolytic phenotype. All except one were motile and had the flagella antigen H7. Seventeen of the isolates were positive for stx(2) gene and one carried both the stx(1) and stx(2) genes. Of the 17 isolates with stx genes, 16 were verocytotoxin-positive in a reversed passive latex agglutination test after polymyxin extraction but only eight without extraction. The isolates belonged to 10 different pulsed-field gel electrophoresis (PFGE) patterns. The most common PFGE pattern (1.42) was detected in eight isolates (42.1%). Four PFGE patterns (1.1; 1.6; 1.12; 1.14) were identical with those isolated from humans in Finland, suggesting that at least some human E. coli O157 infections may be of bovine origin.

Adhesins, Bacterial↗