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1.
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2.
Objective To report the occurrence and pathology of porcine circovirus type 2 (PCV2)‐associated disease (PCVAD) of postweaning pigs in two Australian pig herds. Methods Mortality data from two commercial piggeries that experienced higher than normal postweaning illthrift and mortalities were examined. Gross and histopathological examinations were performed on the index cases, and at weekly intervals thereafter for a period of 10 weeks. Specimens were submitted to the laboratory for routine diagnostic testing and for exclusion of porcine reproductive and respiratory syndrome virus (PRRSV). The genomes of two strains of PCV2 isolated during testing were sequenced. Results Mortality rates in weaned, 5–12‐week‐old pigs spiked significantly during mid to late 2007. This increase in the mortalities was mainly attributed to salmonella‐associated diarrhoea and illthrift. Salmonellosis was diagnosed in 73/110 cases inclusive of both piggeries. Many pigs also had chronic granulomatous lymphadenitis and diffuse histiocytic interstitial pneumonia consistent with PCVAD and associated with varying amounts of PCV2 antigen and inclusion bodies. All samples tested for PRRSV were negative. Sequence analysis of the PCV2 isolates showed strain differences between piggeries. Conclusion This report describes the first outbreaks of PCVAD in growing pigs in Western Australia (WA) and describes lesions not previously seen in this laboratory. It also describes the first isolation of a PCV2 group 1 virus in WA associated with PCVAD. Although the outbreaks of PCVAD occurred with concurrent salmonellosis, the two diseases were unrelated. Neither of the outbreaks met the Australian case definition for the diagnosis of postweaning multisystemic wasting syndrome.  相似文献   

3.
The housing, management and internal parasite control practices used in piggeries in Western Australia was surveyed by interviewing the owner/manager of 100 randomly selected piggeries. At the time of the interview 20 faecal samples were collected from pigs and examined for evidence of internal parasites. Most herds (80%) in which anthelmintics were used, had evidence of nematode infection. Some pig producers were using an anthelmintic that was ineffective against nematode species present while some herds had nematodes that should have been controlled by the anthelmintic being used. Prevalence of nematode infection was higher in pigs run in paddocks than in pigs housed intensively. Washing sows prior to farrowing was associated with a lower prevalence of nematode infection. The findings suggested that pig producers should ensure that the anthelmintic used is effective against the nematodes present in their pigs. It was concluded that administering anthelmintics as a single dose in the feed may not be the most effective method of deworming pigs.  相似文献   

4.
Objective   To describe how various antimicrobials are used in commercial pig herds in Australia and for what disease conditions.
Procedure   Managers of large pig herds (> 200 sows) across Australia and their veterinarians participated in an internet-based survey in 2006. Questions were asked about herd management, the occurrence of bacterial diseases and the type and frequency of antimicrobial use. An antimicrobial usage index for each herd was derived as a summary of the risk of selection for antimicrobial resistance. Relationships between responses were explored with univariate and multivariate analysis.
Results   Responses were received for 197 herds estimated to represent at least 51% of all large pig herds in Australia. Most piggeries relied on drugs of low importance in human medicine (e.g. tetracyclines, penicillins and sulfonamides). For the two drugs of high importance in human medicine that can be legally prescribed to pigs in Australia, ceftiofur use was reported in 25% of herds and virginiamycin in none. Infections attributed to Lawsonia , Mycoplasma and Escherichia coli motivated the most use of antimicrobials. No useful association was found between management factors and the antimicrobial use index.
Conclusion   Most antimicrobial use in the Australian pig industry is based on drugs of low importance to public health. Enhanced control of E. coli infections without reliance on antimicrobials would further reduce the risk of selecting for antimicrobial resistance relevant to public health. The amount of variation in the usage index between herds suggests that antimicrobial use should be constantly reviewed on a herd by herd basis.  相似文献   

5.
Faeces samples collected from diarrhoeic dairy calves in the first 8 weeks of life were examined for the presence of 5 enteropathogens. The majority of the 108 diarrhoea cases occurred in the first 5 weeks of life and a commercial ELISA kit detected bovine enteric coronavirus (BEC) in 38.9%, serogroup A rotavirus (RV) in 16.7% and K99 (F5) fimbrial adhesin-positive Escherichia coli (K99 ETEC) in 11.1 per cent. Concurrent infections of these enteropathogens were detected in 14.8% of samples (30.8% of samples positive for these agents). No evidence of cryptosporidial infection was found using a differential staining method on faecal smears nor was salmonella excretion detected. On 2 of the 8 farms only BEC was present; the other 6 farms were positive for all 3 agents. It is concluded that BEC is the major infectious cause of neonatal calf diarrhoea in the Ethiopian dairy herds studied with RV and K99 ETEC also contributing to morbidity, either alone or as mixed infections.  相似文献   

6.
OBJECTIVE: To use the technique of ribotyping to investigate the genetic diversity of Australian isolates of Pasteurella multocida associated with outbreaks of clinical disease in Australian pigs. DESIGN: One hundred and seven porcine P multocida isolates were analysed by ribotyping using the restriction enzymes HpaII and HindIII. The genetic population structure of the Australian porcine P multocida isolates was determined through statistical analysis of the joint ribotype patterns, and this was then compared with biochemical and epidemiological data available for the population. RESULTS: A total of 25 combined ribotypes were recognised, which were grouped into five ribotype clusters. Despite the deliberate selection of diverse isolates, the study revealed only a limited degree of genetic diversity. Fourteen of the ribotypes contained multiple isolates, and 12 of these ribotypes were present on more than one farm. Three of the seven biovars analysed in the study showed very limited diversity. All fifteen biovar 2 isolates (subsp multocida) were found in a single cluster (III), while all four biovar 8 isolates, which correspond to P multocida subsp gallicida, were allocated by themselves to a single cluster (IV). All nine of the biovar 12 isolates (lactose-positive subsp multocida) were assigned to a single cluster (I), together with the single biovar 14 isolate, which was the only other lactose-positive isolate in the population (ODC-negative). CONCLUSION: A limited number of ribotypes of P multocida are associated with Australian pigs. The majority of these ribotypes are widely distributed across multiple farms, and across multiple states. Individual farms can possess multiple ribotypes of P multocida. Some of the unusual biochemical variants of P multocida present in Australian pigs have a very limited genetic diversity. The nature of pig production in Australia, primarily involving continuous flow systems with few closed herds, has possibly contributed to the widespread distribution of a limited number ribotypes.  相似文献   

7.
The aim of this retrospective study was to use RT-PCR and nucleotide sequencing analysis to determine the G (VP7 gene) and P (VP4 gene) genotypes of 155 Brazilian bovine rotavirus A (RVA) wild-type strains detected in diarrheic calves from all Brazilian geographical regions from 2006 to 2015. The RVA strains evaluated belonged to the G6, G10, P[5], and P[11] genotypes. The G6P[5] genotype was prevalent (65.5%; P < 0.05) in beef, and the G10P[11] (38.4%) and G6P[11] (30.8%) genotypes were more prevalent in dairy cattle herds. The Midwest was the region with the highest number of genotyped RVA strains, where the genotypes G6, P[5], and P[11] were identified. Genotype combination G6-IV/P[5]-IX, prevalent in beef herds, and G6-III/P[11]-III or G10-IV/P[11]-III, prevalent in dairy herds, were detected. In addition, for the first time in Brazil, we detected the P[5] and P[11] genotype RVA strains that belong to lineage II and VII, respectively.  相似文献   

8.
Bovine Group A Rotavirus (RVA) is one of the main causes of neonatal calf diarrhea worldwide. The present study reports the genotyping of bovine RVA strains circulating in Argentinean cattle from 2004 to 2010. Additionally, a new set of typing primers was designed and tested to differentiate between G8 and G6 (lineage III and IV) RVA strains. Bovine RVA was detected in 30% (435/1462) of the tested samples, corresponding to 49% (207/423) of the studied outbreaks with a similar detection rates in beef (53%; 67/127) and dairy herds (52%; 65/126). The RVA strains circulating in Argentinean cattle belonged to the common bovine genotypes G6 (lineages III and IV), G8, G10, P[5] and P[11]. A different RVA G/P-genotype distribution was found between the exploitation types, with the combination G6(IV)P[5] being by fare the most prevalent RVA strain in beef herds (58%), whereas a more even distribution of G6(III)P[11] (15%), G10P[11] (17%), G6(IV)P[5] (14%), and G6(IV)P[11] (6%) RVA strains was detected in dairy herds. G8 RVA strains were found in two dairy farms in calves co-infected with G8+G6(III)P[11]. A high percentage of co-infections and co-circulation of RVA strains with different genotypes during the same outbreak were registered in both exploitation types (20% of the outbreaks from beef herds and 23% from dairy herds), indicating a potential environment for reassortment. This finding is significant because G10P[11] and G6(III)P[11] strains may possess zoonotic potential. Continuous surveillance of the RVA strains circulating in livestock provides valuable information for a better understanding of rotavirus ecology and epidemiology.  相似文献   

9.
Between September 1982 and March 1984, 101 Western Australian piggeries with 15 or more sows were surveyed to determine the prevalence of internal parasites and examine the relationship between parasitism and management practices. Faecal samples were collected from 20 pigs in 4 age groups in randomly selected piggeries, and examined for the presence of eggs of helminth parasites and protozoan cysts. Evidence of nematode parasites was found in 79% of piggeries. Sows were more commonly affected than other classes of pigs with worm eggs being found in 68% of herds. Oesophagostomum spp was the most prevalent worm species, being found in pigs from 65% of piggeries and in sows in 60% of herds. Ascaris suum was the most common species of worm found in growing pigs. There was no evidence of infection with either Metastrongylus spp or Strongyloides spp in any of the herds sampled. Oocysts of coccidia were found in pigs from 56% of piggeries and Balantidium coli cysts were detected in pigs from 42% of piggeries sampled.  相似文献   

10.
《Veterinary microbiology》2015,175(2-4):195-210
Viral enteritis is a serious problem accounting for deaths in neonatal animals and humans worldwide. The absence of surveillance programs and diagnostic laboratory facilities have resulted in a lack of data on rotavirus associated diarrheas in pigs in East Africa. Here we describe the incidence of group A rotavirus (RVA) infections in asymptomatic young pigs in East Africa. Of the 446 samples examined, 26.2% (117/446) were positive for RVA. More nursing piglets (78.7%) shed RVA than weaned (32.9%) and grower (5.8%) pigs. RVA incidence was higher in pigs that were either housed_free-range (77.8%) or tethered_free-range (29.0%) than those that were free-range or housed or housed-tethered pigs. The farms with larger herd size (>10 pigs) had higher RVA prevalence (56.5%) than farms with smaller herd size (24.1–29.7%). This study revealed that age, management system and pig density significantly (p < 0.01) influenced the incidence of RVA infections, with housed_free-range management system and larger herd size showing higher risks for RVA infection. Partial (811–1604 nt region) sequence of the VP4 gene of selected positive samples revealed that different genotypes (P[6], P[8] and P[13]) are circulating in the study area with P[8] being predominant. The P[6] strain shared nucleotide (nt) and amino acid (aa) sequence identity of 84.4–91.3% and 95.1–96.9%, respectively, with known porcine and human P[6] strains. The P[8] strains shared high nt and aa sequence identity with known human P[8] strains ranging from 95.6–100% to 92–100%, respectively. The P[13] strains shared nt and aa sequence identity of 83.6–91.7% and 89.3–96.4%, respectively, only with known porcine P[13] strains. No P[8] strains yielded RNA of sufficient quality/quantity for full genome sequencing. However analysis of the full genome constellation of the P[6], two P[13] and one untypeable strains revealed that the P[6] strain (Ke-003-5) genome constellation was G26-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1, P[13] strains (Ug-049 and Ug-453) had G5-P[13]-I5-R1-C1-M1-A8-N1-T7-E1-H1 while the untypeable strain (Ug-218) had G5-P[?]-I5-R1-C1-M1-A8-N1-T1-E1-H? In conclusion, P[6] and P[8] genotypes detected were genetically closely related to human strains suggesting the possibility of interspecies transmission. Further studies are required to determine the role of RVA in swine enteric disease burden and to determine the genetic/antigenic heterogeneity of the circulating strains for development of accurate diagnostic tools and to implement appropriate prophylaxis programs.  相似文献   

11.
The main purpose of this study was to investigate the prevalence of Neospora caninum and bovine viral diarrhoea virus (BVDV) in some dairy herds in Southern Vietnam, and to ascertain whether there were differences in seroprevalences between herds with imported and locally bred cows. Serum samples collected on five state farms and 97 smallholder herds were analysed for the presence of antibodies to N. caninum and BVDV. All BVDV antibody-negative sera were further tested by antigen-ELISA in order to identify persistently infected individuals. The N. caninum prevalence varied between 16% and 53% in the state herds, and was higher in the four herds that had imported cows than in the herd that only had locally bred cows. Nineteen percent of the samples collected on smallholder farms, which all had only locally bred cows, had antibodies to N. caninum. The BVDV seroprevalence varied between 58% and 93% on the state farms. In smallholder herds, the prevalence of BVDV among the sampled cows was 18% and even lower on the state farms. Despite the high seroprevalence for BVDV in the state herds, no persistently BVDV infected cows were found. Given the high prevalence for Neospora and BVDV among herds with imported cows, it seems advisable to test for both infections before cattle are imported into the country.  相似文献   

12.
Objective To determine in Australian pig herds the accuracy of French protocols for risk factor assessment of post-weaning diarrhoea and illthrift.
Procedure French protocols for the collection of data on health indicators and risk factors for post-weaning diarrhoea were conducted on 54 batches of weaner pigs from 28 Western Australian pig herds during three years.
Results Large variations in post-weaning performance were found. About one-third of the batches were growing at <200 g/day during the 3 weeks after weaning, and 54% had growth rates of <250 g/day. Weaning age and weight of at least 30 days and 7.9 kg, respectively, optimised weaner performance. Other risk factors associated with little post-weaning diarrhoea and good weaner performance were high creep feed intakes, relatively little diarrhoea as suckers, and, contrary to expectations, large temperature fluctuations.
Conclusion Overall, the 'predictability' of post-weaning problems as assessed by measurement of risk status, was good. However, the model was less accurate at predicting the performance of a single batch of pigs.  相似文献   

13.
The stomachs of pigs (n=15,741) originating from 136 herds from the Australian states of Queensland, Western Australia, Victoria and New South Wales were examined at slaughter for the presence of oesophago-gastric ulcers (OGUs). Stomachs were categorised as being normal, hyperkeratotic, eroded, ulcerated, or having strictures. A questionnaire was distributed to piggery owners to identify factors associated with an above-average herd prevalence of OGU. Thirty percent of all pigs examined had OGU (median within-herd prevalence of 17%). The median within-herd prevalence in Victoria (53%) was significantly higher than in Western Australia (30%) or Queensland (7%). The prevalence of OGU in culled breeding animals was significantly higher than in porkers or baconers from the same herds. There was no difference between the prevalence of OGU in male and female pigs sampled from the same Western Australian herds. The relationship between OGU and herd and pig risk factors was assessed by random effects logistic-regression analysis. Herds with a high prevalence of OGU were more likely to feed ad libitum (OR=13.7), use automated feeding systems (OR=7.8), feed a pelleted ration (OR=384) and get water from a dam rather than from a bore or river (OR=3.8). Furthermore, for every change in the ration formulation for finisher pigs, the risk of OGU increased 1.5 times.  相似文献   

14.
Since 2001 the Pig Health Unit of Utrecht University has been consulted by various pig farms regarding neonatal diarrhoea. When preventive measures against E. coli-induced diarrhoea had no or limited results, the diarrhoeic piglets were investigated further. The microbiological and pathological findings were indicative of infection with Clostridium perfringens. Toxin typing by polymerase chain reaction led to the detection of genes encoding a-toxin (cpa) and beta2-toxin (cpb2). Surprisingly, alpha- and beta2-toxin-producing C. perfringens was isolated from all tested herds with piglets with neonatal diarrhoea. From our observations, it is likely that many herds in the Netherlands are infected with beta2-toxin-producing C. perfringens strains. As present vaccines lack beta2-toxoid and thus do not provide piglets with protection against beta2-induced diarrhoea.  相似文献   

15.
Rotavirus C (RVC) causes enteric disease in multiple species, including humans, swine, bovines, and canines. To date, the evolutionary relationships of RVC populations circulating in different host species are poorly understood, owing to the low availability of genetic sequence data. To address this gap, we sequenced 45 RVC complete genomes from swine samples collected in the United States and Mexico. A phylogenetic analysis of each genome segment indicates that RVC populations have been evolving independently in human, swine, canine, and bovine hosts for at least the last century, with inter‐species transmission events occurring deep in the phylogenetic tree, and none in the last 100 years. Bovine and canine RVC populations clustered together nine of the 11 gene segments, indicating a shared common ancestor centuries ago. The evolutionary relationships of RVC in humans and swine were more complex, due to the extensive genetic diversity and multiple RVC clades identified in pigs, which were not structured geographically. Topological differences between trees inferred for different genome segments occurred frequently, including at nodes deep in the tree, indicating that RVC's evolutionary history includes multiple reassortment events that occurred a long time ago. Overall, we find that RVC is evolving within host‐defined lineages, but the evolutionary history of RVC is more complex than previously recognized due to the high genetic diversity of RVC in swine, with a common ancestor dating back centuries. Pigs may act as a reservoir host for RVC, and a source of the lineages identified in other species, including humans, but additional sequencing is needed to understand the full diversity of this understudied pathogen across multiple host species.  相似文献   

16.
A total of 91 isolates of Treponema hyodysenteriae which were obtained from 62 piggeries located around Australia were typed by serology and by DNA restriction endonuclease analysis (REA). The isolates fell into eight serogroups, of which groups B and D were the most common. Isolates with different REA patterns were recognised within serogroups, whilst a few isolates with the same REA pattern were placed into different serogroups. Some of the latter isolates were either from the same piggery or from farms with epidemiological links, thus indicating the bacteria may have altered their antigenic properties. A total of 31 different REA patterns were recognised amongst the Australian isolates. These comprised eight major patterns, with four of these being subdivided on the basis of minor differences in banding. Where a number of isolates were obtained from individual piggeries these all had the same REA pattern, and in one piggery isolates with the same pattern were recovered over a five year period. Plasmid bands were observed in 70 of the Australian isolates (77%), and in six of the seven overseas isolates included in the study for comparison. These plasmids did not affect the REA pattern. Of the States from which substantial numbers of isolates were examined, the greatest number of different strains (12 amongst 19 piggeries) were found from Victoria, and there were 10 REA patterns in strains from 24 piggeries in Queensland. Despite the large total number of different strains of T. hyodysenteriae in Australia, only three were found in more than one State.  相似文献   

17.
Pig mycobacteriosis is the most common animal mycobacterial disease in Finland with a long-term average prevalence of 0.34% and temporary peaks as high as 0.85%. In the current study Mycobacterium-specific real-time qPCR and 16S rRNA sandwich hybridization were utilized for culture-independent detection and measurement of potentially infectious mycobacteria in selected piggeries. Participating herds (n=5) were selected according to prevalence of tuberculous lesions (>4%) in slaughtered carcasses. When DNA extracted from piggery bedding materials was analyzed by Mycobacterium-targeted qPCR using the SYBR green I dye for detection of amplification products, 10(5) to 10(7) cell equivalents of mycobacterial DNA were detected in unused bedding materials and 10(8) to 10(10)g(-1) dry weight in used bedding materials. When Mycobacterium-specific hybridization probes were used for detection of amplification products, 10(5) to 10(7) cell equivalents of mycobacterial DNA g(-1) dry weight were detected in unused bedding materials in four out of the five piggeries studied and up to 10(8) cell equivalents in used bedding material. The results were confirmed by the Mycobacterium-specific 16S rRNA sandwich hybridization assay. The present results show, that mycobacteria occur in organic materials commonly used on pig farms, and may proliferate in bedding materials during use. We also show that DNA- and RNA-based methods may be utilized for detection of environmental reservoirs of mycobacteria causing porcine and human infection.  相似文献   

18.
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19.
A postal survey was conducted to determine the management and husbandry procedures adopted by a sample of 101 Western Australian pig farmers. Seventy seven replies were received and analysed. Over 80% of farmers vaccinated breeding stock against leptospirosis and erysipelas, 35% vaccinated against parvo virus and 15% vaccinated against Escherichia coli. Most farmers used antibiotics: 72% incorporated them into their pig diets and 60% used parenteral antibiotics. Fifty three per cent of farmers reported that they regularly used a veterinarian. Over 59% of piggeries had another piggery located within 10 km, thus increasing the possibility for disease transmission between herds. It is concluded that there is potential for veterinarians to offer advice to pig farmers, particularly on disease control measures and adoption of technological advances.  相似文献   

20.
OBJECTIVE: To examine piggeries in Queensland for evidence of infection with Hendra virus and Nipah virus. DESIGN: A serological survey was designed to provide 99% confidence of detecting at least one infected pig herd in Queensland, assuming that for each virus, at least 5% of herds would have been exposed to virus and that at least 40% of the finisher pigs in these herds would have detectable antibodies to virus. PROCEDURE: A two stage sampling regimen was used. All samples were tested with serum neutralisation tests developed and performed at the Australian Animal Health Laboratory. RESULTS: There was no evidence of antibody to either virus in the 500 samples collected from 100 herds. CONCLUSION: The results of the survey support a case that commercial pigs in Queensland are free of both Hendra virus and Nipah virus infections.  相似文献   

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