Detection of porcine reproductive and respiratory syndrome virus in pigs with low positive or negative ELISA s/p ratios.
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Animals↗
Biomedical subjects
H S Joo
Publications and source records attributed to H S Joo.
Antibiotic selective pressure for the maintenance of antibiotic resistant genes in coliform bacteria isolated from the aquatic environment.
Coliform bacteria isolated from the aquatic environment were investigated for antibiotic susceptibility and detailed structures of class 1 integrons. A high proportion of isolates were found to be resistant to sulfamethoxazole, aminoglycosides, and beta-lactams. The 750 (53.6%) isolates were resistant to one or more of the antibiotics tested out of 1,400 coliform bacteria. Based on the MIC of antibiotics and antibiogram, 150 isolates were selected and further studied for class 1 integrons. The intI1 gene was found in 36 (24.0%) of the 150 isolates. Twelve isolates carried the gene cassettes responsible for antibiotic resistance, while no gene cassettes were found in 24 isolates. Seven different genes, dfrA5, dfrA7, dfrA12, dfrA17, aaA2, aaA5, and aad(3'), were detected in gene cassettes. The dfrA and aad genes located on class 1 integrons were responsible for resistance to trimethoprim and aminoglycosides. The remaining 24 coliform bacteria had the incomplete or non-functional class 1 integrons. These results indicated that antibiotic selective pressures may play an important role to maintain gene cassettes of class 1 integrons and in the absence of sustained antibiotic pressures, such as the aquatic environment, coliform bacteria may carry empty or non-functional class 1 integrons.
Drug Resistance, Microbial↗
Effects of environmental endocrine disruptors on the sex differentiation in Korean rockfish, Sebastes schlegeli.
The effects of estradiol-17beta, methyltestosterone, tributyltin, bisphenol A and 2,4-dinitrophenol on sex differentiation were investigated in the Korean rockfish, Sebastes schlegeli. The 51 day-old fry with undifferentiated gonads were fed with food containing the chemicals at 0.05, 0.5, 5, 50 and 100 micro/g diet for 29 days. Sex ratio and gonadal abnormality after the chemical treatment were determined by histological examination of gonads. In control group, the sex ratio of fry was 1:1.3 (female:male), and more males than females appeared. The sex of fry fed with estradiol-17beta at 5, 50 and 100 micro/g diet was all females. Feminization of the fry was induced by exogenic estradiol-17beta. In the methyltestosterone group, sex ratio of fry was 1:10.2 in 0.05 micro/g diet, 1:2.4 in 0.5 micro/g diet, 1:3.1 in 5 micro/g diet, 1:1.2 in 50 micro/g diet and 1:2.3 in 100 micro/g diet. Masculinization of the fry was induced by methyltestosterone at the lowest concentration. Furthermore, intersex of the fry was observed. The number of intersex fry was 23.3, 25.0 and 35.3 at 0.5, 5 and 50 micro/g diet of methyltestosterone, respectively. Sex ratio of bisphenol A group showed no difference with that of the control. The sex of fry fed with 2,4-dinitrophenol at 5, 50 and 100 micro/g diet was all females. 2,4-dinitrophenol should be considered as a new member of endocrine disruptors. In tributyltin group, the sex ratio of fry at 100 micro/g diet of tributyltin was 5.4:1. Tributyltin induced the feminization of the fry at the highest dose. Tributyltin showed an estrogenic effect in the Korean rockfish in contrast to an androgenic effect in gastropods.
Administration, Oral↗
Transmission of porcine reproductive and respiratory syndrome virus by needles.
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Animals↗
Prevalence of swine influenza virus subtypes on swine farms in the United States.
Serologic and virologic prevalence of infection with different swine influenza virus (SIV) subtypes was investigated using swine sera, nasal swabs and lung samples that had been submitted for a diagnosis to the Minnesota Veterinary Diagnostic Laboratory. A total of 111,418 pig sera were tested for SIV antibody between 1998 and 2000, and 25,348 sera (22.8%) were found to be positive by the hemagglutination inhibition (HI) test. Of the positive samples, 16,807 (66.7%) and 8,541 (33.7%) had antibody to H1 and H3 subtypes, respectively. Between January 1998 and May of 2001, a total of 3,561 nasal swabs or lung samples were examined for the presence of SIV, and SIV was isolated from 1,124 samples (31.7%). Of these isolates, 869 (77.3%) and 255 (22.7%) were subtyped as H1 and H3, respectively, by the HI method. For further characterization, 120 SIV isolates each from 1998 to 2001 were randomly selected from a culture collection and their hemagglutinin (HA) and neuraminidase genes examined by reverse transcription-PCR and sequencing. Of the 480 isolates, 322 (67.1%), 22 (4.6%) and 129 (26.9%) were subtyped as H1N1, H1N2 and H3N2, respectively. The remaining 7 samples (1.5%) were found to contain both H1N1 and H3N2 viruses. The SIV H1N2 subtype was isolated from 1, 8, and 13 samples in 1999, 2000, and 2001, respectively. The 22 H1N2 isolates originated from 9 different states of the United States. Genetic screening of the HA genes of 12 selected H1N2 isolates showed that 8 of them had a close phylogenetic relationship with the Indiana isolate of H1N2 (A/Swine/Indiana/9K035/99), while 4 isolates were closely related to classical SIV H1N1.
Amino Acid Sequence↗
Detection and subtyping of swine influenza H1N1, H1N2 and H3N2 viruses in clinical samples using two multiplex RT-PCR assays.
A total of 360 type A swine influenza virus-positive samples including cell culture isolates, nasal swabs or lung tissues along with 30 virus-negative samples were tested for the detection and subtyping of H1N1, H1N2 or H3N2 by two multiplex reverse transcription (RT)-PCR assays. The positive samples had been collected between 1999 and 2001 from pigs with respiratory diseases, and type A influenza virus was isolated and subtyped by hemagglutination inhibition (HI) test at the Minnesota Veterinary Diagnostic Laboratory (MVDL). Two multiplex RT-PCR assays specific for H1 and H3, and N1 and N2 were developed. RT-PCR products with unique sizes characteristic of each subtype of influenza A virus were sequenced, and the sequences were demonstrated to be specific for H1N1, H1N2 or H3N2. Genomic RNAs or DNAs from 12 common swine pathogens other than type A influenza viruses were not amplified when the PCR assays were performed with these primer sets. Positive amplification reaction could be visualized with RNA extracted from up to 10(-5) dilution of each reference virus with original infectivity titer of 10(5) TCID(50)/ml. Of the 360 samples tested, swine influenza virus H1N1, H1N2 and H3N2 were identified in 200, 13 and 139 samples, respectively. The remaining eight samples were positive for both H1N1 and H3N2 viruses. The results of multiplex RT-PCR were 100% in agreement with those of virus isolation. These results demonstrate the usefulness of multiplex RT-PCR for detection and identification of influenza A virus subtypes. The results also indicate an increased occurrence of H1N2 in US swine population.
Animals↗
The intubating laryngeal mask airway after induction of general anesthesia versus awake fiberoptic intubation in patients with difficult airways.
UNLABELLED: We performed the current study to compare tracheal intubation (TI) using awake fiberoptic intubation (AFOI) and TI using the intubating laryngeal mask airway (ILMA) in patients with difficult airway. Our hypothesis was that patients with difficult airways could be safely intubated after induction of anesthesia using the ILMA. After ethics approval and informed consent, 38 patients who were identified to have difficult airways were randomly assigned to AFOI or TI using the ILMA. Patients in the AFOI group had the usual sedation and airway topicalization. Patients in the ILMA group were induced with propofol for ILMA insertion and succinylcholine for TI. The first TI attempt was done blindly via the ILMA and all subsequent attempts were performed with fiberoptic guidance. All patients in the ILMA group were successfully ventilated. Successful TI was achieved in all patients in both groups. However, in 10% of the patients in the ILMA group, TI was achieved by a second anesthesiologist who was more experienced with the use of the ILMA. In a postoperative questionnaire, patients in the ILMA group were more satisfied with their method of TI (P < 0.01). The ILMA is a useful device in the management of patients with difficult airways and may be a valuable alternative to AFOI when AFOI is contraindicated or in the patient with the unanticipated difficult airway. IMPLICATIONS: The intubating laryngeal mask airway is a useful device in the management of patients with difficult airways and may be a valuable alternative to awake fiberoptic intubation (AFOI) when AFOI is contraindicated or in the patient with the unanticipated difficult airway.
Adult↗
A comparison of patient-controlled sedation using either remifentanil or remifentanil-propofol for shock wave lithotripsy.
UNLABELLED: Patient-controlled sedation (PCS) has been used for extracorporeal shock wave lithotripsy (SWL) because it allows for rapid individualized titration of anesthetics. Because of its sedating effects, the addition of propofol to remifentanil may improve patient tolerance of SWL with PCS. One hundred twenty patients were randomly assigned to receive remifentanil 10 microg or remifentanil 10 microg plus propofol 5 mg for PCS with zero-lockout interval. Nine patients in the Remifentanil group and three patients in the Remifentanil-Propofol group required additional sedatives to complete their SWL (P = 0.128). Compared with the Remifentanil group, the Remifentanil-Propofol group required less remifentanil, had a decreased incidence of postoperative nausea and vomiting, and had a better overall satisfaction level. However, they had an increased incidence of transient apnea and oxygen desaturation. The incidence of apnea was 15% in the Remifentanil group and 52% in the Remifentanil-Propofol group (P < 0.001). All patients were able to move themselves to the stretcher at the end of SWL, and median time to home discharge was <70 min in both groups. Both remifentanil and remifentanil-propofol were useful for PCS during SWL. IMPLICATIONS: The addition of propofol to remifentanil improves patient satisfaction and decreases postoperative nausea and vomiting. However, it causes more respiratory depression than remifentanil alone. When remifentanil-propofol is used with patient-controlled sedation, appropriate monitoring and a minimum 1-2 min lockout interval is required.
Adolescent↗
Identification of novel Helicobacter species in pig stomachs by PCR and partial sequencing.
Evidence of infection with Helicobacter species in pig stomach was investigated by the use of a PCR with Helicobacter genus-specific primers. Forty pig stomachs, each of four different ulcer lesion grades, 0, 1, 2, and 3 in the pars esophagea area, were collected from a slaughterhouse in Minnesota. Of 160 stomach samples examined, 102 (63.8%) were positive by the PCR assay. The 40 samples each of lesion grades 0, 1, 2, and 3 showed 22.5, 52.5, 85.0, and 95.0% PCR-positive results, respectively. There was a significant trend (P < or = 0.01) in the proportions of PCR-positive cases relative to severity of the lesion. About 80% of the 16S rRNA gene was amplified, and PCR-restriction fragment length polymorphism (RFLP) patterns were analyzed. Of 102 PCR-positive samples, the PCR-RFLP patterns resulted in four different types, 32 samples being classified into type MN 1, 16 samples into type MN 2, 43 samples into type MN 3, and 11 samples into type MN 4. When the sequences of each RFLP type were compared to those reported in databases by using BLAST software, types MN 1, MN 2, MN 3, and MN 4 showed homologies of 97.3, 95.4, 96.7, and 99.5% with the 16S ribosomal DNA of Helicobacter flexispira taxon 3, Helicobacter sp. strains MIT 94-022 and MZ 640285, and Helicobacter suis, respectively. None of the 102 samples positive for the Helicobacter genus were positive with a primer set specific for Helicobacter pylori. Attempts to culture the organisms from selected stomachs in vitro were unsuccessful.
Abattoirs↗
Sevoflurane versus propofol for anesthetic induction: a meta-analysis.
UNLABELLED: We performed this meta-analysis to compare the characteristics of sevoflurane and propofol for the induction of routine anesthesia and for laryngeal mask airway (LMA) insertion. The variables assessed were 1) time to loss of consciousness, 2) incidence of apnea during induction, 3) induction complications, 4) time for successful LMA insertion, 5) success with LMA insertion on first attempt, 6) patient dissatisfaction, and 7) postoperative nausea and vomiting. MEDLINE, Embase, and the Cochrane library databases between January 1992 and October 1999 were reviewed for randomized, controlled trials comparing anesthetic induction between sevoflurane/nitrous oxide and propofol. Data from the 12 randomized, controlled studies were used for the meta-analysis. Sevoflurane induction was associated with a trend toward higher patient dissatisfaction and higher first-time success with LMA. Apnea was less common in the sevoflurane group. The incidence of postoperative nausea and vomiting was significantly more frequent in the sevoflurane group (P < 0.05). This effect was still present when all other variables, except the induction methods, were controlled. The other pooled variables did not show a significant difference between sevoflurane and propofol. Sevoflurane and propofol had similar efficacy for anesthetic induction. However, for routine outpatient surgery, propofol may still be the preferred induction anesthetic because of its favorable induction of anesthesia characteristics, high patient satisfaction, and less frequent incidence of postoperative nausea and vomiting. IMPLICATIONS: Sevoflurane and propofol had similar efficacy for anesthetic induction. However, for routine outpatient surgery, propofol may still be the preferred induction anesthetic because of its favorable induction of anesthesia characteristics, high patient satisfaction, and less frequent incidence of postoperative nausea and vomiting.
Anesthesia↗
The intubating laryngeal mask airway with and without fiberoptic guidance.
UNLABELLED: We conducted this feasibility study using the intubating laryngeal mask airway (ILMA) and a polyvinyl chloride tracheal tube to compare success rates, hemodynamic effects, and postoperative morbidity with two methods of tracheal intubation. After ethics approval and informed consent, 90 healthy ASA physical status I or II women with normal airways were enrolled in the randomized, controlled study. After a standardized inhaled anesthesia induction protocol, tracheal intubations using ILMA with fiberoptic guidance (ILMA-FOB) and ILMA inserted blindly without fiberoptic guidance (ILMA-Blind) were compared with the control group of direct laryngoscopy (laryngoscopy group). All 90 patients were successfully ventilated. For tracheal intubation, success rates were equal in all three groups (97%). Total intubation times were longer for the ILMA-FOB group (77 s versus 48.5 s for laryngoscopy and 53.5 s for ILMA-Blind). The laryngoscopy group had a larger increase in mean arterial blood pressure to tracheal intubation. There were no differences in postoperative sore throat or hoarseness among the groups. In conclusion, success rates are equally high for tracheal intubation using ILMA-Blind and ILMA-FOB techniques in women with normal airways. IMPLICATIONS: The intubating laryngeal mask airway (ILMA) can be used as a primary airway for oxygenation and ventilation. Both methods of tracheal intubation using the ILMA were equally successful. Postoperative morbidity in the ILMA groups was similar to that in the laryngoscopy group. For women with normal airways, both the ILMA inserted blindly and the ILMA with fiberoptic guidance are suitable alternatives to laryngoscopy for tracheal intubation.
Adult↗
Attempted elimination of porcine reproductive and respiratory syndrome virus from a seedstock farm by vaccination of the breeding herd and nursery depopulation.
An attempt was made to eliminate the virus of porcine reproductive and respiratory syndrome from a seedstock farm by using the combined strategies of vaccination and nursery depopulation. The breeding herd was vaccinated with a modified-live virus vaccine; all breeding and lactating adult animals were vaccinated twice, with a 30-day interval between vaccinations. All the sows were vaccinated in this way except for those in the third trimester of gestation (66 to 114 days) which were vaccinated on day 7 of lactation and 30 days later. A serological profiling system was developed to assess when the piglets became infected. Pigs from vaccinated sows were profiled at weekly intervals after weaning, using immunofluorescence tests for the detection of IgM and IgG, a serum neutralising antibody test, and virus isolation. After completion of the protocol, the nursery and finishing sites were monitored for 15 months. Evidence of reinfection in the finishing stage was detected 16 months after depopulation, but not in the nursery or the breeding herd. The source of the virus was not determined, but suspected origins included a lack of biosecurity, aerosol transmission from another infected farm or a persistently infected pig.
Animal Husbandry↗
Evaluation of the effects of nursery depopulation of the profitability of 34 pig farms.
The financial impact of nursery depopulation was assessed on 34 pig farms by constructing a partial budget model to measure the profitability of the nursery production. The model measured margin over variable cost and used production data generated from a previous study; it assumed that fixed costs remained constant throughout the study and that feed cost, weaned pig cost and market price per nursery pig also remained fixed. The mean margin over variable cost per sow on the 34 farm after nursery depopulation was Pounds 116. Thirty-two of the farms showed reductions in this cost, ranging from Pounds 20 to Pounds 408 per sow, in the 12 months after nursery depopulation compared with the previous 12 months. Of the two farms which did not show an increase in profitability, one showed no change and the other showed a net loss of Pounds 8 per sow. The sows' serostatus for porcine reproductive and respiratory syndrome virus infection was monitored but there was no significant difference between the margin over variable cost per sow of the seropositive (Pounds 130) and seronegative (Pounds 170) herds.
Animal Husbandry↗
Evaluation of the effects of nursery depopulation on the persistence of porcine reproductive and respiratory syndrome virus and the productivity of 34 farms.
Nursery depopulation has been described as an effective strategy for improving the performance of weaned pigs. In order to assess whether the strategy was effective under a wide range of conditions, a study was carried out on 34 farms in the USA. Four groups with different depopulation protocols were designed on the basis of the location of the depopulated facility (on site vs off site) and the period for which the nursery remained empty (seven days vs 14 days). The changes in average daily liveweight gain, percentage mortality, feed efficiency and treatment cost per pig produced were assessed 12 months before and after nursery depopulation. The ability to eliminate porcine reproductive and respiratory syndrome (PRRS) virus was examined by indirect fluorescent antibody testing of the nursery pigs. Significant improvements (P < 0.0001) were detected in both average daily gain and percentage mortality after depopulation when the differences within an individual group were analysed, but no significant differences (P > 0.14) were observed between the study groups. Serological testing indicated that antibodies to PRRS virus were still present in 14 of the 34 farms after depopulation.
Animals↗
Indirect fluorescent IgM antibody response of pigs infected with porcine reproductive and respiratory syndrome syndrome virus.
IgG and IgM antibody responses were examined by an indirect fluorescent antibody method in pigs following inoculation with different porcine reproductive and respiratory syndrome virus (PRRSV) isolates or a vaccine virus. Viremia was also examined in the pigs. The IgG antibody was first detected between 9 and 14 days post inoculation (PI) and maintained high titers for at least 7 weeks PI. No change in IgG antibody titers was observed when the pigs were reinoculated with PRRSV 35 days PI. IgM antibody was detected between 5 and 28 days PI in the pigs. Reinoculation at 35 days PI caused a short term rise of IgM antibody. Virus was isolated from sera collected between 2 and 21 days PI. The IgM antibody was detected regularly in sera collected during viremia and up to 1-2 weeks after the viremic periods. These results suggest that pigs with detectable IgM antibody are probably pigs with recent infection and that routine testing of IgM antibody in purchased breeding pigs from seropositive farms may be useful in identification of pigs with recent infection.
Animals↗
Induction of dual infections in newborn and three-week-old pigs by use of two plaque size variants of porcine reproductive and respiratory syndrome virus.
OBJECTIVE: To determine whether pigs can be dually infected with different plaque variants of porcine reproductive and respiratory syndrome virus (PRRSV). ANIMALS: 2 pregnant sows, 20 newborn pigs, and 20 three-week-old pigs. PROCEDURE: The 2 late-term pregnant sows were inoculated with the PRRSV small-plaque variant MN-Hs, and their pigs were challenge exposed at 7 days of age with the PRRSV large-plaque variant MN-HI. In addition, twelve 3-week-old pigs were inoculated with MN-Hs virus. Two groups of the pigs were challenge exposed with MN-HI virus at 14 and 42 days after initial inoculation. Virus was isolated from the pigs at various intervals, plaque sizes were examined, and serologic testing was performed. RESULTS: From the 2 groups of ten 7-day-old pigs, small-plaque PRRSV was isolated form 8 and 10 pigs. After subsequent challenge exposure, dual infections were diagnosed in 3 of 10 inoculated and 4 of 10 contact control pigs. In 3-week-old pigs infected with MN-Hs virus, dual infections were documented in 2 of 6 pigs when challenge exposed 14 days after initial infection. Virus was not isolated from sera of another 6 pigs challenge exposed 42 days after initial infection. Serum neutralization antibody was detected in all 6 pigs at challenge exposure. CONCLUSIONS: Dual infections were documented in viremic newborn pigs and 3-week-old pigs, using 2 plaque variants of PRRSV.
Animals↗
Airborne transmission of Actinobacillus pleuropneumoniae and porcine reproductive and respiratory syndrome virus in nursery pigs.
OBJECTIVE: To document airborne transmission of Actinobacillus pleuropneumoniae and porcine reproductive and respiratory syndrome virus (PRRSV) infection in nursery pigs. ANIMALS: 32 two-week-old pigs obtained from 3 farms, but with similar Landrace X Yorkshire genetics for trial 1 of each experiment; 16 pigs for trial 2 of the A pleuropneumoniae experiment; and 14 pigs for trial 2 of the PRRSV experiment. PROCEDURE: In experiment 1, pigs were inoculated with A pleuropneumoniae serotype 1 (6/8) or were left as contacts (2/8). At the beginning of trial 1, pigs were seronegative to A pleuropneumoniae serotypes 1 and 5 on the basis of results of an ELISA, but had positive results on the A pleuropneumoniae hemolysin I (Apx1)-neutralization test. Pigs in trial 2 had negative results on both tests. Pigs of trial 1 of experiment 2 were inoculated with a PRRSV virulent field isolate (MN-1b); pigs of trial 2 were inoculated with the virus reference strain VR-2332. Aerosol-exposed pigs were placed on the other side of the air duct and kept there for 2 to 7 weeks depending on evidence of airborne transmission. RESULTS: In trial 1 of experiment 1, evidence of airborne transmission was not found. In trial 2, most airborne-exposed pigs died as a result of A pleuropneumoniae infection 12 days after initiation of the experiment. In trial 1 of experiment 2, all inoculated pigs (8/8) seroconverted, but only 2 of 8 contact-exposed pigs seroconverted. Aerosol-exposed pigs did not seroconvert nor was virus isolated. In trial 2, all inoculated and contact-exposed pigs seroconverted. All aerosol-exposed pigs seroconverted after 21 days, and virus was isolated at 16 days. CONCLUSIONS: A pleuropneumoniae was transmitted by air at a distance of 1 m when pigs were fully susceptible to the organism. Transmission of PRRSV appeared to be strain dependent; when reference strain VR-2332 was used, airborne transmission of PRRSV was documented.
Actinobacillus Infections↗
Performance of ELISA antigens prepared from 8 isolates of porcine reproductive and respiratory syndrome virus with homologous and heterologous antisera.
Porcine reproductive and respiratory syndrome virus (PRRSV) ELISA antigens of high quality were produced using 8 different isolates of PRRSV: the European Lelystad virus (LV), the U.S. MN-1b, 89-46448, 93-44927, and 93-24025B, and the Canadian LHVA-93-3, PA-8 and GH-6 virus isolates. The performance of each of these 8 antigens and a commercial PRRSV antibody test kit (Idexx's HerdChek) were measured against antisera raised in 5 groups of 6 piglets inoculated with either LV, MN-1b, 89-46448, 93-44927, or 93-24025B. Among the 8 isolates, the 89-46448 isolate produced the broadest spectrum of antigen and resulted in earlier detection of antibodies to various North American PRRSV isolates, followed by MN-1b as the 2nd best ELISA antigen for the detection of North American PRRSV antibodies. The GH-6 and PA-8 viral antigens exhibited restricted detection of PRRSV antibodies. The LV and 89-46448 combined antigens produced the best performance for the detection of antibodies against both European and North American antigenic types of PRRSV. Using 173 panel samples collected at 11 to 60 d after intranasal inoculation with 1 of the 5 PRRSV isolates, the sensitivities of the indirect ELISA used were 73.4%, 98.3%, 90.8%, 98.3%, 83.2%, 93.1%, 77.1%, 64.2%, 98.8% and 95.9% for LV, MN-1b, LHVA-93-3, 89-46448, 93-44927, 93-24025B, PA-8, GH-6 antigens, 89-46448-LV combined antigens and Idexx's PRRSV antibody test kit, respectively. All 8 antigens gave negative results with preinfection porcine sera (n = 30); high background or nonspecific reactions were not observed with the antigens.
Animals↗