• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.113-117
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• 2015

Cryptosporidium spp., ubiquitous enteric parasitic protozoa of vertebrates, recently emerged as an important cause of economic loss and zoonosis. The present study aimed to determine the distribution and species of Cryptosporidium in post-weaned and adult pigs in Shaanxi province, northwestern China. A total of 1,337 fresh fecal samples of post-weaned and adult pigs were collected by sterile disposable gloves from 8 areas of Shaanxi province. The samples were examined by Sheather's sugar flotation technique and microscopy at${\times}400$ magnification for Cryptosporidium infection, and the species in positive samples was further identified by PCR amplification of the small subunit (SSU) rRNA gene. A total of 44 fecal samples were successfully amplified by the nested PCR of the partial SSU rRNA, with overall prevalence of 3.3%. The average prevalence of Cryptosporidium infection in each pig farms ranged from 0 to 14.4%. Species identification by sequencing of SSU rRNA gene revealed that 42 (3.1%) samples were Cryptosporidium suis and 2 (0.15%) were Cryptosporidium scrofarum. C. suis had the highest prevalence (7.5%) in growers and the lowest in breeding pigs (0.97%). C. suis was the predominant species in pre-weaned and adult pigs, while C. scrofarum infected pigs older than 3 months only. A season-related difference of C. suis was observed in this study, with the highest prevalence in autumn (5.5%) and the lowest (1.7%) in winter. The present study provided basic information for control of Cryptosporidium infection in pigs and assessment of zoonotic transmission of pigs in Shaanxi province, China.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.121-128
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• 1999

The present study was conducted to investigate the incidence of pneumonic lesions with special regard to enzootic pneumonia and the microbiology of pneumoic lungs from 544 slaughter pigs during the period from October 1995 to September 1996. The incidence of enzootic pneumonic lesion was 76.3% (41s/s44) and pleurisy was detected from 7.9% of slaughter pigs. Seasonal prevalence of pneumonic lesions in slaughter pigs were in order of prevalence of 82.9% in spring, 76.8% in winter, 74.8% in autumn and 69.0% in summer, respectively. Pasteurella multocida, Streptococcus sp, Str suis, Corynebacterium sp, Actinobacillus pleuropneumoniae, Hemophilus parasuis, and Klebsiella pneumoniae were detected in order of prevalence from 16.9%, 15.9%, 7.5%, 6.0%, 1.4%, 1.0% and 0.5% of 415 pneumonic lungs, respectively. P multocida were susceptible to oxytetracycline, polymyxin-B, streptomycin, and vancomycin, while the majority of them were resistant to amoxicillin, ampicillin, cephalothin, kanamycin, and penicillin-G. Str suis were susceptible to amoxicillin, ampicillin, cephalothin, penicillin-G, although the majority of them were resistant to erythromycin, oxytetracycline, streptomycin, vancomycin. A pleuropneumoniae were susceptible to ampicillin, and cephalothin, but the majority of them were resistant to oxytetracycline.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.461-468
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• 2016

In recent years, various naturally occurring defence peptides such as plectasin have attracted considerable research interest because they could serve as alternatives to antibiotics. However, the production of plectasin from natural microorganisms is still not commercially feasible because of its low expression levels and weak stability. A tandemly arrayed plectasin gene (1,002 bp) from Pseudoplectania nigrella was generated using the isoschizomer construction method, and was inserted into the pPICZαA vector and expressed in Pichia pastoris. The selected P. pastoris strain yielded 143 μg/ml recombinant plectasin (Ple) under the control of the methanol-inducible alcohol oxidase 1 (AOX1) promoter. Ple was estimated by SDS-PAGE to be 41 kDa. In vitro studies have shown that Ple efficiently inhibited the growth of several gram-positive bacteria such as Streptococcus suis and Staphylococcus aureus. S. suis is the most sensitive bacterial species to Ple, with a minimum inhibitory concentration (MIC) of 4 μg/ml. Importantly, Ple exhibited resistance to pepsin but it was quite sensitive to trypsin and maintained antimicrobial activity over a wide pH range (pH 2.0 to 10.0). P. pastoris offers an attractive system for the cost-effective production of Ple. The antimicrobial activity of Ple suggested that it could be a potential alternative to antibiotics against S. suis and S. aureus infections.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.247-256
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• 2021

The recombinant lysozyme-HJL34 proteins were expressed and purified using commercial Escherichia (E.) coli expression system. Stx2e⁺ F18⁺ E. coli, Actinobacillus pleuropneumoniae (APP), Streptococcus (S.) suis, and Clostridium (C.) perfringens strains were isolated from pigs. The minimum inhibitory concentrations (MICs) of the recombinant lysozyme-HJP34 proteins were examined by means of the microtiter plate method, according to the NCCLS recommendations. The possibility of its as the alternatives to antibiotics was tested in piglets. The MICs were determined as 75 ㎍/mL, 300 ㎍/mL, 75 ㎍/mL, 35.5 ㎍/m against Stx2e⁺ F18⁺ E. coli, APP, S. suis, C. perfringens, respectively. A total of 25 piglets were divied 5 groups. The piglets in group A~C were fed with commercial feed and those in groups D, E were fed with commercial feedstuff. All piglets in groups B~E were challenged with virulent Stx2e⁺ F18⁺ E. coli, APP, S. suis strains. Groups C and D were treated with antimicrobial from 24 h after challenge. All piglets in group B died within 3 days after challenge. Among 5 piglets in groups C and D piglets, 80% survived after challenge. Among group E piglets, 60% were alive until the end of this study. Therefore, this study indicates that recombinant lysozyme-HJP34 proteins is a suitable possibility as a feed additive for reduction of diseases by bacterial pathogens in piglet feed.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.187-190
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• 2009

Cryptosporidium spp. were detected in 17 of 135 swine lagoon samples from five farms by 18S ribosomal DNA locus and PCR. Seventeen positive samples identified were included two distinctive genotypes C. suis and Cryptosporidium sp. based on a small-subunit rRNA gene-based PCR-restriction fragment length polymorphism analysis. Cryptosporidium spp. were detected out of farrowing, farrowing and nursery (mix), and finishing. Prevalence rate was 12.6% with infection rates between 3.7 and 18.5%. We concluded that Cryptosporidium oocysts can persist in treated lagoon and potentially contaminate surface water through improper discharge. This study was undertaken for the evaluation of the infection status of the genotypes of Cryptosporidium spp. in swine lagoon.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.589-594
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• 1998

The in vitro screening tests against the in vitro cultivated $L_3$ of Ascaris suum (in vitro $L_3$), which were cultivated from the embryonated egg to third-stage larva on 7 days in culture(DIC) and the in vivo rat's lung-derived $L_3$ of Ascaris suum (in vivo $L_3$), which were recovered from the lungs of rat on 7 days after infection, carried out in order to compare the anthelmintic efficacy of in vitro $L_3$ and that of in vivo $L_3$ in RPMI medium 1640 with 5% bovine calf serum. And also a screening test of efficacy against adult worms of Trichuris suis performed. The efficacies of screening tests were as follows : 1. The screening efficacies of abamectin and ivermectin against the in vitro $L_3$ were all 100% at the 10ppm concentration in RPMI medium 1640 on 5 DIC. 2. The screening efficacies of abamectin and ivermectin against the in vivo $L_3$ were all 100% at the 20ppm on 5 DIC or at 40ppm on 3 DIC. 3. The screening efficacies of abamectin and ivermectin against the adult worms of Trichuris suis were all 100% at 20ppm on 4 DIC. And therefore, the in vitro cultivated $L_3$ of Ascaris suum were used in the screening test as well as the in vivo rat's lung-derived $L_3$ of Ascaris suum. And also the adult worms such as Trichuris suis and filaroids which is small size and difficult to cultivate to vitro, were used in the screening test in vitro.

• Korean Journal of Veterinary Research
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• v.11 no.1
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• pp.1-39
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• 1971

The purpose of present study was to investigate the possibility to immunize guineapigs and swine against Metastrongylus apri infection by the administration of irradiated infective larvae. Four main experiments were undertaken. Firstly, three groups of infective larvae irradiated at $3{\times}10^4r$, $4{\times}10^4r$, and $5{\times}10^4r$ respectively were inoculated to guineapigs and their immunogenic effects were examined from the clinical, anatomical, and serological viewpoints to decide the optimal dose of X-ray for the atenuation of them. Secondly, the migratory behavior of the larvae irradiated at the optimal dose was compared with that of normal infective larvae. Thirdly, pigs were inoculated with each 5,000 infective larvae irradiated at the optimal dose and the clinical, anatomical and serological responses of them before and after challenge were examined. Fourthly, the heated extract of adult M. apri which had been used as an antigen in the serological examinations was analyzed and compared with that of adult Ascaris suis and of adult Trichuris suis by immunoelectrophoretic method. The results obtained are summerized as follows: 1) The optimal dose of X-ray for the atenuation of the infective larvae which can minimize the pathogenecity but keep the antigenecity of the infective larvae was $5{\times}10^4r$. 2) Guineapigs could become completely resistant to subsequent challenge infection by the administration of 1,000 infective larvae irradiated at $5{\times}10^4r$, without showing any symptom of disease before and after the challenge. 3) There were some indication that guineapigs could acquire complete immunity after they overcome the infection with normal infective larvae. 4) It was shown that, in guineapigs, the $5{\times}10^4r$-irradiated larvae can migrate to the large intestine and mesenteric lymph node within a day, where they stay for as long as 16 days to stimulate the host's immunity. 5) It also was shown that, in guineapigs, the normal infective larvae challenged to resistant guineapigs can migrate to the large intestine and mesenteric lymph node, where they are affected by the immune mechanism of host within 10 days without further migration. 6) Pigs could become partially resistant to subsequant challenge by the administration of 5,000 infective larve irradiated at $5{\times}10^4r$; no clinical symptom occurred after the administration, but milder symptoms of parasitic bronchitis were observable after the challenge infection and fewer number of worms were detected from the lungs at autopsy compared with severe symptoms and much number of worms in control pigs. 7) It was shown that, in pigs, a few of the $5{\times}10^4r$-irradiated larvae can migrate to the lungs, where they stay for as long as 104 days in stunted and sterile states; their body-lengths were short and their uteri developted no eggs. 8) There was evidence that the male larvae were more susceptible to X-ray than the female larvae. 9) Antibodies relating to the administration with $5{\times}10^4r$-irradiated or normal larvae were detected from the sera of both guineapigs and pigs by means of indirect haemagglutination and agar diffusion precipitin tests. Relatively higher antibody titers were recorded by the former test, but precipitin bands were demonstrable only when the positive sera were concentrated in one tenth of original volume in the later one. 10) The antibody titers of pig sera began to rose on 14 days, kept their peak during the period from 14 th day to 21st day, and fell to a low level on 28 days after the administration of $5{\times}10^4r$ or normal infective larvae. 11) A slight increase in gamma globublin of the pig sera occurred following the administration. The gamma globulin level showed a tendency to fluctuate in acordance with the antibody level. 12) A marked eosionophilia occurred in pigs on 7 or 14 days following the administration. The eosinophil count showed the same tendency to fluctuate as the gamma globulin did. 13) It was shown that the serum antibodies detected by the heated extract of adult Metastrongylus apri react crossly with the heated extract of adult Ascaris suis but not with that of adult Trichuris suis in indirect haemagglutination and agar diffusion preciption reactions. 14) The heated extract of adult Metastrongylus apri could he divided into 9 antigenic components by immunoelectrophoresis, one (arc 4) of which was shown to be common to both extracts of adult Ascaris suis and adult Trichuris suis, and the other one (arc 9) to only the extract of adult Ascaris suis.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.771-781
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• 2015

To examine if the molecular chaperone DnaK operon proteins of Streptococcus suis type 2 (SS2) are involved in adhesion to host cells, the abundance values of these proteins from the surface of two SS2 strains of different adhesion capability were compared. Their roles in growth and adhesion to human laryngeal epithelial cell line HEp-2 cells were investigated on SS2 strain HA9801 and its mutants with DnaK operon genes partially knocked-out (PKO mutant) under heat stress. The major difference was that DnaJ was more abundant in strain HA9801 than in strain JX0811. Pretreatment of the bacteria with hyperimmune sera to DnaJ, but not with those to other proteins, could significantly reduce SS2 adhesion to HEp-2 cells. PKO of dnaJ g ene resulted in decreased SS2 growth at 37℃ and 42℃, and reduced its adhesion to HEp-2 cells. The wild-type strain stressed at 42℃ had increased expression of DnaJ on its surface and elevated adhesion to HEp-2 cells, which was also inhibitable by DnaJ specific antiserum. These results indicate that the DnaJ of S. suis type 2 is important not only for thermotolerance but also for adhesion to host cells. Because DnaJ expression is increased upon temperature upshift with increased exposure on the bacterial surface, the febrile conditions of the cases with systemic infections might help facilitate bacterial adhesion to host cells. DnaJ could be one of the potential candidates as a subunit vaccine because of its good immunogenicity.

• Korean Journal of Veterinary Service
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• v.39 no.4
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• pp.231-237
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• 2016

The present study was conducted to investigate the lesion of red internal organs in slaughtered pigs and provided assistant data for pig farms. During March to December 2015, a total of 1,160 lung samples out of 58 herds were collected randomly from pigs slaughtered in Jeonbuk province. In addition, 290 hilar lymph nodes from pig with pneumonic lung lesion (5 samples per herd) were screened for selected viral and bacterial pathogens. Gross lesions of lungs such as swine enzootic pneumonia (SEP), pleuritis, pleuropneumonia, pericarditis and liver white spots were examined. The overall prevalence of SEP was 64.3% (746/1,160). In the analysis of seasonal prevalence, there was an increase of occurrence during the spring months (287/400, 71.8%) and decrease during the fall months (93/200, 46.5%) among the whole herds. The mean number of SEP score per pig was $1.20{\pm}1.28$. The prevalence of pleuropneumonia, pleuritis, pericarditis, and milk spot was 25.5% (296/1,160), 44.1% (512/1,160), 3.8% (44/1,160) and 17.6% (204/1,160), respectively. The most frequent region with lung lesion was diaphragmatic lobes (left 17.1%, right 17.3%). In the detection of viral pathogens by PCR, porcine circovirus type2 (PCV2) was positive in 86.9% (252/290), while porcine reproductive and respiratory syndrome virus (PRRSV) was not detected, In the case of bacterial pathogens, 50 microorganisms were isolated by PCR and/or microbiological test. The most frequently isolated bacteria was Streptococcus suis (20, 34.4%), followed by Pasteurella multocida (17, 29.3%), Streptococcus spp. (11, 3.4%), Actinobacillus pleuropneumoniae (2, 8.9%).

• Korean Journal of Veterinary Research
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• v.9 no.2
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• pp.43-47
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• 1969

In a survey of the internal parasites of 1000 swine at Quelpart Island (Cheju-do), Incidence of the parasites was 99.6 percent and negative result was 0.4 percent only. The results was obtained as follows; Metastrongylus apri-51.6% Ascarops strongylina-23.5% Hyostrongylus rubidus -4.1% Trichuris suis -34.8% Ascaris lumbricoides-64.3% Cesophagostomum spp. -74.9% Strongyloides ransomi-8.1% Cysticercus cellulosae -3.8% Cysticercus tenuicollis -17.1% Echinococcus -11.8% Coccidia -61.5% Balantidium coli -23.4%.