• Journal of Veterinary Science
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• v.24 no.5
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• pp.70.1-70.14
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• 2023

Background: Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic and progressive granulomatous enteritis and economic losses in dairy cattle in subclinical stages. Subclinical infection in cattle can be detected using serum MAP antibody enzyme-linked immunosorbent assay (ELISA) and fecal polymerase chain reaction (PCR) tests. Objectives: To investigate the differences in blood parameters, according to the detection of MAP using serum antibody ELISA and fecal PCR tests. Methods: We divided 33 subclinically infected adult cattle into three groups: seronegative and fecal-positive (SNFP, n = 5), seropositive and fecal-negative (SPFN, n = 10), and seropositive and fecal-positive (SPFP, n = 18). Hematological and serum biochemical analyses were performed. Results: Although the cows were clinically healthy without any manifestations, the SNFP and SPFP groups had higher platelet counts, mean platelet volumes, plateletcrit, lactate dehydrogenase levels, lactate levels, and calcium levels but lower mean corpuscular volume concentration than the SPFN group (p < 0.017). The red blood cell count, hematocrit, monocyte count, glucose level, and calprotectin level were different according to the detection method (p < 0.05). The SNFP and SPFP groups had higher red blood cell counts, hematocrit and calprotectin levels, but lower monocyte counts and glucose levels than the SPFN group, although there were no significant differences (p > 0.017). Conclusions: The cows with fecal-positive MAP status had different blood parameters from those with fecal-negative MAP status, although they were subclinically infected. These findings provide new insights into understanding the mechanism of MAP infection in subclinically infected cattle.

• Journal of applied mathematics & informatics
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• v.7 no.3
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• pp.925-940
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• 2000

The spatial spread of a disease in an SIRS epidemic model with immunity imparted by subclinical infection on a population has been considered. The incidence rate of infection and the rate of immunization are both of nonlinear type. The dynamics of the infectious disease and its endemicity in local and global sense have been investigated.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.47-52
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• 1991

A total of 2,024 quarters of 515 dairy cattle in Kangweon area were examined for incidence of subclinical mastitis. Milk samples from cattle infected with subclinical mastitis were studied bacteriologically and the bacterial strains isolated were further examined for sensitivity to 12 antibacterial agents. And the status of carrying out the mastitis control program in 28 dairy farms was examined. The results obtained were summerized as follows ; 1. A total of 308(59.8%) of 515 cattle and 656(32.4%) of 2,024 quarters were found to be infected with subclinical mastitis. 2. The 277 strains of etiological agents were isolated from 358 subclinical quarters. These were identified as Staphylococcus aureus(14.4%), other staphylococci(36.5%), Streptoccus agalatiae(8.7%), other streptococci(30.7%), Bacillus spp.(1.8%), Corynebacterium spp.(1.4%) and coliform(0.7%). 3. The 109 strains of streptococci and 141 strains of staphylococci were examined for sensitivity to 12 antibacterial agents. All the strains of streptococci were sensitive to penicillin, ampicillin and cephalothin, and they were also sensitive to erythromycin(88.1%), clindamycin(83.5%), enrofloxacin(75.2%), trimethoprim＋sulfamethoxazole(67.9%), The strains of staphylococci were sensitive to cephalothin(97.2%), gentamicin(83.0%). enroflozacin(80.9%), trimethoprim＋sulfamethoxazole(78.0%), erythromycin(71.6%) and clindamycin(71.6%). But all the strains resisted to colistin. 4. In the 28 dairy farms examined, condition of udder before washing was dirty in most of the farms (89.7%). Hygiene of milking equipment was only good in the 5 farms(17.9%). Teat preparation before milking was good in the 6 farms(21.4%). The farms in which teat dipping after milking was conducted were 46.4%. Dry cow treatment for the complete herd was carried out in most of the farms(89.3%) but mastitis checking was only carried out in the 8 farms(28.6%) irregularly.

• Journal of Veterinary Clinics
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• v.2 no.1
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• pp.115-120
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• 1985

To probe the subclinical mastitis in a herd of cows in Chonnam district, the electrical conductivity(EC) of 825 foremilk samples were measured for 2 years. Normal (n=487) and mastitic(n=110) foremilk samples were classified by the California mastitis test (CMT) and direct somatic cell count(DSCC) and investigated the relations between the changes of the EC value and the calving history, age, days of postpartum, estrus and causative organism isolated. Obtained results are summarized as follows. 1. In the normal foremilk samples, positive correlation, though not significant, was found between the EC value and calving history (r=0.573) and age (r=0.247). 2. In the normal foremilk samples, the EC values were lowered at 30～120 days of postpartum through the whole lactation period and revealed a tendencies to higher values following the day of postpartum increased untill to the drying off (r=0.823), and the days of postpartum was recognized as one of a influencing factor on the EC value(p<0.05). 3. In the mastitic foremilk samples, significant correlation between EC value and resazurin reduction test (RRT) were observed (r=0.904, p<0.05). 4. In the mastitic foremilk samples, EC values were obtained in the E. coli infection as 63.9mM-NaCl, in the Streptococcus spp. infection as 60.5mM-NaCl and in the Staphylococcus spp. infection as 57.0mM-NaCl. 5. At day 0 of estrus, the mean EC values of normal and mastitic foremilk samples were 41.2mM-NaCl and 68.3mM-NaCl respectively and the EC value of day 0 of estrus was higher than that of days before and after estrus.

• Korean Journal of Veterinary Service
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• v.33 no.2
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• pp.97-103
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• 2010

Foot-and-mouth disease (FMD) commonly infects cloven-hoofed livestock animals such as cattle, pig, sheep, and goat and its clinical signs are well-known. Besides livestock, FMD can be transmitted among cloven-hoofed animals in the wild. FMD mostly affects livestock animals in farms, but, wild animals are likely to play a pivotal role in spreading the disease due to their way of free living. In the case of deer, the clinical signs of FMD vary widely from subclinical to severe infections. Thus, in some deer species, it may be hard to verify clinical signs of FMD. A deer may carry the virus up to 11 weeks after exposure, shedding the virus during the period. However, deer is not considered as a typical host for persistent infection like buffalo, cattle or sheep. In Korea, small-scale livestock farms which have less than 10 animals make up 63.6% of the entire livestock farms. Considering raising environment in deer farms, it is assumed that the risk of virus excretion and consequent transmission of FMD among deers is relatively lower than other cloven-hoofed animals. However, Sika deer and Elk which are typical deer species in Korea would manifest mild to subclinical symptoms upon FMD infection. Therefore, laboratory testing is necessary to confirm FMD in these animals because of difficulty in verifying clinical signs and the risk of virus shedding during inapparent infection.

• Korean Journal of Veterinary Pathology
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• v.1 no.1
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• pp.66-71
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• 1997

Eighteen NZW rabbits used for local skin irritation study were examined grossly and microscopically for natural infection with Encephalitozoon cuniculi. For microscopic tissue evaluation histochemical techniques such as PAS Gram iron hematoxylin and HE stain were used. Although rabbits in the study had no abnormal clinical signs 7/18(38.9%) animals were microscopically infected with E. cuniculi. The affected rabbits had gray-whitish and depressed approximately 0.1∼0.6 cm diameter lesions in the kidneys. All other organs examined were grossly unremarkable. Histopathologically however in addition to segmental interstitial nephritis focal lymphocytic myocarditis and granulomatous inflammatory reaction in portal areas of the liver multifocal granulomatous foci with vasculitis were present in the brain kidney and lungs. Aggregates of minute oval organisms were observed in brain and kidney sections frequently within the granulomatous foci and sometimes without any inflammatory reaction particularly in the renal tubules. in histochemical stains the organisms were gram positive stained with iron hematoxylin and had PAS positive granule at one pole. They measured approximately 1.5×2.5μm consistent with E. cuniculi. Histochemical characterization is important to differentiate E. cuniculi from other common protozoal infection such as Toxoplasma gondii. This study demonstrate the importance of subclinical. E. cunuculi infection and the associated histological alterations may interfere with tissue evaluation in toxicologic studies.

• Korean Journal of Veterinary Research
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• v.15 no.2
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• pp.315-320
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• 1975

A total of 364 quarter milk samples of 91 dairy cattle from 4 area around Jeonju in Jeonbug area were examined for infection rate and causative abets of mastitis by the Laboratory Procedures used in the Connecticut Mastitis-Control Program. The results obtained were as follows: 1. One hundred and thirty quarters (35.7%) from 67 cows (73.6%) were found to be infected with mastitis. It was found that 5 (1.37%) of the infected quarters were clinical mastitis and all of the rest were subclinical mastitis (125 quarters). 2. The main causative agents were found to be Staphylococcus aureus (46 quarters), Streptococcus agalactiae (49 quarters), streptococcus disgalactiae (18 quarters), Steptococcus uberis (13 quarters). Corynebacteria, Coliform organisms, Pseudomonas were also occasionally found to be causative organisms. 3. Having examined the number of infection Quarter per head of mastitis dairy cattle samplings, major findings were that the average number of infection quarter to total dairy cattle examined was 1.4 quarters, and that average number of infection quarter to the infected cattle was 1.9 quarters.

• Clinical and Experimental Pediatrics
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• v.63 no.2
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• pp.52-55
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• 2020

Background: Immunomodulatory properties of interferon (IFN) have been documented. It may induce autoimmune diseases such as autoimmune thyroiditis with hypo- or hyperthyroidism. In addition, it may impair thyroid hormone synthesis through affecting iodide organification in thyroid gland. Purpose: The aim of this study was to describe thyroid function tests disturbances in children with chronic hepatitis C (CHC) receiving pegylated interferon-alpha (PEG IFN-α) plus ribavirin. Methods: Fifty children with CHC virus infection who received combined pegylated interferon-alpha with ribavirin were selected. Other 50 apparently healthy children of matched age and sex (considered as control group) were selected. All children (100) were subject to liver function tests, virological studies, and follow-up of thyroid function test during and after the treatment course. Results: Our study showed that 28% of children received combined PEG IFN-α plus ribavirin showed subclinical hypothyroidism. After 24 weeks treatment with combined therapy of IFN plus ribavirin, the mean level of thyroid stimulating hormone (TSH) was 3.23±88 mU/mL, while TSH was 1.16±0.77 mU/mL before starting treatment. On the other hand, mean TSH was 1.09±0.92 mU/mL in normal control group. Conclusion: This study revealed an association between subclinical thyroid dysfunction and treatment with IFN-alpha and ribavirin in children. Further studies on larger number of patients and longer follow-up duration are recommended for further confirmation.

• Korean Journal of Veterinary Research
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• v.55 no.2
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• pp.89-95
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• 2015

Johne's disease, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is one of the most widespread and economically important diseases in cattle. Current diagnostic methods are based on the detection of anti-MAP antibodies in serum or isolation of the causative agent. However, these techniques are often not applicable for cases of subclinical infection due to relatively low sensitivity. Therefore, finding new antigen candidates that strongly react with the host immune system had been attempted. To effectively detect infection during the subclinical stage, several antigen candidates were selected based on previous researches. Characteristics of the selected antigen candidates were analyzed using bioinformatics-based prediction tools. A total of nine antigens were selected (MAP0862, MAP3817c, MAP2077c, MAP0860c, MAP3954, MAP3155c, MAP1204, MAP1087, and MAP2963c) that have MAP-specific and/or high immune responses to infected animals. Using a transmembrane prediction tool, five of the nine antigen candidates were predicted to be membrane protein (MAP3817c, MAP3954, MAP3155c, MAP1087, and MAP1204). Some of the predicted protein structures identified using the I-TASSER server shared similarities with known proteins found in the Protein Data Bank database (MAP0862, MAP1204, and MAP2077c). In future studies, the characteristics and diagnostic efficiency of the selected antigen candidates will be evaluated.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.393-398
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• 2023

We identified mastitis-causing pathogens using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) in an organic dairy farm and evaluated the effects of antimicrobial restriction on antimicrobial susceptibility. A total of 43 Holstein cows without any clinical sign of mastitis were used in this study, and 172 quarter milk samples were cultured on blood agar plates for 24 hours at 37℃. Subsequently, bacterial species were identified and antimicrobial susceptibility tests were performed. The subclinical mastitis infection rates in the cows and quarters were 58.1% (25/43) and 25.6% (44/172), respectively. In the species identification, Staphylococcus aureus (40.9%) was the most prominent isolate, followed by S. chromogenes (22.7%), S. epidermis (18.2%), S. simulans (11.4%), S. haemolyticus (2.3%), S. muscae (2.3%), and S. xylosus (2.3%). In the antimicrobial susceptibility test, all isolates were 100% susceptible to 24 of 28 antibiotics, except for benzylpenicillin, cefalotin, cefpodoxime, and trimethoprim/sulfamethoxazole. The resistance rates of S. aureus, S. chromogenes, and S. muscae isolates to trimethoprim/sulfamethoxazole were 27.8%, 10%, and 100%, respectively, and the resistance rates of S. epidermis and S. xylosus to benzylpenicillin were 50% and 100%, respectively. S. chromogenes, S. epidermis, S. simulans, S. haemolyticus, and S. xylosus were resistant to cefalotin and cefpodoxime. In conclusion, restrictions on antimicrobial use for organic dairy farm certification have resulted in a high Staphylococcus spp. infection rate. Therefore, our study indicates the importance of mastitis management strategies implemented by farmers together with veterinary practitioners, even if mastitis does not appear clinically in organic dairy farms.