Serological responses and protection levels in chickens administered with Newcastle disease vaccines

Vaccination against Newcastle disease (ND) is the most effective means of controlling the disease, and these vaccines are commercialized only after their safety and effectiveness have been verified through tests that comply with Korean Standards of National Lot Release for Veterinary Biologics. This study investigated whether a relatively convenient and safe serological test can be used in place of the challenge test using highly virulent ND virus. Hemagglutination inhibition (HI) assay and enzyme-linked immunosorbent assay (ELISA) were considered positive of log2 2 or more and cutoff value of 200 or more, respectively, in both live and inactivated vaccines. However, when the antibody levels of the live and inactivated vaccines induced using the Ulster 2C, KBNP-C4152R2L, and K148/08 strains were compared, the antibody titers for inactivated vaccines were significantly higher than those for live vaccines in both the HI assay and ELISA. A strong positive correlation was observed between HI and ELISA antibody titers. The live vaccines corresponded to a survival rates of ≥ 80% and the inactivated vaccines corresponded to 100% survival rates. This study confirmed that standard efficacy tests can serve as serological tests, and can replace the challenge test and that the vaccine approval process can be improved.

Pathological, immunohistochemical, and bacteriological findings in dogs infected with Brucella canis

This study describes pathological, immunohistochemical, and bacteriological findings in adult dogs and fetuses naturally infected with Brucella (B) canis. A total of 42 dogs including 40 dogs and 2 aborted fetuses were examined. The most common gross lesions in infected dogs were swelling of lymph nodes and spleen. The testes showed marked swelling with multifocal to diffuse reddish discoloration. The most significant histopathological lesions were observed in the placenta. Placental trophoblasts were markedly hypertrophied due to the accumulation of intra-cellular gram-negative bacteria. Lymphocytic inflammation of varying severity was observed in the reproductive organs such as male testis, epididymis, and prostate gland and female uterus. Strong immunolabelling was observed in the cytoplasm of most trophoblasts in the placental tissues using immunohistochemistry. However, immunohistochemical staining did not demonstrate any organisms in other organs of dogs and fetuses. B. canis isolates were most frequently obtained from the whole blood (82.5%) and superficial inguinal lymph node (77.5%) in both sexes. In addition, the isolation rate was higher in male genital organs than in those of females. Hence, management of male dogs is most important because infected dogs can play a role as carriers.

Prevalence state of canine brucellosis in South Korea during 2015 and 2016

We investigated the prevalence of canine brucellosis in companion and stray dogs between March 2015 and December 2016 and determined the disease characteristics based on the geographic distribution, sex and age of the dogs in South Korea. We conducted a large-scale survey using serological and bacteriological tests. Samples were collected from 2,394 dogs (1,825 companions and 569 strays). Thirty (1.3%) samples were positive for Brucella canis antibodies including 16 (0.9%) from companion dogs and 14 (2.5%) from stray dogs. Two (1.0%) of the 196 samples cultured from the stray dogs were positive. When compared with male dogs, the female companion and stray dogs had a significantly higher prevalence of brucellosis. Moreover, the prevalence of canine brucellosis was significantly higher in stray dogs older than 6 years and the prevalence of the disease in companion dogs was highest in Incheon (2.1%) and Jeolla (2.1%) provinces. Stray dogs from the Daejeon metropolitan area had the highest prevalence of brucellosis (7.9%). National control measures for canine brucellosis have not previously been implemented. Our findings suggest that appropriate screening tests and control measures are necessary to improve the health of dogs and to protect public health in Korea, particularly with the rapid growth of the companion animal industry.

Prevalence state of canine brucellosis in South Korea during 2015 and 2016 / 대한수의학회지

We investigated the prevalence of canine brucellosis in companion and stray dogs between March 2015 and December 2016 and determined the disease characteristics based on the geographic distribution, sex and age of the dogs in South Korea. We conducted a large-scale survey using serological and bacteriological tests. Samples were collected from 2,394 dogs (1,825 companions and 569 strays). Thirty (1.3%) samples were positive for Brucella canis antibodies including 16 (0.9%) from companion dogs and 14 (2.5%) from stray dogs. Two (1.0%) of the 196 samples cultured from the stray dogs were positive. When compared with male dogs, the female companion and stray dogs had a significantly higher prevalence of brucellosis. Moreover, the prevalence of canine brucellosis was significantly higher in stray dogs older than 6 years and the prevalence of the disease in companion dogs was highest in Incheon (2.1%) and Jeolla (2.1%) provinces. Stray dogs from the Daejeon metropolitan area had the highest prevalence of brucellosis (7.9%). National control measures for canine brucellosis have not previously been implemented. Our findings suggest that appropriate screening tests and control measures are necessary to improve the health of dogs and to protect public health in Korea, particularly with the rapid growth of the companion animal industry.

Isolation and characterization of Brucella abortus isolates from wildlife species in South Korea

A total of 782 blood and 465 tissue samples from 1,039 wild animals and 127 dairy goats were collected from January 2011 to December 2013 in 10 provinces of South Korea and tested for the presence of brucellosis. The Rose Bengal test revealed that 8.0% (52/650) of the serum samples were seropositive, while 4.2% (33/782) of the serum samples were positive for Brucella antibodies by competitive enzyme-linked immunosorbent assay. Of the 650 sera examined, only 16 (2.5%) were positive by both serological tests. Direct polymerase chain reaction (PCR) assay using B4/B5 primers for Brucella abortus (BCSP31) revealed the prevalence of Brucella to be 26.5% (129/487) in blood samples and 21% (98/465) in tissue samples while, 16S rRNA PCR detected Brucella DNA in 6.8% (33/487) and 2.6% (12/465) in blood and tissue samples, respectively. Of PCR-positive samples, only 6.2% (30/487) of blood samples and 2.4% (11/465) of tissue samples were found to be positive by both BCSP31 and 16S rRNA PCRs. However, Brucella strains were isolated by blood culture from only two out of 487 blood samples (0.4%). This characterization and identification of pathogenic Brucella isolates is the first to clearly indicate that the organisms were Brucella abortus biovar 1.

Identification of Brucella melitensis isolates originating from Mongolia and diagnostic real-time PCR evaluation using a specific SNP / 대한수의학회지

A real-time PCR assay using hybridization probe (HybProbe) has been developed to detect Brucella (B.) melitensis strains. The primer and HybProbe sets were designed based on the gap gene of chromosome I with a specific single nucleotide polymorphism of B. melitensis. Specificity of the assay was confirmed by comparison to reference Brucella species and other related strains. In the melting curve analysis, B. melitensis generated a peak at 67degrees C unlike those for other Brucella species observed at 61degrees C. Sensitivity of the assay for B. melitensis ranged from 20 ng to 200 fg of genomic DNA. The ability to identify 94 Mongolian B. melitensis isolates using the real-time PCR assay was identical to that of classical biotyping methods and differential multiplex PCR. These data showed that this new molecular technique is a simple and quick method for detecting B. melitensis, which will be important for the control and prevention of brucellosis.

Epidemiology of brucellosis among cattle in Korea from 2001 to 2011

In the present study, the outbreak patterns of bovine brucellosis in Korea from 2000 to 2011 were analyzed to understand the epidemiological evolution of this disease in the country. A total of 85,521 brucella reactor animals were identified during 14,215 outbreaks over the 12-year study period. The number of bovine brucellosis cases increased after 2003 and peaked in 2006 before decreasing thereafter. The majority of the bovine brucellosis cases were Korean native cattle, Han Woo. The numbers of human brucellosis cases and cattle outbreaks increased and decreased in the same pattern. The correlation coefficient for human and bovine cases per year was 0.96 (95% confidence interval = 0.86~0.99; p < 10(-3)). The epidemiological characteristics of bovine brucellosis appeared to be affected by the intensity of eradication programs that mainly involved a test-and-slaughter policy. Findings from the present study were based on freely available statistics from web pages maintained by government agencies. This unlimited access to information demonstrates the usefulness of government statistics for continually monitoring the health of animal populations.

Seroprevalence of Q-fever in Korean native cattle / 대한수의학회지

Q-fever is a vector-borne (Coxiella [C.] burnetii) zoonotic disease that is an increasing public health concern. To date, some research about Q-fever prevalence in dairy herds and human patients has been reported in Korea, but information about Korean native cattle is scarce. To measure the prevalence rates of C. burnetii in Korean native cattle, a total of 1,095 bovine serum samples collected during 2010~2013 were analyzed with an enzyme-linked immunosorbent assay. Sixty-eight heads of cattle were diagnosed as positive and while 19 heads were suspected (positive rate = 6.2%). Interestingly, Jeju province had a seropositivity rate six times greater than that of other provinces (18.9% vs. 3.2%). High seroprevalence might be caused by wide distribution of ticks in Jeju province compared to other regions. Based on these data, extensive monitoring of C. burnetii infection in cattle, tick distribution, and climate changes is required.

Seroprevalence of Q-fever in Korean native cattle / 대한수의학회지

Q-fever is a vector-borne (Coxiella [C.] burnetii) zoonotic disease that is an increasing public health concern. To date, some research about Q-fever prevalence in dairy herds and human patients has been reported in Korea, but information about Korean native cattle is scarce. To measure the prevalence rates of C. burnetii in Korean native cattle, a total of 1,095 bovine serum samples collected during 2010~2013 were analyzed with an enzyme-linked immunosorbent assay. Sixty-eight heads of cattle were diagnosed as positive and while 19 heads were suspected (positive rate = 6.2%). Interestingly, Jeju province had a seropositivity rate six times greater than that of other provinces (18.9% vs. 3.2%). High seroprevalence might be caused by wide distribution of ticks in Jeju province compared to other regions. Based on these data, extensive monitoring of C. burnetii infection in cattle, tick distribution, and climate changes is required.

Serological monitoring on brucellosis in livestock of Korea / 대한수의학회지

In Korea, brucellosis has been reported periodically in cattle and rarely in dogs; however, it has not previously been screened in domestic animals such as elk, pigs and goats. To investigate the serological prevalence, serum samples were taken from the aforementioned animals annually during 2007-2013 and screened by the rose-bengal test (RBT) or modified RBT, after which positive sera were evaluated by the standard tube agglutination test (STAT). Finally, RBT and STAT-positive sera were confirmed by competitive-ELISA. Brucella abortus biovar 1 was isolated from three elk that were shown to be positive serologically in 2008. There was no evidence of brucellosis in pigs. Based on serological monitoring and investigation of etiological agents, there is no evidence of outbreak of brucellosis in elk, pigs or goats of Korea since 2008. However, the possibility for brucellosis from cattle to affect these other livestock exists; therefore, extensive and continuous serological monitoring is required to maintain their brucellosis-free status.

Diagnosis of canine brucellosis using recombinant ribosomal protein L7/L12 / 대한수의학회지

Brucella (B.) canis is mainly transmitted by direct or indirect contact with aborted fetuses and placenta. It's also known to be able to infect human, which likely results in providing veterinarians and companion animal owners for infectious risk. To develop diagnostic ELISA, we cloned and expressed rp1L gene of B. canis, which encodes the ribosomal protein L7/L12. Using this purified recombinant protein, indirect-ELISA (iELISA) was evaluated using 78 positive and 44 negative sera. The sensitivity and the specificity of iELISA were 94% and 89%, respectively. The results indicated that indirect-ELISA using recombinant ribosomal protein L7/L12 may be useful for diagnosis of canine brucellosis.

Brucellosis in sheep and goat of Bogra and Mymensingh districts of Bangladesh / 대한수의학회지

Brucellosis is the most important bacterial disease of livestock in Bangladesh. The present study was conducted to determine the seroprevalence of brucellosis in goat and sheep in Mymensingh and Bogra districts of Bangladesh using slow agglutination test and Rose Bengal test as screening test and indirect enzyme linked immunosorbent assay as confirmatory test. Questionnaire based data on age, gender, area, client's complaint, number of animals in herds, disease history, reproductive problems such as abnormal uterine discharge, abortion or previous abortion in sheep and goat and their reproductive diseases were recorded. A total of 200 sera samples were collected from 80 sheep and 120 goats. The prevalence of brucellosis in goat was 2.50% and 1.25% in sheep. Positive reactors were only detected in female of both goat and sheep. In this study, there existed a significant association among abortion and the prevalence of brucellosis (p < 0.01). The prevalence of brucellosis in sheep and goat in Bangladesh is not negligible, and it is therefore worth considering the adoption of preventive measures.