Forensic analysis of toxic substances in fatalities with suspected companion animal cruelty

The increasing prevalence of toxic substance-exposure in pets in South Korea endangers the health and safety of numerous companion animals, and has become a cause for concern. Notably, the annual incidence of forensic analysis in pets has increased by more than 150% in South Korea, mainly in populous regions such as Seoul, Incheon, and Gyeonggi. In response to this growing issue, veterinary forensic examinations were conducted on 549 dogs and cats from 2019 to 2022. This study revealed the presence of various toxic substances, including pesticides, insecticides, and drugs such as analgesics, anesthetics, antidepressants, and muscle relaxants, in pets. Among the 38 different toxins identified in pets, coumatetralyl, methomyl, terbufos, and buprofezin were the most frequently detected. In this study, toxic substances for pets were identified based on the “toxic agent list for humans,” developed by the National Forensic Services, because no list of toxic agents for animals currently exists and data regarding potentially toxic substances for dogs and cats is limited. This is one of the limitations of this study, and necessitates the establishment of a toxic agent list for animals. Continued monitoring and research is also recommended to reveal the incidence, causes, and solutions of toxicity in animals.

Salmonella enterica serotype Choleraesuis infection in weaned pigs: a first clinicopathological case report from Korea

Salmonella enterica serotype Choleraesuis causes swine paratyphoid, with clinical findings of enterocolitis and septicemia. However, the clinicopathological features of S. Choleraesuis infections in pigs have not been reported in Korea. We describe the pathological findings of two weaned pigs with S. Choleraesuis infections, presenting with diarrhea, cough, and sudden death. Pathological examination indicated severe necrotic colitis in pig 1 and septicemic lesions in pig 2. Multidrug-resistant S. Choleraesuis was isolated from the pigs’ lungs and intestinal contents. Further research is required for the surveillance of S. Choleraesuis infections in pigs and the virulence estimation in the S. Choleraesuis isolates.

Investigation of bovine tuberculosis outbreaks by using a trace-back system and molecular typing in Korean Hanwoo beef cattle

Bovine tuberculosis is a chronic contagious disease responsible for major agricultural economic losses. Abattoir monitoring and trace-back systems are an appropriate method to control bovine tuberculosis, particularly in beef cattle. In the present study, a trace-back system was applied to bovine tuberculosis cases in Korean native Hanwoo beef cattle. Bovine tuberculosis was detected in three index beef cattle during abattoir monitoring in Jeonbuk Province, Korea, and the original herds were traced back from each index cow. All cattle in each original herd were subjected to tuberculin skin test. The positive rates in the tuberculin skin test were 64.6% (62 of 96), 4.8% (2 of 42), and 8.1% (3 of 37) at farms A, B, and C, respectively. On post-mortem examination of 56 tuberculin-positive cattle, 62% had granulomatous lesions, and Mycobacterium bovis was cultured from 40 (71.4%) of the cattle. Molecular typing by spoligotyping and the mycobacterial interspersed repetitive unit-variable-number tandem repeat assay revealed the genotype of the M. bovis strains from the index cattle were same as the M. bovis genotype in each original herd. The results suggest that tracing back from index cattle to the original herd is an effective method to control bovine tuberculosis in beef cattle.

Mycobacterium bovis infection in a wild sow (Sus scrofa): the first case in Korea

Mycobacterium (M.) bovis causes tuberculosis and has a broad host range, including humans, livestock, and wild animals. M. bovis infection of wild boar has been reported in several European countries. We report here the first case of M. bovis infection in a domesticated wild sow in Korea. Granulomatous and necrotizing lesions with small numbers of acid-fast bacilli were observed in nodules of the lung of wild sow. Furthermore, the M. bovis isolate from the wild sow had spoligotype SB0140 and a novel MIRU-VNTR allelic profile, which is not found in cattle and deer in Korea.

Performance of the SD Bioline TB Ag MPT64 Rapid test for quick confirmation of Mycobacterium bovis isolates from animals

Mycobacterium (M.) bovis, a bacterium in the M. tuberculosis complex, is a causative agent of bovine tuberculosis, a contagious disease of animals. Mycobacterial culture is the gold standard for diagnosing bovine tuberculosis, but this technique is laborious and time-consuming. In the present study, performance of the SD Bioline TB Ag MPT4 Rapid test, an immunochromatographic assay, was evaluated using reference bacterial strains and M. bovis field isolates collected from animals. The SD MPT64 Rapid test produced positive results for 95.5% (63/66) of the M. bovis isolates from cattle and 97.9% (46/47) of the isolates from deer. Additionally, the test had a sensitivity of 96.5% (95% CI, 91.2-99.0), specificity of 100% (95% CI, 96.7-100.0), positive predictive value of 100% (95% CI, 96.7-100.0), and negative predictive value of 92.9% (95% CI, 82.7-98.0) for M. bovis isolates. In conclusion, the SD MPT64 Rapid test is simple to use and may be useful for quickly confirming the presence of M. bovis in animals.

Characterization of antimicrobial resistance and application of RFLP for epidemiological monitoring of thermophilic Campylobacter spp. isolated from dogs and humans in Korea / 대한수의학회지

An antimicrobial susceptibility test was conducted to compare the resistance rates among Campylobacter spp. isolates from dogs (n = 50) raised under diverse conditions and humans (n = 50). More than 60% of Campylobacter (C.) jejuni from dogs and humans showed resistance to nalidixic acid, enrofloxacin and ciprofloxacin. C. jejuni isolates from humans showed higher resistance to tetracycline (83.3%) and ampicillin (91.3%) than those from dogs. None of the C. jejuni or Campylobacter coli isolates from humans or dogs were resistant to erythromycin. Overall, 85% of Campylobacter spp. isolates showed a multidrug resistant phenotype. Nucleotide sequencing analysis of the gryA gene showed that 100% of NA(R)/CIP(R) C. jejuni isolates from dogs and humans had the Thr-86th-Ile mutation, which is associated with fluoroquinolone resistance. flaA PCR restriction fragment length polymorphism (RFLP) typing to differentiate the isolates below the species level revealed 12 different clusters out of 73 strains. The human isolates belonged to eight different RFLP clusters, while five clusters contained dog and human isolates.

Prevalence of virulence and cytolethal distending toxin (CDT) genes in thermophilic Campylobacter spp. from dogs and humans in Gyeongnam and Busan, Korea / 대한수의학회지

The prevalence of thermophilic Campylobacter (C.) spp. in stray, breeding, and household dogs was 25.2, 12.0, and 8.8%, respectively. C. jejuni and C. upsaliensis were the predominant Campylobacter spp. from household dogs. cdtA, cdtB, and cdtC were detected by PCR in all isolates. Despite the high cytolethal distending toxin (CDT) gene prevalence, only 26 (31%) C. jejuni strains and one (15.3%) C. coli strain showed evidence of CDT production in HEp-2 cell cytotoxicity assays. Virulence-associated genes detected in the C. jejuni and C. coli isolates were cadF, dnaJ, flaA, racR, ciaB, iamA, pldA, virB11, ceuE, and docC. cadF, dnaJ, flaA, and ceuE were found in all C. jejuni and C. coli isolates. When detecting Guillain-Barre syndrome-associated genes (galE, cgtB, and wlaN), galE was identified in all isolates. However, cgtB and wlaN were more prevalent in C. jejuni isolates from humans than those from dogs. Adherence and invasion abilities of the C. jejuni and C. coli strains were tested in INT-407 cells. A considerable correlation (adjusted R2 = 0.678) existed between adherence and invasion activities of the Campylobacter spp. isolates.

Comparison of tuberculin skin test with Interferon-gamma assay for the diagnosis of bovine tuberculosis in Korean cattle / 대한수의학회지

Bovine tuberculosis (bTB), caused primarily by Mycobacterium bovis, continues to exert an economic loss, even in countries with active control measures, and is one of zoonotic diseases enable to be transmitted to human. The control and eradication of bTB are mainly based on a test and slaughter policy and/or abattoir surveillance. Various factors including limitation of diagnostic tests have been considered as major constraints to eradication. Single intradermal test (SIT) is the official diagnostic test. New diagnostic methods are needed to be developed, because of limitations of the test. In the present study SIT was compared with single intradermal comparative cervical test (SICCT) and interferon (IFN)-gamma assay. There was very low correlation between SIT and SICCT. However, high correlation was shown between SIT and IFN-gamma assay while no correlation was observed between SICCT and IFN-gamma assay. Therefore, our results suggest the possibility of replacement of SIT with IFN-gamma assay for the diagnosis of bovine tuberculosis.

Alteration in gyrA and parC Gene Associated with Fluoroquinolone Resistance of Enterococcus spp. Isolated from Feces of Chicken

The purpose of this study was to investigate the fluoroquinolone resistance frequency of Enterococcus spp. from normal chicken feces and to analyse mutations of the gyrA and parC gene associated with fluoroquinolone resistance. Among 52 Enterococcus faecalis and 25 E. faecium isolates, 23 (44.2%) E. faecalis and 7 (28.0%) E. faecium were resistant to ciprofloxacin (CIP) by disc diffusion method. Genetic exchange in gyrA and parC gene among 2 CIP intermediate isolates and 15 CIP resistant isolates were found in the amino acid codon of Ser-83 and Asp-87, and Ser-80 and Glu-84, respectively. These mutants contained a change from Ser to Phe, Val, Tyr, Ile, Thr or Pro at codon 83 and from Glu to Gly or Leu at codon 87 in gyrA gene, and a change from Ser to Ile or Thr at codon 80 and from Glu to Asp or Lys at codon 84 in parC gene. The isolates with mutation in gyrA regardless of a mutation in parC showed high resistance (MIC > or =32 microgram/ml) to CIP, enrofloxacin, norfloxacin and ofloxacin. These results suggested that gyrA gene is the primary target for 4 fluoroquinolones resistance in Enterococcus spp.