Evaluation of selective enrichment broths and chromogenic media for Salmonella detection in highly contaminated chicken carcasses.

We evaluated the effectiveness of 2 selective enrichment broths, Rappaport-Vassiliadis Soy (RVS) and Muller-Kauffmann tetrathionate with novobiocin (MKTTn), for the isolation of Salmonella from chicken carcasses obtained from 3 different types of retail markets. We also compared a chromogenic agar, chromID Salmonella agar (SM-ID 2), with a classic plating medium, xylose lysine deoxycholate agar (XLD). Salmonella were isolated from 118 of the 180 samples (65.5%). Salmonella were detected in 105 samples (88%) plated on XLD and 111 samples (94%) plated on SM-ID 2 when RVS broth was used for enrichment, and 43 samples (36.4%) plated on XLD and 67 samples (56.8%) plated on SM-ID 2 when the MKTTn broth was used. The highest sensitivity was found in the RVS-XLD combination (0.99), followed by RVS-SM-ID 2 (0.97). The specificity of the RVS-SM-ID 2 combination was the highest (0.89), but that of the MKTTn-XLD combination was zero. The results of this study indicate that the selective enrichment broths had a great effect on the sensitivity and specificity of plating media, and our study confirms that the RVS broth is the most suitable enrichment for the investigation of Salmonella in chicken carcasses. This observation suggests that use of RVS broth for selective enrichment and SM-ID 2 for selective isolation may be the best combination to determine the presence of Salmonella in chicken carcasses.

Antimicrobial susceptibility of coagulase-negative staphylococci isolated from bovine mastitis between 2003 and 2008 in Korea.

A total of 1,444 coagulase-negative staphylococci (CNS) isolates from bovine mastitic milk samples collected during 2003-2008 in Korea were identified to the species level. Of 14 species identified, S. simulans, S. haemolyticus, and S. sciuri accounted for over 60% of the isolates. All the CNS isolates were tested for susceptibility to eight antimicrobials commonly used in dairy cattle. With a few exceptions, similar resistance patterns were observed among the CNS species: penicillin and ampicillin showed the lowest activity while amikacin, cephalothin, and gentamycin were highly effective. About 39% (557/1,444) of the CNS isolates were pan-susceptible, while 12% (175/1,444) showed resistance to four or more antimicrobials tested.

Feed contaminated with classical swine fever vaccine virus (LOM strain) can induce antibodies to the virus in pigs.

In November 2004, antibodies to classical swine fever virus (csfv) were detected in finishing pigs during the annual serological surveillance in Jeju Province, Korea. In addition, csf vaccine viruses (lom strain) had recently been isolated from pigs raised on farms known to have csfv antibody-positive pigs. In contrast with mainland Korea, Jeju Province had been csf free and its pigs had not been vaccinated against csf for more than five years. An epidemiological investigation team from the National Veterinary Research and Quarantine Service investigated the current status of csf prevention on the Korean mainland and in Jeju Province to determine possible routes of introduction of the virus into the province. It was concluded that improperly processed blood meals, manufactured on mainland Korea, had been contaminated with the csf vaccine lom strain, and that the lom strain had been transmitted to pigs fed feed or feedstuffs containing the contaminated meal.

Simulation analyses to evaluate alternative control strategies for the 2002 foot-and-mouth disease outbreak in the Republic of Korea.

Using the stochastic and spatial simulation model of between-farm spread of disease, InterSpread Plus, we evaluated the effect of alternative strategies for controlling the 2002 epidemic of foot-and-mouth disease (FMD) in the Republic of Korea. InterSpread Plus was parameterised to simulate epidemics of FMD in the population of farms containing susceptible animal species in the Korean counties of Yongin, Icheon, Pyongtaek, Anseong, Eumseong, Asan, Cheonan, and Jincheon. The starting point of our analyses was the simulation of a reference strategy, which approximated the real epidemic. The results of simulations of alternative epidemic-control strategies were compared with this reference strategy. Ring vaccination (when used with either limited or extended pre-emptive depopulation) reduced both the size and variability of the predicted number of infected farms. Reducing the time between disease incursion and commencement of controls had the greatest effect on reducing the predicted number of infected farms.

Highly pathogenic avian influenza in magpies (Pica pica sericea) in South Korea.

Highly pathogenic avian influenza (HPAI) is an extremely infectious, systemic viral disease of birds that produces high mortality and morbidity. HPAI was diagnosed in the three dead magpies (Pica pica sericea) submitted to the National Veterinary Research and Quarantine Service. At necropsy, the prominent lesions were multifocal or coalescing necrosis of the pancreas with enlargement of the livers and spleens. Microscopically, there were severely necrotizing pancreatitis and lymphocytic meningoencephalitis. Influenza viral antigen was also detected in areas closely associated with histologic lesions. Avian influenza virus was isolated from cecal tonsils and feces of the magpies. The isolated virus was identified as a highly pathogenic H5N1, with hemagglutinin proteolytic cleavage site deduced amino acid sequence of QREKRKKR/GLFGAIAG. To determine the pathogenicity of the isolate, eight 6-wk-old specific-pathogen-free chickens were inoculated intravenously with the virus, and all birds died within 24 hr after inoculation. This is the first report of HPAI in magpies.

Epidemiology of the Foot-and-Mouth Disease Serotype O Epidemic of November 2010 to April 2011 in the Republic Of Korea.

The largest epidemic of foot-and-mouth disease (FMD) in Korea since the first record in 1911 occurred between November 2010 and April 2011. The outbreak was confirmed in 153 farms, and more than three million animals were destroyed. This study presents the temporal and spatial distribution patterns, epidemiological investigation and the control measures for the 2010/2011 epidemic in Korea. The index case of this 2010/2011 FMD epidemic was reported in a pig-farming complex with five piggeries in Andong, GyeongBuk Province, on 28 November 2010, and the outbreak lasted 145 days. The largest number of new detection of the infected farms per day was recorded in mid-January. Epidemiological investigation revealed that the FMD virus had spread from farm to farm through routine movements associated with animal husbandry operations. In contrast to FMD epidemics in other countries in which movement of the infected animals largely contributed to the spread of the disease, human behaviours were major factors in the spread of the FMD virus in the Korean epidemic. The 2010/2011 epidemic was first confirmed in a local small and medium city where share of smallholder producers is higher than that of other provinces. Although Korea had a well-developed emergent response system with the experience of controlling infection and re-obtaining FMD-free status after the previous epidemics, Korea was prompted to revise their contingency plan by tailoring it to its unique livestock environment. Practical contingency plans tailored to Korea for control of FMD can be fully effective when farmers, livestock-related agencies, veterinary service providers and the general public work together.

Unusual cellular fatty acids and distinctive ultrastructure in a new spiral bacterium (Campylobacter pyloridis) from the human gastric mucosa.

Spiral bacteria, named Campylobacter pyloridis, were obtained from endoscopic biopsies of the gastric antrum of 14 patients with active chronic gastritis. Methyl esters of their cellular fatty acids were prepared by acid-catalysed transmethylation of whole cells. Their major fatty acids were tetradecanoic acid (14:0) and cis-9,10-methyleneoctadecanoic acid (19:0 delta), with a very small amount of hexadecanoic acid (16:0). This is markedly different from the fatty acids of other Campylobacter sp. whose major fatty acids are hexadecanoic, octadecenoic (18:1) and hexadecenoic acids (16:1). This is also different from other enterobacteria. Thin-section electronmicroscopy of gastric mucosal biopsies, and negative staining of cultured C. pyloridis, revealed features that differ from those of other campylobacters so far studied. C. pyloridis has a smooth not a rugose surface and multiple unipolar flagella of the sheathed type, each with a terminal bulb. Flagellar sheaths were in continuity with the unit membrane of the outer cell wall. The proposed species C. pyloridis does not belong among the spirochaetes and its DNA composition is incompatible with membership of the genera Spirillum or Vibrio but is compatible with Campylobacter. Thus C. pyloridis is either an atypical member of the genus Campylobacter, the limits of which may have to be redefined to accommodate the new species, or a representative of a new genus.

Response of Campylobacter pyloridis to antibiotics, bismuth and an acid-reducing agent in vitro--an ultrastructural study.

Campylobacter pyloridis was cultured for maximal growth in liquid medium, and effects of exposure to various beta-lactam and macrolide antibiotics, metronidazole, tripotassium dicitrato bismuthane (TDB) and cimetidine were monitored by transmission electronmicroscopy after periods of exposure up to 24 h. With amoxycillin and benzylpenicillin (0.12-1 mg/L) and cephalexin (2 mg/L) the normal bacilliform morphology was replaced by bulging and dumb-bell-like profiles showing cell-wall blebbing and vesiculation, and eventually by swollen forms with incomplete cell walls undergoing lysis. These changes developed progressively between 2 h and 24 h and were accelerated at the higher antibiotic concentrations. Erythromycin and clindamycin caused central clearing, ribosomal coagulation and impaired cross-wall formation. There were no gross structural changes in the presence of metronidazole (4 mg/L), TDB (1000 and 2400 mg/L) or cimetidine (1000 and 2000 mg/L); but with TDB focal accumulation of particulate bismuth complex was detected under the cell wall, affecting nearly all organisms by 24 h. In parallel viability tests, metronidazole and TDB both showed bactericidal activity, but cimetidine did not. These findings support the clinical experience that favours combination therapy with bismuth plus an appropriate systemic antibiotic as the regimen of choice for effective clearance of the organisms in C. pyloridis-associated gastritis.

Influence of soluble haemagglutinins on adherence of Helicobacter pylori to HEp-2 cells.

In a study of six laboratory strains of Helicobacter pylori, two different modes of bacterial adherence to HEp-2 cells were found. Electronmicroscopy revealed that strains known to possess soluble haemagglutinin adhered intimately to the cell surfaces, with cupping of the plasma membrane and coalescence of glycocalyces at sites of attachment. Strains of H. pylori without soluble haemagglutinin also attached, but did not induce membrane cupping or show glycocalyx fusion. Light microscopy did not distinguish between these patterns of adherence. Bacterial attachment was unaffected by pre-treatment of HEp-2 cells with neuraminidase. Exposure of the bacteria to trypsin or to colloidal bismuth subcitrate (CBS) before being added to HEp-2 cells markedly impaired bacterial adherence. This effect of CBS may contribute to the known efficacy of bismuth therapy in patients with H. pylori-related gastritis.

Fasciola hepatica: comparison of flukes from Korea and the United States by isoelectric focusing banding patterns of whole-body protein.

Comparisons were made between the flukes from Chonnam, Korea and Oregon, USA by isoelectric focusing (IEF) of whole-body protein. Adult Fasciola hepatica were recovered from bile ducts of Korean native cattle. Whole-body protein of the flukes was subjected to IEF, and the banding patterns of the fluke protein were compared with those of North American F. hepatica recovered from experimentally infected calves. The overall banding pattern of F. hepatica from Korea was essentially identical to that of F. hepatica from the United States. These results provide further support for the usefulness of this technique in differentiating Fasciola species in other geographical areas.

A case of primary cutaneous actinomycosis.

Primary cutaneous actinomycosis is very uncommon because of the exclusively endogenous habitat of the organism. We report a case of primary cutaneous actinomycosis characterized by histopathological "sulfur granules". The patient had a well-defined subcutaneous nodule on the left thigh without any other lesion and was treated with surgical excision and subsequent oral ampicillin for six weeks. There has been no recurrence during a 1-year period of follow-up.

Pesticide poisoning events in wild birds in Korea from 1998 to 2002.

We describe cases of pesticide poisoning of wild birds diagnosed at the National Veterinary Research and Quarantine Service (Kyunggi, Korea) from 1998 to 2002. Forty-one mortality events (759 birds) of 87 incidents (2,464 birds) investigated were associated with pesticide poisoning, and six organophosphates or carbamates were identified as being responsible for the poisoning. Phosphamidon was most frequently identified as the cause of poisoning, accounting for 23 mortality events. Other pesticides identified as poisons for birds were organophosphates monocrotophus, fenthion, parathion, EPN, and diazinon, and the carbamate carbofuran. Pesticide poisoning is a problem in wild birds in Korea.

Clinical manifestations of foot-and-mouth disease during the 2010/2011 epidemic in the Republic of Korea.

We reviewed the clinical signs of the foot-and-mouth disease (FMD) incidences in the Republic of Korea occurring from November 2010 to April 2011. Profuse salivation, vesiculation, lameness or ataxia, and ulceration were the most commonly observed clinical signs of FMD among the infected animals, irrespective of the species. The clinical signs of FMD manifested more clearly in the dairy cattle and pigs compared to the beef cattle, deer and goats on infected farms. About 54% of the infected dairy farms reported vesicles on the teats as the primary clinical sign, while vesiculation on the nose, including the snout and muzzle, was the major lesion observed in infected beef cattle and pig farms. The teat and feet were the second most frequently vesiculated body parts on infected pigs. Although the average age of the first-to-appear clinical lesion in the animals in the beef and dairy cattle farms subjected to vaccination was higher than that observed in the animals in the farms not subjected to vaccination, a reverse pattern was observed in the pig farms. In this study, the clinical signs of FMD were described on the basis of the subjective observations by the farm workers. The present results highlight the clinical signs expected on specific body parts of different types of susceptible animals, and therefore, they may be useful for generating public awareness, particularly among farm workers, as well as for early detection of future FMD outbreaks.

Using field-based epidemiological methods to investigate FMD outbreaks: an example from the 2002 outbreak in Korea.

Relevant to foot and mouth disease (FMD), most published epidemiological studies have been conducted using quantitative methods and substantial regional or national datasets. Veterinary epidemiology also plays a critical role during outbreak investigations, both to assist with herd-level decision-making and to contribute relevant information to assist with ongoing national or regional control strategies. Despite the importance of this role, however, little information has been published on the use of applied (field-based) epidemiological methods during disease outbreaks. In this study, we outline an investigative template for FMD, and a case study of its use during the 2002 FMD outbreak in Korea. Suitable for use during field-based epidemiological investigations of individual farms within a broader regional/national response, the template considers three steps including confirming infection, estimating date of introduction and determining method of introduction. A case study was conducted on IP13 (the 13th infected premises), the only IP during the 2002 FMD outbreak in Korea that was geographically isolated from all other known cases. The authorities first became aware of FMD on IP13 on 2 June, however, infection may have been present from 12 May. Infection was confirmed on 3 June 2002. FMD was probably spread to IP13 by a contract worker who had participated during 2-4 May in the culling operations on IP1. Other routes of spread were ruled out during the investigation. The contract worker lived in the locality of IP13 and worked on a part-time basis at a pork-processing plant that was adjacent to this farm. The contractor became heavily contaminated during the cull, but did not comply fully with cleaning and disinfection requirements once the cull had been completed. The investigative template contributed structure and focus to the field-based investigation. Results from this case study demonstrate the need for strict management of personnel in disease control and adherence to the sanitary rules by all those involved.

Epidemiological characteristics of the 2002 outbreak of foot-and-mouth disease in the Republic of Korea.

The Republic of Korea experienced a foot-and-mouth disease (FMD) outbreak during May-June 2002. The present study describes epidemiological characteristics of the 2002 FMD outbreak in Korea, including the pattern of the outbreak in both time and space, transmission routes among infected farms, and control measures. One of the notable features of the 2002 FMD epidemic in Korea was that the virus infected mostly pigs [15 of 16 infected premises (IPs)], despite the presence of other susceptible animals on infected and neighbouring farms. The epidemic showed temporal clustering at 8-9 day intervals, suggesting five generations of infection during the outbreak, and 13 of 16 (81.3%) IPs were located within a 10 km-radius of the index case. The clinical signs that prompted notification of infection included vesicles around hooves and snouts. The age of lesions was significantly less among cases reported by farmers compared with veterinarians. The high awareness of farmers from an earlier FMD outbreak greatly helped the animal hygiene authority in efforts associated with disease control and eradication. The outbreak was eradicated within <2 months as a result of the intensive control efforts of the animal hygiene authorities and the cooperation of the Korean people. Although the outbreak was a costly lesson for the Korean people, the experience gained will contribute to future efforts in the prevention and control of animal infectious diseases.