Pathogenicity and virulence of Yersinia

The genus Yersinia includes human, animal, insect, and plant pathogens as well as many symbionts and harmless bacteria. Within this genus are Yersinia enterocolitica and the Yersinia pseudotuberculosis complex, with four human pathogenic species that are highly related at the genomic level including the causative agent of plague, Yersinia pestis. Extensive laboratory, field work, and clinical research have been conducted to understand the underlying pathogenesis and zoonotic transmission of these pathogens. There are presently more than 500 whole genome sequences from which an evolutionary footprint can be developed that details shared and unique virulence properties. Whereas the virulence of Y. pestis now seems in apparent homoeostasis within its flea transmission cycle, substantial evolutionary changes that affect transmission and disease severity continue to ndergo apparent selective pressure within the other Yersiniae that cause intestinal diseases. In this review, we will summarize the present understanding of the virulence and pathogenesis of Yersinia, highlighting shared mechanisms of virulence and the differences that determine the infection niche and disease severity.

A Novel Postbiotic Product Based on Weissella cibaria for Enhancing Disease Resistance in Rainbow Trout: Aquaculture Application

Postbiotics are innovative tools in animal husbandry, providing eco-friendly solutions for disease management within the industry. In this study, a new postbiotic product was evaluated for its impact on the health of rainbow trout (Oncorhynchus mykiss). In vivo studies were conducted to assess the safety of the Weissella cibaria strains used in postbiotic production. Additionally, this study evaluated the impact of diet supplementation with 0.50% postbiotics on growth performance during a 30-day feeding trial; the gut microbial communities, immunomodulation, and protection against Yersinia ruckeri infection were evaluated. The strains did not harm the animals during the 20-day observation period. Furthermore, the effect of postbiotics on growth performance was not significant (p < 0.05). The treated group showed a significant increase in acid-lactic bacteria on the 30th day of the feeding trial, with counts of 3.42 ± 0.21 log CFU/mL. Additionally, there was an up-regulation of the pro-inflammatory cytokine IL-1β in head kidney samples after 48 h of feed supplementation, whereas cytokines IL-10, IL-8, INF-γ, and TNF-α were down-regulated. The findings indicate that rainbow trout fed with postbiotics saw an improvement in their survival rate against Y. ruckeri, with a 20.66% survival improvement in the treated group. This study proves that incorporating postbiotics from two strains of W. cibaria previously isolated from rainbow trout into the diet of fish has immunomodulatory effects, enhances intestinal microbial composition, and improves fish resistance against Y. ruckeri.

Case report: First isolation of Yersinia pseudotuberculosis from the blood of a cat

A 14-year-old female domestic short-haired cat with a diagnosed diabetes mellitus and acromegaly was presented for lethargy and dysorexia. On clinical presentation, the patient showed hyperglycemia, hyperthermia, dull mentation, and dehydration. With the suspicion of an inflammatory or infectious complication of diabetes, she was hospitalized with constant rate infusion of insulin, and empirical ampicillin sulbactam was started. Blood culture revealed positivity for Yersinia pseudotuberculosis and the septic picture was confirmed by blood analysis, with leukocytosis, neutrophilia, and an increased serum amyloid A concentration. The isolated Y. pseudotuberculosis strain showed susceptibility to every antimicrobial tested. During the second day of hospitalization, the onset of hypoglycemia and hypotension was treated with norepinephrine and glucose in fluid therapy. The cat recovered well and was discharged with insulin and amoxicillin-clavulanate. This is the first case of septicemia associated with Y. pseudotuberculosis in a cat, suspected of developing the infection after contact with natural reservoirs such as rodents or birds. This route of transmission should be highlighted especially in relation to the zoonotic potential of the bacteria.

salmonicida

The use of antibiotics in aquaculture leads to the proliferation of multidrug-resistant bacteria, and an urgent need for developing new alternatives to prevent and control disease has, thus, arisen. In this scenario, postbiotics represent a promising tool to achieve this purpose; thus, in this study, isolation and selection of bacteria to further produce and evaluate their postbiotics antibacterial activity against fish pathogens was executed. In this respect, bacterial isolates from rainbow trout and Nile tilapia were obtained and tested in vitro against Yersinia ruckeri and Aeromonas salmonicida subsp. salmonicida. From 369 obtained isolates, 69 were selected after initial evaluation. Afterwards, additional screening was carried out by spot-on-lawn assay to finally select twelve isolates; four were identified as Pediococcus acidilactici, seven as Weissella cibaria, and one as Weissella paramesenteroides by matrix assisted laser desorption/ionization, time-of-flight mass spectrometry (MALDI-TOF MS). Selected bacteria were used to obtain postbiotic products to test their antagonistic activity through coculture challenge and broth microdilution assays. The influence of incubation time prior to postbiotic production on antagonistic behavior was also recorded. Two isolates identified as W. cibaria were able to significantly reduce (p < 0.05) A. salmonicida subsp. salmonicida's growth in the coculture challenge up to 4.49 ± 0.05 Log CFU/mL, and even though the reduction in Y. ruckeri was not as effective, some inhibition on the pathogen's growth was reported; at the same time, most of the postbiotic products obtained showed more antibacterial activity when obtained from broth cultures incubated for 72 h. Based on the results obtained, the preliminary identification of the isolates that expressed the highest inhibitory activity was confirmed by partial sequencing as W. cibaria. Through our study, it can be concluded that postbiotics produced by these strains are useful to inhibit the growth of the pathogens and could, thereby, be applicable in further research to develop suitable tools as feed additives for disease control and prevention in aquaculture.

Co-existence of two Yersinia ruckeri biotypes and serotype O1a retrieved from rainbow trout (Oncorhynchus mykiss) farmed in Puno, Peru

Yersinia ruckeri causes important economic losses for rainbow trout (Oncorhynchus mykiss) farms worldwide. This bacterial disease is likely the most common among trout in Peru; however, no commercial vaccine is available nationally, which is, in part, due to a lack of information on the bacterium. The aim of the current study was to characterize 29 Y. ruckeri isolates sampled from seven cage-reared farms in the Puno Region, the focal point for aquaculture activities in Peru. For this, samples were taken from fish with clinical signs (i.e. haemorrhages, uni- or bilateral exophthalmia, hyphaemia and/or melanosis). Notable among our findings was the existence of both Y. ruckeri biotype 1 (9 isolates) and biotype 2 (20 isolates; negative for sorbitol and Tween 80). The isolates further differed in API profiles 5307100 (21 isolates), 1307100 (4 isolates), 1305100 (2 isolates), 1307120 (1 isolate) and 5305100 (1 isolate), with the main differences being in the tests for lysine decarboxylase, gelatine hydrolysis and D-saccharose fermentation. Despite these differences, all isolates shared identical ERIC-PCR and REP-PCR profiles and belonged to the O1a serotype. Fingerprints were identical to the reference strain CECT 955 (serotype O1a). The information obtained will be used for epidemiological purposes by health authorities and for the development of a vaccine against Y. ruckeri, a prominent request made by fish farmers in Peru.

Epizootic Yersinia enterocolitica in captive African green monkeys (Chlorocebus aethiops sabaeus)

Yersinia enterocolitica is a Gram-negative bacterium that typical results in enterocolitis in humans and poses significant worldwide risks to public health. An outbreak of yersiniosis in the Vervet/African green monkey colony at the WFSM during the winter of 2015-2016 accounted for widespread systemic infection with high morbidity and mortality. Most of the cases had extensive necrosis with suppuration and large colonies of bacilli in the large bowel and associated lymph nodes; however, the small intestine, stomach, and other organs were also regularly affected. Positive cultures of Yersinia enterocolitica were recovered from affected tissues in 20 of the 23 cases. Carrier animals in the colony were suspected as the source of the infection because many clinically normal animals were culture-positive during and after the outbreak. In this study, we describe the gross and histology findings and immune cell profiles in different organs of affected animals. We found increased numbers of myeloid-derived phagocytes and CD11C-positive antigen-presenting cells and fewer adaptive T and B lymphocytes, suggesting an immunocompromised state in these animals. The pathogen-mediated microenvironment may have contributed to the immunosuppression and rapid spread of the infection in the vervets. Further studies in vervets could provide a better understanding of Yersinia-mediated pathogenesis and immunosuppression, which could be fundamental to understanding chronic and systemic inflammatory diseases in humans.

Biotyping reveals loss of motility in two distinct Yersinia ruckeri lineages exclusive to Norwegian aquaculture

Non-motile strains of Yersinia ruckeri, known as Y. ruckeri biotype 2, now dominate amongst clinical isolates retrieved from rainbow trout internationally. Due to an acute increase in the number of yersiniosis cases in Norway in recent years, followed by introduction of widespread intraperitoneal vaccination against the disease, an investigation on the prevalence of Y. ruckeri biotype 2 in Norwegian aquaculture was conducted. We biotyped 263 Y. ruckeri isolates recovered from diseased salmonids in Norway between 1985 and 2020. A total of seven biotype 2 isolates were identified, four of which were collected between 1985 and 1987, and three of which belong to the current epizootic clone, isolated from two different sea-farms in 2017. Whole-genome sequencing revealed single non-synonymous nucleotide polymorphisms in the flagellar genes flhC in isolates from the 1980s, and in fliP in isolates from 2017. In both variants, motility was restored both by complementation with wild-type alleles in trans and via spontaneous mutation-driven reversion following prolonged incubation on motility agar. While biotype 2 strains do not yet seem to have become broadly established in Norwegian aquaculture, the seven isolates described here serve to document a further two independent cases of Y. ruckeri biotype 2 emergence in salmonid aquaculture.

Outbreak in African lions of Yersinia pseudotuberculosis infection, with aberrant bacterial morphology

A concurrent outbreak of infection with Yersinia pseudotuberculosis occurred in adult captive African lions (Panthera leo). Two 17-y-old male lions and one 14-y-old female lion developed respiratory distress, lethargy, ataxia, and hyporexia. Within 3-5 d of the onset of clinical signs, one male and the female lion died and were submitted for postmortem examination. Macroscopically, the liver and spleen had multifocal-to-coalescing, semi-firm, pale-tan nodules throughout the parenchyma. The lungs were non-collapsed and marked by petechiae. Histologic examination identified lytic, necrosuppurative foci in the liver, spleen, lungs, and kidney, with abundant intralesional gram-negative coccobacilli in the male lion. Similar findings were seen in the female lion in the liver, spleen, kidney, and mesenteric lymph node; however, the intralesional bacterial colonies were more pleomorphic, comprising rod and filamentous morphologies. Aerobic bacterial culture of the liver, spleen, and lung revealed Y. pseudotuberculosis growth. The source of infection is unknown, and an epidemiologic study was performed. Sources to be considered are from the predation of rodent and/or bird reservoirs, or contaminated soil or water. Mortality associated with Y. pseudotuberculosis has been described in an African lion cub, however, to our knowledge, Y. pseudotuberculosis has not been reported in adult African lions, and this is only the second report of Y. pseudotuberculosis with aberrant bacterial morphology observed histologically.

Overview of basic epidemiological characteristics and descriptive analysis of the incidence of human yersiniosis in the Czech Republic in 2018-2020

OBJECTIVE

The aim was to provide an overview of the basic epidemiological characteristics of human yersiniosis and to analyze the reported epidemiological data on the incidence of this disease in the Czech Republic (CZ) in 2018-2020.

METHODS

A descriptive analysis was performed of cases of yersiniosis captured in the Infectious Disease Information System (ISIN) in the CZ in 2018-2020. MS Excel 2010 was used for data processing and sorting.

RESULTS

In the CZ, a total of 1,686 cases of yersiniosis were reported in 2018-2020 (average annual incidence of 5/100,000 population). The highest average age-specific incidence was recorded in the age group 1-4 years (31.3/100,000), followed by 0-year-olds (26.9/100,000). In the study period, 942 cases were male and 744 cases were female, with the respective incidences of 6.0 /100,000 and 4.6/100,000. By administrative region, the highest average annual incidences were recorded in the South Moravian (9.1/100,000) and Moravian-Silesian (7.5/100,000) Regions. Hospital admission was required for 14.3% (n = 241) of reported cases. No death or outbreak was reported during the study period. A total of 31 cases were imported from usual recreational destinations. No seasonality was detected in the CZ; however, more cases always occur in January and in the second half of the year. Over the last three years, a stagnant trend in the incidence of the disease has been observed in the CZ.

CONCLUSIONS

In 2018 and 2019, yersiniosis (caused by Y. enterocolitica and rarely Y. pseudotuberculosis) was the fourth most commonly reported zoonosis in humans in the European Union (EU), with a stable trend in 2014-2019. The CZ reports an incidence up to three times higher but a 2.5 lower share of hospitalized patients compared to the EU average, which probably indicates that the CZ has an effective surveillance system in place. The trend in the incidence of the disease has stagnated in the CZ and the EU in recent years. The most common vehicle for transmission of yersiniosis to humans is contaminated food, especially undercooked pork, less often vegetables or water. Contamination of products from home slaughtered animals intended for private consumption is likely and would also explain the increased incidence of the disease, particularly in the winter months.

Yersiniosis in Poland in 2018-2020

AIM

The aim of the study was to assess the epidemiological situation of yersiniosis in Poland in 2018-2020 and compare it to previous years.

MATERIAL AND METHODS

To assess the epidemiological situation of yersiniosis in Poland, data from individual case reports prepared by Sanitary Epidemiological Stations as part of routine epidemiological surveillance were used. Incidence, number of cases and data on hospitalizations by voivodship included in the bulletins "Infectious Diseases and Poisons in Poland" for 2015-2020 were also used.

RESULTS

In 2018-2020, a total number of 542 cases of yersiniosis were registered, including 456 intestinal and 86 extraintestinal forms. The incidence in 2018 was 0.53/100,000 in 2019 0.59/100,000 and in 2020 0.29/100,000. The number of cases in 2020 compared to 2019 decreased by 52%, and compared to 2018 by 45.8%. The percentage of hospitalizations in each year was at a similar level of 65.5% in 2018, 62.4% in 2019, and 60% in 2020. The highest incidence was noted in the 0-4 age group at 44.7% of cases in 2018, 42.9% in 2019 and 55.6% in 2020, respectively (all cases of the intestinal form). The predominant species was Y. enterocolitica in both intestinal and extraintestinal forms. The most common serotype was serotype O:3, which was identified in 34 isolates in 2018, 43 isolates in 2019 and 9 isolates in 2020.

SUMMARY AND CONCLUSIONS

Since 2009, Poland has had a decreasing trend in the incidence of yersiniosis. In 2020, both Poland and Europe saw a sharp decline in the number of cases compared to previous years. This is a result of the occurrence of the COVID-19 pandemic in March 2020, during which many measures were introduced to limit the spread of the SARS-CoV-2 virus, which may also have affected the number of other infections. Although the numbers of cases and incidence of yersiniosis among children under the age of 5 are the highest compared to other age groups, the highest number of hospitalizations was reported in the 10-19 age group, which most likely reflects the decreasing number of laboratory tests ordered on an outpatient basis with age and the significant underreporting of cases in this and older age groups.

A Case Series of Diarrheal Diseases Associated with Yersinia frederiksenii

To date, Yersinia pestis, Yersinia enterocolitica, and Yersinia pseudotuberculosis are the three Yersinia species generally agreed to be pathogenic in humans. However, there are a limited number of studies that suggest some of the “non-pathogenic” Yersinia species may also cause infections. For instance, Yersinia frederiksenii used to be known as an atypical Y. enterocolitica strain until rhamnose biochemical testing was found to distinguish between these two species in the 1980s. From our regional microbiology laboratory records of 18 hospitals in Eastern Ontario, Canada from 1 May 2018 to 1 May 2021, we identified two patients with Y. frederiksenii isolates in their stool cultures, along with their clinical presentation and antimicrobial management. Both patients presented with diarrhea, abdominal pain, and vomiting for 5 days before presentation to hospital. One patient received a 10-day course of sulfamethoxazole-trimethoprim; his Y. frederiksenii isolate was shown to be susceptible to amoxicillin-clavulanate, ceftriaxone, ciprofloxacin, and sulfamethoxazole-trimethoprim, but resistant to ampicillin. The other patient was sent home from the emergency department and did not require antimicrobials and additional medical attention. This case series illustrated that diarrheal disease could be associated with Y. frederiksenii; the need for antimicrobial treatment should be determined on a case-by-case basis.

Evaluation of the efficacy of enrofloxacin in rainbow trout (Oncorhynchus mykiss) following experimental challenge with Yersinia ruckeri

BACKGROUND

Use of enrofloxacin in trout farms is reported, especially for the treatment of yersiniosis, albeit various dosing regimens have been used. Therefore, optimal doses should be investigated.

METHODS

Five groups of 15 fish were challenged with Y. ruckeri. Two days later, three groups received feed containing enrofloxacin (ENR) at 1, 2.5 and 5 mg/kg fish respectively, during 7 days; one group received a single intraperitoneal injection of ENR at 10 mg/kg; and one group was left untreated. On day 15, surviving fish were euthanized.

RESULTS

All fish survived in the group treated by injection, compared to 53%, 60% and 40% of the fish treated with 1, 2.5 and 5 mg/kg oral ENR, respectively, and 53% in the infected untreated group.

CONCLUSION

A single intraperitoneal injection of ENR at 10 mg/kg seems more relevant than repeated oral administrations. The ENR oral doses used in trout farms should be revised.

Yersiniosis in New Zealand

The rate of yersiniosis in New Zealand (NZ) is high compared with other developed countries, and rates have been increasing over recent years. Typically, >99% of human cases in NZ are attributed to Yersinia enterocolitica (YE), although in 2014, a large outbreak of 220 cases was caused by Yersinia pseudotuberculosis. Up until 2012, the most common NZ strain was YE biotype 4. The emergent strain since this time is YE biotype 2/3 serotype O:9. The pathogenic potential of some YE biotypes remains unclear. Most human cases of yersiniosis are considered sporadic without an identifiable source. Key restrictions in previous investigations included insufficient sensitivity for the isolation of Yersinia spp. from foods, although foodborne transmission is the most likely route of infection. In NZ, YE has been isolated from a variety of sick and healthy domestic and farm animals but the pathways from zoonotic reservoir to human remain unproven. Whole-genome sequencing provides unprecedented discriminatory power for typing Yersinia and is now being applied to NZ epidemiological investigations. A "One-Health" approach is necessary to elucidate the routes of transmission of Yersinia and consequently inform targeted interventions for the prevention and management of yersiniosis in NZ.

Yersiniosis in Poland in 2017

AIM

The aim of the study is to assess epidemiological situation of yersiniosis in Poland in 2017 in comparison to previous years.

MATERIAL AND METHODS

The evaluation is based on analysis of data from the annual bulletins “Infectious diseases and poisoning in Poland”, information from individual yersiniosis case reports entered and shared by local sanitary-epidemiological stations through Electronic Registry of Epidemiologic Forms (SRWE), information from individual extraintestinal case reports fulfilled by local sanitary-epidemiological station and sent to the Departments of Epidemiology, National Institute of Public Health - National Institute of Hygiene by regional sanitary-epidemiological stations, information on outbreaks shared through the Electronic Registry of Epidemic Outbreaks (ROE) and data on deaths from the Department of Demographic Studies of the Central Statistical Office.

RESULTS

In 2017 255 cases of yersiniosis, including 191 intestinal and 64 extraintestinal were registered. Incidence in 2017 was 0.66/100 000 population. Number of cases registered in 2017 was higher than in 2015 and 2016 (for both years 205 cases with incidence 0.53/100 000 was observed) and similar to the one in 2014 (244 cases, incidence 0.63/100 000). In 2017 all intestinal yersiniosis cases met criteria for confirmed case. Around 35% of cases were registered in mazowieckie voivodship where incidence was similar to the one in European Union. Among Y. enterocolitica isolates, serotype was determined in 62 cases what stands for only 28.7% of all cases. Predominant serotype was 03, it was identified in 81% of serotyped cases. Most of intestinal yersiniosis cases occurred among children under 4 years (54.5% of all registered cases).

CONCLUSIONS

In 2017 increase in number of cases was observed. Yersiniosis in Poland is rarely diagnosed, incidence in Poland is more than twice time lower than in European Union.

Emerging Evasion Mechanisms of Macrophage Defenses by Pathogenic Bacteria

Macrophages participate to the first line of defense against infectious agents. Microbial pathogens evolved sophisticated mechanisms to escape macrophage killing. Here, we review recent discoveries and emerging concepts on bacterial molecular strategies to subvert macrophage immune responses. We focus on the expanding number of fascinating subversive tools developed by Listeria monocytogenes, Staphylococcus aureus, and pathogenic Yersinia spp., illustrating diversity and commonality in mechanisms used by microorganisms with different pathogenic lifestyles.

RETROSPECTIVE REVIEW OF MORTALITY IN CAPTIVE PINK PIGEONS (NESOENAS MAYERI) HOUSED IN EUROPEAN COLLECTIONS: 1977-2018

The Mauritian pink pigeon (Nesoenas mayeri) is vulnerable, with only 400 individuals remaining in the free-living population. A European captive population was established in 1977 and a European Endangered Species Program (EEP) in 1992. The EEP long-term management plan recommends integrating the EEP and free-living Mauritius populations through pigeon transfers. A retrospective mortality review of the captive population was performed as part of a disease risk assessment process and to inform infectious disease screening prior to exporting captive birds to Mauritius. Six hundred pink pigeons from 34 institutions died from 1977 to 2018. Each individual was categorized according to age at time of death. Records from 404 individuals were categorized according to cause of death. Neonatal mortality (39%) and juvenile mortality (10.8%) were most commonly caused by noninfectious diseases (52% and 54.4%, respectively), including parental neglect and failure to thrive in neonates and nutritional secondary hyperparathyroidism in juveniles. Trauma (43.1%) was the most common cause of mortality in adults, with significantly higher mortality in males from interspecific aggression and in females due to intraspecific aggression. Yersinia pseudotuberculosis, Mycobacterium avium, and Escherichia coli were the most common infectious causes of adult mortality, and E. coli was the most common infectious cause in neonates. The following infectious diseases were identified as priorities for pre-export disease risk analysis, though not all caused mortality: Y. pseudotuberculosis, M. avium, Trichomonas spp., Chlamydia psittaci, and Coccidia spp. Husbandry changes have been made over the years to mitigate many of the noninfectious causes of mortality. These include alterations to nest sites to reduce neonatal trauma and abandonment, ultraviolet light supplementation and diet optimization to reduce metabolic disorders, improving enclosure design to reduce impact trauma, allowing females rest periods during breeding season, and avoiding housing with certain species.

Vaccine Potential of a Recombinant Bivalent Fusion Protein LcrV-HSP70 Against Plague and Yersiniosis

To counteract the deadly pathogens, i.e., Y. pestis, Y. enetrocolitica, and Y. pseudotuberculosis, we prepared a recombinant DNA construct lcrV-hsp70 encoding the bivalent fusion protein LcrV-HSP70. The lcrV gene of Y. pestis and hsp70 domain II DNA fragment of M. tuberculosis were amplified by PCR. The lcrV amplicon was first ligated in the pET vector using NcoI and BamHI restriction sites. Just downstream to the lcrV gene, the hsp70 domain II was ligated using BamHI and Hind III restriction sites. The in-frame and the orientation of cloned lcrV-hsp70 were checked by restriction analysis and nucleotide sequencing. The recombinant bivalent fusion protein LcrV-HSP70 was expressed in E. coli and purified by affinity chromatography. The vaccine potential of LcrV-HSP70 fusion protein was evaluated in formulation with alum. BALB/c mice were vaccinated, and the humoral and cellular immune responses were studied. The fusion protein LcrV-HSP70 induced a strong and significant humoral immune response in comparison to control animals. We also observed a significant difference in the expression levels of IFN-γ and TNF-α in LcrV–HSP70-immunized mice in comparison to control, HSP70, and LcrV groups. To test the protective efficacy of the LcrV–HSP70 fusion protein against plague and Yersiniosis, the vaccinated mice were challenged with Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis separately. The bivalent fusion protein LcrV–HSP70 imparted 100% protection against the plague. In the case of Yersiniosis, on day 2 post challenge, there was a significant reduction in the number of CFU of Y. enterocolitica and Y. pseudotuberculosis in the blood (CFU/ml) and the spleen (CFU/g) of vaccinated animals in comparison to the LcrV, HSP70, and control group animals.

Serological Evidence of Yersiniosis, Tick-Borne Encephalitis, West Nile, Hepatitis E, Crimean-Congo Hemorrhagic Fever, Lyme Borreliosis, and Brucellosis in Febrile Patients Presenting at Diverse Hospitals in Kenya

Data on pathogen prevalence is crucial for informing exposure and disease risk. We evaluated serological evidence of tick-borne encephalitis (TBE), West Nile (WN), Hepatitis E virus (HEV), Crimean-Congo Hemorrhagic Fever (CCHF), Yersiniosis, Lyme Disease (LD), and brucellosis in 1033 patients presenting with acute febrile illness at 9 health care facilities from diverse ecological zones of Kenya: arid and semiarid (Garissa District Hospital, Lodwar District Hospital, Marigat District Hospital, Gilgil District Hospital), Lake Victoria basin (Kisumu District Hospital, Alupe District Hospital, Kombewa Sub-County Hospital), Kisii highland (Kisii District Hospital), and coastal (Malindi District Hospital). Epidemiological information of the patients such as geography, age, gender, and keeping animals were analyzed as potential risk factors. Of the 1033 samples, 619 (59.9%) were seropositive to at least one pathogen by IgM (current exposure), IgG/IgM (recent exposure), and IgG (past exposure). Collective seroprevalence for current, recent, and past to the pathogens was 9.4%, 5.1%, and 21.1% for LD; 3.6%, 0.5%, and 12.4% for WN; 0.9%, 0.5%, and 16.9% for HEV; 5.8%, 1.3%, and 3.9% for brucellosis; 5.7%, 0.2%, and 2.3% for yersiniosis; 1.7%, 0%, and 6.2% for TBE; and 0.4%, 0%, and 1.9% for CCHF. Brucellosis risk was higher in patients recruited at Garissa District Hospital (odds ratio [OR] = 3.41), HEV (OR = 2.45) and CCHF (OR = 5.46) in Lodwar District Hospital, LD in Alupe District Hospital (OR = 5.73), Kombewa Sub-district hospital (OR = 8.17), and Malindi District hospital (OR = 3.3). Exposure to LD was highest in the younger age group, whereas yersiniosis did not vary with age. Age was a significant risk for WN, brucellosis, CCHF, TBE, and HEV and in those aged >14 years there was an increased risk to WN (OR = 2.30, p < 0.0001), brucellosis (OR = 1.84, p = 0.005), CCHF (OR = 4.35, p = 0.001), TBE (OR = 2.78, p < 0.0001), and HEV (OR = 1.94, p = 0.0001). We conclude that LD is pervasive and constitutes a significant health burden to the study population, whereas yersiniosis and CCHF are not significant threats. Going forward, community-based studies will be needed to capture the true seroprevalence rates and the associated risk factors.

PREVALENCE OF YERSINIA AMONG WILD SIKA DEER (CERVUS NIPPON) AND BOARS (SUS SCROFA) IN JAPAN

We examined the prevalence of Yersinia, including pathogenic species such as Yersinia enterocolitica and Yersinia pseudotuberculosis, among wild sika deer (Cervus nippon) and boars (Sus scrofa) captured in Japan. The prevalence of Yersinia in the wild deer was 75% (207/277) and in the boars was 74% (40/54). A total of 417 isolates of nine Yersinia species were isolated from the animals examined: the largest number of isolates (48%, 200/417) were Y. enterocolitica biotype 1A. Pathogenic Y. enterocolitica 1B/O:8 were also isolated from two deer, and Y. pseudotuberculosis serogroups 3 and 4 were isolated from two boars and a deer, respectively. The pathogenic Y. enterocolitica 1B/O:8 isolates carried four virulence genes (ail, ystA, yadA, and virF), and Y. pseudotuberculosis serogroups 3 and 4 isolates carried three virulence genes (inv, yadA, and lcrF). Although the Y. enterocolitica 1B/O:8 and Y. pseudotuberculosis isolates were sensitive to almost all the antimicrobials tested, the two Y. enterocolitica 1B/O:8 isolates were resistant to azithromycin and ampicillin, and the three Y. pseudotuberculosis isolates were resistant only to azithromycin. These findings suggested that wild deer and boars might be important reservoirs for the agent causing human yersiniosis.

A Study of a Potent Inhibitor Against a GDP-6-Deoxy-α-d-Manno-Heptose Biosynthesis Pathway as Antibiotic Candidates

The GDP-6-deoxy-α-d-manno-heptose is a key building block molecule in constructing lipopolysaccharide of Gram-negative bacteria. Therefore, blockage of the biosynthesis pathway of GDP-6-deoxy-α-d-manno-heptose is lethal or increases antibiotics susceptibility to pathogens. In this study, we assayed d-glycero-α-d-manno-heptose-1-phosphate guanylyltransferase (HddC) from Yersinia pseudotuberculosis (Yp) using an efficient assay method supplying its natural substrate. Using the method, 102 chemical compounds were tested to search inhibitory compounds and electrospray ionization mass spectrometry was used to detect the HddC from Y. pseudotuberculosis (YpHddC) reaction product, GDP-d-glycero-α-d-manno-heptose. Interestingly, one promising lead, ethyl 5-({[(5-benzyl-1, 3, 4-oxadiazol-2-yl) thio] acetyl} amino)-4-cyano-3-methyl-2-thiophenecarboxylate (Chembridge 7929959), was discovered. The inhibitory activity of the lead compound against YpHddC has been proven by blocking its nucleotidyltransferase activity transferring the GMP moiety to α-d-mannose-1-phosphate (αM1P). Chembridge 7929959 shows that the half maximal inhibitory concentration (IC₅₀) is 0.222 μM indicating its affinity with αM1P.

pestis YopENt138-LcrV Fusion Elicits Broad Protection against Plague and Yersiniosis in Mice

In this study, a novel recombinant attenuated Yersinia pseudotuberculosis PB1+ strain (χ10069) engineered with ΔyopK ΔyopJ Δasd triple mutations was used to deliver a Y. pestis fusion protein, YopE amino acid 1 to 138-LcrV (YopENt138-LcrV), to Swiss Webster mice as a protective antigen against infections by yersiniae. χ10069 bacteria harboring the pYA5199 plasmid constitutively synthesized the YopENt138-LcrV fusion protein and secreted it via the type 3 secretion system (T3SS) at 37°C under calcium-deprived conditions. The attenuated strain χ10069(pYA5199) was manifested by the establishment of controlled infection in different tissues without developing conspicuous signs of disease in histopathological analysis of microtome sections. A single-dose oral immunization of χ10069(pYA5199) induced strong serum antibody titers (log10 mean value, 4.2), secretory IgA in bronchoalveolar lavage (BAL) fluid from immunized mice, and Yersinia-specific CD4+ and CD8+ T cells producing high levels of tumor necrosis factor alpha (TNF-α), gamma interferon (IFN-γ), and interleukin 2 (IL-2), as well as IL-17, in both lungs and spleens of immunized mice, conferring comprehensive Th1- and Th2-mediated immune responses and protection against bubonic and pneumonic plague challenges, with 80% and 90% survival, respectively. Mice immunized with χ10069(pYA5199) also exhibited complete protection against lethal oral infections by Yersinia enterocolitica WA and Y. pseudotuberculosis PB1+. These findings indicated that χ10069(pYA5199) as an oral vaccine induces protective immunity to prevent bubonic and pneumonic plague, as well as yersiniosis, in mice and would be a promising oral vaccine candidate for protection against plague and yersiniosis for human and veterinary applications.

Yersiniosis in Poland in 2015 and 2016

OBJECTIVE

The aim of this study is to assess the epidemiological situation of yersiniosis in Poland in 2015 and 2016 in comparison to the previous years.

MATERIAL AND METHODS

The evaluation is based on analysis of data from the annual bulletins „Infectious diseases and poisoning in Poland” (4,5), information from individual yersiniosis case reports sent to the Department of Epidemiology of Infectious Diseases and Surveillance, NIPH-NIH by regional sanitaryepidemiological stations, information on outbreaks delivered by local sanitary-epidemiological stations through the system „Rejestr Ognisk Epidemicznych” (Electronic Registry of Epidemic Outbreaks) and data on deaths from the Department of Demographic Studies of the Central Statistical Office.

RESULTS

The number of registered yersiniosis cases in Poland in 2015 and 2016 was the same – 205 cases, corresponding to annual incidence of 0.53/100 000. Among them in 2015 there were 172 intestinal yersiniosis cases and 33 extraintestinal yersiniosis cases and in 2016 – 167 intestinal yersiniosis cases and 38 extraintestinal yersiniosis cases. In 2015 and 2016 all intestinal yersiniosis cases met the criteria for confirmed case. In turn, among extraintestinal yersiniosis cases in 2015 26 cases met criteria for probable case and 7 for confirmed case and in 2016 – 32 for probable and 6 for confirmed case. Both in 2015 and in 2016 the incidence in mazowieckie voivodeship (1.61/100 000 in 2015 and 1.55/100 000 in 2016) largely exceeded the average incidence in Poland. The overall proportion of hospitalizations, 59.5% in 2015 and 58% in 2016, remained at the level similar to the preceding years. Serotype of the isolated Yersinia enterocolitica in 2015 in Poland was determined in 59 cases (32% of all Y. enterocolitica isolates). In 2016 serotype was determined in 47 cases of Y. enterocolitica infections (27% of all Y. enterocolitica isolates). Predominant serotype was O3. As in the previous years about 1/3 of infections occurred among children aged 0-4 (110 cases, 34.9% in 2015 and 92 cases, 30.9% in 2016). In 2015 there were no yersiniosis outbreaks, in 2016 there was one outbreak caused by Y. enterolitica.

CONCLUSION

Yersiniosis in Poland is rarely diagnosed and is likely underreported. The percentage of serotyped isolates continues to be low.

Systemic Yersinia pseudotuberculosis as a Cause of Osteomyelitis in a Captive Ring-tailed Lemur (Lemur catta)

Yersinia pseudotuberculosis and Yersinia enterocolitica are ubiquitous pathogens with wildlife and domestic animal reservoirs. Outbreaks of 'non-plague' yersiniosis in man and non-human primates are reported frequently (including zoological specimens and research breeding colonies) and are usually characterized by enteritis, mesenteric lymphadenitis and occasionally organ abscessation. In people, non-septic reactive arthritis is a common sequela to yersiniosis. However, there have been rare reports in people of septic arthritis and osteomyelitis because of active systemic infection with Y. pseudotuberculosis. Osteomyelitis has also been reported rarely in historical yersiniosis outbreaks in farmed turkeys in England and the USA. This paper reports the first case of osteomyelitis caused by systemic infection with Y. pseudotuberculosis O:1 in a non-human primate, a captive ring-tailed lemur (Lemur catta). The lemur had a short clinical history of hyporexia and weight loss with reduction in mobility, especially of the left hindlimb. On post-mortem examination there was evidence of multi-organ abscessation. In addition, severe necrosis, inflammation and large bacterial colonies were present in the musculature, periosteum and bone marrow in the hip, ribs and a vertebra at the cervicothoracic junction. Osteomyelitis should be considered as a rare clinical presentation in non-human primates with systemic Y. pseudotuberculosis infection.

First isolation of Yersinia entomophaga in human urinary tract

Yersinia entomophaga is an insect pathogen first isolated from larvae of Coleoptera in New Zealand in 2011. We report here the first isolation of Y. entomophaga from human urine. Using whole-genome sequencing, we confirmed the presence of specific chromosomal virulence genes and identified a plasmid harbouring a quinolone resistance gene.

Assessment of the efficacy of an autogenous vaccine against Yersinia pseudotuberculosis in young Merino sheep

AIMS To assess the efficacy of an autogenous vaccine against Yersinia pseudotuberculosis III in preventing clinical disease and deaths due to yersiniosis in young Merino sheep, and to determine the effect of vaccination on the prevalence of faecal shedding of pathogenic Yersinia spp., daily liveweight gain, and development of antibodies to Yersinia spp. following vaccination and natural exposure. METHODS In six groups (three groups each from two farms) of young Merino sheep, 148-150 animals were systematically allocated to be vaccinated twice with an autogenous, formalin- killed bacterin vaccine containing Y. pseudotuberculosis serotype III or to remain non-vaccinated. All vaccinated and non-vaccinated sheep were run together in their original groups throughout the trial. Faecal and blood samples were collected, and liveweight measured, at the time of vaccination and subsequently over a 6-month period to determine faecal shedding of Y. enterocolitica and Y. pseudotuberculosis, seroprevalence of antibodies to Yersinia outer membrane proteins (YOP) and changes in liveweight. RESULTS None of the six trial groups experienced an outbreak of clinical yersiniosis during the study period. On Farm A, the prevalence of shedding of either or both Yersinia spp. was <40% on all but one sampling occasions. On Farm B the prevalence of shedding of both Yersinia spp. peaked at 98%, 96 days after vaccination. Mean liveweight and daily liveweight gain at the end of the study were similar in vaccinated and non-vaccinated groups on both farms (p>0.1), as was the prevalence of faecal shedding of Yersinia spp. (p>0.2), and the proportion of animals that became seropositive for antibodies to YOP following vaccination (p>0.1). CONCLUSIONS AND CLINICAL RELEVANCE This vaccine had, at most, limited effects on seroconversion and, under the conditions of this study, had no demonstrable impact on liveweight, mean daily liveweight gain or faecal shedding of Yersinia spp. Further studies are needed to determine the efficacy of this vaccine during outbreaks of yersiniosis or following experimental challenge with pathogenic Yersinia spp..

Multilocus Variable-Number Tandem-Repeat Analysis of Yersinia ruckeri Confirms the Existence of Host Specificity, Geographic Endemism, and Anthropogenic Dissemination of Virulent Clones

This comprehensive population study substantially improves our understanding of the epizootiological history and nature of an internationally important fish-pathogenic bacterium. The MLVA assay developed and presented represents a high-resolution typing tool particularly well suited for Yersinia ruckeri infection tracing, selection of strains for vaccine inclusion, and risk assessment. The ability of the assay to separate isolates into geographically linked and/or possibly host-specific clusters reflects its potential utility for maintenance of national biosecurity. The MLVA is internationally applicable and robust, and it provides clear, unambiguous, and easily interpreted results. Typing is reasonably inexpensive, with a moderate technological requirement, and may be completed from a harvested colony within a single working day. As the resulting MLVA profiles are readily portable, any Y. ruckeri strain may rapidly be placed in a global epizootiological context.

A multilocus variable-number tandem-repeat analysis (MLVA) assay was developed for epizootiological study of the internationally significant fish pathogen Yersinia ruckeri, which causes yersiniosis in salmonids. The assay involves amplification of 10 variable-number tandem-repeat (VNTR) loci in two five-plex PCRs, followed by capillary electrophoresis. A collection of 484 Y. ruckeri isolates, originating from various biological sources and collected from four continents over 7 decades, was analyzed. Minimum-spanning-tree cluster analysis of MLVA profiles separated the studied population into nine major clonal complexes and a number of minor clusters and singletons. The major clonal complexes could be associated with host species, geographic origin, and serotype. A single large clonal complex of serotype O1 isolates dominating the yersiniosis situation in international rainbow trout farming suggests anthropogenic spread of this clone, possibly related to transport of fish. Moreover, subclustering within this clonal complex indicates putative transmission routes and multiple biotype shift events. In contrast to the situation in rainbow trout, Y. ruckeri strains associated with disease in Atlantic salmon appear as more or less geographically isolated clonal complexes. A single complex of serotype O1 exclusive to Norway was found to be responsible for almost all major yersiniosis outbreaks in modern Norwegian salmon farming, and site-specific subclustering further indicates persistent colonization of freshwater farms in Norway. Identification of genetically diverse Y. ruckeri isolates from clinically healthy fish and environmental sources also suggests the widespread existence of less-virulent or avirulent strains.

IMPORTANCE This comprehensive population study substantially improves our understanding of the epizootiological history and nature of an internationally important fish-pathogenic bacterium. The MLVA assay developed and presented represents a high-resolution typing tool particularly well suited for Yersinia ruckeri infection tracing, selection of strains for vaccine inclusion, and risk assessment. The ability of the assay to separate isolates into geographically linked and/or possibly host-specific clusters reflects its potential utility for maintenance of national biosecurity. The MLVA is internationally applicable and robust, and it provides clear, unambiguous, and easily interpreted results. Typing is reasonably inexpensive, with a moderate technological requirement, and may be completed from a harvested colony within a single working day. As the resulting MLVA profiles are readily portable, any Y. ruckeri strain may rapidly be placed in a global epizootiological context.

Prevalence of Yersinia enterocolitica Bioserotype 3/O:3 among Children with Diarrhea, China, 2010-2015

Yersinia enterocolitica is thought to not significantly contribute to diarrheal disease in China, but evidence substantiating this claim is limited. We determined the prevalence of Y. enterocolitica infection and strain types present among children <5 years of age with diarrhea in China. The overall prevalence of pathogenic isolates was 0.59%. Prevalence of pathogenic bioserotype 3/O:3 varied geographically. In this population, the presence of fecal leukocytes was a characteristic of Y. enterocolitica infection and should be used as an indication for microbiological diagnostic testing, rather than for the diagnosis of bacillary dysentery. In contrast with Y. enterocolitica isolates from adults, which were primarily biotype 1A, isolates from children were primarily bioserotype 3/O:3. Most pathogenic isolates from children shared pulsed-field gel electrophoresis patterns with isolates from pigs and dogs, suggesting a possible link between isolates from animals and infections in children. Our findings underscore the need for improved diagnostics for this underestimated pathogen.

Primary cellulitis and cutaneous abscess caused by Yersinia enterocolitica in an immunocompetent host: A case report and literature review

Primary extraintestinal complications caused by Yersinia enterocolitica are extremely rare, especially in the form of skin and soft-tissue manifestations, and little is known about their clinical characteristics and treatments. We presented our case and reviewed past cases of primary skin and soft-tissue infections caused by Y enterocolitica. We report a case of primary cellulitis and cutaneous abscess caused by Y enterocolitica in an immunocompetent 70-year-old woman with keratodermia tylodes palmaris progressiva. She presented to an outpatient clinic with redness, swelling, and pain of the left ring finger and left upper arm without fever or gastrointestinal symptoms 3 days before admission. One day later, ulceration of the skin with exposed bone of the proximal interphalangeal joint of the left ring finger developed, and cefditoren pivoxil was described. However, she was admitted to our hospital due to deterioration of symptoms involving the left finger and upper arm. Cefazolin was initiated on admission, then changed to sulbactam/ampicillin and vancomycin with debridement of the left ring finger and drainage of the left upper arm abscess. Wound culture grew Y enterocolitica serotype O:8 and methicillin-sensitive Staphylococcus aureus. Blood cultures were negative and osteomyelitis was ruled out. Vancomycin was switched to ciprofloxacin, then skin and soft-tissue manifestations showed clear improvement within a few days. The patient received 14 days of ciprofloxacin and oral amoxicillin/clavulanate and has since shown no recurrence. We reviewed 12 cases of primary skin and soft-tissue infections caused by Y enterocolitica from the literature. In several past cases, portal entry involved failure of the skin barrier on distal body parts. Thereafter, infection might have spread to the regional lymph nodes from the ruptured skin. Y enterocolitica is typically resistant to aminopenicillins and narrow-spectrum cephalosporins. In most cases, these inefficient antibiotic agents were initially prescribed, but patient conditions rapidly improved after implementing appropriate therapy and drainage. In addition, primary skin and soft-tissue infections occurred even in patients lacking risk factors. Physicians should consider the rare differential diagnosis of Y enterocolitica infection when seeing patients with deteriorating skin lesions under standard treatment, even if the patient is immunocompetent.

Yersinia enterocolitica Affects Intestinal Barrier Function in the Colon

Infection with Yersinia enterocolitica causes acute diarrhea in early childhood. A mouse infection model presents new findings on pathological mechanisms in the colon. Symptoms involve diarrhea with watery feces and weight loss that have their functional correlates in decreased transepithelial electrical resistance and increased fluorescein permeability. Y. enterocolitica was present within the murine mucosa of both ileum and colon. Here, the bacterial insult was of focal nature and led to changes in tight junction protein expression and architecture. These findings are in concordance with observations from former cell culture studies and suggest a leak flux mechanism of diarrhea.

Mesenteric lymphadenitis caused by Yersinia enterocolitica

Yersiniosis is an acute or chronic, zoonotic disease caused by infection of Gram-negative rods Yersinia enterocolitica. It can be transmitted by the consumption of originally contaminated food products (pork, unpasteurized milk) or secondarily contaminated with animal or vegetable products. The clinical picture of infection may have a variable course is related to the age and physical condition of the patient, or pathogenic properties of microorganisms. Infection caused by Y. enterocolitica can occur in different clinical forms: food poisoning, colitis, mesentric lymphadenitis, erythema nodosum, arthritis, pharyngitis, pneumonia, meningitis, sepsis. The aim of this study was to present a rare case of infection with Y. enterocolitica mesenteric lymph nodes coexistent with appendicitis.

Yersiniosis in Atlantic cod, Gadus morhua (L.), characterization of the infective strain and host reactions

A disease outbreak in farmed Atlantic cod caused by Yersinia ruckeri is reported. Mortality started following vaccination of cod reared in two tanks (A and B). The accumulated mortality reached 1.9% in A and 4.8% in B in the following 30 days when treatment with oxytetracycline was applied. Biochemical and molecular analysis of Y. ruckeri isolates from the cod and other fish species from fresh and marine waters in Iceland revealed a high salinity-tolerant subgroup of Y. ruckeri serotype O1. Infected fish showed clinical signs comparable with those of Y. ruckeri -infected salmonids, with the exception of granuloma formations in infected cod tissues, which is a known response of cod to bacterial infections. Immunohistological examination showed Y. ruckeri antigens in the core of granulomas and the involvement of immune parameters that indicates a strong association between complement and lysozyme killing of bacteria. Experimental infection of cod with a cod isolate induced disease, and the calculated LD50 was 1.7 × 10(4) CFU per fish. The results suggest that yersiniosis can be spread between populations of freshwater and marine fish. Treatment of infected cod with antibiotic did not eliminate the infection, which can be explained by the immune response of cod producing prolonged granulomatous infection.

Yersiniosis in Poland in 2012

AIM

The aim of this study is to assess the epidemiology of yersiniosis in Poland in 2012 compared to previous years.

MATERIAL AND METHODS

We reviewed surveillance data published in the annual bulletin "Infectious diseases and poisonings in Poland" from 2007 to 2012 (MP Czarkowski et al., NIH and GIS) and individual yersiniosis case reports from 2012 sent by the Sanitary-Epidemiological Stations. Additionally, we used data from the Department of Demographic Surveys in Central Statistical Office.

RESULTS

In Poland in 2012 a total of 231 yersiniosis cases were reported including 201 cases of intestinal and 30 cases of extraintestinal yersiniosis; 61.9% of patients were hospitalized. The incidence rate was 0.6 per 100 000 inhabitants. No deaths related to the disease were reported. Intestinal yersiniosis was manifested mostly by following symptoms: diarrhoea (87%), fever (76%), abdominal pain (47%) and vomiting (31%). The most affected group in intestinal infections were children younger than 4 years - 145 cases (72% of all cases). Extraintestinal form of infection was more common than in 2011 (19 cases) and usually involved symptoms from the osteoarticular system, noted in 90% of patients. Similarly to the previous year (2011) most cases of yersiniosis were reported from Mazowieckie province (103), no case has been reported from Świętokrzyskie province. Serological types of Yersinia enterocolitica were identified in 120 cases (52%): serotype O3 (96.7%), O8 (2.5%) and O9 (<1%). There were two household outbreaks. In comparison to previous years the total number of cases caused by serotype O8 has significantly decreased - from 55 cases in 2011 to 3 cases in 2012.

CONCLUSIONS

A large percentage (48%) of unknown Yersinia serotypes is a consequence, that physicians do not always request serotyping in routine diagnostics. Reporting cases of extraintestinal yersiniosis from only few provinces may suggest that the real number of infections remains underreported.

Post-transcriptional regulation of gene expression in Yersinia species

Proper regulation of gene expression is required by bacterial pathogens to respond to continually changing environmental conditions and the host response during the infectious process. While transcriptional regulation is perhaps the most well understood form of controlling gene expression, recent studies have demonstrated the importance of post-transcriptional mechanisms of gene regulation that allow for more refined management of the bacterial response to host conditions. Yersinia species of bacteria are known to use various forms of post-transcriptional regulation for control of many virulence-associated genes. These include regulation by cis- and trans-acting small non-coding RNAs, RNA-binding proteins, RNases, and thermoswitches. The effects of these and other regulatory mechanisms on Yersinia physiology can be profound and have been shown to influence type III secretion, motility, biofilm formation, host cell invasion, intracellular survival and replication, and more. In this review, we discuss these and other post-transcriptional mechanisms and their influence on virulence gene regulation, with a particular emphasis on how these processes influence the virulence of Yersinia in the host.

The first imported human case of Yersinia pseudotuberculosis serotype O1 septicemia presents with acute appendicitis-like syndrome in Taiwan

Human nonplague yersiniosis occurs more commonly in temperate regions than in tropical or subtropical regions. In Taiwan, which is located in a subtropical region of Southeast Asia, only environmental isolates and human infection of Yersinia enterocolitica were reported, but a human case of Y. pseudotuberculosis infection had not been identified. We report the first person with Y. pseudotuberculosis serotype O1 septicemia who presented with acute appendicitis-like syndrome and who was probably contracted the infection via ingestion of raw foods in a barbecue restaurant in Japan.

Occurrence of infectious fish diseases in fish farms in northern Finland

A total of 47 fish located in 10 lake and river systems in northern Finland were examined for furunculosis, enteric redmouth diseases (ERM), viral fish diseases and the parasite Gyrodactylus salaris. Furunculosis was found in 2 fish farms in different watercourses, ERM in 8 fish farms in 3 watercourses and viral diseases were not found at all. G. salaris was looked for only in salmon and rainbow trout and was found in both species in 3 farms belonging to 2 watercourses.