High Mortality Events Research Articles

Clinical-epidemiological factors associated with mortality in patients diagnosed with acute heart failure

Introduction: acute heart failure is a high mortality event in the population that may depend on various clinical and epidemiological factors.Objective: determine the clinical-epidemiological factors associated with the mortality of patients diagnosed with acute heart failure.Method: a cross-sectional descriptive study was carried out with the purpose of determining the clinical-epidemiological factors associated with the mortality of patients with a diagnosis of acute heart failure, admitted to the cardiology ward of the “Saturnino Lora Torres” Provincial Hospital of Santiago de Cuba in the period from January 2021 to December 2023. The universe consisted of 454 patients, from whom a sample was taken (n=70) and divided into two groups: deceased and alive. The Chi Square value (x2) was estimated to determine the statistical association. Results: clinical-epidemiological factors associated with mortality in patients diagnosed with acute heart failure include age over 80 years, male sex, history of arterial hypertension and diabetes mellitus, presentation as acute coronary syndrome, as well as less than 3 days of hospital stay.Conclusions: the clinical-epidemiological factors of the patients studied were very similar to those described in the bibliography consulted and despite the multiple protocols and guidelines implemented, in-hospital mortality remains high.

Molecular Characterization of a Clade 2.3.4.4b H5N1 High Pathogenicity Avian Influenza Virus from a 2022 Outbreak in Layer Chickens in the Philippines.

H5 subtype high-pathogenicity avian influenza (HPAI) viruses continue to devastate the poultry industry and threaten food security and public health. The first outbreak of H5 HPAI in the Philippines was reported in 2017. Since then, H5 HPAI outbreaks have been reported in 2020, 2022, and 2023. Here, we report the first publicly available complete whole-genome sequence of an H5N1 high-pathogenicity avian influenza virus from a case in Central Luzon. Samples were collected from a flock of layer chickens exhibiting signs of lethargy, droopy wings, and ecchymotic hemorrhages in trachea with excessive mucus exudates. A high mortality rate of 96-100% was observed within the week. Days prior to the high mortality event, migratory birds were observed around the chicken farm. Lungs, spleen, cloacal swabs, and oropharyngeal-tracheal swabs were taken from two chickens from this flock. These samples were positive in quantitative RT-PCR assays for influenza matrix and H5 hemagglutinin (HA) genes. To further characterize the virus, the same samples were subjected to whole-virus-genome amplification and sequencing using the Oxford Nanopore method with mean coverages of 19,190 and 2984, respectively. A phylogenetic analysis of the HA genes revealed that the H5N1 HPAI virus from Central Luzon belongs to the Goose/Guangdong lineage clade 2.3.4.4b viruses. Other segments also have high sequence identity and the same genetic lineages as other clade 2.3.4.4b viruses from Asia. Collectively, these data indicate that wild migratory birds are the likely source of H5N1 viruses from the 2022 outbreaks in the Philippines. Thus, biosecurity practices and surveillance for HPAI viruses in both domestic and wild birds should be increased to prevent and mitigate HPAI outbreaks.

Changes in Human Vulnerability to Flood and Landslide: Evidences from Historical Data

Human impact by floods and landslides (FLs) is a significant concern, necessitating a deeper understanding to implement effective reduction measures, in line with the Sendai Framework for Disaster Risk Reduction’s goal to reduce disaster mortality between 2020 and 2030. This study examines the evolution of human interaction with FLs over the past 70 years in Calabria, Italy. By systematically analyzing regional newspapers and historical archives from 1951–1960 and 2011–2020, a database was created documenting fatalities, injuries, and the involvement of people in FL incidents. For each victim, the database includes demographic details, accident time and place, circumstances of death or injury, and whether the victim’s behavior was hazardous or protective. Results indicate a drastic reduction in both the total number of fatalities (196 versus 20) and high mortality events from 1951–1960 to 2011–2020 (6 versus 1). However, the number of people involved in incidents has increased (202 versus 1102), although this may be partly due to improved dissemination of information. Changes in population habits and the construction of more robust houses have significantly reduced high-fatality events, enhancing security. The study highlights the importance of data collection for developing locally tailored risk reduction strategies, increasing community resilience by addressing specific vulnerabilities and strengths.

First Report of Aeromonas schubertii Infection in Striped Snakehead Channa striata (Bloch, 1793) Fingerlings in Malaysia

Striped snakehead fingerlings Channa striata reared in a concrete pond with size 13.5 m3 (3 m ´ 3 m ´ 1.5 m) in a hatchery farm, in Labu, Negeri Sembilan, Malaysia had more than 70% mortality. The pond contained 1500 fingerlings of 5–7 cm in total length (TL). The purpose of this study was to investigate the high mortality event on the farm as part of a veterinary diagnostics service. Clinical signs observed were skin discoloration, lethargy, and anorexia. Necropsy was performed in 10 fish with gross lesions of 1–2 mm and multiple whitish nodules in the abdominal organs and most notably in the liver, and kidney. Following necropsy, bacteriology samples from the kidney and liver were inoculated onto Tryptic Soy Agar (TSA) and Blood Agar (BA). Pure colonies were observed and were Gram-negative with short rod morphology. The full-length 16S rRNA gene was amplified from the pure colonies followed by sequencing using the Nanopore MinION™ (Oxford Nanopore, UK). The isolated strain was identified as Aeromonas schubertii based on the assembled 16S rRNA sequence showing nucleotide identity of 99.73% (top hit) to A. schubertii (GenBank Accession: NR_037014.2) while only a nucleotide identity of 97.55% was observed against Aeromonas hydrophila (GenBank Accession: NR_119190.1-), respectively. Histopathological examination from the liver, kidney, spleen, and intestine revealed granulomatous nephritis, and degeneration of tubular epithelium, with granulomatous hepatitis, splenitis, and enteritis. The prognosis of this case was grave. No treatment was given as the owner had decided to dispose of all current stock. This is the first A. schubertii infection in C. striata described in Malaysia. The findings of the present study may serve as a reference for similar cases in C. striata in the future so rapid diagnosis and treatment can be made if required.

Genomic characterization of Streptococcus equi subspecies zooepidemicus from a 2021 outbreak in Indiana with increased sow mortality.

This study highlights a Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) strain isolated from an outbreak in Indiana, which resulted in mortality events among a swine herd in 2021. The Indiana outbreak strain was found to be genetically and phylogenetically distant to a strain isolated from the 2019 outbreaks in Ohio and Tennessee, which caused high swine mortality. We also discovered multiple unique genetic features in the Indiana outbreak strain, including distinct S. zooepidemicus genomic islands, and notable S. zooepidemicus virulence genes-many of which could serve as biomarkers for the diagnosis of this strain. These findings provide significant insights into monitoring and potentially preventing severe outbreaks caused by the Indiana outbreak strain in the future.

Assessment of flood mortality indices in a Mediterranean framework: A comparative analysis between western Algeria and southern Italy

Assessment of flood mortality indices in a Mediterranean framework: A comparative analysis between western Algeria and southern Italy

Increased Fungal Infection Mortality Induced by Concurrent Viral Cellular Manipulations.

Certain respiratory fungal pathogen mono-infections can cause high mortality rates. Several viral pathogen mono-infections, including influenza viruses and coronaviruses including SARS-CoV-2, can also cause high mortality rates. Concurrent infections by fungal pathogens and highly manipulative viral pathogens can synergistically interact in the respiratory tract to substantially increase their mortality rates. There are at least five viral manipulations which can assist secondary fungal infections. These viral manipulations include the following: (1) inhibiting transcription factors and cytokine expressions, (2) impairing defensive protein expressions, (3) inhibiting defenses by manipulating cellular sensors and signaling pathways, (4) inhibiting defenses by secreting exosomes, and (5) stimulating glucocorticoid synthesis to suppress immune defenses by inhibiting cytokine, chemokine, and adhesion molecule production. The highest mortality respiratory viral pandemicsup to now have had substantially boosted mortalities by inducing secondary bacterial pneumonias. However, numerous animal species besides humans are also carriers of endemic infections by viral and multidrug-resistant fungal pathogens. The vast multi-species scope of endemic infection opportunities make it plausible that the pro-fungal manipulations of a respiratory virus can someday evolve to enable a very high mortality rate viral pandemic inducing multidrug-resistant secondary fungal pathogen infections. Since such pandemics can quickly spread world-wide and outrun existing treatments, it would be worthwhile to develop new antifungal treatments well before such a high mortality event occurs.

Projecting fish community responses to dam removal – Data-limited modeling

Projecting fish community responses to dam removal – Data-limited modeling

Pathogenicity of two lineages of infectious hematopoietic necrosis virus (IHNV) to farmed rainbow trout (Oncorhynchus mykiss) in South Korea

In May 2015, a high mortality event in farmed rainbow trout occurred in Jeollabuk-do province in Korea. Histopathological analysis revealed necrosis in the kidney, liver, branchial arch, and gills of moribund fish, and infectious hematopoietic necrosis virus (IHNV) was detected in the lesions by immunohistochemistry. Cytopathic effects were observed in EPC, FHM, and RTG-2 cell lines after inoculation with kidney and spleen tissues and IHNV was detected by reverse transcription polymerase chain reaction (PCR). The amplified PCR product was sequenced, and phylogenetic analysis placed IHNV in the JRt Nagano group. Both in vivo and in vitro trials were performed to compare the virulence properties between RtWanju15 isolate, which causes 100% mortality in imported fry, and a previous isolate RtWanju09 of the JRt Shizuoka group isolated from eggs of healthy broodfish. In vivo challenge with high dose on specific pathogen free (SPF) rainbow trout fry performed in Denmark with isolates RtWanju09, RtWanju15 and DF04/99 isolates showed a survival rates of 60%, 37.5% and 52.5% (average), respectively without statistical difference. The replication efficiency of the two isolates in the in vitro challenge was similar.

The Occurrence of Catastrophic Multiple-Fatality Flash Floods in the Eastern Mediterranean Region

Despite recent technological advances, many parts of the world continue to experience flood disasters accompanied by significant loss of human lives. Understanding how frequent these deadly catastrophes are creates many uncertainties, especially in areas where disaster records are scarce or have short timeframes. It is, however, very important from a preparedness and civil protection standpoint to assess the frequency of such high-mortality events, especially considering the threat of climate change. This work develops a high-mortality flood event database using multiple international sources, covering a relatively long time window (1882–2021), exploring the deadliest floods in the Eastern Mediterranean region, and examining their seasonal distribution, their temporal evolution, and their basic spatial patterns. The study identifies 132 flash flood events (causing ≥10 fatalities) with a return period of only 1.56 years. Additionally, higher-magnitude events (>85th percentile) were found to be less common but still not very rare (return period = 9.1 years). The number of events shows an increase in recent decades, while seasonal and spatial patterns were identified as well. Overall, the findings provide a foundation for understanding how common catastrophic flood events are in the region, are beneficial for policymakers and relevant professionals, and are an important stepping stone towards a complete understanding of how extreme floods have changed in the last century or will change in the near future.

Implementation evaluation of a rapid response system in a regional emergency department: a dual-methods study using the behaviour change wheel

Failure to recognise and respond to clinical deterioration is a major cause of high mortality events in emergency department (ED) patients. Whilst there is substantial evidence that rapid response teams reduce hospital mortality, unplanned intensive care admissions, and cardiac arrests on in-patient settings, the use of rapid response teams in the ED is variable with poor integration of care between emergency and specialty/intensive care teams. The aim of this study was to evaluate uptake and impact of a rapid response system on recognising and responding to deteriorating patients in the EDand identify implementation factors and strategies to optimise future implementation success. A dual-methods design was used to evaluate an ED Clinical Emergency Response System (EDCERS) protocol implemented at a regional Australian ED in June 2019. A documentation audit was conducted on patients eligible for the EDCERS during the first 3 months of implementation. Quantitative data from documentation audit were used to measure uptake and impact of the protocol on escalation and response to patient deterioration. Facilitators and barriers to the EDCERS uptake were identified via key stakeholder engagement and consultation. An implementation plan was developed using the Behaviour Change Wheel for future implementation. The EDCERS was activated in 42 (53.1%) of 79 eligible patients. The specialty care team were more likely to respond when the EDCERS was activated than when there was no activation ([n=40, 50.6%] v [n=26, 32.9%], p=0.01). Six facilitators and nine barriers to protocol uptake were identified. Twenty behaviour change techniques were selected and informed the development of a theory-informed implementation plan. Implementation of the EDCERS protocol resulted in high response rates from specialty and intensive care staff. However, overall uptake of the protocol by emergency staff was poor. This study highlights the importance of understanding facilitators and barriers to uptake prior to implementing a new intervention.

P384 SUDDEN CARDIAC ARREST: LET’S LOOK BEYOND CORONAROPATHY

Abstract Introduction Sudden cardiac arrest (SCA) is a high mortality event. Up to 70% of SCAs are caused by an acute coronary syndrome; nevertheless, it is essential to consider also non–ischemic causes while evaluating a post–SCA patient. Clinical Case A 68–year–old male patient with history of hypertension and dyslipidemia, presenting to the emergency room (ER) for syncope. While waiting in the ER, another sincopal episode happened and ventricular fibrillation was detected, therefore he was treated with a DC shock. At the ECG record after SCA, any acute alteration was seen. At the blood tests, an early rise of myocardial injury markers was found. At bedside echocardiography, a slight apical hypokinesia with hypertrabeculation was reported. Hence, coronarography was performed and a multivasal ateromasic coronaropathy was treated with angioplasty and drug–eluting stenting of left main artery, left anterior descending artery and left circumflex artery. In the following days, other ventricular tachyarrhythmias episodes happened and were treated with DC shocks. Due to ventricular arrhythmias relapses and echocardiographic findings, a cardiac MRI was performed, showing subepicardial fatty infiltration in the mid–apical lateral wall with parietal bulging suggesting left ventricle arrhythmogenic cardiomyopathy. So, a cardiac defibrillator was implanted in secondary prevention. Genetic analysis was run and reported a VUS mutation on RYR2 gene, still under evaluation as a possible cause for the clinical events. Conclusions The present clinical case shows that many causes may lead to SCA. Our patient experienced syncopal episodes related to ventricular arrhythmias and an arrhythmic storm which were most likely caused by an ischemic event on the base of an undiagnosed left ventricle arrhythmogenic cardiomyopathy.

Leveraging Machine Learning and Geo-Tagged Citizen Science Data to Disentangle the Factors of Avian Mortality Events at the Species Level

Abrupt environmental changes can affect the population structures of living species and cause habitat loss and fragmentations in the ecosystem. During August–October 2020, remarkably high mortality events of avian species were reported across the western and central United States, likely resulting from winter storms and wildfires. However, the differences of mortality events among various species responding to the abrupt environmental changes remain poorly understood. In this study, we focused on three species, Wilson’s Warbler, Barn Owl, and Common Murre, with the highest mortality events that had been recorded by citizen scientists. We leveraged the citizen science data and multiple remotely sensed earth observations and employed the ensemble random forest models to disentangle the species responses to winter storm and wildfire. We found that the mortality events of Wilson’s Warbler were primarily impacted by early winter storms, with more deaths identified in areas with a higher average daily snow cover. The Barn Owl’s mortalities were more identified in places with severe wildfire-induced air pollution. Both winter storms and wildfire had relatively mild effects on the mortality of Common Murre, which might be more related to anomalously warm water. Our findings highlight the species-specific responses to environmental changes, which can provide significant insights into the resilience of ecosystems to environmental change and avian conservations. Additionally, the study emphasized the efficiency and effectiveness of monitoring large-scale abrupt environmental changes and conservation using remotely sensed and citizen science data.

An outbreak of systemic chlamydiosis in farmed American alligators (Alligator mississippiensis)

Chlamydia spp are reported to causes systemic disease in a variety of hosts worldwide including few reports in crocodilians. Disease presentations vary from asymptomatic to fulminant disease, some of which are zoonotic. The aim of this study was to describe the pathological, immunohistochemical, and molecular findings associated with the occurrence of a previously unreported Chlamydia sp infection causing a major mortality event in farmed American alligators (Alligator mississippiensis). The outbreak presented with sudden death in juvenile alligators mainly associated with necrotizing hepatitis and myocarditis, followed by the occurrence of conjunctivitis after the initial high mortality event. The widespread inflammatory lesions in multiple organs correlated with intralesional chlamydial organisms identified via immunohistochemistry and confirmed by 23S rRNA-specific real-time quantitative polymerase chain reaction (qPCR) for Chlamydiaceae bacteria. By sequencing and phylogenetic analysis of the OmpA gene, this uncultured Chlamydia sp grouped closely with Chlamydia poikilothermis recently described in snakes. This study highlights the significance of such outbreaks in farmed populations. Enhanced epidemiological monitoring is needed to gain further insight into the biology of Chlamydia sp in alligators, disease dynamics, risk factors, and role of carrier animals.

Associations between Weather, Air Quality and Moderate Extreme Cancer-Related Mortality Events in Augsburg, Southern Germany.

While many authors have described the adverse health effects of poor air quality and meteorological extremes, there remain inconsistencies on a regional scale as well as uncertainty about the single and joint effects of atmospheric predictors. In this context, we investigated the short-term impacts of weather and air quality on moderate extreme cancer-related mortality events for the urban area of Augsburg, Southern Germany, during the period 2000–2017. First, single effects were uncovered by applying a case-crossover routine. The overall impact was assessed by performing a Mann–Whitney U testing scheme. We then compared the results of this procedure to extreme noncancer-related mortality events. In a second step, we found periods with contemporaneous significant predictors and carried out an in-depth analysis of these joint-effect periods. We were interested in the atmospheric processes leading to the emergence of significant conditions. Hence, we applied the Principal Component Analysis to large-scale synoptic conditions during these periods. The results demonstrate a strong linkage between high-mortality events in cancer patients and significantly above-average levels of nitrogen dioxide (NO2) and particulate matter (PM2.5) during the late winter through spring period. These were mainly linked to northerly to easterly weak airflow under stable, high-pressure conditions. Especially in winter and spring, this can result in low temperatures and a ground-level increase and the accumulation of air pollution from heating and traffic as well as eastern lateral advection of polluted air. Additionally, above-average temperatures were shown to occur on the days before mortality events from mid-summer through fall, which was also caused by high-pressure conditions with weak wind flow and intense solar radiation. Our approach can be used to analyse medical data with epidemiological as well as climatological methods while providing a more vivid representation of the underlying atmospheric processes.

Replication of Streptococcus equi subspecies zooepidemicus infection in swine

Streptococcus equi subspecies zooepidemicus (SEZ) is a commensal bacterium of horses and causes infections in mammalian species, including humans. Historically, virulent strains of SEZ caused high mortality in pigs in China and Indonesia, while disease in the U.S. was infrequent. More recently, high mortality events in sows were attributed to SEZ in North America. The SEZ isolates from these mortality events have high genetic similarity to an isolate from an outbreak in China. Taken together, this may indicate SEZ is an emerging threat to swine health. To generate a disease model and evaluate the susceptibility of healthy, conventionally raised pigs to SEZ, we challenged sows and five-month-old pigs with an isolate from a 2019 mortality event. Pigs were challenged with a genetically similar guinea pig isolate or genetically distinct horse isolate to evaluate comparative virulence. The swine isolate caused severe systemic disease in challenged pigs with 100 % mortality. Disease manifestation in sows was similar to field reports: lethargy/depression, fever, reluctance to rise, and high mortality. The guinea pig isolate also caused severe systemic disease; however, most five-month-old pigs recovered. In contrast, the horse isolate did not cause disease and was readily cleared from the respiratory tract. In conclusion, we were able to replicate disease reported in the field. The results indicate differences in virulence between isolates, with the highest virulence associated with the swine isolate. Additionally, we generated a challenge model that can be used in future research to evaluate virulence factors and disease prevention strategies.

Dietary Phospholipids Enhance Growth Performance and Modulate Cold Tolerance in Meagre (Argyrosomus regius) Juveniles.

Simple SummaryMeagre is a target species to diversify marine aquaculture in Europe due to its high growth rates and an excellent nutritional profile. Nevertheless, this species is highly sensitive to low temperatures. The objective of this study was to evaluate the effect of dietary phospholipid (PL) levels on growth and cold tolerance. Animals fed with a PL-enriched diet grew faster and significantly reduced the risk of death and increased the lethal doses 50 and 90 without modifying the average temperature at death. Regarding lipid profiles, the cold challenge promoted a general fatty acid accumulation in the liver that was attenuated in fish fed with the PL-enriched diet preventing the negative effect of a fatty liver.Meagre (Argyrosomus regius) is a fast-growing species currently produced in aquaculture. This species is highly sensitive to low environmental temperatures which results in high mortality events during production cycles. In this study, the effects of dietary phospholipids (PLs) on growth and cold tolerance were evaluated. For this purpose, control (CTRL) and PL-enriched diets (three-fold higher levels than CTRL) were supplied to meagre juveniles (12.9 ± 2.5 g) for 60 days, and growth was determined using a longitudinal approach. Weight gaining and SGR reduction were significantly different between dietary treatments. Animals fed with the PL-enriched diet were 4.1% heavier and grew 3.2% faster than those fed with the CTRL diet. Survival was higher than 98% in both groups. After finishing the growth trial, animals were submitted to two cold challenges and cold tolerance was evaluated as temperature at death (Tdeath), risk to death and lethal doses (LD) 50 and 90 using the cumulative degree cooling hours 6 h (CD6H). Tdeath ranged between 7.54 and 7.91 °C without statistical differences between dietary treatments. However, risk to death was significantly smaller (0.91-fold lower) and LD50 and LD90 were higher in animals fed with the PL-enriched than those supplied the CTRL diet. To assess the fatty acid (FA) composition of liver and brain in animals fed both diets after a cold challenge, FA profiles were determined in juveniles maintained at 14 °C and challenged at 7 °C. FA amounts increased in the liver of animals challenged at 7 °C. In contrast, several FAs reduced their levels in the PL-enriched diet with respect to CTRL indicating that these animals were able to mobilize efficiently lipids from this organ mitigating the negative effects of lipid accumulation during the cold challenge. In brain, the PL-enriched diet increased DHA level during the cold shock indicating a role in maintaining of brain functions. These results open a new research line that could improve the cold tolerance of meagre through dietary supplementation before winter.

Seasonal composition of immature germ cells in the Yesso scallop identified by vasa-like gene (my-vlg) and protein expression, with evidence of irregular germ cell differentiation accompanied with a high mortality event

Abstract The objective of this study was to understand germ cell renewal and differentiation in the Yesso scallop Mizuhopecten yessoensis throughout its reproductive cycle. First, we identified a Yesso scallop vasa-like gene (my-vlg) as a useful marker for immature germ cells. Both in situ hybridization and immunohistochemistry confirmed the germ-cell-specific expression of my-vlg and protein, especially in spermatogonia, oogonia, and primary oocytes. An immunohistochemistry with anti my-Vasa antibody further revealed that immature germ cells (i.e., gonial cells) are located on the basal membrane of germinal acini and are present during all maturational stages in both the ovary and testis. Quantitative analysis revealed a shift in germ cell number and change in germ cell composition associated with the gonadal maturation process, indicating a persistence of my-Vasa-positive immature germ cells throughout the reproductive cycle. In the testis, a gradual increase in my-Vasa-positive immature germ cells was seen from November to March. In the ovary, an increase in my-Vasa-positive immature germ cells was observed from September until November. We also used gonad index (GI) to summarize and evaluate the maturational changes of scallops in the 2018 generation. This generation had a background of relatively high mortality and shell deformity in the previous year, and we noted a small irregular peak of GI in the summer (July–August). We confirmed that the germ cells proliferating in the summer were my-Vasa-positive, implying that germ cell developmental progression occurred in the 2018 generation during the non-reproductive period. In conclusion, this study establishes an immuno-identification method for my-Vasa-positive immature germ cells and reveals germ cell composition in a bivalve species throughout its reproductive cycle. These results will support monitoring techniques for gonad development and the reproductive status of brood stock in shellfish seed production hatcheries.

Metabolomics investigation of summer mortality in New Zealand Greenshell™ mussels (Perna canaliculus)

Increasing water temperatures due to climate change have resulted in more frequent high mortality events of New Zealand Greenshell™ mussels (Perna canaliculus Gmelin 1791). These events have significant impacts within mussel farms which support a major shellfish industry for New Zealand. The present study investigates metabolic responses of farmed mussels during a summer mortality event in order to identify health impacts and elucidate mechanistic effects of external stressors on mussels. A gas chromatography-mass spectrometry (GC-MS)-based metabolomics approach was used to identify metabolic perturbations and flow cytometry assays were used to assess viability, oxidative stress and apoptosis of haemocytes from healthy and unhealthy mussels during a summer mortality event. The results showed significantly higher mortality and apoptosis of haemocytes in unhealthy mussels compared to healthy mussels. Reactive oxygen species (ROS) production, which is an indicator of oxidative stress was very high in both mussel groups, but no differences were observed between the two mussel groups. Metabolomics revealed alterations of many metabolites in both haemolymph and hepatopancreas (digestive gland) of unhealthy mussels compared to healthy mussels, reflecting perturbations in several molecular pathways, including energy metabolism, amino acid metabolism, protein degradation/tissue damage and oxidative stress. An increased level of itaconic acid which is an antimicrobial metabolite and biomarker of pathogen infection was observed in haemolymph, but not in hepatopancreas samples. This investigation provides the first detailed metabolic characterization of mussel immune responses to a summer mortality event and illustrates the benefits of using an integrated metabolomics and flow cytometry workflow for mussel health assessment and biomarker identification for summer mortality early detection.

Genetic characterization of Streptococcus equi subspecies zooepidemicus associated with high swine mortality in the United States.

High mortality events due to Streptococcus equi subspecies zooepidemicus (Streptococcus zooepidemicus) in swine have not previously been reported in the United States. In September and October 2019, outbreaks with swine mortality up to 50% due to S.zooepidemicus septicaemia were reported in Ohio and Tennessee. Genomic epidemiological analysis revealed that the eight outbreak isolates were clustered together with ATCC 35246, a Chinese strain caused outbreaks with high mortality, also closely related to three isolates from human cases from Virginia, but significantly different from an outbreak-unrelated swine isolate from Arizona and most isolates from other animal species. Comparative genomic analysis on two outbreak isolates and another outbreak-unrelated isolate identified several genomic islands and virulence genes specifically in the outbreak isolates only, which are likely associated with the high mortality observed in the swine population. These findings have implications for understanding, tracking and possibly preventing diseases caused by S.zooepidemicus in swine.