Dairy cows inoculated with highly pathogenic avian influenza virus H5N1.

Highly pathogenic avian influenza (HPAI) H5N1 hemagglutinin clade 2.3.4.4b was detected in the United States in 2021. These HPAI viruses caused mortality events in poultry, wild birds, and wild mammals. On March 25, 2024, HPAI H5N1 clade 2.3.4.4b was confirmed in a dairy cow in Texas in response to a multi-state investigation into milk production losses.1 Over 200 positive herds were identified in 14 U.S. states. The case description included reduced feed intake and rumen motility in lactating cows, decreased milk production, and thick yellow milk.2,3 The diagnostic investigation revealed viral RNA in milk and mammary tissue with alveolar epithelial degeneration and necrosis and positive immunoreactivity of glandular epithelium. A single transmission event, likely from birds, was followed by limited local transmission and onward horizontal transmission of H5N1 clade 2.3.4.4b genotype B3.13.4 We sought to experimentally reproduce infection with genotype B3.13 in Holstein yearling heifers and lactating cows. Heifers were inoculated by aerosol respiratory route and cows by intramammary route. Clinical disease was mild in heifers, but infection was confirmed by virus detection, lesions, and seroconversion. Clinical disease in lactating cows included decreased rumen motility, changes to milk appearance, and production losses. Infection was confirmed by high levels of viral RNA detected in milk, virus isolation, lesions in mammary tissue, and seroconversion. This study provides the foundation to investigate additional routes of infection, pathogenesis, transmission, and intervention strategies.

Human Topoisomerase IIα Promotes Chromatin Condensation Via a Phase Transition.

Topoisomerase II (topo II) enzymes are essential enzymes known to resolve topological entanglements during DNA processing. Curiously, while yeast expresses a single topo II, humans express two topo II isozymes, topo IIα and topo IIß, which share a similar catalytic domain but differ in their intrinsically disordered C-terminal domains (CTDs). During mitosis, topo IIα and condensin I constitute the most abundant chromosome scaffolding proteins essential for chromosome condensation. However, how topo IIα enables this function is poorly understood. Here, we discovered a new and functionally distinct role for human topo IIα - it condenses DNA and chromatin at a low topo IIα concentration (100 pM or less) during a polymer-collapse phase transition. The removal of the topo IIα CTDs effectively abolishes its condensation ability, indicating that the condensation is mediated by the CTDs. Although topo IIß can also perform condensation, it is about 4-fold less effective. During the condensation, topo IIα-DNA condensates form along DNA, working against a DNA tension of up to 1.5 pN, greater than that previously reported for yeast condensin. In addition, this condensation does not require ATP and thus is independent of topo IIα's catalytic activity. We also found that condensation and catalysis can concurrently proceed with minimal mutual interference. Our findings suggest topo IIα may directly participate in chromosome condensation during mitosis.

Indication for endoscopic retrograde cholangiopancreatography and development of hemorrhage: a systematic review and meta-analysis.

Background: Hemorrhage is a common complication associated with endoscopic retrograde cholangiopancreatography (ERCP), usually following sphincterotomy. Studies investigating risk factors for hemorrhage including ERCP indication have been conflicting. Therefore, we conducted a systematic review and meta-analysis to characterize the association between the ERCP indication and hemorrhage. Methods: Database searches of MEDLINE, EMBASE, and CENTRAL were conducted to identify articles up to December 12, 2022. Randomized trials or observational studies of adult patients undergoing ERCP were included. Quality assessment using the Cochrane Risk of Bias 2.0 and Newcastle-Ottawa Scales for randomized trials and observational studies respectively was conducted. A random effects meta-analysis generating pooled odds ratios with 95% confidence intervals was conducted. Results: A total of 1323 articles were identified of which 26 were included with up to 25 121 subjects in each meta-analysis. Rates of sphincterotomy (median 96.1%; IQR 60.5-100), biliary stent placement (median 17.2%; IQR 10.6-34.4), antiplatelet use (median 6.0%; IQR 0-10.1), and anticoagulant use (median 1.9%; IQR 0%-3.2%) varied among included studies. No specific indication was associated with hemorrhage in the meta-analyses including cholangitis (OR 1.50; 95% CI 0.97-2.32), choledocholithiasis/biliary stone (OR 1.28; 95% CI 0.95-1.73), malignancy (OR 0.97; 95% CI 0.66-1.42), sphincter of Oddi dysfunction (OR 1.32; 95% CI 0.72-2.40), and acute pancreatitis (OR 0.81; 95% CI 0.44-1.49). Conclusions: Overall, no indication was significantly associated with increased hemorrhage following ERCP. However, given limitations in the included studies (ie, significant heterogeneity between studies), additional research to better characterize these associations is needed. Protocol Registration Number: PROSPERO (CRD42021283978).

Pathogen Detection in Early Phases of Experimental Bovine Tuberculosis.

Bovine tuberculosis is caused by Mycobacterium bovis, a member of the M. tuberculosis complex of mycobacterial species that cause tuberculosis in humans and animals. Diagnosis of bovine tuberculosis has relied on examinations of cell-mediated immune responses to M. bovis proteins using tuberculin skin testing and/or interferon gamma release assays. Even when using these methods, disease detection during the earliest phases of infection has been difficult, allowing a window for cattle-to-cattle transmission to occur within a herd. Alternative means of diagnosis could include methods to detect M. bovis or M. bovis DNA in bodily fluids such as nasal secretions, saliva, or blood. During the first 8 weeks after experimental aerosol infection of 18 calves, M. bovis DNA was detected in nasal swabs from a small number of calves 5, 6, and 8 weeks after infection and in samples of saliva at 1, 7, and 8 weeks after infection. However, at no time could culturable M. bovis be recovered from nasal swabs or saliva. M. bovis DNA was not found in blood samples collected weekly and examined by real-time PCR. Interferon gamma release assays demonstrated successful infection of all calves, while examination of humoral responses using a commercial ELISA identified a low number of infected animals at weeks 4-8 after infection. Examination of disease severity through gross lesion scoring did not correlate with shedding in nasal secretions or saliva, and calves with positive antibody ELISA results did not have more severe disease than other calves.

CRISPR-prime editing, a versatile genetic tool to create specific mutations with a single nucleotide resolution in Leptospira.

Leptospirosis, caused by pathogenic bacteria from the genus Leptospira, is a global zoonosis responsible for more than one million human cases and 60,000 deaths annually. The disease also affects many domestic animal species. Historically, genetic manipulation of Leptospira has been difficult to perform, resulting in limited knowledge on pathogenic mechanisms of disease and the identification of virulence factors. The application of CRISPR/Cas9 and its variations have helped fill these gaps but the generation of knockout mutants remains challenging because double-strand breaks (DSBs) inflicted by Cas9 nuclease are lethal to Leptospira cells. The novel CRISPR prime editing (PE) strategy is the first precise genome-editing technology that allows deletions, insertions, and base substitutions without introducing DSBs. This revolutionary technique utilizes a nickase Cas9 that cleaves a single strand of DNA, coupled with an engineered reverse transcriptase and a modified single-guide RNA (termed prime editing guide RNA) containing an extended 3' end with the desired edits. We demonstrate the application of CRISPR-PE in both saprophytic and pathogenic Leptospira from multiple species and serovars by introducing deletions or insertions into target DNA with a remarkable precision of just one nucleotide. Additionally, we demonstrate the ability to genetically manipulate Leptospira borgpetersenii, a prevalent pathogenic species of humans, domestic cattle, and wildlife animals. Rapid plasmid loss by mutated strains in liquid culture allows for the generation of knockout strains without selective markers, which can be readily used to elucidate virulence factors and develop optimized bacterin and/or live vaccines against leptospirosis.IMPORTANCELeptospirosis is a geographically widespread bacterial zoonosis. Genetic manipulation of pathogenic Leptospira spp. has been laborious and difficult to perform, limiting our ability to understand how leptospires cause disease. The application of the CRISPR/Cas9 system to Leptospira enhanced our ability to generate knockdown and knockout mutants; however, the latter remains challenging. Here, we demonstrate the application of the CRISPR prime editing technique in Leptospira, allowing the generation of knockout mutants in several pathogenic species, with mutations comprising just a single nucleotide resolution. Notably, we generated a mutant in the Leptospira borgpetersenii background, a prevalent pathogenic species of humans and cattle. Our application of this method opens new avenues for studying pathogenic mechanisms of Leptospira and the identification of virulence factors across multiple species. These methods can also be used to facilitate the generation of marker-less knockout strains for updated and improved bacterin and/or live vaccines.

The translocation activity of Rad54 reduces crossover outcomes during homologous recombination.

Homologous recombination (HR) is a template-based DNA double-strand break repair pathway that requires the selection of an appropriate DNA sequence to facilitate repair. Selection occurs during a homology search that must be executed rapidly and with high fidelity. Failure to efficiently perform the homology search can result in complex intermediates that generate genomic rearrangements, a hallmark of human cancers. Rad54 is an ATP dependent DNA motor protein that functions during the homology search by regulating the recombinase Rad51. How this regulation reduces genomic exchanges is currently unknown. To better understand how Rad54 can reduce these outcomes, we evaluated several amino acid mutations in Rad54 that were identified in the COSMIC database. COSMIC is a collection of amino acid mutations identified in human cancers. These substitutions led to reduced Rad54 function and the discovery of a conserved motif in Rad54. Through genetic, biochemical and single-molecule approaches, we show that disruption of this motif leads to failure in stabilizing early strand invasion intermediates, causing increased crossovers between homologous chromosomes. Our study also suggests that the translocation rate of Rad54 is a determinant in balancing genetic exchange. The latch domain's conservation implies an interaction likely fundamental to eukaryotic biology.

Persistence of viral RNA in North American elk experimentally infected with an ancestral strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

White-tailed deer (Odocoileus virginianus) have emerged as a reservoir host for SARS-CoV-2 given their susceptibility to infection and demonstrated high rates of seroprevalence and infection across the United States. As SARS-CoV-2 circulates within free-ranging white-tailed deer populations, there is the risk of transmission to other wildlife species and even back to the human population. The goal of this study was to determine the susceptibility, shedding, and immune response of North American elk (Cervus elaphus canadensis) to experimental infection with SARS-CoV-2, to determine if another wide-ranging cervid species could potentially serve as a reservoir host for the virus. Here we demonstrate that while North American elk do not develop clinical signs of disease, they do develop a neutralizing antibody response to infection, suggesting the virus is capable of replicating in this mammalian host. Additionally, we demonstrate SARS-CoV-2 RNA presence in the medial retropharyngeal lymph nodes of infected elk three weeks after experimental infection. Consistent with previous observations in humans, these data may highlight a mechanism of viral persistence for SARS-CoV-2 in elk.

A five-year quasi-experimental study to evaluate the impact of empiric antibiotic order sets on antibiotic use metrics among hospitalized adult patients.

OBJECTIVE: Evaluation of adult antibiotic order sets (AOSs) on antibiotic stewardship metrics has been limited. The primary outcome was to evaluate the standardized antimicrobial administration ratio (SAAR). Secondary outcomes included antibiotic days of therapy (DOT) per 1,000 patient days (PD); selected antibiotic use; AOS utilization; Clostridioides difficile infection (CDI) cases; and clinicians' perceptions of the AOS via a survey following the final study phase. DESIGN: This 5-year, single-center, quasi-experimental study comprised 5 phases from 2017 to 2022 over 10-month periods between August 1 and May 31. SETTING: The study was conducted in a 752-bed tertiary care, academic medical center. INTERVENTION: Our institution implemented AOSs in the electronic medical record (EMR) for common infections among hospitalized adults. RESULTS: For the primary outcome, a statistically significant decreases in SAAR were detected from phase 1 to phase 5 (1.0 vs 0.90; P < .001). A statistically significant decreases were detected in DOT per 1,000 PD (4,884 vs 3,939; P = .001), fluoroquinolone orders (407 vs 175; P < .001), carbapenem orders (147 vs 106; P = .024), and clindamycin orders (113 vs 73; P = .01). No statistically significant change in mean vancomycin orders was detected (991 vs 902; P = .221). A statistically significant decrease in CDI cases was also detected (7.8, vs 2.4; P = .002) but may have been attributable to changes in CDI case diagnosis. Clinicians indicated that the AOSs were easy to use overall and that they helped them select the appropriate antibiotics. CONCLUSIONS: Implementing AOS into the EMR was associated with a statistically significant reduction in SAAR, antibiotic DOT per 1,000 PD, selected antibiotic orders, and CDI cases.

Wildlife Immune Responses to Mycobacterium bovis and to Bacille of Calmette-Guerin.

Bovine tuberculosis (bTB) is a zoonotic bacterial disease presenting public health, veterinary, and economic threats around the globe. Although cattle producers rely on regular testing and management practices to minimize domestic herd exposure, wildlife species around the world continue to be the main reservoirs for disease. Wildlife reservoirs for bTB include the Eurasian badger (Meles meles) in Great Britain and Ireland, the brushtail possum (Trichosurus vulpecula) in New Zealand, wild boar (Sus scrofa) in Spain, as well as white-tailed deer (Odocoileus virginianus) in the United States and red deer (Cervus elaphus) in Spain. Although all reservoir species share the ability to infect cattle, they differ in transmission capability, disease pathogenesis, diagnostic detection, and vaccination strategies. In this review, bTB interactions with these wildlife reservoirs are discussed, illustrating the need to address bTB disease in wildlife hosts to achieve eradication in domestic livestock.

Vaccination of White-Tailed Deer with Mycobacterium bovis Bacillus Calmette-Guérin (BCG): Effect of Mycobacterium avium ssp. paratuberculosis Infection.

In many parts of the world, bovine tuberculosis eradication efforts are hampered by wildlife reservoirs of Mycobacterium bovis, which serve as a constant source of M. bovis for nearby cattle. The human tuberculosis vaccine, M. bovis BCG has been investigated for use in several wildlife species, including deer. In the US, white-tailed deer in Michigan have been the source of infection for over 82 cattle herds since M. bovis was discovered in free-ranging deer in 1995. The efficacy of BCG may be influenced by many factors, including prior exposure or infection with non-tuberculous mycobacteria, that is, species other than members of the M. tuberculosis complex. M. avium subspecies paratuberculosis (Map) infection is not uncommon in ruminants such as deer. Using natural exposure to Map and experimental infection with M. bovis, we demonstrate that Map infection increased BCG vaccine efficacy as measured by lesion severity scores.

The devil you know and the devil you don't: current status and challenges of bovine tuberculosis eradication in the United States.

Having entered into its second century, the eradication program for bovine tuberculosis (bTB, caused by Mycobacterium bovis) in the United States of America occupies a position both enviable and daunting. Excepting four counties in Michigan comprising only 6109 km2 (0.06% of US land area) classified as Modified Accredited, as of April 2022 the entire country was considered Accredited Free of bTB by the US Department of Agriculture for cattle and bison. On the surface, the now well-described circumstances of endemic bTB in Michigan, where white-tailed deer (Odocoileus virginianus) serve as a free-ranging wildlife maintenance host, may appear to be the principal remaining barrier to national eradication. However, the situation there is unique in the U.S., and far-removed from the broader issues of bTB control in the remainder of the country. In Michigan, extensive surveillance for bTB in deer over the last quarter century, and regulatory measures to maximize the harvest of publicly-owned wildlife, have been implemented and sustained. Prevalence of bTB in deer has remained at a low level, although not sufficiently low to eliminate cattle herd infections. Public attitudes towards bTB, cattle and deer, and their relative importance, have been more influential in the management of the disease than any limitations of biological science. However, profound changes in the demographics and social attitudes of Michigan's human population are underway, changes which are likely to force a critical reevaluation of the bTB control strategies thus far considered integral. In the rest of the U.S. where bTB is not self-sustaining in wildlife, changes in the scale of cattle production, coupled with both technical and non-technical issues have created their own substantial challenges. It is against this diverse backdrop that the evolution of whole genome sequencing of M. bovis has revolutionized understanding of the history and ecology of bTB in Michigan, resolved previously undiscernible epidemiological puzzles, provided insights into zoonotic transmission, and unified eradication efforts across species and agencies. We describe the current status of bTB eradication in the U.S., how circumstances and management have changed, what has been learned, and what remains more elusive than ever.

Bovine Rectoanal Junction In Vitro Organ Culture Model System to Study Shiga Toxin-Producing Escherichia coli Adherence.

Studies evaluating the interactions between Shiga toxin-producing Escherichia coli O157:H7 (O157) and the bovine recto-anal junction (RAJ) have been limited to either in vitro analyses of bacteria, cells, or nucleic acids at the RAJ, providing limited information. Alternatively, expensive in vivo studies in animals have been conducted. Therefore, our objective was to develop a comprehensive in vitro organ culture system of the RAJ (RAJ-IVOC) that accurately represents all cell types present in the RAJ. This system would enable studies that yield results similar to those observed in vivo. Pieces of RAJ tissue, obtained from unrelated cattle necropsies, were assembled and subjected to various tests in order to determine the optimal conditions for assaying bacterial adherence in a viable IVOC. O157 strain EDL933 and E. coli K12 with known adherence differences were used to standardize the RAJ-IVOC adherence assay. Tissue integrity was assessed using cell viability, structural cell markers, and histopathology, while the adherence of bacteria was evaluated via microscopy and culture methods. DNA fingerprinting verified the recovered bacteria against the inoculum. When the RAJ-IVOC was assembled in Dulbecco's Modified Eagle Medium, maintained at a temperature of 39 °C with 5% CO2 and gentle shaking for a duration of 3-4 h, it successfully preserved tissue integrity and reproduced the expected adherence phenotype of the bacteria being tested. The RAJ-IVOC model system provides a convenient method to pre-screen multiple bacteria-RAJ interactions prior to in vivo experiments, thereby reducing animal usage.

Safe drugs with high potential to block malaria transmission revealed by a spleen-mimetic screening.

Malaria parasites like Plasmodium falciparum multiply in red blood cells (RBC), which are cleared from the bloodstream by the spleen when their deformability is altered. Drug-induced stiffening of Plasmodium falciparum-infected RBC should therefore induce their elimination from the bloodstream. Here, based on this original mechanical approach, we identify safe drugs with strong potential to block the malaria transmission. By screening 13 555 compounds with spleen-mimetic microfilters, we identified 82 that target circulating transmissible form of P. falciparum. NITD609, an orally administered PfATPase inhibitor with known effects on P. falciparum, killed and stiffened transmission stages in vitro at nanomolar concentrations. Short exposures to TD-6450, an orally-administered NS5A hepatitis C virus inhibitor, stiffened transmission parasite stages and killed asexual stages in vitro at high nanomolar concentrations. A Phase 1 study in humans with a primary safety outcome and a secondary pharmacokinetics outcome ( https://clinicaltrials.gov , ID: NCT02022306) showed no severe adverse events either with single or multiple doses. Pharmacokinetic modelling showed that these concentrations can be reached in the plasma of subjects receiving short courses of TD-6450. This physiologically relevant screen identified multiple mechanisms of action, and safe drugs with strong potential as malaria transmission-blocking agents which could be rapidly tested in clinical trials.

Pulmonary hamartoma in an elk calf.

Hamartomas are benign tumor-like lesions composed of disorganized growth of mature mesenchymal or epithelial tissues indigenous to the organ involved. Sporadically observed in ruminants, vascular, fibrous, nasal, and pulmonary hamartomas have been reported in calves; pulmonary and cutaneous forms have been reported in sheep. A full-term elk calf found dead had a large intrathoracic mass replacing the left caudal lung lobe and compressing other thoracic organs. Histologically, cross- and tangential sections of bronchi were separated by collagenous mesenchyme and irregularly shaped canaliculi and saccules resembling terminal bronchioles. Rarely present were regions in which saccules, lined by simple cuboidal epithelium, transitioned into attenuated epithelium lining fully developed alveoli. These findings are consistent with a pulmonary hamartoma. To our knowledge, pulmonary hamartoma has not been reported previously in a non-domestic ruminant.

An intranasal recombinant NDV-BRSV Fopt vaccine is safe and reduces lesion severity in a colostrum-deprived calf model of RSV infection.

Human respiratory syncytial virus (HRSV) is a major cause of severe lower respiratory tract disease in infants and the elderly, yet no safe, effective vaccine is commercially available. Closely related bovine RSV (BRSV) causes respiratory disease in young calves, with many similar features to those seen in HRSV. We previously showed that a Newcastle disease virus (NDV)-vectored vaccine expressing the F glycoprotein of HRSV reduced viral loads in lungs of mice and cotton rats and protected from HRSV. However, clinical signs and pathogenesis of disease in laboratory animals following HRSV infection differs from that observed in human infants. Thus, we examined whether a similar vaccine would protect neonatal calves from BRSV infection. Codon-optimized rNDV vaccine (rNDV-BRSV Fopt) was constructed and administered to colostrum-deprived calves. The rNDV-BRSV Fopt vaccine was well-tolerated and there was no evidence of vaccine-enhanced disease in the upper airways or lungs of these calves compared to the non-vaccinated calves. We found two intranasal doses reduces severity of gross and microscopic lesions and decreases viral load in the lungs. Furthermore, serum neutralizing antibodies were generated in vaccinated calves. Finally, reduced lung CXC chemokine levels were observed in vaccinated calves after BRSV challenge. In summary, we have shown that rNDV-BRSV Fopt vaccine is safe in colostrum-deprived calves, and is effective in reducing lung lesions, and decreasing viral load in upper respiratory tract and lungs after challenge.

Mycobacterium bovis Strain Ravenel Is Attenuated in Cattle.

Mycobacterium tuberculosis variant bovis (MBO) has one of the widest known mammalian host ranges, including humans. Despite the characterization of this pathogen in the 1800s and whole genome sequencing of a UK strain (AF2122) nearly two decades ago, the basis of its host specificity and pathogenicity remains poorly understood. Recent experimental calf infection studies show that MBO strain Ravenel (MBO Ravenel) is attenuated in the cattle host compared to other pathogenic strains of MBO. In the present study, experimental infections were performed to define attenuation. Whole genome sequencing was completed to identify regions of differences (RD) and single nucleotide polymorphisms (SNPs) to explain the observed attenuation. Comparative genomic analysis of MBO Ravenel against three pathogenic strains of MBO (strains AF2122-97, 10-7428, and 95-1315) was performed. Experimental infection studies on five calves each, with either MBO Ravenel or 95-1315, revealed no visible lesions in all five animals in the Ravenel group despite robust IFN-γ responses. Out of 486 polymorphisms in the present analysis, 173 were unique to MBO Ravenel among the strains compared. A high-confidence subset of nine unique SNPs were missense mutations in genes with annotated functions impacting two major MBO survival and virulence pathways: (1) Cell wall synthesis & transport [espH (A103T), mmpL8 (V888I), aftB (H484Y), eccC5 (T507M), rpfB (E263G)], and (2) Lipid metabolism & respiration [mycP1(T125I), pks5 (G455S), fadD29 (N231S), fadE29 (V360G)]. These substitutions likely contribute to the observed attenuation. Results from experimental calf infections and the functional attributions of polymorphic loci on the genome of MBO Ravenel provide new insights into the strain's genotype-disease phenotype associations.

Differential detection of IgM and IgG antibodies to chimeric antigens in bovine tuberculosis.

Recent studies have suggested the potential of innovative serologic tests for accurate and rapid detection of bovine tuberculosis (bTB). Dual Path Platform (DPP) technology has been used to develop rapid animal-side antibody tests for Mycobacterium bovis infection in a range of livestock and wildlife host species. The present study evaluated diagnostic performance of DPP BovidTB IgM/IgG assay designed for differential detection of bovine IgM and IgG antibodies against two chimeric antigens, DID38 and TBf2, respectively, using 662 well-characterized serum samples from M. bovis-infected and bTB-free cattle collected in the United States, Great Britain, France, and South Africa. Test sensitivity and specificity ranged from 71% to 100% and from 95% to 100%, respectively, depending on the country, with overall accuracy of 83%. No significant risk of cross-reactivity with serum samples from cattle infected with most relevant species of mycobacteria other than M. bovis was found. The DPP BovidTB IgM/IgG assay may be suitable for use in multi-test algorithms to improve current strategies for bTB surveillance.

Potential for improved detection of bovine tuberculosis by targeting combined blood biomarkers in multi-test algorithms.

Bovine tuberculosis (bTB) control programs can be improved by combined use of tests for humoral and cell-mediated immune responses targeting multiple biomarkers of Mycobacterium bovis. To further the diagnostic benefits of this approach, we used Dual Path Platform (DPP) technology to test sera from cattle with naturally acquired bTB in the United States (US) and Spain for the presence of M. bovis antigen, IgM and/or IgG antibodies to MPB70/MPB83 fusion antigen in conjunction with tuberculin skin tests (TST) or interferon-gamma release assays (IGRA). When TST was complemented with detection of IgM and IgG antibodies, the diagnostic sensitivity increased from 85.4% to 95.1% in the US and from 64.2% to 81.5% in Spain. Likewise, adding the DPP assays enhanced IGRA diagnostic sensitivity from 82.7% to 93.8% in Spain. Detection of circulating M. bovis antigen showed added value when used in combination with the DPP antibody assays but it was limited when analyzed in the context of TST or IGRA results. Present findings support the benefits of a multi-test approach for the ante-mortem diagnosis of bTB in cattle.

Factors controlling the transfer of biogenic organic species from seawater to sea spray aerosol.

Ocean waves transfer sea spray aerosol (SSA) to the atmosphere, and these SSA particles can be enriched in organic matter relative to salts compared to seawater ratios. A fundamental understanding of the factors controlling the transfer of biogenic organic matter from the ocean to the atmosphere remains elusive. Field studies that focus on understanding the connection between organic species in seawater and SSA are complicated by the numerous processes and sources affecting the composition of aerosols in the marine environment. Here, an isolated ocean-atmosphere system enables direct measurements of the sea-air transfer of different classes of biogenic organic matter over the course of two phytoplankton blooms. By measuring excitation-emission matrices of bulk seawater, the sea surface microlayer, and SSA, we investigate time series of the transfer of fluorescent species including chlorophyll-a, protein-like substances, and humic-like substances. Herein, we show the emergence of different molecular classes in SSA at specific times over the course of a phytoplankton bloom, suggesting that SSA chemical composition changes over time in response to changing ocean biological conditions. We compare the temporal behaviors for the transfer of each component, and discuss the factors contributing to differences in transfer between phases.