Antiviral activity of adenoviral vector expressing human interferon lambda-4 against influenza virus.

Interferon lambda (IFNλ), classified as a type III IFN, is a representative cytokine that plays an important role in innate immunity along with type I IFN. IFNλ can elicit antiviral states by inducing peculiar sets of IFN-stimulated genes (ISGs). In this study, an adenoviral vector expression system with a tetracycline operator system was used to express human IFNλ4 in cells and mice. The formation of recombinant adenovirus (rAd-huIFNλ4) was confirmed using immunohistochemistry assays and transmission electron microscopy. Its purity was verified by quantifying host cell DNA and host cell proteins, as well as by confirming the absence of the replication-competent adenovirus. The transduction of rAd-huIFNλ4 induced ISGs and inhibited four subtypes of the influenza virus in both mouse-derived (LA-4) and human-derived cells (A549). The antiviral state was confirmed in BALB/c mice following intranasal inoculation with 109 PFU of rAd-huIFNλ4, which led to the inhibition of four subtypes of the influenza virus in mouse lungs, with reduced inflammatory lesions. These results imply that human IFNλ4 could induce antiviral status by modulating ISG expression in mice.

A combined 3D printed metal and resin digital denture: 5-year follow-up data and a creative design concept.

Many denture frameworks are currently manufactured using metal 3-dimensional (3D) printing technology. However, this advanced technology is still limited to conventional denture designs. A metal 3D printing-based denture design concept was developed and is presented based on a nonwear occlusal surface, a nonfracture denture base, and a novel connection between metal and resin.

Neurologic Effects of SARS-CoV-2 Transmitted among Dogs.

SARS-CoV-2 induces illness and death in humans by causing systemic infections. Evidence suggests that SARS-CoV-2 can induce brain pathology in humans and other hosts. In this study, we used a canine transmission model to examine histopathologic changes in the brains of dogs infected with SARS-CoV-2. We observed substantial brain pathology in SARS-CoV-2-infected dogs, particularly involving blood-brain barrier damage resembling small vessel disease, including changes in tight junction proteins, reduced laminin levels, and decreased pericyte coverage. Furthermore, we detected phosphorylated tau, a marker of neurodegenerative disease, indicating a potential link between SARS-CoV-2-associated small vessel disease and neurodegeneration. Our findings of degenerative changes in the dog brain during SARS-CoV-2 infection emphasize the potential for transmission to other hosts and induction of similar signs and symptoms. The dynamic brain changes in dogs highlight that even asymptomatic individuals infected with SARS-CoV-2 may develop neuropathologic changes in the brain.

Live recombinant Newcastle disease virus vectored vaccine expressing the haemagglutinin of H9N2 avian influenza virus suppresses viral replication in chickens.

In 2020, the Y280-lineage H9N2 low-pathogenic avian influenza virus (LPAIV) was introduced into South Korea for the first time. Current vaccines are focused on the control of Y439-like viruses; however, there are continuous reports of decrease in egg production and secondary infections caused by Y280-lineage H9N2 LPAI infection in chickens. Therefore, there is an urgent need to develop effective novel vaccines against Y280-lineage H9N2 LPAI. Most commercialized avian influenza vaccines are oil-adjuvanted inactivated vaccines, which are labour-intensive to administer and require higher dosage. In this study, rK148/Y280-HA, a novel recombinant Newcastle disease virus (NDV) vectored vaccine against Y280-lineage H9N2 LPAI, was developed and evaluated using two mass-applicable administration methods, spray vaccination and drinking water vaccination. Regardless of low serum antibody haemagglutination inhibition titres against NDV and Y280-lineage H9N2 LPAI after applying the rK148/Y280-HA vaccine, vaccination with either administration method protected chickens against virulent NDV and Y280-lineage H9N2 LPAIV after the challenge. Taken together, these results indicate that the rK148/Y280 vaccine can be administered using facile mass-application methods to provide protection against the Y280-lineage LPAI.RESEARCH HIGHLIGHTS NDV vectored vaccine harbouring Y280-lineage H9N2 HA protein was successfully generated.NDV vectored vaccine provides protection against NDV.NDV vectored vaccine with H9N2 HA protects against homologous H9N2 LPAIV.

Production of a chimeric porcine reproductive and respiratory syndrome virus (PRRSV)-2 vaccine using a lab-scale packed-bed bioreactor CelCradle.

BACKGROUND: We developed a MARC-145 cell culture and porcine reproductive and respiratory syndrome (PRRS) vaccine production using a novel CelCradle bioreactor. CelCradle is a packed-bed bioreactor capable of both batch and perfusion culture, and the operating parameters are easy to optimize. RESULTS: In this study, CelCradle reached a maximum cell density of 8.94 × 105 cells/mL at 5 days post-seeding when seeded at 8.60 × 104 cells/mL (doubling time = 35.52 h). Inoculation of PRRS vaccine candidate, K418DM1.1, was performed at a multiplicity of infection (MOI) of 0.01 at 5 days post-seeding, which resulted in a high viral titer of 2.04 × 108 TCID50/mL and total viral load of 1.02 × 1011 TCID50/500 mL at 2 days post-infection (dpi). The multilayer cultivation system, BioFactory culture, yielded a higher doubling time (37.14 h) and lower viral titer (i.e., 8.15 × 107 TCID50/mL) compared to the CelCradle culture. Thus, the culture medium productivity of the CelCradle culture was 2-fold higher than that of the BioFactory culture. In the animal experiment, the CelCradle-produced vaccine induced high levels of neutralizing antibodies and effectively protected pigs against homologous challenge, as shown by the significantly lower levels of viremia at 1- and 7-days post-challenge (dpc) compared to the non-vaccinated pigs. CONCLUSIONS: Overall, this study demonstrates that the CelCradle system is an economical platform for PRRS vaccine production.

Analgosedation during flexible fiberoptic bronchoscopy: comparing the clinical effectiveness and safety of remifentanil versus midazolam/propofol.

BACKGROUND: There are limited data regarding the efficacy and safety of remifentanil sedation for diagnostic bronchoscopy. The aim of this study was to evaluate the clinical efficacy and safety of remifentanil by comparing it with those of conventional drugs, midazolam and propofol. METHODS: A retrospective study of 186 patients who underwent diagnostic bronchoscopy at Chonbuk National University Hospital was performed. Patients were classified into the remifentanil group and midazolam/propofol group according to the drugs used during bronchoscopy. RESULTS: Of the 186 patients, 111 patients received remifentanil and 75 received midazolam/propofol during the bronchoscopy. The proportion of patients who required bronchoscopy for endobronchial inspection alone was significantly higher in the midazolam/propofol group than in the remifentanil group (93.3% vs. 73.0%; p <  0.001). In contrast, the proportion of patients who required more invasive procedures, such as bronchoscopic biopsy, bronchoalveolar lavage, or transbronchial lung biopsy, was significantly higher in the remifentanil group than in the midazolam/propofol group (27.0% vs. 6.7%; p <  0.001). The recovery time was significantly shorter in the remifentanil group than in the midazolam/propofol group (mean 6.4 min vs. 11.6 min, p <  0.001). There were no significant differences between the groups with regard to safety events including desaturation, hypotension, and arrhythmia. CONCLUSIONS: Despite the higher proportion of patients who underwent more invasive procedures in the remifentanil group than in the midazolam/propofol group, there was no significant difference in safety events between the groups. Those in the remifentanil group also demonstrated a faster recovery time than those in the midazolam/propofol group.

Evidence of hepatitis E virus infection in specific pathogen-free rabbits in Korea.

Rabbits are considered a new natural reservoir of hepatitis E virus (HEV). In this study, HEV infection was verified by the detection of partial genomic sequence of HEV and anti-HEV antibodies in specific pathogen-free (SPF) rabbits. HEV RNA was found in 6.4% serum and 13.5% fecal samples from 126 SPF rabbits. Anti-HEV antibodies were also detected in 4.0% of the SPF rabbits. HEV genetic sequences isolated from the rabbits were clustered into a rabbit HEV clade with other rabbit HEV isolates; they were found to be most closely related with a rabbit HEV sequence previously reported in Korea. Therefore, HEV infection should be diagnosed before conducting experiments involving SPF rabbits.

Evaluation and optimization of a conventional SPCE for FMD post-vaccination monitoring.

BACKGROUND: Foot-and-mouth disease (FMD) can be controlled by either stamping out or vaccination, a choice which depends on both the economic importance of the livestock sector as well as the disease status. In FMD-free countries with vaccination, such as Korea, vaccination programs should guarantee prevention against transmission of FMD. Monitoring of vaccination programs is also essential for ensuring sufficient coverage that will limit the transmission of FMDV. There are several methods to screen FMD virus (FMDV) structural protein (SP) antibodies including SPCE (Solid-phase competitive ELISA), LPBE (Liquid-phase blocking ELISA), and VNT (Virus neutralization test). Among these, SPCE is widely used for serological monitoring since VNT-the gold standard method-has certain practical limitations, such as high costs in terms of time and labor. However, whether SPCE can ensure the vaccination status of individual animals and whole farms is unclear. In this study, SPCE, LPBE and VNT were compared with respect to correlation with each other and sensitivity at commercial pig farms. RESULTS: The positive results obtained by PrioCHECK SPCE differed from those obtained by LPBE and VNT. The sensitivity of SPCE relative to those of the other tests was fairly low. The raw data of SPCE were most highly correlated with those of VNT with XJ strain, while their positivity and negativity were most highly correlated with LPBE. The results of ROC analysis proposed new cut-off for PrioCHECK SPCE higher than the previous 50% inhibition. CONCLUSIONS: The high false positive rate of PrioCHECK SPCE suggested that high seropositivity by SPCE may not guarantee a true vaccination coverage. Adjusting the cut-off percentage (%) inhibition value for SPCE is needed to address this problem, and it is highly recommended that routine FMDV serological monitoring programs using PrioCHECK SPCE should be combined with alternative methods such as LPBE or VNT.

Prevalence and genetic features of rabbit hepatitis E virus in Korea.

Hepatitis caused by hepatitis E virus (HEV) is a public health concern worldwide. HEV strains have been isolated from several animal species, some of which induce zoonosis. Recently, the isolation of HEV from rabbits was reported. Here, the partial capsid gene (320 bp) of HEV was detected in rabbit feces via reverse transcriptase-polymerase chain reaction (RT-PCR). Rabbit HEV was found in two of six rabbit farms and 17 of 264 rabbit fecal samples (6.4%). A phylogenetic analysis of the partial capsid gene classified the 17 HEV isolates into the putative rabbit HEV clade. A full genomic sequence, KOR-Rb-1, was obtained from one rabbit HEV isolate by 5' and 3' rapid amplification of cDNA ends-PCR and RT-PCR, and comprised 7275 bp excluding the 3' poly(A) tail. It shared 77.5-86.8%, 86.6%, and 80.2-84.3% nucleotide identities with rabbit HEV isolates from China, the US, and France, respectively. It also shared 72.3-73.0%, 71.4%, 76.7-78.3%, 72.8-73.3%, and 47.1-47.2% nucleotide identities with representative strains of HEV-1, HEV-2, HEV-3, HEV-4, and avian HEV, respectively. A full-genome phylogenetic analysis classified KOR-Rb-1 into the provisional rabbit HEV clade. This isolate could be used to study the pathogenesis and zoonotic potential of rabbit HEV.

Experimental evidence of hepatitis A virus infection in pigs.

Hepatitis A virus (HAV) is the leading cause of acute viral hepatitis worldwide, with HAV infection being restricted to humans and nonhuman primates. In this study, HAV infection status was serologically determined in domestic pigs and experimental infections of HAV were attempted to verify HAV infectivity in pigs. Antibodies specific to HAV or HAV-like agents were detected in 3.5% of serum samples collected from pigs in swine farms. When the pigs were infected intravenously with 2 × 10(5) 50% tissue culture infectious dose (TCID50 ) of HAV, shedding of the virus in feces, viremia, and seroconversion were detected. In pigs orally infected with the same quantity of HAV, viral shedding was detected only in feces. HAV genomic RNA was detected in the liver and bile of intravenously infected pigs, but only in the bile of orally infected pigs. In further experiments, pigs were intravenously infected with 6 × 10(5) TCID50 of HAV. Shedding of HAV in feces, along with viremia and seroconversion, were confirmed in infected pigs but not in sentinel pigs. HAV genomic RNA was detected in the liver, bile, spleen, lymph node, and kidney of the infected pigs. HAV antigenomic RNA was detected in the spleen of one HAV-infected pig, suggesting HAV replication in splenic cells. Infiltration of inflammatory cells was observed in the livers of infected pigs but not in controls. This is the first experimental evidence to demonstrate that human HAV strains can infect pigs.

Pre-immune state induced by chicken interferon gamma inhibits the replication of H1N1 human and H9N2 avian influenza viruses in chicken embryo fibroblasts.

BACKGROUND: Interferon gamma (IFN-γ), an immunoregulatory cytokine, is known to control many microbial infections. In a previous study, chicken interferon gamma (chIFN-γ) was found to be up-regulated following avian influenza virus (AIV) infection in specific pathogen-free chickens. We aimed to investigate whether the pre-immune state induced by chIFN-γ could generate an antiviral response against influenza virus. METHODS: We generated a chIFN-γ-expressing plasmid and transfected it into chicken embryo fibroblasts (CEFs) and then infected the cells with human origin H1N1 or avian origin H9N2 influenza viruses. Viral titers of culture medium were evaluated in MDCK cell and the viral RNA and IFN-stimulated genes (ISGs) were then quantified by real-time reverse transcriptase polymerase. To further evaluate the role of the antiviral effect of chIFN-γ by using a backward approach, synthetic small interfering RNAs (siRNA) targeting chIFN-γ were used to suppress chIFN-γ. RESULTS: The chIFN-γ-stimulated CEFs inhibited the replication of viral RNA (vRNA) and showed a mild decrease in the infectious virus load released in the culture medium. Compared to the mock-transfected control, the messenger RNA (mRNA) levels of type I IFNs and IFN-stimulated genes were up-regulated in the cells expressing chIFN-γ. After treatment with the siRNA, we detected a higher expression of viral genes than that observed in the mock-transfected control. CONCLUSIONS: Our results suggest that apart from the important role played by chIFN-γ in the antiviral state generated against influenza virus infection, the pre-immune state induced by chIFN-γ can be helpful in mitigating the propagation of influenza virus.

Genotyping of infectious laryngotracheitis virus using allelic variations from multiple genomic regions.

Live attenuated vaccines are extensively used worldwide to control the outbreak of infectious laryngotracheitis. Virulent field strains showing close genetic relationship with the infectious laryngotracheitis virus (ILTV) vaccines of chicken embryo origin have been detected in the poultry industry. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, a reliable molecular epidemiological method, of multiple genomic regions was performed. The PCR-RFLP is a time-consuming method that requires considerable amount of intact viral genomic DNA to amplify genomic regions greater than 4 kb. In this study, six variable genomic regions were selected and amplified for sequencing. The multi-allelic PCR-sequence genotyping showed better discrimination power than that of previous PCR-sequencing schemes using single or two target regions. The allelic variation patterns yielded 16 strains of ILTV classified into 14 different genotypes. Three Korean field strains, 550/05/Ko, 0010/05/Ko and 40032/08/Ko, were found to have the same genotype as the commercial vaccine strain, Laryngo Vac (Zoetis, Florham Park, NJ, USA). Three other Korean field strains, 40798/10/Ko, 12/07/Ko, and 30678/14/Ko, showed recombined allelic patterns. The multi-allelic PCR-sequencing method was proved to be an efficient and practical procedure to classify the different strains of ILTV. The method could serve as an alternate diagnostic and differentiating tool for the classification of ILTV, and contribute to understanding of the epidemiology of the disease at a global level.

Pathogenicity of the Korean H5N8 highly pathogenic avian influenza virus in commercial domestic poultry species.

In 2014, the highly pathogenic avian influenza (HPAI) virus H5N8 triggered outbreaks in wild birds and poultry farms in South Korea. In the present study, we investigated the pathogenicity of the H5N8 HPAI virus, belonging to the clade 2.3.4.4, in different species of poultry. For this, we examined clinical signs and viral shedding levels following intranasal inoculation of the virus in 3-week-old commercial layer chickens and quails, 10-week-old Korean native chickens, and 8-week-old Muscovy ducks. Intranasal inoculation with 10(6.0) viruses at 50% egg-infective dose resulted in 100% mortality in the layer chickens (8/8) and quails (4/4), but 60% and 0% deaths in the Korean native chickens (3/5) and Muscovy ducks (0/4), respectively. In addition, transmission of the inoculated virus to contact-exposed birds was evident in all the species used in this study. Based on our results, we conclude that the H5N8 HPAI virus has lower pathogenicity and transmissibility in poultry species compared with previously reported H5N1 HPAI viruses.

Analysis of cytokine production in a newly developed canine tracheal epithelial cell line infected with H3N2 canine influenza virus.

The Madin-Darby canine kidney (MDCK) cell line is typically used to analyze pathological features after canine influenza virus (CIV) infection. However, MDCK cells are not the ideal cell type, because they are kidney epithelial cells. Therefore, we generated an immortalized canine tracheal epithelial cell line, KU-CBE, to more reliably study immune responses to CIV infection in the respiratory tract. KU-CBE cells expressed the influenza virus receptor, α-2,3-sialic acid (SA), but not α-2,6-SA. KU-CBE and MDCK cells infected with H3N2 CIV demonstrated comparable virus growth kinetics. Gene expression levels of interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-ß were estimated in both KU-CBE and MDCK cells infected with CIV by real-time reverse transcription polymerase chain reaction (qRT-PCR). Of these cytokines, IL-4, IL-10, TNF-α, and IFN-ß mRNAs were detected in both cell lines. Gene expression of IL-4, IL-10, and TNF-α was not significantly different in the two cell lines. However, MDCK cells exhibited a significantly higher level of IFN-ß mRNA than KU-CBE cells at 18 h post infection. Additionally, the protein concentrations of these four cytokines were determined by enzyme-linked immunosorbent assay (ELISA) using cell culture supernatants obtained from the two CIV-infected cell lines. MDCK cells produced significantly higher amounts of IL-4 and IFN-ß than KU-CBE cells. However, KU-CBE cells produced a significantly higher amount of TNF-α than MDCK cells. These data indicated that the newly developed canine tracheal epithelial cells exhibited different cytokine production patterns compared to MDCK cells when infected with CIV. Inflammation of the respiratory tract of dogs induced by CIV infection may be attributed to the elevated expression level of TNF-α in canine tracheal epithelial cells.

A study on usefulness evaluation of SUV measured in mini-PACS for each one of PET/CT equipment.

To save and analyze the data from a positron emission tomography/computed tomography (PET/CT) scan, it is sometimes important to use a server away from the workstation of the equipment or to install and operate mini-picture archiving and communication system (PACS). Mini-PACS was developed to save the data from a scan and measure the standard uptake value (SUV) in PACS that could be measured only in PET/CT equipment manufactured by many companies. Against this background, this study examined whether the SUV measured in PET/CT equipment was the same value in mini-PACS. This study evaluated Biograph 16 and Biograph 40 manufactured by SIEMENS and Discovery Ste 8 manufactured by GE, all of which are installed in this hospital. The SUV of the aorta of 30 patients, who had undergone an (18)F-FDG whole body PET scan in the period from February to October 2012, was measured at the height of the liver and mediastinum. In the mini-PACS program, the SUV was also measured and analyzed in an image with the same phase. According to the study results, the coefficient of the SUV of the liver in PET/CT equipment and mini-PACS was 0.99, 0.98, and 0.64 in Biograph 16, Biograph 40, and Discovery Ste 8, respectively, where the coefficient of the SUV of aorta was 0.98, 0.98, and 0.66 in Biograph 16, Biograph 40, and Discovery Ste 8, showing a positive correlation in all equipment.

Induction of immunocastration in pre-pubertal boars immunized with recombinant gonadotropin-releasing hormone conjugated with Salmonella Typhimurium flagellin fljB.

Immunocastration is an alternative method used to replace surgical castration commonly performed in swine farms. In boars, the main effects of immunocastration are reduction of gonadotropin-releasing hormone (GnRH) and the resulting inhibition of testicular function. The aim of this study was to evaluate immunocastration efficacy in pre-pubertal boars vaccinated with a recombinant GnRH protein conjugated with Salmonella Typhimurium flagellin fljB (STF2). A total of 35 boars were assigned to three groups: the untreated group (n = 5), the surgically castrated group (n = 5), and the immunocastrated group (n = 25). Pigs in the immunocastration group were immunized with the GnRH-STF2 vaccine at pre-pubertal ages 4 and 8 weeks. All experimental pigs were kept for 26 weeks before slaughter. Anti-GnRH antibody levels of immunocastrated pigs were significantly higher than those of untreated pigs (P < 0.001). In contrast, testosterone levels of immunocastrated pigs were significantly lower than those of untreated pigs (P < 0.001). Statistical significances were not found in the body weights and backfat thicknesses of untreated vs. immunocastrated pigs. Weights of the testes and epididymides of immunocastrated pigs were significantly lower than those of untreated pigs (P < 0.001). Testicular tissues of immunocastrated pigs were severely suppressed compared with those of untreated pigs. In conclusion, immunization with the STF2-GnRH vaccine effectively induced immunocastration in pre-pubertal boars.

Diagnosis of Leucocytozoon caulleryi infection in commercial broiler breeders in South Korea.

This report confirms a recent outbreak of a Leucocytozoon caulleryi infection in a commercial broiler breeder flock in South Korea. Seven, 18-day-old broiler breeders (Gallus gallus) were necropsied following a history of depression, sudden death, and subcutaneous hemorrhages. On necropsy, subcutaneous hemorrhages were identified in the wings and legs, pectoral and thigh muscles, thymus, epicardium, pancreas, and kidneys. On histopathology, there were numerous schizonts and merozoits of a Leucocytozoon sp. noted in the heart, spleen, liver, kidneys, thymus, and bursa of Fabricius. Molecular analysis of the mitochondrial cytochrome oxidase b confirmed that the causative agent was Leucocytozoon caulleryi. Although L. caulleryi was diagnosed previously in South Korea, there had been no reports of L. caulleryi over the past several decades.

Prevalence and characterization of Salmonella species in entire steps of a single integrated broiler supply chain in Korea.

The purpose of this study was to investigate the distribution of Salmonella species in an integrated broiler supply chain in Korea. A total of 1,214 samples from various steps of an integrated broiler production company including broiler breeder farms, broiler farms, broiler trucks, slaughterhouse, and retail chicken meats were collected and investigated. Salmonella was detected in 195 of the samples. The highest prevalence of Salmonella was observed in broiler transporting trucks (71.43%), followed by the slaughterhouse (63.89%) and broiler farms (16.05%). Salmonella Hadar was the most frequently isolated serotype (83.08%). All Salmonella Hadar isolates investigated in this study with pulsed-field gel electrophoresis showed the same XbaI pulsed-field gel electrophoresis pulsotype.

Intratracheal cobinamide (vitamin B12 analog) administration increases survivability in rabbits exposed to a lethal dose of inhaled hydrogen sulfide.

BACKGROUND: Hydrogen sulfide is a highly toxic, flammable, and colorless gas. Hydrogen sulfide has been identified as a potential terrorist chemical threat agent in mass-casualty events. Our previous studies showed that cobinamide, a vitamin B12 analog, effectively reverses the toxicity from hydrogen sulfide poisoning. In this study, we investigate the effectiveness of intratracheally administered cobinamide in treating a lethal dose hydrogen sulfide gas inhalation and compare its performance to saline control administration. METHODS: A total of 53 pathogen-free New Zealand White rabbits were used for this study. Four groups were compared: (i) received no saline solution or drug intratracheally (n = 15), (ii) slow drip saline intratracheally (n = 15), (iii) fast drip saline intratracheally (n = 15), and (iv) slow drip cobinamide intratracheally (n = 8). Blood pressure was continuously monitored, and deoxy- and oxyhemoglobin concentration changes were monitored in real-time in vivo using continuous wave near-infrared spectroscopy. RESULTS: The mean (± standard deviation) weight for all animals (n = 53) was 3.87 ± 0.10 kg. The survival rates of the slow cobinamide and the fast saline groups were 75 percent and 60 percent, respectively, while the survival rates in the slow saline and control groups were 26.7 percent and 20 percent, respectively. A log-rank (Mantel-Cox) test showed that survival in fast saline and slow cobinamide groups were significantly greater than those of no saline control and slow saline groups (P < 0.05). The slow and no saline control groups were not significantly different (P = 0.59). The slow cobinamide group did significantly better than the slow saline group (P = 0.021). DISCUSSION: The ability to use intratracheal cobinamide as an antidote to hydrogen sulfide poisoning is a novel approach to mass-casualty care. The major limitations of this study are that it was conducted in a single species at a single inhaled hydrogen sulfide concentration. Repeated investigations in other species and at varying levels of hydrogen sulfide exposure will be needed before any definitive recommendations can be made. CONCLUSIONS: We demonstrated that intratracheal cobinamide and fast saline drip improved survival for hydrogen sulfide gas inhalation in rabbit models. Although further study is required, our results suggest that intratracheal administration of cobinamide and fast saline may be useful in hydrogen sulfide mass-casualty events.