Objective:To observe the prevalence and the characteristics of infectious disease outbreak on international cruise ships from 2006 to 2020，and to explore relevant prevention and control measures.Methods:Sourced from the website of the Vessel Sanitation Program at the U.S. Centers for Disease Control and Prevention，the data of 223 cases that met the definition of infectious disease outbreaks on international cruise ship and took place between 2006 to 2020 were analyzed using epidemiological statistics methods.Results:From 2006 to 2020，the number of infectious disease outbreak on international cruise ships generally showed a downward trend，though with small fluctuations. Among the 192 outbreaks of infectious diseases with identified pathogens，181 outbreaks arose from viral infectious diseases（81.17%），10 from bacterial infectious diseases（4.48%），and 1 from other infectious diseases（0.45%）. Besides，there were another 31 outbreaks（13.90%）with unidentified causes or unavailable specimens. Norovirus，Enterotoxigenic Escherichia coli（ETEC），and Shigella and Salmonella were the main pathogens that gave rise to the outbreak of infectious diseases on international cruise ships. January to April was the peak time of infectious disease outbreak on international cruise ships，while other months kept a low incidence of such outbreak. The prevalence of common ship infectious diseases among crew members（2.01%）was lower than that of passengers（7.20%）.Conclusion:Infectious disease outbreak on cruise ships has its own characteristics and developing patterns. The main susceptible group to infectious diseases on cruise ships are passengers. The main routes of transmission are food and water．

Objective:To observe the prevalence and the characteristics of infectious disease outbreak on international cruise ships from 2006 to 2020，and to explore relevant prevention and control measures.Methods:Sourced from the website of the Vessel Sanitation Program at the U.S. Centers for Disease Control and Prevention，the data of 223 cases that met the definition of infectious disease outbreaks on international cruise ship and took place between 2006 to 2020 were analyzed using epidemiological statistics methods.Results:From 2006 to 2020，the number of infectious disease outbreak on international cruise ships generally showed a downward trend，though with small fluctuations. Among the 192 outbreaks of infectious diseases with identified pathogens，181 outbreaks arose from viral infectious diseases（81.17%），10 from bacterial infectious diseases（4.48%），and 1 from other infectious diseases（0.45%）. Besides，there were another 31 outbreaks（13.90%）with unidentified causes or unavailable specimens. Norovirus，Enterotoxigenic Escherichia coli（ETEC），and Shigella and Salmonella were the main pathogens that gave rise to the outbreak of infectious diseases on international cruise ships. January to April was the peak time of infectious disease outbreak on international cruise ships，while other months kept a low incidence of such outbreak. The prevalence of common ship infectious diseases among crew members（2.01%）was lower than that of passengers（7.20%）.Conclusion:Infectious disease outbreak on cruise ships has its own characteristics and developing patterns. The main susceptible group to infectious diseases on cruise ships are passengers. The main routes of transmission are food and water．

OBJECTIVETo investigate the effects of simulated nitrogen-oxygen saturation exposure at a water depth of 50 m on the expression of inflammatory mediators including interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-α) in the external auditory canal (EAC) of rabbits.

METHODSTwo batches of New Zealand rabbits were exposed to nitrogen-oxygen saturated at a water depth of 50 m. After exposure, the epithelial tissue in the EAC was analyzed using hematoxylin-eosin (HE) staining, and the changes in expression of inflammatory mediators including IL-6, IL-10, and TNF-α in the EAC of rabbits were determined by real-time polymerase chain reaction (PCR).

RESULTSAccording to the result of HE staining, more inflammatory cell infiltration, small vascular congestion, and mucosal edema in the EAC of rabbits were observed in the exposure group than in the control group. Additionally, compared with the control group, the exposure group had increased expression of IL-6 and TNF-α and reduced expression of IL-10 in the EAC of rabbits according to the result of real-time PCR.

CONCLUSIONThe nitrogen-oxygen saturation exposure at a water depth of 50 m can cause inflammatory injuries in the EAC of rabbits. The mechanism may be associated with increased expression of IL-6 and TNF-α and reduced expression of IL-10.

Animals ; Disease Models, Animal ; Ear Canal ; physiopathology ; Environmental Exposure ; adverse effects ; Inflammation Mediators ; metabolism ; Interleukin-10 ; metabolism ; Interleukin-6 ; metabolism ; Nitrogen ; adverse effects ; Oxygen ; adverse effects ; Rabbits ; Tumor Necrosis Factor-alpha ; metabolism ; Water ; adverse effects

Objective To investigate the synergistic effect of formaldehyde pre-exposure on the damage to the respiratory system in rats after microbial aerosol inhalation.Methods The intoxication model was established in rats by the dynamic aerosol exposure system.Serum IgM concentration and SOD activity were measured by ELISA and luminescence assay respectively.Morphologic injury of the lung tissue was detected by HE staining.Tunnel chromogenic in-situ detection was used to detect the apoptosis of lung epithelial cells and Gram staining was performed to detect the capacity of lung epithelial cells in bacterial clearance.Results Serum IgM levels in rats increased significantly,after microbial aerosol inhalation,when compared with that of the control group,with the serum IgM levels of the formaldehyde combined with microbial aerosol inhalation group increased more significantly [(0.35 ±0.09) g/L].The serum SOD activity of the experimental groups all increased,with the level of the formaldehyde combined with microbial aerosol inhalation group [(2.22 ± 0.25) × 106 U/L] being significantly higher than that of the 2 other groups [(1.50 ±0.37) × 106 U/L] and [(1.58 ± 0.34) × 106 U/L].Morphological observation showed that widened alveolar septum,interstitial edema and inflammatory cell infiltration could be clearly noted in the lung tissue of the 3 experimental groups,with the pathological changes in the formaldehyde combined with microbial aerosol inhalation group being most significant.Tunnel detection also indicated that the nnmber of apoptotic cells in the lung tissue for the formaldehyde combined with microbial aerosol inhalation group increased significantly.Gram staining showed that the number of residue bacteria in the rat bronchiole for the rats of the formaldehyde combined with microbial aerosol inhalation group after 2-hour air intervention was significantly more than that of the simple bacteria exposure group.Conclusions Formaldehyde pre-exposure combined with microbial aerosol inhalation could induce synergistic damage to the rat lung tissue and decrease the capacity of the lung tissue to clear out heterogeneous pollutants.

Objective To investigate the synergistic effect of formaldehyde pre-exposure on the damage to the respiratory system in rats after microbial aerosol inhalation.Methods The intoxication model was established in rats by the dynamic aerosol exposure system.Serum IgM concentration and SOD activity were measured by ELISA and luminescence assay respectively.Morphologic injury of the lung tissue was detected by HE staining.Tunnel chromogenic in-situ detection was used to detect the apoptosis of lung epithelial cells and Gram staining was performed to detect the capacity of lung epithelial cells in bacterial clearance.Results Serum IgM levels in rats increased significantly,after microbial aerosol inhalation,when compared with that of the control group,with the serum IgM levels of the formaldehyde combined with microbial aerosol inhalation group increased more significantly [(0.35 ±0.09) g/L].The serum SOD activity of the experimental groups all increased,with the level of the formaldehyde combined with microbial aerosol inhalation group [(2.22 ± 0.25) × 106 U/L] being significantly higher than that of the 2 other groups [(1.50 ±0.37) × 106 U/L] and [(1.58 ± 0.34) × 106 U/L].Morphological observation showed that widened alveolar septum,interstitial edema and inflammatory cell infiltration could be clearly noted in the lung tissue of the 3 experimental groups,with the pathological changes in the formaldehyde combined with microbial aerosol inhalation group being most significant.Tunnel detection also indicated that the nnmber of apoptotic cells in the lung tissue for the formaldehyde combined with microbial aerosol inhalation group increased significantly.Gram staining showed that the number of residue bacteria in the rat bronchiole for the rats of the formaldehyde combined with microbial aerosol inhalation group after 2-hour air intervention was significantly more than that of the simple bacteria exposure group.Conclusions Formaldehyde pre-exposure combined with microbial aerosol inhalation could induce synergistic damage to the rat lung tissue and decrease the capacity of the lung tissue to clear out heterogeneous pollutants.