Number Of Infectious Organisms Research Articles

Reintroducing beavers Castor fiber to Britain: a disease risk analysis

Abstract Eurasian beavers Castor fiber are potential hosts for a range of infectious diseases and parasites, including those typical of common European rodents. A number of infectious organisms are potentially zoonotic and may be notifiable under animal health legislation. The official trial beaver reintroductions to Scotland, the retrospectively licensed releases in England, and the increasingly obvious presence of large numbers of unlicensed illegally released animals have highlighted potential disease risks. We aimed to conduct a disease risk analysis, based on peer reviewed publications, for selection and health screening of Eurasian beavers prior to release into the wild in Britain. Adapted from the International Union for the Conservation of Nature’s ‘Guidelines for Disease Risk Analysis’, a four‐step process was used to formulate a disease risk analysis: 1) problem description; 2) hazard identification based on literature review; 3) risk assessment, which resulted in categorisation of pathogens into low, medium, and high risk; and 4) risk management: identification of mitigating measures, followed by risk re‐evaluation in light of the reported effectiveness of the mitigation measures. The highest‐risk pathogens identified in the literature review process included: parasites, specifically Cryptosporidium parvum, Echinococcus multilocularis, Eimeria spp., Fasciola hepatica, Giardia spp., Trichinella britovi; bacteria, specifically Escherichia coli, Franciscella tularensis, Mycobacterium avium, Salmonella spp., Yersinia spp.; a fungus Chrysosporium parvum (Emmonsia parva); and terrestrial rabies virus. Most could be mitigated by sourcing beavers from Britain. The rest could be mitigated by pre‐release testing procedures that are already established. The risk of introducing significant disease to humans, domestic animals, or wildlife by releasing into the wild in Britain a beaver that was captive‐bred in Britain or a wild beaver from Scotland, based on the current evidence of disease incidence, and assuming the use of robust, peer reviewed, pre‐release health screening techniques, can be viewed as low.

Scope of photodynamic therapy in periodontics.

Periodontal disease results from inflammation of the supporting structure of the teeth and in response to chronic infection caused by various periodontopathic bacteria. The mechanical removal of this biofilm and adjunctive use of antibacterial disinfectants and antibiotics have been the conventional methods of periodontal therapy. However, the removal of plaque and the reduction in the number of infectious organisms can be impaired in sites with difficult access. Photodynamic therapy (PDT) is a powerful laser-initiated photochemical reaction, involving the use of a photoactive dye (photosensitizer) activated by light of a specific wavelength in the presence of oxygen. Application of PDT in periodontics such as pocket debridement, gingivitis, and aggressive periodontitis continue to evolve into a mature clinical treatment modality and is considered as a promising novel approach for eradicating pathogenic bacteria in periodontitis.

Antimicrobial photodynamic therapy: An overview

Inflammatory periodontal disease caused by dental plaque is characterized by the clinical signs of inflammation and loss of periodontal tissue support. The mechanical removal of this biofilm and adjunctive use of antibacterial disinfectants and antibiotics have been the conventional methods of periodontal therapy. But the removal of plaque and the reduction in the number of infectious organisms can be impaired in sites with difficult access. The possibility of development of resistance to antibiotics by the target organism has led to the development of a new antimicrobial concept with fewer complications. Photodynamic therapy (PDT) involves the use of low power lasers with appropriate wavelength to kill micro organisms treated with a photosensitizer drug. PDT could be a useful adjunct to mechanical as well as antibiotics in eliminating periopathogenic bacteria.

IL-10 modulates host responses and lung damage induced by Pneumocystis carinii infection.

Host responses to Pneumocystis carinii infection mediate impairment of pulmonary function and contribute to the pathogenesis of pneumonia. IL-10 is known to inhibit inflammation and reduce the severity of pathology caused by a number of infectious organisms. In the present studies, IL-10-deficient (IL-10 knockout (KO)) mice were infected with P. carinii to determine whether the severity of pathogenesis and the efficiency of clearance of the organisms could be altered in the absence of IL-10. The clearance kinetics of P. carinii from IL-10 KO mice was significantly enhanced compared with that of wild-type (WT) mice. This corresponded to a more intense CD4(+) and CD8(+) T cell response as well as an earlier neutrophil response in the lungs of IL-10 KO mice. Furthermore, IL-12, IL-18, and IFN-gamma were found in the bronchoalveolar lavage fluids at earlier time points in IL-10 KO mice suggesting that alveolar macrophages were activated earlier than in WT mice. However, when CD4(+) cells were depleted from P. carinii-infected IL-10 KO mice, the ability to enhance clearance was lost. Furthermore, CD4-depleted IL-10 KO mice had significantly more lung injury than CD4-depleted WT mice even though the intensity of the inflammatory responses was similar. This was characterized by increased vascular leakage, decreased oxygenation, and decreased arterial pH. These data indicate that IL-10 down-regulates the immune response to P. carinii in WT mice; however, in the absence of CD4(+) T cells, IL-10 plays a critical role in controlling lung damage independent of modulating the inflammatory response.