From 2005 to 2009, cruise-related LD cases accounted for ∼5% of travel-associated legionelloses reported to the U.S. SLDSS and 7.6% of cases on average in Europe during the same time frame. As previously reported, Legionella has become a problem for cruise ships in a similar fashion as for hotels; both must manage complex air-handling networks as well as potable and recreational water distribution systems with the potential for Legionella growth and transmission. Defective or improperly maintained on board water systems may present an increased LD risk for the older average cruising demographic, which is between 55 and 61 years of age .
Eighty-eight cases of Legionnaires’ disease, of which one was fatal, have occurred in the south-western part of Edinburgh since 24 May 2012 when the first case was reported to have fallen ill. Although the exact source of the outbreak has not yet been identified, the clustering of cases in the southwestern part of Edinburgh and the evolving number of cases suggests an ongoing source in this part of the city. Environmental investigations to confirm the source and treatment of local cooling towers in the area are ongoing. The implementation of precautionary control measures at any identified suspected risk installations are of utmost importance to decrease the risk of exposure. In the absence of an identified and controlled source of Legionella, there may be an ongoing risk of exposure to Legionella for persons living or visiting the area, although the risk is assessed to be low for the general public due to implemented control measures.
Complete eradication of Legionella does not seem to be a possibility. Proliferation however, can be controlled using thermal or chemical (ie. silver, H2O2) water treatments as well as regular testing of man-made reservoirs. This practice is guided and monitored by The Health and Safety Executive and British Standards Institute. A recent Scottish study identified that 15 of 24 potting mixes tested positive for the presence of multiple Legionella spp.
The 1970s marked the beginning of a new era for biology with the development of recombinant DNA technology. This allowed the manipulation of DNA making the study of genes possible and providing the ability to harness them for the development of novel medicine and biotechnology. The most common format of recombinant DNA experiments includes the extraction DNA from a donor organism which is enzymatically cleaved and joined to another cloning vector for the formation of a new recombinant molecule. This cloning-vector is then transferred and maintained within a host cell such as E. coli (transformation). The host cells which are able to take up the DNA construct are then identified and if required, the DNA construct can be manipulated to ensure that the protein product encoded by the cloned DNA sequence is produced.
Recombinant DNA technology has had a profound effect on fields such as medical genetics through its astonishing capabilities of allowing the identification and isolation of a single gene or DNA segment of interest from the vast number genes present in a genome. With this technology it has become possible to treat various diseases through the insertion of new genes, replacing damaged or faulty genes in the human body and bringing revolutionary changes to the field of medicine.
There are new approaches being made towards treatment through the biosynthesis of therapeutically important products and eventually through gene therapy. The former was already been achieved through the insertion of a gene which codes for a particular peptide into suitable vectors and is cloned to enable the synthesis of medical products (insulin and human growth hormone). This lead to a variety of other products being made in E. Coli, such as tumour necrosis factor for the treatment of certain tumour cells and interleukin-2 for HIV infection.
The production of insulin is extremely important as diabetic patients often require injections of human insulin. Through the use of recombinant DNA, human insulin can now be mass produced across the pharmaceutical industry rather than obtaining it through animal sources.. Furthermore the production of blood clotting factors such haemophilic clotting factor VII has reduced the requirements of blood donations and allows larger quantities to be used.