Legionnaires Disease is a potentially fatal form of pneumonia which can affect anybody, but which principally affects those who are susceptible because of age, illness and immune system suppression.
It is caused by the bacterium Legionella pneumophila and related bacteria that can be found naturally in environmental water sources such as rivers, lakes and reservoirs, usually in low numbers. As they are commonly found in environmental sources they may also be found in purpose built water systems such as cooling towers, evaporative condensers and whirlpool spas. If conditions are favourable the bacterium may grow creating conditions in which the risk from legionnaires' disease is increased.
Written by Dr Charlie Easmon, specialist adviser in travel medicine
What is cholera
Cholera is an infectious disease caused by a bacterial toxin that affects the absorption of water in the small intestine, released from Vibrio cholerae. The cholera toxin has the unpleasant ability to affect the cells of the gastrointestinal tract, so that the affected person doesn't just get ordinary diarrhoea but also starts to lose large quantities of fluid. It's this fluid loss that can be serious.
In severe cases, it produces violent diarrhoea within only a few days. The dangerous aspect of cholera is the vast loss of fluid that can occur in a short space of time. It's particularly dangerous in children in developing countries.
If untreated, the loss of fluid can be fatal within 24 hours of developing the disease. On the other hand, treatment is simple: replace the fluid with the right mix of sugar and salts – water alone is not adequately absorbed.
Improved sanitation and hygiene are the basic foundation of the fight against cholera in those countries where it occurs.
What causes cholera?
How is cholera transmitted?
Bacteria are excreted in faeces and if this comes into contact with drinking water, the bacteria can infect people.
Bacteria can also...