Legionnaires' disease fever experience fever and muscle aches without pneumonia. They generally recover in 2-5 days without treatment. For Pontiac fever, the time between exposure and symptoms is generally a few hours to 2 days. Over 90% of cases of Legionnaires' disease are caused by "Legionella pneumophila." Other types include "L. longbeachae", "L. feeleii", "L. micdadei", and "L. anisa". Legionnaires' disease is usually spread by the breathing in of aerosolized water and/or soil contaminated with the "Legionella" bacteria. Experts have stated that Legionnaires' disease is not transmitted from person to person. In 2014, one case of possible spread from someone sick to
Rare disease assumption odds ratio (OR) is equal to 16 and the relative risk (RR) is equal to 8.65. Although the prevalence in our example equals 10% it is very difficult to apply the rare disease assumption because OR and RR can hardly be considered to be approximately the same. However, in this example the disease is not particularly "rare"; a 10% prevalence value means 1 in 10 people would have it. As the prevalence drops lower and lower, OR approaches the RR much more closely. This is one of the most problematic aspects of the rare disease assumption, since there is no