When an individual develops a chronic ailment as the result of the work he performs or due to his occupational activity, it is said that the person has developed an occupational disease. It is an ailment that is directly linked with work performed. In general, it is usually the case that more than one individual who performs the same type of work will be afflicted with the same type of symptoms. The frequency of a particular disease appearing within a group of individuals who perform the same task is generally much higher than the rate of that disease found in the general population.