[Milker's fever, an occupational disease on the increase].

In order to obtain a better picture of the course of dairy farm fever, a leptospirosis caused by hardjo, an inquiry by means of questionnaires was conducted into its symptomatology and its trade-connected risk factors. The inquiry was performed in 32 seropositive dairy farmers and a matched-pair control group. All persons involved were living or working on contaminated farms. Of the seropositive persons 63% reported symptoms suggestive of dairy farm fever and in all of them there had been obvious fatigue of an extreme and protracted nature and an often lengthy period of recovery. The results of this investigation suggest underreporting of this disease. Besides vaccination and/or treatment of the dairy cattle adjustment of operations on dairy farms (e.g. wearing personal protection) might be feasible for prevention. The causal relationship between occupation and dairy farm fever indicates an occupational disease.