An outbreak of leptospirosis in cattle and man.

On 20 May 1983 a 23 year old dairy farmer became ill with headache and aching joints. His symptoms worsened during the next week, and he was admitted to hospital on 27 May because he was vomiting and had neck stiffness. He was thought to have viral meningitis; a lumbar puncture produced cerebrospinal fluid containing 300 lymphocytes and 30 polymorphs per ,ul; protein and glucose were within normal limits. He was much better the next morning and was discharged on 29 May. He has remained well. His brother aged 20 took over the milking, and within the first few days he noted that five cows had an atypical mastitis, with a sudden drop in milk yield and clots in two or more quarters of the udder. There was, however, no pain or swelling of the udder. On 8 June a cow aborted. The fetus was submitted to Starcross Veterinary Investigation Centre, where infection with Leptospira interrogans serogroup Hebdomadis serotype hardjo was confirmed by fluorescence antibody test in fetal lung and kidney, with the help of the Central Veterinary Laboratory, Weybridge. Subsequently the cow was found to have an antibody titre to L hardjo on the microscopic agglutination test of 1/1600 at abortion declining to 1/400 after two weeks, confirming recent infection. The farmer's mother read in the farming press a description of the human disease caused by L hardjo which closely matched her son's illness and communicated her suspicions to their general practitioner. A specimen of her son's blood was collected on 5 July and compared with the specimen taken on 25 May. Rising titres from <1/10 to 1/40 to the leptospira group antigen were shown by complement fixation test. The Leptospira Reference Unit reported titres rising from < 1/40 to 1/1280 to serogroup Hebdomadis, serovar hardjo predominating, in the microscopic agglutination test. On 1 July the farmer's brother developed an influenza-like illness. He was treated at home by the general practitioner with oral phenoxymethylpenicillin 500 mg four times daily, and his symptoms improved at first, but on 6 July he was admitted to hospital with headache, vomiting, and photophobia. No abnormal physical signs were observed, and his cerebrospinal fluid contained 240 red cells, three polymorphs, and three lymphocytes per ,ul. He was treated with intravenous penicillin for five days followed by oral phenoxymethylpenicillin (500 mg four times daily) for a week. He was discharged from hospital on 12 July still suffering from mild frontal headaches. Sera collected