Summary In 72 consecutive cases of “ Q ” fever, with no death, the commonest symptoms were headache and anorexia. Myalgia, sore eyes, cough, chills and sweats were also frequent. The commonest signs were a relative bradycardia, hepatomegaly and splenomegaly. Minor chest signs were frequently found. The total duration of fever was 10 days or less in the majority of cases. The longest duration of continuous fever was 24 days, and of intermittent fever 34 days. Common laboratory findings included an increased erythrocyte sedimentation rate, the presence of atypical mononuclear cells during the acute illness and an absolute lymphocytosis during convalescence. Only three patients had radiologically demonstrable pneumonic changes. However, respiratory infection of a lower severity was frequent, and this suggests that local strains of Coxiella burneti may be less virulent than overseas strains. Subclinical involvement of the liver was common, and in seven cases there was electrocardiographic evidence of transient myocardopathy. About 70% of patients returned to work within six weeks from the onset, but the convalescence of the remainder was protracted. The duration of convalescence was prolonged with increasing age. Infection with C. burneti may become chronic. Cases are described in which “ Q ” fever was complicated by pneumonia, pleural effusion, thrombocytopenia, encephalitis and endocarditis, and in which the problem of chronicity is illustrated.

SummaryThe effect of tetracycline in the treatment of “Q” fever was investigated in 56 cases, by a technique of sequential analysis.Tetracycline reduced the duration of fever after commencement of treatment by approximately 50%. However, treatment must be commenced within the first three days of illness for this to be of importance.The severity of liver involvement, as estimated by “Bromsulphalein” retention, was significantly less in the treated group.The incidence of phase 1 complement‐fixing antibody six months or more after the onset was significantly less in the treated group.Treatment, essentially blind therapy, is probably justified only for patients who are severely ill, who are at risk of endocarditis because of previous cardiac disease, or who are in the older age groups.

1. An attempt has been made to follow up a consecutive series of seventy-two patients for the presence of Phase 1 C.F. antibody approximately 2 years or more after the acute illness. Fifty-one of the series were tested.2. Fifteen of the fifty-one patients had detectable amounts of antibody, generally in low titre.3. The presence of Phase 1 antibody correlated well, in older age-groups, with the duration of convalescence following the acute illness. There was no correlation with the duration of fever.4. All cases with Phase 1 antibody also had Phase 2 antibody, usually in slightly higher titre. In no case in which Phase 2 antibody was absent or present in low titre was Phase 1 antibody found.5. It is suggested that the presence of Phase 1 C.F. antibody is an indication of past persistent infection. It cannot necessarily be concluded that it is an indication of present persisting infection.We wish to thank Dr H. Silverstone, Senior Lecturer in Medical Statistics, University of Queensland, for statistical advice.

Summary In 72 consecutive cases of “Q” fever, hepatomegaly occurred in 47, and jaundice in three. Abnormal results for serum cephalin‐cholesterol flocculation, thymol turbidity or serum alkaline phosphatase activity were found in 61 cases. The test that most commonly produced an abnormal result was the cephalin‐cholesterol flocculation test (56 cases); this was followed by the serum alkaline phosphatase estimation (26 cases) and the thymol turbidity test (25 cases). During the first four weeks, the serum alkaline phosphatase level was related to the degree of cephalin‐cholesterol flocculation. Positive cephalin‐cholesterol flocculation commonly persisted for several months. Increased serum alkaline phosphatase levels were frequently the first, and occasionally the only, biochemical evidence of liver involvement. Quite high values were seen at times. Serum transaminase activity was only moderately increased, even in jaundiced patients. Liver biopsy was performed on 13 patients of the series, and on an additional jaundiced patient admitted to hospital subsequently. The predominant histological pattern was one of focal inflammation. This was of all grades, from small collections of mixed inflammatory cells to frank granulomas with central necrosis and fibroblastic reaction. In one patient a focal inflammatory lesion was found in the liver 17 weeks after the onset of the illness.

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