War Surgery and Medicine
Clinical details of the epidemic which was investigated at 2 NZ General Hospital have been published in the British Medical Journal, 16 February 1946, Vol. 1, page 227. The principal clinical features will be here summarised.
The epidemic occurred between February and April 1945, and during this period 511 cases were reported in the area, 161 of which were treated at 2 NZ General Hospital. Fifty consecutive cases were studied in detail clinically and by serial pathological and radiological investigation. In most there was a prodromal period of about six days. The actual onset was abrupt in 96 per cent of cases. Severe headache, malaise, lassitude, and anorexia were the most constant symptoms. Pyrexia from the onset averaged 8.6 days: was over 103 degrees in 70 per cent of cases and defervescence was by lysis in 86 per cent. The pulse followed the temperature though showing a tendency to a relative bradycardia. The respiratory rate was little affected. Cough occurred about the fifth day and was present in 94 per cent, although it was not an outstanding feature. Sputum was scanty and in 28 per cent contained blood. Chest pains occurred in 46 page 585 per cent of cases. (These symptoms were similar to those of the patients treated in 2 NZ General Hospital a year previously.)
Severe toxaemia was a feature of some and one-third showed generalised rhonchi on admission, but the most characteristic sign was a localised patch of sticky persistent crepitations heard on an average on the sixth day from the onset of the acute symptoms. Pleural friction occurred in 26 per cent of those with chest pains. There was usually enlargement of glands and the spleen was palpable in 36 per cent of cases. Scanty small pink macules fading on pressure were observed on the chest, back, and flanks in the early stages of the disease in 34 per cent of cases.
The results of serial pathological investigation can be summarised in brief. The white count revealed a slight polymorphonuclear response, followed by a slight depression which was maximal at the end of the first week. Thereafter there was a rise of polymorphs and lymphocytes, reaching a peak at the sixteenth to eighteenth day. Differential counts showed a slight relative lymphocytosis after the initial period. The blood sedimentation rate was elevated for two to three weeks. Cephalin-cholesterol flocculation was insignificant early in the disease, but increased rapidly after convalescence had been established in the second week, thereafter falling slowly. Using horse cells, a significant positive heterophil antibody reaction was found in 36 per cent of the cases at some stage of the disease. All but three, which were weakly positive, gave negative tests for cold agglutinins at all stages of the disease.
Posterior-anterior and lateral X-ray studies were made in all cases. The characteristic findings were the localisation of the lesion to one or more broncho-pulmonary segments. The infiltrations could be described as hazy, mottled densities. These investigations also revealed the importance of the lateral studies for the demonstrations of lesions situated behind the heart shadow or in that portion of the lung situated behind the summit of the dome of the diaphragm. In the majority complete radiological resolution occurred within six weeks of the onset. No specific treatment was found to be of any use and sulphonamides had no effect.
Serological investigation of some of these cases was carried out two years later by Caughey and Dudgeon. Sera from twenty of the cases were tested for complement fixation against antigen prepared from a strain of the Rickettsia burneti isolated in Italy. Nineteen gave a positive complement fixation test. The sera were also tested for antibody to the virus of psittacosis, and all were negative. In view of these findings, it seemed reasonable to assume that the infective agent in these cases was the Italian strain of the Rickettsia burneti.