MICROCOCCI 229 



This is an endemic pyrexial disease, occasionally pre- 

 vailing as an epidemic, having a long and indefinite 

 duration and an irregular course, with, almost invariably, 

 pyrexial relapses of an undulatory type. The illness 

 may last from 20 to 300 or more days, averaging 60 to 

 70 days, and having a mortality of about 2 per cent. 

 The chief mode of spread formerly was the ingestion of 

 goat's milk, in which the micrococcus was being excreted. 

 The urine of patients is also infectious. The Mediterranean 

 Fever Commission conclude that Malta fever is a septi- 

 caemia, in which the specific organism can be recovered 

 from the peripheral blood, the urine, and the faeces. 

 Infection is not conveyed by the sputum, sweat, breath, 

 or skin-scrapings of patients. It does not take place if 

 contact is limited to skin surfaces only, and if urinary and 

 faecal contamination are excluded. It is probably occasion- 

 ally conveyed by sexual intercourse. About 10 per cent of 

 the Maltese goats excrete the micrococcus, and 50 per cent 

 give a positive agglutination reaction. Goat's milk is prob- 

 ably the prime source of the disease in most cases if not in all. 



Characteristics. Micrococcus melitensis is a very small 

 coccus, 0-3 micron in diameter, occurs singly or in pairs, 

 and at times in short chains. It is non-motile and Gram- 

 negative ; does not ferment glucose (unlike ordinary strepto- 

 coccus), and renders milk slowly alkaline. It is easily 

 stained. Some observers describe it as a minute bacillus. 



Cultures. On agar, it forms minute transparent colonies 

 likened to dew-drops, but only after 2 to 3 days' culture at 

 37-5 C. On gelatin, liquefaction is not produced. In 

 broth, no indol is formed, nor odour ; but a slight turbidity. 

 On potato, a moist transparent growth is formed. 



Agglutination of the organism by the patient's serum 

 is shown after the fifth day. In some cases it persists for 

 years. 



Resistance. Is a vigorous organism and resists desicca- 

 tion for weeks. 



Malta Fever. Other symptoms of the disease are : 

 shifting rheumatic-like pains, profuse sweatings, con- 

 stipation, local neuritis, emaciation, and almost always 

 enlarged spleen. The micrococcus may be isolated by 

 splenic puncture or from the blood. 



