MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 791 



These infections are indicated by dullness, lack of appetite, fever, 

 inflammation of the udder, and by small nodules or cord-like swelling 

 within and lengthwise of the teat. 



It must be borne in mind that the infecting microorganism is the 

 thing to be controlled. Outbreaks of this disease frequently have origin 

 in infected cows added to the herd. Some cows are unsuspected "car- 

 riers." New cows should be suspected until found free by careful 

 examination. 



Affected cows should be isolated if possible, and always milked last. 

 Their milk should be boiled and fed to hogs, and the milker's hands 

 suitably disinfected. 



MALTA FEVER* 



Micrococcus melitensis 



This disease is endemic along the shores of the Mediterranean, in 

 South Africa, India, China, the Philippines, and the West Indies. 



The period of incubation is usually about six to ten days. 



The ordinary variety shows an intermittent or undulatory fever 

 which may be protracted to six months or more, accompanied by consti- 

 pation and general debility with various complications such as neural- 

 gias, arthritis, orchitis, etc. Relapses occur after periods of absence of 

 symptoms. Malignant cases are described which may be fatal in a 

 week or ten days. The mortality is 2 per cent and no characteristic 

 pathological changes are found. 



The etiological factor is M. melitensis and was described by Bruce 

 in 1887. - 



The organism can be obtained from the blood and in many cases 

 from the urine. The most recently reported favorable medium for 

 blood cultures is peptone broth with the addition of bile. 



It is generally recognized as an oval coccus, although it is also described as a 

 bacillus. Its maximum measurements have been found to be o.Sju by 0.53^1, its 

 minimum diameters 0.55^ by 0.4^. It occurs singly, in pairs, in irregular groups and 

 in short chains. (Recently the organism has been described as motile and possessing 

 a single flagellum at the extremity of the long diameter of the oval coccus.) It 

 stains by ordinary aniline dyes and is Gram-negative. It grows slowly at room 

 temperature, better at body temperature and does not seem to be markedly sensitive 

 to acidity or alkalinity of reaction. It grows aerobically. On plain agar after 



* Prepared by Edward Fidlar 



