218 BACTERIA IN MILK AND MILK PRODUCTS 



Characteristics of Milk-borne Epidemics 



The following are the chief characteristics of infectious disease 

 carried by milk : — 



(a) There is a special incidence of disease upon the track of the 

 implicated milk supply. It is localised to such areas. 



(6) Better-class houses and persons generally suffer most. 



(c) Milk drinkers are chiefly affected, and those suffer most who 

 are large consumers of raw milk. 



(d) Women and children suffer most, and frequently adults suffer 

 proportionately more than children. 



(e) Incubation periods are shortened. 



(/) There is a sudden onset and a rapid decline. 

 (g) Multiple cases in one house occur simultaneously. 

 (h) Chnically, the attacks of disease are often mild, contact infec- 

 tivity is reduced, and the mortality rate is lower than usual. 



Other Diseases Conveyed by Milk 



In addition to the above, there are other diseases spread by 

 means of polluted mUk. From time to time exceptional cases have 

 occurred in which diseases like anthrax, or some forms of foot-and- 

 mouth disease have been spread by this means. But it is not to 

 such rare cases that we refer. There are three very common diseases 

 in which milk has been proved to play a not inconsiderable part, 

 viz., thriosh, sore throat, and diarrhoea. 



Thrush. — The mould which gives rise to the curd-like patches in 

 the throats of children, and which is known as Oidium albicans, 

 frequently occurs in milk. Soft, white specks are seen on the 

 tongue and mucous membrane of the cheeks and Ups, looking not 

 unlike particles of milk curd. If a scraping be placed upon a glass 

 slide with a drop of glycerine, and examined by means of the micro- 

 scope, the spores and mycelial threads of this mould will be seen. 

 The spores are oval, and possess a definite capsule. The threads are 

 branched and jointed at somewhat long intervals. Milk affords an 

 excellent medium for the growth of this parasite. Thus undoubtedly 

 we must hold milk partly responsible for spreading this complaint. 

 Penicillium, Aspergillus, and Muoor are also frequent moulds in 

 milk. 



Sore -Throat Illnesses. — The obscure mUk-borne epidemics of 

 which sore throat has been the chief symptom, are among the 

 most interesting of all the diseases conveyed by milk. The usual 

 symptoms are congestion of the tonsils and mucous membrane of 

 the throat, with sometimes ulceration, enlargement of the cervical 

 glands, and some pyrexia, and general malaise. In not a few 



