828 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



Isolation and disinfection are to be recommended on general prin- 

 ciples. Immunization by present methods appears to be very 

 questionable. 



LEPROSY* 

 Bacterium lepra 



Leprosy is a disease almost as old as history itself but modern leprosy 

 cannot be definitely identified with the leprosy of the Old Testament, 

 and to-day is found chiefly in oriental countries and in Norway, Iceland 

 and Russia. The disease is present in some of the provinces of Canada 

 and in the States of Louisiana, California and Minnesota, and practic- 

 ally limited to Scandinavians in the latter states. The natural incuba- 

 tion period is difficult to ascertain but is probably a matter of months 

 or years. 



Clinically there are two main types of the disease, the tubercular 

 or nodular and the anaesthetic types. In the first form, nodules develop 

 in the face or other parts of the body usually preceded by an erythe- 

 matous patch. The mucous membranes become affected more or less 

 extensively and the hair and eyebrows fall out. In the anaesthetic 

 type after various disturbances of sensation which may sometimes be 

 followed by maculae there develop areas of anaesthesia. Bullae, ulcers 

 and necrosis may occur with resulting deformities or again this type 

 may exist for years without leading to such results. 



The bacteria of leprosy were first described by Hansen in 1879 and 

 almost at the same time Neisser published similar descriptions. Culti- 

 vation of Bact. lepra has been successful in the hands of Clegg, Duval 

 and others. 



The microorganisms can be shown in tissue by the use of the Ziehl- 

 Nielsen or Gabbet methods. 



In tissue the bacterium closely resembles the bacterium of tuberculosis, but 

 usually appears somewhat longer (5^ to 7/1) and thicker (about O.SJLI) straighter and 

 less beaded. Flagella have not been demonstrated. The bacterium can be stained 

 with the ordinary aniline dyes. It is Gram-positive. The staining reactions on the 

 whole are like those of Bact. tuberculosis but Bact. lepra stains more readily and also 



* Prepared by Edward Fidlar. 



