m 
Lice and Disease 
III. MISCELLANEOUS INFECTIVE DISEASES WHICH LICE 
MAY SERVE TO SPREAD. 
Lice have been suspected as possible carriers of plague, typhoid 
fever, leprosy and beri-beri, the evidence adduced being as follows: 
Plague: Bulloch and Douglas (1909, p. 374) state, without giving 
a reference, that Herzog in Manila found Bacillus pestis in three head- 
lice removed from a child dead of plague. Swellengrebel and Often 
(vn. 1914, p. 601), in Dutch East India, experimented with clothes-lice 
taken from the garments of persons dead of plague. The clothes 
were chloroformed and the insects shaken out after 15 minutes; 24 hours 
later, the lice were crushed and inoculated cutaneously in lots of 11 
to 254 into guinea-pigs. Of nine guinea-pigs that were thus inoculated, 
seven died, of plague. The authors conclude that lice may convey 
plague under natural conditions by being crushed upon the skin. Raadt 
(1916, p. 39) took head-lice from a female plague patient, ground them 
up in salt solution and inoculated rodents therewith; all of the animals 
(five) thus inoculated died of plague. 
There is no evidence that plague can be conveyed by the bites of 
infected lice, as occurs in the case of fleas. 
Typhoid Fever: Abe (ix. 1907, p. 1929) believes that lice may play 
an important part in the spread of enteric fever. We know that 
Bacillus typhosus occurs in the blood, the organism having been found 
in about 93 % of blood samples taken from the roseola spots. Abe, 
who examined head- and body-lice fed on typhoid patients, found 
that 75 % of the insects harboured the bacilli. This requires con¬ 
firmation. 
Leprosy: Joly (1898, pp. 67-70) cites Sabrazes as suspecting lice 
of carrying this disease. It is well known that Bacillus leprae is present 
in enormous numbers in the skin in cases of cutaneous leprosy. Joly 
noted the prevalence of lice among the poorer classes in Algeria, these 
classes furnishing the greater number of lepers in that country. Lice 
which feed on such lepers cannot avoid imbibing the bacilli; and might- 
well transfer the bacillus from affected to healthy individuals. Leprosy 
bacilli have since been found in two head-lice out of many examined 
by McCoy and Clegg (1912, p. 1464). It has still to be proved that 
lice can convey leprosy. 
Beri-beri: Ma-nson (1909, p. 627) has advanced the hypothesis that 
lice may possibly transmit beri-beri, a disease whose cause still remains 
undetermined. 
