60 CIRCULAR 9 7 7. U. S. DEPARTMENT OF AGRICULTURE 



incidence usually is not high in military personnel. It is" prevalent 

 in some foreign countries and is considered to be an important 

 military problem. 



At the Orlando laboratory an emulsifiable concentrate was developed 

 for use in a spray or wash for controlling both lice and scabies. Re- 

 search at this laboratory led to recommendations for louse control 

 that were adopted by the military during World War II and were 

 applied extensively under various field conditions. During the Ko- 

 rean war body lice that were highly resistant to DDT were encoun- 

 tered, and further research was required to develop a substitute 

 insecticide. 



The following control measures are those developed or investigated 

 for the Armed Forces at Orlando, although other methods, such as 

 methyl bromide fumigation and steam sterilization (No. 15, table 3; 

 Xos. 2 and 3, table 4) of clothing, are also in use. 



BODY LICE 



The body louse spends its life in the clothing except for a short 

 time on the skin while feeding. The eggs are laid on the cloth, at- 

 tached to the fibers. Woolen cloth is much preferred to other kinds. 

 In looking for infestations one should examine the clothing along the 

 seams and folds, especially on the inside of the underwear. Because 

 of the habits of this louse, control measures are directed largely 

 toward the treatment of clothing. 



Louse Powders 



Three kinds of louse powders are carried as stock items or are 

 under specification — 10 percent of DDT in pyrophyllite (No. 5), 1 

 percent of lindane in pyrophyllite (No. 3), and MYL-type powder 

 (No. 6), containing pyrethrins with or without allethrin, a pyre thrum 

 synergist, and a louse ovicide. 



The 10-percent DDT powder is the standard material issued for 

 louse control. It is packaged in 2-ounce sifter-top cans for individual 

 use and in 5- and 25-pound containers for mass use. With the sifter- 

 top can the powder should be applied over the inner surface of the 

 underwear (fig. 24), with special attention to the seams, and evenly 

 distributed by hand. The seams inside the shirt and trousers should 

 be treated in a similar manner. The socks should also be treated. 

 About 1 ounce of powder is necessary for one treatment. If it is not 

 feasible to remove the clothing, the powder may be shaken into the 

 clothing through the openings in the shirt and trousers. 



DDT is rather slow in action, but the lice are usually immobilized 

 in less than 6 hours. It is not ovicidal, but owing to its long-lasting 

 effect a single application can eradicate an infestation since the eggs 

 normally hatch in less than 2 weeks. 



Mass treatment has been employed with great success for the 

 control of lice in large units of troops and prisoners of war and for 

 control of epidemic typhus in civilian populations. A hand-operated 

 plunger duster (fig. 25) and a gasoline-powered unit with 10 duster 

 heads (fig. 26) are issue items (Nos. 6 and 7). The powder is blown 

 between the underwear and the skin. It is blown down the neck of 

 the shirt, up the sleeves, and into the loosened trousers from as many 



