2204 



THE DERMATOZOIASES 



Formiciasis. 



Ant-bites usually only produce local pain, inflammation, and swelling ; but 

 the larger tropical ants may cause faintness, shivering, and even temporary 

 paralysis by their bites. In Ceylon the very small ants, which infest the beds, 

 produce urticarial pomp hi. These bites are best treated by applying a 

 solution of carbohc acid (i in 20), and as a preventative against ants infecting 

 beds some powdered camphor may be dusted in the sheets (see p. 222). 



2. Dermatites caused by Blistering Fluids excreted by the Adult. 



The insects which act in this manner are the well-known * blister 

 heetUs ' (vide p. 226), which cause the eruption called ' Seasonal 

 bullous dermatitis' (synonym, Seasonal vesicular dermatitis), which 

 we will now describe. 



Seasonal Bullous Dermatitis. 



Definition. — -Seasonal bullous dermatitis is characterized by an 

 epidemic of bullse of varying{size and shape in healthy people at a 

 definite season of the year. The bullae or blisters are followed by 

 sensations of itching, burning, or jpain, and are caused by blister 

 beetles. 



Historical. — Beetles have been known to cause bhsters and 

 eschars on the skin since jthe days of Archigenes, a contemporary of 

 Celsus, or, according to 'other authors, since the time of Aretaeus 

 the Cappadocian. Pliny says that authorities differ as to the origin 

 of the blistering jfiuid, some thinking that it comes from the mouth 

 and others from the feet.|^ Moffat, in 1634, wrote a long chapter on 

 these insects, and Linnseus, Fabricius, and Latreille gathered to- 

 gether quite an amount of information on these beetles and their 

 varieties. 



Tn 1890 Beauregard wrote a large book on ' Les Insectes Vesi- 

 cants,' but notwithstanding all this ancient and modern knowledge 

 works on tropical medicine were singularly silent on the subject. 



In 1912 P. Da Silva drew attention to an outbreak of this eruption 

 among cultivators on the banks of the rivers Sao Francisco, Itapi- 

 curu, and Jacuricy, in the interior of Bahia, which was traced to a 

 vesicant beetle, PcBderus columbinus. In 1913 Adolf Eysell men- 

 tioned P. peregrinus as the cause of the same eruption in the island 

 of Sunda, in the Malay Archipelago. In 1915 Rodhain and Houssiau 

 saw the disease in Leopoldville, in the Belgian Congo, and Bequaret 

 at Boma. In 1916 P. A. Ross noted it at Nairobi, in British East 

 Africa, and in 1917 Chalmers and King gave an account of its occur- 

 rence in Khartoum, Anglo-Egyptian Sudan. 



etiology. — The bhsters are caused by the fluid which exudes from 

 the joints of the legs, especially the so-called knee-joint of certain 

 species of insects belonging to the order Coleoptera Linnseus, I735> 

 and to the families StaphylinidcB Leach, 1817, and CantharidcB Leach, 

 1817. The following is a list of those known to cause the complaint, 

 though doubtless many more insects can do so equally well : — 



