240 THE FILTERABLE VIRUSES 



constantly in the skin of scarlet fever cases, also in the skin in cases 

 of measles and in anti-toxin rashes. 



By several observers they have been considered to be artefacts or 

 degeneration products in the epithelial cells. 



The virus of scarlatina is now considered to be filterable and 

 transmissible to monkeys. 



Dengue Fever. This is an acute infectious disease of the 

 tropics, characterized by fever, skin eruptions, rheumatoid pains, an 

 afebrile remission and a febrile end, due to a filterable virus, trans- 

 mitted by the mosquito, Culex fagitans. The virus is in the blood 

 stream. One attack gives immunity; little is known of the virus. 



Three-day or Sand-fly Fever. A mild infectious disease 

 chiefly of southeastern Europe, due to a virus which will pass 

 through a bacteria-proof filter and is transmitted by the sand- fly, 

 Phlebotomus pappatacii. Cultures have not been obtained. 



Typhus Fever or Spotted Fever. An acute epidemic disease 

 with prolonged course, prostration, a macular eruption, ending by 

 crisis, transmitted by the body louse, Pediculus vestamenti. The 

 virus is filterable but is obtained with difficulty. It is found best 

 toward the end of the fever. It may be transmitted to monkeys. 

 It has not been cultivated. It is destroyed quickly at 52 C. 

 Brill's disease is a mild typhus fever. 



Poliomyelitis. An acute infectious disease, chiefly of children 

 characterized by a short febrile attack, followed by a rapidly 

 appearing paralysis in various muscles. Means of transmission 

 from child to child is unknown, but it has lately been shown that 

 the stable fly, Stomoxys calcitrant, can transmit it from monkey to 

 monkey. The virus is in the central nervous system, lymphatic 

 system, blood, succus entericus, nasal mucous and various organs. 

 It is said to be constantly in the nasal mucosa of not only patients 

 but of the well in their vicinity. This is supposed to be its portal 

 of entry to the body. It is transmitted to monkeys by injecting 

 emulsions of the virus-containing parts into the brain, blood- 

 stream or peritoneum. It can be filtered through porcelain. It 



