Vol 39 No. 1-4, May-August 1929
No. of Page: 40





Filterable Virus Diseases of Man and Animals

Varicella: Chicken Pox


By Earl Baldwin McKinley


Definition. Varicella is a markedly contagious disease, characterized by a cutaneous eruption that is confined to the superficial layers of the skin. Chicken pox is usually a harmless disease and is rarely malignant. Death never results from this disease, and as a rule there are only mild constitutional symtoms associated with it. The exact cause of chicken pox is unknown, but it is thought to be caused by a filterable virus.

History. Undoubtedly chicken pox has existed since ancient times, thought it was confused with small pox (see Chaprter II) until the nineteenth century. By most the early physicians this disease was regarded as a benign form of smallpox. Chicken pox has always been an mild disease, but it was early recognized to be highly contagious and is one of the most important diseases of children from the standpoint of loss of time from schools, and is an important consideration in institutions such as hospitals for children. We are informed by Vaughan that even during the latter half of the nineteenth century Hebra, of the Department of Dermatology in the University of Vienna, taught that chicken pox is a mild form of smallpox. There is no question as to the relation of chicken pox to smallpox since it is now well known that neither condition will give  any immunity against the other, although an attack of either disease confers an immunity against a subsequent attack of the same disease. Chicken pox is found everywhere. No age is exempt, although the majority of cases occur in the fifth or sixth year. It has been estimated that 2 per cent of adults have had the disease during childhood. The disease is more prevalent in girls than in boys, and among white children than among colored chidlren.

The virus of chicken pox. Little is known concerning the virus causing this disease. Numerous attempts have been made to infect human beings articially with varicella material and to transmit the disease to laboratory animals. Bryce, in  1816, inculated the vesicular material taken from cases of chicken pox representing all stages of the disease, into the skin of children who had never had smallpox or chicken pox. None of the children with varicellous material and in seventeen of them obtained a slight local reaction, while nine developed a general reaction. Other investigators have had more or less success, but in general, the reports dealing with experimental chicken pox are at most unsatisfactory. In animals practically, no success has been met with. Rivers and Tillett have, succeeded in inducing lessions in rabbits and monkeys with material taken from chicken-pox vesicles. The possible relation of varicella to herpes zoster has been the subject of numerous papers during the last few years. Le Feuvre is of the opinion that these two diseases . . . . read more