VARIETIES 



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This rise of temperature may last from a few hours to a day, and 

 generally declines by crisis, with or without perspiration, on the 

 sixth day. The skin eruption usually lasts from two to eight days, 

 after which occasionally there is a desquamation, which may 

 continue for two to three weeks. 



The typical disease shows a first attack, a remission or inter- 

 mission, and a second attack, though the two attacks may become 

 merged together. The typical rash may be absent, and sometimes 

 the disease is so mild that it ends on the third day with the first 

 crisis. 



Convalescence may be quick and permanent, but, on the other 

 hand, it may be protracted and complicated with sequelae. Im- 

 munity is said to be complete twenty-four days after recovery 

 from a typical attack. 



Varieties. — It is now generally agreed that seven days' fever is 

 merely a variety of dengue fever, and therefore for comparison we 

 attach a description of it to this chapter. 



Megaw distinguishes the following varieties: — 



1. The Evanescent Type, with only a short slight attack of fever, 

 and corresponds with one variety of the old febricula, and cannot 

 be recognized except during an epidemic of dengue fever. 



2. The Interrupted Fever Type. — ^This is the three days' fever, 

 followed after one or two days of apyrexia with another attack, and 

 is typical dengue fever. True intermission is, however, rare, a fever 

 of the saddle-back type being much commoner. 



3. The Saddle-Back Type. — ^l^his is the so-called seven days' fever. 



4. The Continued Fever Type. — ^This is rare, and is characterized 

 by a lack of the usual remission or intermission of the fever. 



Complications. — ^The rarity of the symptoms of haemorrhage may 

 perhaps justify its mention as a complication. It takes place from 

 the mucosae, as akeady mentioned, of the nose, stomach, intestines, 

 and uterus. Hyperpyrexia may occur as a complication, but is 

 rare, and pleurisy, pericarditis, orchitis, endocarditis, and menin- 

 gitis sometimes complicate the disease and alter its characteristics. 

 We have seen enteric develop in three typical cases of dengue, and 

 appendicitis in two cases. 



Sequelae. — -The most important sequelae are the pains in the joints 

 and muscles, which worry patients considerably. This polyarthritis 

 affects joints of all kinds, both small and large, and is associated 

 with swellings, so that the condition is like rheumatism, but sali- 

 cylates are useless. The severe type is rare, but is very distressing, 

 and may last six to eight weeks or longer. It is not uncommon in a 

 milder form, with pain in various joints and slight swelling, and in 

 this condition may last for months. 



Relapses are said to take place, but Ashburn and Craig doubt 

 whether any occur a short time after an attack, as the persons who 

 were supposed to relapse, in their experience, really suffered from 

 malarial fever ; for, as a matter of fact, there is an acquired immunity 

 for some little time after an attack which prevents such relapses. 



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