DENGUE 377 



An epidemic or pandemic takes place about every twenty years 

 (Manson). 



Often 75 per cent, of the population are attacked. 



It prefers the coast line, deltas and valleys of great rivers, but there 

 are many exceptions to this. 



In 1870 to 1873 it spread all over India. 



iETIOLOGY. 



An unknown organism living in the blood is the cause. 



An intravenous injection of 20 c.c. of dengue-fever blood, filtered 

 or unfiltered, produces, after an incubation of two to three days, the 

 typical symptoms of the disease. 



This organism passes through a filter which will retain M. melit- 

 ensis, the filtrate producing the fever. 



Some people appear to have natural immunity against the disease. 



An attack produces a temporary acquired immunity. 



Hot countries suffer most. Cold limits the disease. 



SYMPTOMATOLOGY. 



Incubation, two to six days. 



Prodromata are usually absent. 



Onset is sudden, introduced often by some severe cold, extreme 

 fatigue, deep flushing of the face, a shivering in man, convulsions or 

 delirium in children. 



Initial fever commences with a rapidly rising temperature, 103*-* to 

 106° F., pulse quickens, 90 to 140, buccal mucosa becomes congested, 

 conjunctivae injected, while occasionallv vomiting and diarrhoea are 

 present. 



Severe pains in the head, eyeballs, lumbar region and legs. 



Joints when moved actively cause agonizing pain, but when moved 

 passively are almost painless, hence the pain is really caused by the 

 adjoining muscles. Very rarely are the joints red and swollen. 



The patient may be unable to w^alk because of the pains. 



Gastric disturbance and vomiting may occur. 



The lymphatic glands are not enlarged. 



Insomnia and delirium are not infrequent. 



Leucopenia is almost constant, 3,800 per c.mm. 



The small lymphocytes are increased and the polvmorphonuclears 

 decreased. OtherAvise the blood is normal. 



Intermission or remission then occurs from the second to the fourth 

 day as a rule. The temperature falls by crisis, accompanied bv profuse 

 perspiration, diuresis, diarrhoea, and sometimes epistaxis. The latter 

 relieves the headache at once. The pains almost disappear and the 

 patient may be able to resume his work. 



