184 
MALARIA 
ical attack terminates spontaneously the 
rigors stop before the fever paroxysms. A 
progressive decline in the height of the quo¬ 
tidian or tertian fever peaks is prognostic 
of the imminent cessation of the rigors; 
further decline in the height of the tem¬ 
perature after the chills have stopped fore¬ 
casts an early spontaneous termination of 
the clinical attack. 
Observations made by Kitchen (1940) on 
P. vivax paroxysms showed that (1) 90 per 
cent of the paroxysms in their patients 
occurred during the post meridian hours 
and 70 per cent from 3 to 9 p.m., (2) the 
majority of paroxysms initiated by rigors 
reached an observed maximum temperature 
of between 104° and 105° F, whereas the 
majority of rigorless elevations attained an 
observed maximum of between 100° and 
101° F, (3) fewer paroxysms exhibited 
rigors in the lighter attacks, (4) the maxi¬ 
mum fever experienced by an individual 
during his attack is not usually reached 
until about a week after clinical onset, (5) 
the majority of rigors fell within a dura¬ 
tion period of 45 to 60 minutes, and (6) 
over 70 per cent of rigors commenced with 
a temperature of less than 100° F and the 
largest group (36 per cent) terminated 
with a temperature of between 103° and 
104° F. 
Excepting their shorter duration, the 
paroxysms of P. vivax infections have little 
to distinguish them from the paroxysms of 
the other two malarial fevers of humans. 
The most noteworthy characteristic of the 
P. vivax infection is the rapid improvement 
in the patients condition within a few hours 
after the temperature has returned to nor¬ 
mal. The average duration of the P. vivax 
paroxysm is shorter than that due to P. 
malariae or P. falciparum. The febrile 
paroxysm has the same v *outline as that of 
quartan and but seldom presents the double 
peak often seen in the fewer curve of fal¬ 
ciparum malaria. 
Nausea and vomiting. Vomiting may be 
an early sign of an attack of P. vivax 
malaria. The patient may experience a 
violent nausea and the attack of vomiting 
may be almost projectile in nature. This 
generally occurs a few minutes before the 
malaria paroxysm, and may recur just be¬ 
fore each succeeding malaria chill. 
Jaundice is much less common in P. vivax 
than in P. falciparum infections. It is 
seldom seen during the first week or ten 
days of the clinical attack and is observed 
only in patients in whom a high degree of 
parasitization of erythrocytes has produced 
a rapid and extreme anemia. Jaundice is 
more apt to be observed in cases in which 
the red blood cell count has fallen below 
2,000,000 per cmm within a period of a week 
or ten days, than it is to be seen in cases 
where this degree of anemia has been at¬ 
tended by an acute clinical attack of three 
weeks or more. It would appear that the 
jaundice is due to rapid destruction of red 
blood cells and not to biliary obstruction. 
Herpes labialis is extremely common. 
The herpes ordinarily does not occur until 
the clinical course is well advanced. Occa¬ 
sionally the lesions may be so severe as to 
involve all the oral region and local inter- 
current infection may result. These lesions 
disappear in a few days or within a week 
after the clinical attack is terminated. 
Urticaria is not an uncommon finding in 
P. vivax infections and appears 1 to 2 hours 
after the rigor begins. It is transient, dis¬ 
appearing within 8 or 10 hours after its 
first manifestation, and may recur at the 
time of the next paroxysm. Its origin is 
not clear. 
Oedema. In a very few cases of P. vivax 
malaria a pronounced oedema of the legs 
and ankles is observed after the patients 
have experienced an acute clinical attack 
of 2 to 4 weeks duration and the red cell 
count is below two million. Ascites does 
not follow this oedema as may be the case 
in quartan malaria. There is no ready ex¬ 
planation for this phenomenon which dis¬ 
appears rather slowly, 3 to 4 weeks after 
cessation of the acute clinical attack. 
Splenic enlargement is not evident until 
the clinical course of the infection is well 
established (Stratman-Thomas 1935). In 
white adults the spleen is usually not palp¬ 
able until about 7 days after the first detec¬ 
tion of parasites. It was noted in Cyprus 
