THE INFECTION IN THE INTERMEDIATE HOST 
SYMPTOMATOLOGY: VIVAX MALARIA 
By WARREN K. STRATMAN-THOMAS 
DIVISION OF PREVENTIVE MEDICINE, UNIVERSITY OF TENNESSEE SCHOOL OF MEDICINE, MEMPHIS, TENN. 
Vivax malaria, due to infection by Plas¬ 
modium vivax, is the predominant malarial 
fever in temperate endemic zones. The 
terms “tertian malaria” or “benign ter¬ 
tian malaria,” by which it is commonly 
known, while descriptive in so far as the 
cycle of the parasite is concerned, are per¬ 
haps unfortunate in that they do not tend 
to give a representative impression of the 
clinical course. 
Objective Symptoms 
During the incubation period there are 
no objective • symptoms unless one accepts 
the first detection of parasites in the periph¬ 
eral blood smears as marking the end 
of the incubation period. In the experience 
of Boyd and Stratman-Thomas (1934c), this 
most commonly occurred on the 13th day 
following inoculation. In some instances 
this marking point occurs a few days fol¬ 
lowing the clinical onset. 
Fever. Fever of 100° F marking the 
clinical onset is usually not observed be¬ 
fore the 10th day after natural inoculation. 
If, however, a large number of infected 
mosquitoes has been used to inoculate a 
patient (as has been done in the admin¬ 
istration of therapeutic malaria), a tem¬ 
perature of 100° F or higher may appear 
as early as the eighth day. 
The first objective symptom to appear is 
a fever of about 100° F or above, which 
occurs within 1 to 3 days preceding or fol¬ 
lowing the first appearance of P. vivax in 
the blood. The fever may be continuous or 
remittent over a period of 1 to 3 days 
(initial stage of James 1926) or may be an 
intermitten quotidian or, rarely following 
the onset, tertian. No chills occur during 
the period of continued fever. In P. vivax 
infections, unlike P. falciparum infections, 
a period of continued fever is rarely seen 
excepting at the end of the incubation 
period. The intermittent febrile paroxysms 
may assume a variety of sequences, quotid¬ 
ian fever being followed by tertian; a series 
of tertian changing to quotidian, even iso¬ 
lated quartan intervals have been noted. 
In patients exhibiting the continued quo¬ 
tidian and tertian fever, these generally 
follow one another in the order named. 
The fully developed paroxysm consists of 
the three classical stages, namely, the period 
of chill or rigor, the pyrexial stage, and 
the sweating stage, or period of deferves¬ 
cence. Only rarely is the first paroxysm 
preceded by a chill. In the majority of 
patients 5 or more days of intermittent 
fever occur before the first chill is experi¬ 
enced. A peak temperature of less than 
102° F is rarely preceded by a chill. Onset 
of an attack by a paroxysm attended with 
a chill suggests either (a) that the attack 
represents a relapse or (b) that the patient 
has had previous experience with malaria. 
The paroxysms may occur at any time 
of the day, and those due to the same para¬ 
site cycle may recur at approximately the 
same time. However, by anticipation or 
postponement those of one cycle in succes¬ 
sive paroxysms may occur a short time 
before or after the hour of their immediate 
predecessors. Thus a certain cycle may gain 
or lose 24 hours or more over a period of 
time. When the paroxysms are quotidian, 
sometimes those of one cycle may occur in 
the morning and those of the other in the 
afternoon. When the fever is quotidian, 
rigors may accompany only one cycle and 
thus may be experienced only every other 
day. As the clinical course continues, the 
duration of the rigor may increase from 5 
minutes to an hour, although 25 to 40 
minutes is their usual duration. 
In nearly all instances in which the clin- 
