INFECTION IN INTERMEDIATE HOST: FALCIPARUM 
201 
are secondary contributors; nevertheless 
this inherent dangerous tendency of P. fal¬ 
ciparum must not be minimized. Other 
patients may show quite a degree of toler¬ 
ance for relatively high densities of para¬ 
sites and after a comparatively mild attack 
symptoms will disappear. The attacks, as 
Boyd and Kitchen (1937a) have pointed 
out, tend to be of shorter duration than 
those due to P. vivax. The mean in our 
series was 10.8 days, although the maximum 
duration noted was 36 days (it must be re¬ 
membered that our data were gathered from 
persons undergoing therapeutic malaria and 
as little quinine as was compatible with 
their safe management was administered 
during these infections). 
Of the group of estivo-autumnal infec¬ 
tions which tends to attack predominantly 
some system of the body, the majority are 
characterised by a severity which has 
earned them the name pernicious. These 
forms, distinguished by symptoms which 
indicate a danger to life, are found chiefly 
in the tropics and particularly under epi¬ 
demic conditions or in areas of high ende- 
micity. Sternberg (1884) notes that in 
temperate zones pernicious symptoms are 
usually preceded by one or more simple 
paroxysms, and Craig (1909) states that the 
“great majority of pernicious attacks occur 
in persons who have suffered repeatedly 
from malarial paroxysms which have not 
been properly treated . . . and . . . often 
develop . . . during an apparently mild 
paroxysm.” Certain predisposing causes 
undoubtedly aid the development of malig¬ 
nant symptoms. Among these may be de¬ 
bility (as in convalescence), malnutrition, 
excessive fatigue, chronic alcoholism, heat 
prostration, drug addiction (Most 1940a) 
and pre-existing anatomic lesions. In this 
type of infection there is usually a high 
density of parasites, though it is not neces¬ 
sarily evident in the peripheral circulation. 
The degree and type of fever does not cor¬ 
relate with the pernicious features of these 
attacks. Mannaberg (1905) concluded that 
“perniciousness is associated with no defi¬ 
nite elevation of temperature and no par¬ 
ticular type of fever” although he recog¬ 
nized that “the majority of pernicious cases 
manifest a subcontinued fever.” 
Manson-Bahr (1931) divided the per¬ 
nicious types into two groups, (a) the cere¬ 
bral forms and (b) the algid forms. In the 
cerebral group he included those patients 
whose symptoms pointed predominantly to 
damage of some part of the nervous system. 
The chief feature of the algid group, as the 
name suggests, is coldness of the body sur¬ 
face. Collapse and a tendency to syncope 
are prominent features. Among this group 
are infections involving conspicuously the 
gastro-intestinal tract, hemorrhagic forms, 
syncopal types and acute hemolytic anemia. 
Inasmuch as these pernicious forms are 
not disease entities but are caused by the 
same parasite that produces mild infections, 
it is proposed not to describe an almost 
endless series of syndromes that have been 
met with, but rather to list systems of 
organs that have been particularly involved, 
together with syndromes and symptoms that 
have been observed: 
(а) Nervous system: Hemiplegia, para¬ 
plegia, localized paralysis, epileptiform sei¬ 
zures, neuritis, headache, irritability, rest¬ 
lessness, delirium, convulsions, coma, trem¬ 
ors, ataxy, speech changes, aphasia, amnesia, 
psychoses and milder mental changes. 
(б) Gastro-intestinal system: Syndromes 
of acute appendicitis, hemorrhagic pan¬ 
creatitis, acute gastritis, cholera, dysentery 
and acute peritonitis. Vomiting (bilious 
or hematemesis), icterus, diarrhoea and 
melena. 
(c) Cardiovascular and hemopoietic sys¬ 
tems: Rupture of spleen, symptoms of 
thrombosis and hemorrhage, syncope, heart 
failure, dyspnoea, hypotension, angina-like 
pain, anemia and leucopenia. 
(d) Respiratory system: Pneumonia, 
bronchitis. 
(e) Genito-urinary system: Syndromes 
of nephritis and nephrosis (albuminuria, 
casts), hemoglobinuria, hematuria, orchitis, 
and oophoritis. 
(/) Other systems: Involvement of spe¬ 
cial senses as hearing, sight (optic neuritis, 
retinal hemorrhage) and mastitis. 
Splenomegaly. Most writers agree that 
