THE EPIDEMIOLOGY IN MALARIA TERTIANA IN FINLAND DURING THE YEARS 1941-1945

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP83-00423R000500280002-4
• Release Decision: RIPPUB
• Original Classification: U
• Document Page Count: 21
• Document Creation Date: December 23, 2016
• Document Release Date: July 16, 2013
• Sequence Number: 2
• Publication Date: August 26, 1946
• Content Type: REPORT

? f/At istirabo
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
50X1
fi920
The Epidemiology in Malaria Tertiana in Fin-
land During the Years 1941-1945.
By
C. A. HERNBERG.
(Submitted for publication August 26, 1946.)
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Acta Modica Scandinavica. Vol. CXXVII,lasc. 1947.
The incubation time in malaria tertiana has been greatly de-
bated in two respects. On the one hand the time of incubation has
provoked a lively discussion, on the other hand, the habitat of the
malaria plasmodium during the time of incubation has been un-
known so far. Nor have the possibilities of the plasmodium to
hibernate in Finland been investigated.
Up to the present plasmodium malariae has habitually been
found after the time of incubation, which generally is of the durat-
ion of 10-44 days. It has then entered into a red blood corpuscle
and has taken on the appearance of a signet ring. While the erythro-
cyte undergoes destruction the plasmodium gradually passes
through a stage of development, and in 48 hours a manifold
splitting up of the separate parts, the merozoites, placed in ro-
sette-like formations, takes place. The merozoites detach them-
selves and spread into the blood channels. Simultaneously there
is a sudden rise in the patient's temperature. The majority of
merozoites penetrate into the new red blood corpuscles, and the
cycle is again repeated. A few of the merozoites develop into game-
tocytes. The male gametocytes do not continue to live in man.
The female gametocytes may multiply again by division. If
gametocytes of both sexes enter into the mosquito by way of a
fresh mosquito bite the sexual form develops further in the mos-
quito. At a temperature of 25? C the development takes place in
10 to 14 days, at a somewhat lower temperature in 14 to 18 days.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
,
1
1
MALARIA TERTIANA IN FINLAND,
343
If the teMperature is permanently below 15? C there is no further
increase or development in the mosquito.
A pre-requisite condition for conveying malaria is that the
Anopheles mosquito becomes infected with human blood and
then continues to live until the plasmodium has had time to pass
through the sexual phase, and that the mosquito bites and infects
another human being. In Finland 14 to 18 days at least are re-
quired for this purpose. If the incubation time is added thereto,
24-36 days will be required for transmitting the fully developed
disease from man to man.
Malaria is prevalent in enormously wide areas of the world,
in its tropical and temperate countries. Very severe epidemics
occurred in Finland in the nineteenth century and in the begin-
ning of the present century. K. 0. Renkonen mentions that the
worst years included 20,000 to 10,000 cases, according to calcu-
lation. During the two decades preceding the second World
War the disease was almost completely absent in Finland.
During the second World War malaria epidemics broke out in
the majority of the armies. The Americans even considered malaria
the most troublesome of all diseases at the front (Coggeshall).
In the temperate countries it has been noticed that the
malaria epidemic appears fairly regularly in two phases, one
with an accumulation of cases in April?May, and another one in
August?September.
Until about 1930 common opinion was that malaria originates
from hibernating mosquitoes infected with malaria. Robert Koch
was the principal advocate of this theory. However, in 1877 Berg-
man, Sweden, and Korteweg, Holland, propounded the view that
spring malaria was due to a long incubation time and that the
patient had been infected already in the preceding summer.
After the first World War numerous cases of malaria appeared
in Germany among young men who had served in South-European
sectors during the previous year (Moberg). This occurrence does
not, however, seem to have evoked discussion to any extent.
But during the two latter decades several solitary cases were re-
ported in which the incubation time for malaria must be calculated
at about one year (Shute, Sade, Tillich, Bradild, Martini). These
cases generally referred to travellers who had stayed for some short
time in countries infected with malaria and who, later, had re-
turned to their malaria-free home areas. Some of them sickened
within the expected time, after a short incubation period, but
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
344 c. A. HERNBERG.
others again were not afflicted until about nine months later.
The I prolonged time of incubation was later demonstrated by
Korteweg, 1929. The fact of a prolonged incubation time actually
occurring has, however, always been doubted by South-Europeans,
at least regarding sub-tropical areas. They refuse to accept it as
a mass occurrence, in any case. (Missirolli, Berkesy, and others.)
In Finland, spring malaria was closely discussed in the be-
ginning of the present century and the theory that the agents of
malaria were domestic mosquitoes hibernating in stables or dwel-
ling houses was accepted (Siven). As late as in 1943 Renkonen
pointed out the difficulties in considering malaria the result of a
prolOnged incubation period ? without, however, taking a def-
inite standpoint regarding the statement.
The question of malaria was brought into a new phase by ob-
servation made, independently, by Huff and Bloom 1935, Raf-
faele 1934, 1936, James and Tate, 1937, Kikuth and Mudrow
1937, Man.well and Goldstein 1939, and Schulemann 1940, who,
besides the intra-erythrocytic forms of plasmodia, discovered
pigment-free forms, localized extra-erythrocytically, generally in
the endothelial cells of the capillaries of inner organs. In the
literature the cells are stated to belong to the reticulo-endothelial
system, RES.
By infecting animals with tissues containing extra-erythro-
cytic' malaria plasmodia the time of incubation was considerably de-
creased. This had hitherto not been attained below a certain level.
A result was obtained, on the other hand, by irritation of RES
with injections of colloidal palladium (Schulemann) some days
before malaria infection. The incubation time was prolonged
25-30 days and the disease assumed, clinically, a more cerebral
form It was supposed that the changes in the disease were due
to part of the parasites having become phagocyted by RES.
It ' was further noticed that malaria which has arisen from
direct infection with merozoites, as in therapeutic malaria in
parOysis, is of a different character to malaria caused by infec-
tion with sporozoites, as in mosquito bites. In the former case a
violent malaria arises which is very sensitive to therapy, however,
and very rarely recurs. A malaria caused by mosquito bite is more
benign on the other hand, but is inclined to relapse (James).
Before being ready to enter the erythrocytes the sporozoites
have, to pass through a stage of development in RES -- this is
thus considered proved.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
MALARIA TERTIANA IN FINLAND. 345
SuppOrted by this theory Kikuth considered himself able to
explain a number of epidemiological phenomena. The prolonged
time of incubation was due, inter alia, to plasmodia having re-
mained in RES. The recurrences, which even in careful treat-
ment of malaria, always occur in a certain percentage, would be
due to our drugs only attacking the intra-erythrocytic forms and
the gametocytes. For the same reason the drugs do not act during
the incubation time, but, according to some authors, they may
prolong it up to about a year (Kolle, Siebert). The plasmodia in
the reticulo-endothelial system, would, in other words, form an
infection reservoir which we have not been able to influence so
far. Positive accounts of Kikuth's theories are found in German
and English literature, but in France (Sergent) and Italy (Corre-
lati, Missiroli) a certain opposition regarding his hypotheses has
been aroused.
Schulemann considers that the plasmodium may penetrate
into RES not only as sporozoites but also as merozoites.
The Author's own Investigations.
During Finland's second war against the Union of Soviet
cases of malaria appeared in the army. The Russian troops were,
without doubt, the source of infection, as some Of them were
recruited from areas where malaria is endemic. During the first
summer no actual epidemic broke out, however, but solitary cases
were reported at the end of summer 1941, in all 57 cases. Half
the number of patients was from the Hango frontier and a small
number from the Carelian Isthmus and East Carelia. During the
following years the malaria cases were decidedly more numerous:
1942 ? 583 cases
1943 ? 262
1944 ? 892 ?
The disease raged principally among the troops on the Carelian
Isthmus but also to some extent in East Carelia. Men of the ranks
were more pre-disposed to the disease and sickened proportionat-
ely twice as often as did officers. This is quite natural as soldiers
have to serve for long periods in the open and at night in station-
ary warfare.
With soldiers on leave and disbanded soldiers the disease was
carried to civilians in the home areas, fortunately in but few cases,
and only to the south parts of the country (See map, Fig. 1).
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
346
C. A. HERNBERG.
ige
0 .119'1
14
1.04v1fifomet
Fig. 1. On the map each point represents a group of five cases of malaria in
1945. The other figures denote groups of five cases during the years 1941-1945.
The line across is the northern limit of civilian cases. The dotted line in the south-
west corner denotes the border of the district within which no single case of malaria
occurred among civilians in 1942 in the Hang. district.
According to the statistics published by the Medical Board we
have the following civilian cases:
1941 ? no cases
1942 ? 75 cases, probably part of them disbanded soldiers
1943 ? 53 cases, of these 40 from the Wiborg district
1944 ? 17 cases.
Tho majority of military cases from 1944 originated from the
Carelian Isthmus. Fortunately no leave was granted during the
whole of the mosquito period, on account of heavy fighting, and
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
MALARIA TERTIANA IN FINLAND. 347
before thooutbreak of the disease the entire civilian population
on the Isthmus had been transferred. The spread of malaria from
the Isthmus to other parts of Finland was very slight on that
account.
However, after the end of the war, in 1945, a great number of
malaria cases occurred among the civilians (Hernberg and Tuo-
mala).
For the purpose of obtaining a fairly exact figure of the cases
in 1945 the following sources were drawn upon:
1. Statistics published by the Medical Board, 869 cases. In the
reports the name, age, address, and month of sickening was en-
tered for more than half the number of cases, while in the re-
mainder only time and place of sickening was noted.
Nr.of
cases
340
30
280
240
20
160
120
BO
Malaria 1945
15 20 25 30
35 4+0- 45 50
55 ye?,
of 090
Fig. 2. Subdivision of cases in age-groups in 1945.
2. Cases of malaria collected from 25 hospitals in Finland,
597 cases. Thanks to the courtesy of the prefects I was able to
study the case histories from 17 hospitals, which, of course, in-
creased the value of my material greatly.
3. Military cases in 1945 from the peace-time army, 85 cases.
From the total figure, 1,551, cases occurring in two or more
collections are subtracted. We then have 1,252 in. all. This
figure is about that of the total malaria morbidity in the year
1945. Relapses are not included in this figure. More or less com-
plete personal information was obtained from 868 patients. This
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part- Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
348
C. A. HERNBERG.
Fig. 3. Temperature curve for Helsingfors in summer 1945. The cross-line lies
within temperature zone of 15? C.
material will suffice for the purpose of solving the present epide-
miological problem.
To my great surprise there were 856 men and only 12 women
among the 868 patients from whom personal information had
been obtained.
The subdivision according to age is revealed in Fig. 2. As seen,
no cases below 15 or above 53 were observed. This is all the more
strange as malaria is more inclined to attack children than adults.
Between 15 and 20 years of age there were only 45 cases. In
the age-group 20-25 an enormous increase is observed ? as
many as 345 cases were noted. In the following 5-year-groups
the uumber of cases decreased and above the age of 45 there
were 'only 4 cases.
For the purpose of estimating possibilities of transmitting in-
fection, conditioned by temperature, tables covering the tempera-
ture in 1944 and 1945 in 12 different places in Finland were ob-
taMed from Professor Keranen, Chief of the Meteorological
Central Institute. With the view in mind that malaria plasmodium
may 4evelop in mosquitoes it would perhaps be more consistent
to use only the minimum temperature as a norm, but, on the one
hand it is probable that the temperature in the mosquitoes' noc-
turnaj resting-places is above the minimum, and, on the other
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
1
Declassified in
Part - Sanitized Copy Approved for Release @ 5-0-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
MALARIA TERTIANA IN FINLAND.
Fig. 4. Temperature curve for Uleaborg in summer 1945.
349
hand, the higher temperature during daytime must be of impor-
tance in the development of the plasmodium in the mosquito.
On the basis of a study of temperature curves drawn for the 12
places in question the period of warmth may be considered suf-
ficient for transmittance of malaria, with certainty in the latitude
of Helsingfors (Fig. 3), possibly in that of Tammerfors, but in
Ulaborg the temperature seems, on the other hand, to be less
favourable for transmission of malaria infection (Fig. 4). The con-
secutive period of a mean temperature above 15? C is rather too
short for the purpose.
It may seem somewhat audacious to draw a delimiting line
regarding the possibility of conveying malaria, conditioned by
temperature, as the malaria is dependent upon the vitality of
the plasmodium, but an empiric border for the years in question
may be obtained. During the years 1941-4945, those, who, with
all probability, had been infected in their home districts, were
stationed south of a line drawn from Vasa to Suojarvi in latitude
62.5?. This may be considered a northern line of demarcation
regarding malaria in Finland during these years (Map, Fig. 1).
An accumulation of all the malaria cases during 1945 south
of this line was expected, providing the plasmodium had hiber-
nated in the mosquito.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
350
C. A. IIERNBERG.
However, what is the true geographical subdivison,of malaria
in relation to the one conditioned by temperature, the anti-
cipated spread?
On the map (Fig. 1) the 1,252 malaria cases are marked thus:
each point represents about 5 cases. As seen, malaria occurs in
the Most varied parts of the country, subdivided in about 250
communes, without large epidemical accumulations, and in
approximate relation to the density of the population. The
disease occurs more numerously in the large towns, and in Jout-
seno, north of the Carelian Isthmus. Malaria is also met with as
far north as Uleaborg where the disease is not expected on ac-
count of the low temperature in these parts.
Several municipal doctors have informed me that the separate
cases in the commune were often stated several miles apart al-
though the patients had had no communication with one another.
In the preceding year the majority of the places had been free
from malaria. The possibility of infection caused by hibernating
mosquitoes should therefore not be taken into consideration.
Thus the geographical spread does not correspond to the cal-
culated prevalence.
Fig. 5 represents the cases per month calculated according to
the day of sickening. Already in February--April, the mosquito-
free period, we have as many as 142 cases of malaria. The great-
est number of cases accumulated in May, 440 cases, and in June,
352 cases. In July?August, the true mosquito months, the curve
decreases steadily.
As 24-36 days must be assigned in Finland for full develop-
ment of a complete picture of disease in transmission of infec-
tion from man to man via the mosquito, half the number of cases
would have been infected already before the middle of April,
i. e. before there were any mosquitoes at all, providing the infec-
tion had occurred in that year.
Thus the chronological subdivision of the cases does not either
correspond to the one calculated.
I now consider fully evidenced that the majority of the malaria
patients from 1945 had not been infected in the same year. I do
so on account of the following facts:
1. It is impossible that malaria infection which has attack ed
only Men of military age should have taken place in their res-
pective home districts where both sexes and all ages are repre-
sented.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
?
Nr. of
COSX3
360
320
280
260
200
160
i30
MALARIA TERTIANA IN FINLAND.
IV V VI VII II IL kV V VI VII VIII IX
.944 1945
Fig. 5. The right part of the curve represents the malaria epidemic in 1945 sub-
divided according to month. The left part is that of cases with short incubation
time during the epidemic on the Carelian Isthmus in 1944. The ratio between short
and prolonged time of incubation during the same period of infection is clearly
evidenced.
351
2. The separate cases are geographically too far apart for reci-
procally transmitted infection being taken into account.
3. In some districts the temperature was too low during the
summer months for infection transmitted via mosquitoes being
probable.
4. The apex of the morbidity curve of infection by mosquitoes
was reached too early in the year.
5. Infection by hibernating mosquitoes is not probable as the
districts in question were free from malaria in the preceding year.
If the patients were not infected in summer 1945 a preceding
mosquito period is the only explainable source of infection. Where
were they in summer 1944? This question was put to them by
letter. A reply was obtained from 596 patients out of 868.
It was revealed that almost every single patient had been in
military service on the Carelian Isthmus. A great number of
them had been in East Carelia in the beginning of the summer
but had been transported to the Carelian Isthmus already before
the middle of June. Only 13 had been in their respective homes.
In summer 1941 malaria occurred frequently on the Carelian
Isthmus while the disease was very infrequent in other districts.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
352
C. A. IIERNBERG.
On that account I consider that the majority of the patients
from 1945 had obtained their infection on the Carelian Isthmu, in
the slimmer of 1944, and that the disease had broken out after an
incubation time of 6-14 months, or else were recurrent cases.
Among the questions put to the patients in the questionnaire
may be mentioned: where did he sicken in malaria, for the first
time; had he suffered earlier from some kind of fever? Evident
relapses could be eliminated without further in this way; similarly,
if clinical reports were obtained. Atypical slight cases of malaria
with spontaneous healing thus remain. It seems improbable that
such cases should appear, in any case not in such large numbers.
Numerous closely observed cases are included in this material,
such which had decidedly not showed any previous symptoms of in-
fection. A soldier will not omit to report himself sick if he ac-
tually has a temperature ? this with cognisance of soldier-psych-
ology Two military physicians, for example, had shared a room in a
cottage on the Carelian Isthmus in summer 1944. Thirteen months
later both of them sickened with an interval of four days only,
each in his home, outside the malaria zone.
No malaria prophylaxis with antiplasmodica such as quinine,
atabrine, or plasmochin was used in the Finnish army during the
whole war. An extenuation of the incubation time by malaria
prophylaxis is excluded.
My opinion is that the majority of the cases were due to pro-
longed time of incubation.
The cases of malaria, which, due to a prolonged incubation
period, may be thought to originate from 1943 must be deducted
from those on the Carelian Isthmus in summer 1944. If this is done
in a manner which will be described later we have 554 cases,
with short incubation. These 554 cases (from 1944) with short
incubation thus correspond to 1,252 cases (from 1945) with
prolohged incubation, related to the same period of incubation.
This is graphically exposed in Fig. 5.
Thus, the malaria plasmodium may hibernate in man in a
surprising degree. Does it hibernate in the mosquito at all? Com-
mon conception is, of course, that it may do so in the main. Also
this question may be explained to be due to the exceptional
conditions prevalent during the war. Let us return to 1941.
In the Hango-sector 28 cases of malaria were reported in sum-
mer 11941. We take it that the Russians had a far greater number
of ca.Ses. There must have been masses of malaria infected mos-
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
MALARIA TERTIANA IN FINLAND. 353
quitoes around the idyllic bays in the neighbourhood of Hango
in autumn 1941. In the winter the Russians left this district and
the Finnish troops were transferred to more important sectors.
The population was replaced by Finns from malaria-free districts.
If the plasmodia had hibernated in the mosquito, malaria would
have broken out among the inhabitants removed into this district
in summer 1942. However, no cases of malaria occurred in the
area of Hango, not even within a radius of more than 100 km.
(See map, Fig. 1.)
The case was similar on the Carelian Isthmus in autumn 1944,
although the extent was greater. In agreement with Armistice
stipulations the Finnish troops were withdrawn from the Isth-
mus in the autumn and stationed north of the Finnish-Russian
border line of 1940, and the majority of the Russian troops were
transported as they were considered superfluous in this district. In
the following year civilians from Russia settled on the Carelian
Isthmus. Had they come from malaria-free districts an epidemic
among them would indicate that the plasmodium had hibernated
in the mosquito. It is not known, however, whether these people had
come from non-infected districts, but as malaria is greatly pre-
valent in Russia, it is hardly possible. Yet, I have learnt that no
epidemic broke out on the Isthmus. Information regarding spo-
radic cases is lacking. The Carelian Isthmus would, thus, be a
parallel to the Hangii district.
Consequently, it seems probable that the malaria plasmodium
had not hibernated in the mosquito after the summers of 1941
and 1942.
If we adhere to the theory that the malaria plasmodium may
be lodged for long periods of time in RES, one might explain,
in my opinon, why the time of incubation is just about 9 months.
I consider that the vitality of the malaria plasmodium in man
augments with increasing light, but hardly with rising temper-
ature. In an isothermal organism, as that of man, the outside
temperature is said to play a subordinate part as regards the
plasmodium. The temperature plays a great part, on the other
hand, regarding the perpetuation of the plasmodium in the
poikilothermal mosquito. Thence the potential malaria period in
Finland would be the light months of the year. If a person be-
comes infected with malaria in the autumn the plasmodium is
more inclined to lie quiescent in RES, and to awaken to life not
earlier than the following spring.
23?'i70729. Acta med. scandinav. Vol. CXXVII.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
354 c. A. IIERNBERG.
The summer in Finland is short and thus also the virulent
time of the plasmodium. The spring malaria curve and that of
late summer will on that account fall within one another and give
rise t,6 a resultant curve in common, the apex being reached some
time ''during the summer. In countries with longer summers the
curves' become separated, and it may also be expected that the
prolonged incubation time will occur percentually less frequently
in those countries than in Finland, and, possibly, be totally
lacki g in the tropics. The disinclination of investigators in sub-
tropi countries to accept the prolonged incubation time as a mass
occurrence would thereby be elucidated in a natural way.
For the same reason the malaria becomes more benign the
higher up in the north it appears.
A larger number of cases with prolonged incubation might be
expected, percentually, if the malaria epidemic occurs towards
autumn, and a shift for the benefit of a short incubation time if
the epidemic occurs in early summer. I was able to observe this
occurrence during the former epidemics in the army. My thanks
are dile to the administration of the Army and the Archives for
War Wounded for permitting me to study clinical reports regarding
malaria during the duration of the war.
Due to the outbreak of war on June 25, 1941, the soldiers were
sent to the fronts in that month, and were thus exposed to a
potential malaria infection. The first cases appeared one month
later, i. e. in July, as anticipated (Fig. 6, lowest curve.) In August
the curve rose furthermore but did not reach the maximum until
Septeinber. In the following months the curve declined slowly.
It is a non-composed curve constituted only of cases with short
incubation. The slight slant in the curve might denote that more
people had become infected but that the disease had not broken
out. It is also difficult to understand that the cases could have
been located at such distances from one another among closely
packed troops. Three-fifths of the cases were apportioned to Sep-
tember and later. This was distinctly a late summer epidemic.
In the subsequent year 583 cases, excluding the recurrences,
were noted (Fig. 6, second curve from lower edge). The apex of
the epidemic was reached in June. The curve should, however,
be a resultant curve and solvable in two components. One of
the components comprises cases from 1941 with prolonged in-
cubation, the second one cases with short incubation from 1942.
How should the curve be decomposed?
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
240-
220-
200-
180-
160-
140-
120-
100-
80-
60-
40-
20-
-60
40
20
61
140-
[20-
100-
80-
60-
40-
20-
MALAMA TERTIANA IN FINLAND.
II
IV
V
VI
Vs
VIII
IX
X
XI
XII
1943
II III IV V VII VIII IX X XI XII
355
Fig. 6. In the same diagram, but with different absciss lines, the epidemic in
1941-9144 is graphically reproduced. The morbidity curves are solved in their
two components, of which denotes short incubation cases and x x
prolonged incubation cases. The small epidemic in East Carelia is broken out
from the curve for 1944.
As we cannot calculate with SI-cases' in May, on account of
what has been said above, we have the right to consider the entire
left side of the curve as PI-cases1 until the end of May. The right
1 SI ? short incubation, PI ? prolonged incubation.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
356 I C A. IIERNBERG. ?
side of the PI-component is hypothetic. It is highly probable
that it will follow along the resultant curve as malaria infected
mosquitoes do not appear in Finland until the end of June. But,
as we should not follow the most advantageous interpretation of
our reasoning. I have consistently given the right side of the curve,
in this and the following cases, the same general course as that of
cased with malaria in the year 1945 (Fig. 5), which were proved
PI-cases. The mean value of the error should not be particularly
great, notwithstanding possible variations in the right side of the
PI-component curve from year to year. If the hypothetical right
side of the curve is traced into the curve For 1942, the dotted
curve in Fig. 6 is obtained for PI-cases from 1941. If the dotted
curve is subtracted from the total curve the second component
curve, the curve for SI-cases in 1942 is obtained. It is characterized
by an increase in June, with an apex in July, followed by a fairly
rapid decrease of the curve in the following months. In September
and later we find only one-fifth of the SI-cases, e., relatively,
only one-third of autumnal cases as compared with the proceeding
year. This was thus a typical early summer epidemic. The curves
reveal that there were 210 PI-cases in 1941 and 373 SI-cases in
1942. As mentioned, there where 57 SI-cases in 1941. The ratio
short: prolonged time of incubation is 57: 210 = 0.27.
The early summer epidemic in 1942, the curve described above,
might have been expected to be followed by a relatively smaller
number of P1-cases, and this was actually what occurred. The epi-
demic: in 1943, 262 cases, is graphically illustrated in Fig. 6 and
solved in its separate components similarly as in the preceding
curve. The curves show 86 PI-cases and 172 SI-cases. In the pre-
ceding curve the number of SI-cases in 1942 is 373. The ratio
short: prolonged time of incubation in 1942 is 373 : 86 = 4.36 i.e.
sixteen times that of the previous year. Cases belonging to the
same infection period are graphically reproduced in Fig. 7. The
sensibility of the ratio to chronological shift of the SI-curve is sur-
prisingly great.
As the apex of the component curve for SI-cases in 1943 is
reached in August, as revealed in Fig. 6, the ratio for that year
might be expected to be found somewhere between the two pre-
ceding figures and such is also the case. The ratio 172 : 220------- 0.78
is obtained from the decomposed curve of the epidemic in 1944.
(Fig. p.)
The resultant curve for 1944 is somewhat more composed than
nedassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
357
? MALARIA TERTIANA IN FINLAND
Fig. 7. The total number of cases from the same infection period are collected
in one diagram. Observe that the right part is dependent on whether the apex of
the left curve is reached early or late in summer.
the preceding curves. The chronology of the previous curves was
similar in all sectors and the total malaria material could be
treated as a totality. In summer 1944 a great move in the action
of the troops took place and the possibilities for soldiers to be-
come infected was different. The principle habitat of the infec-
tion was the Carelian Isthmus. During the hard fights in the sum- ,
mer the troops were reinforced. The new troops were thus not
exposed to infection until about July. It seems, principally, as
if the stationary warfare at the end of the summer would have
furthered the transmission of infection as the frontier ran through
the swampy districts around AyrapaA, the Vuoksen Valley, and
the?long Bay of Wiborg. The malaria epidemic on the Carelian
Isthmus broke out in full force in August?September. It was
thus a typical late summer epidemic.
A small independent epidemic occurred simultaneously in East
Carelia in the early summer, The total morbidity curve is thus
composed of both the SI- and the PI-components and, besides,
of the epidemic curve from East Carclia. In the figure it has been
broken out from the total morbidity curve. The SI-curve for the
epidemic in the Carelian Isthmus only, comprises 554 cases. Fol-
lowing this typical late summer epidemic the above described
great spring malaria epidemic followed in 1945, with, as mentioned,
at least 1,252 cases. The ratio is thus 554: 1,252 = 0.44 (Fig. 6).
The East Carelian epidemic in 1944 did not cause an accumu-
lation of PI-cases in 1915, partly as the epidemic was very small,
partly as it occurred relatively early in the summer.
The surprising homogeneousness of the epidemic with the
calculated course supports the accuracy of my reasoning.
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
358
C A. I1ERNBERG.
Fig. 8. nap showing malaria in Finland in 1853-1862 according to R. Sievers.
Note the extensive spread of the disease northward, and its affinity to water.
The sensitivity of the malaria plasmodium to a chronological
shift in the time of infection is remarkable. A change of only
one month to the left of the apex of the epidemical curve reduces
the number of prolonged incubation cases to a minimum. This
also elucidates the rare occurrence of long incubation in the
tropics.
The virulence of the malaria plasmodium was evidently fairly
small in Finland during the war-years, and the disease very benign.
Among the total cases of malaria, about 4,000, relapses included,
no single death was noted, notwithstanding the disease being
uew in this country and treatment not always sufficiently
intense or instituted early enough. Nor was the morbidity with
egard to exposure to infection within the array particularly
marked. The plasmodium was not able to hibernate in the mos-
quito, The disease occurred principally in the south parts of
Finland and the spread among civilians was surprisingly small.
The character of malaria not always being similar to the one
described is evflenced in R. Sievers' reports. The map (Fig.
8) illustrating the disease in 1853-1862 reveals the enormous
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
MALARIA TERTIANA IN FINLAND
359
spread of the disease notwithstanding the density- of the populat-
ion then being about half of the present one. The northern limit
of the disease was much farther north than at present, and the
mortality was considerable. It is possible of course that the epi-
demiology of those days differed to that of to-day.
Summary.
In 1945 an epidemic of malaria was observed in Finland. It
'attacked almost exclusively men of military age who had been
in service in malaria infected districts in the preceding summer.
It is considered evidenced that the disease broke out following
an incubation time of about nine months. The possibility of these
cases having been relapses is excluded.
A further study of the malaria epidemics in Finland's army
during the years 1941-1944 revealed the following characteristics
of the prolonged time of incubation:
Prolonged incubation was observed subsequent to each epidemic
of malaria. The ratio short time of incubation: prolonged time of
incubation varied between 0.27 and 4.34.
The prolonged incubation was extremely sensitive to chronol-
ogical shifts in the time of inf ection. An early summer epidemic
supplied less numerous cases with prolonged incubation time than
did an autumnal epidemic.
Prolonged incubation being dependent on light is considered
evident.
Hibernation of malaria plasmodium, did not take place in the
mosquito with all probability ? but in man.
The malaria was benign. No deaths occurred among about 4,000
eases including relapses. The disease differed in this respect from
other epidemics of malaria in Finlana in the nineteenth century.
The theory of the probable correlation between the plasmo-
dium and the reticulo-endothelial system is described.
Literature.
Craig, Charles F.:The malarial fevers p. 510 in The malarial Departm.
of the United states army in the world war Vol. IX 1938. ? Craig,
Charles F.: in Oxford medicine Vol. II p. 741. ? Menck, W.: D. Tropen-
med. Zschr. 1942: 46.: 329. ? Coggeshall, L. T.: Malaria in. Cecil, It.:
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
360 C. A. IIERNBERG.
Textbook of Medicine. 1944.- Abramow, S.: Munch. med. Wschr. 1941:
88: 42 p. 1156. - Korteweg, P. C.: Z. Hyg. 110: 724-731. 1929- -
Missirolli, A.: Riv. malariol. 11: 1-24. 1932. Ref. Kongresszbl. f. inn.
- Sergent: Presse medical 1942. - Berkesy, L. v.: Wier. klin
Wschi. 1931, II: 1110-1112. - Siven, V.0.: F. L. H. 49. 1907 and 54.
1912. H Palmen, J. A.: Duodecim 1900.- Renkonen, K. 0.: Acta med.
scand. 119: 261-275. 1944. - Schulemanr, W.: D. med. Wschr. 1940:
66: nr 10 p. 253 and cited lit. - Schiipfer, W.: D. med. Wschr. 1941:
67: 1251. - Kikuth, W.: Zschr. f. Immunitat u. exper. Thor. N. 104:
148-57. 1943.- Kikuth, W. & Mudrow, Lilly: D. med. Wschr. 1941:
67: 85, and 1942: 68: 42 p. 1024. - Reichenow, E. & Mudrow, Lilly:
D. trOp. Zschr. 1943. Bd 47,288-99. - Raffaele: Riv. malariol 1934 and
1936 cit. Kikuth, D. med. Wschr. 1941. - Huff, C. G. & Coniston,
F.: Top. J. of infect. dis. v. 75. 231-49. 1944. - Wasiliewski, Th. W.:
in Handbuch der arzllichen Ehrfahrungen im Weltkriege. 1922. -
Wilcken, H.: Klin. Wschr. 417-18. 24/25.1943. - Moberg, Erik: Nord.
med. 1939 p. 1727. - Shute, P. G.: Ref. Kongr. Zbl. f. inn. Med. 1942.
- Sade, Georg: Arch. Schiffs- u. Tropenheilk. 42. 503-506. 1938. ref.
Kongr. Zbl. inn. Med. - Tillich, Alfred: Munch. med Wschr. 1936.
- Bradild, R. A.: Dtsch. med. Wschr. 1938. 787-788. Ref. Kongr.
Zbl. 07. - Martini: E: Arch. Schiffs- und Tropenheilkunde 351. 577--
583. 1931. Ref Kongr. Zbl. inn. Med. 1932. - Kolle, W. & Hetsch, H.:
Die experimentelle Bakteriologie und die Infektionskrankheiten.
Berlin & Wien 1929. - Schen, T. D.: Arch. f. exper. Path. u. Pharm.
v. 201. 1943. 502-19. - Siebert, H. B.: D. Tropenmed. Zschr. 1941:
II 5. Ref. Nord. Med. 14. - Schilling, Claus: J. k. arzt. Fortb. 21. IL
10. 4't, 53. Ref. Kongr. Zbl. inn. Med. - Correlati, A.: D. Tropenmed.
Ztschr. Haft 19. Ref. Nord. med. Bd 14. - Sergent, E.: La presse me-
dical e 1941: 49, 52, p. 649. - Sievers, R.: F. L. H. Bd 33, 1891, p. 563.
Hernberg, C. A. & Tuomala, A.: Acta med. scand. XX scand. kongr.
in med. 1947.
Stockholm 1947. Kungl. Boktr. P. A. Norstedt & Mier
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4
Declassified in Part - Sanitized Copy Approved for Release @ 50-Yr 2013/07/16: CIA-RDP83-00423R000500280002-4