New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1904-07-03
CAUSES OF MALARIA.
Trying to Take Some of the Blame
off the UOSQuitO.

With the return of the season when both u1alariaI
fevers and mosquitoes abound medical men are
again considering the Closeness Of the relation
which exists between the two, and endeavoring TO
determine whether the latter alone is responsible
for the spread Of the former Dr. Gerald McCar-
thy, biologist OF the North Carolina State Board Of
Health. IN bulletin Just issued gives some attep-
ton TO this phase OF the subject
Until about 1850 physicians believed that ''chiIls
and fever were acquired by iuhaling some kind Of
gaseous poison emitted by swanps or newly dis
turbed earth, and particularly influential a. twi-
light or evening. The belief was undermined, but
not upset, when Laveran. French army surgeon.
discovered that the victims Of these disorders in
variably had in their blood a certain microscopic
parasite, which he assigned TO the animal king
dom. This revelation made in 1880 three years
before Koch identified the bacillus OF tuberculosis
low form OF vegetable organism. Others have
fully confirmed Laveran's discovery, and have
helped 10 ascertain the succession OF changes
through which the mischief maker found By him
passes II now appears that there are Two species
OF parasite responsible for the so-caIIed ter
tan type OF fever. and the ether for the "quarta
type. both occurring together in many cases. More
than a dozen years elapsed. though, before Ross.
Manson and other biologists demonstrated convtnc-
iagly that the kinds Of parasites often exist
n mosquitoes and that the latter insects original
~ infected by biting one human subject could
convey the disease 10 another by the same opera
don While It was then conceded that the particu-
lar genus OF mosquito IN which malarial germs oc-
might transmit them TO man differences OF
opinion continued 10 prevail concerning the degree
TO which that insect was responsible
One OF the reasons which Dr. Mccarthy offers
for thinking that there may De another channel OF
infection IS that malaria is known to De endemic
IN portions OF India and Africa where there are no
human inhabitants II is probable that he means
here 10 affirm that mosquitoes are found in such
regions IN whose bodies there are malariaI germs
II so. II is hard 10 how the parasites got into
the insects Further light is needed 10 clear up
the mystery Another remarka Die fact has been
observed by DR.. J. NJ Smith. the State Ert0uaolo-
gst Of New-Jersey. He asserts that Of two
ueighborug towns, both with the same kind Of
population and both afflicted with the true malaria
mosquito. VIII be greatly bothered with maIariaI
fever and the other will be practically free from IL
4 satisfactory explanation Of such a discrepancy
not easy to find. and it is probable that similar
differences are encountered in other parts OF The
country.
Another class OF facts are cited which are more
easily interpreted, perhaps. In Paris there
people who once had malaria elsewhere and who
presumably still carry some Of the germs in their
system Mosquitoes Of the right kind for the dis
seuinatlou of organisms are not uncommon in the
French capital Nevertheless, the disease IS almost
unknown there II is conceivable that the Paristans
have developed sort Of immunity. Possibly the
same may be OF the people in other localities.
sun such explanation needs 10 be explained
No doubt some persons are less susceptible 70 an
attack Of malariaI fever than are others just
some are less susceptible 10 grip. smallpox or
dtphtheria than are others. As yet there is little
reason for thinking that immunity IS acquired
through one siege OF malaria. with certain other
malades. though that IS not now incredible II
was customary 70 attribute later attacks OF
this disorder 10 invasion OF the system many
years before. Very likely the true explanation IS
recent reinfection- Even though person may
carry in his blood few surviving germs after his
recovery II doubtful il he have further trouble
unless he is bitten by mosquitoes Stu. he is
looked upon source of danger TO his fellows.
especially fresh arrivals in his neghborhood- A
mosquito might bite him, raise and large
crop OF parasites in its tiny body. and then intro
duce few into one else's blood There
places in Afrtca-Ganbia, for instance-in which SO
per cent OF the native children go about with ma
IariaI germs in their veins. Europeans visiting
there catch the disease readily from them.
Most Of the uncertainty created by the stories
told by Dr. Mccarthy relates to the failure OF mos
qutoes TO spread disease where the conditions are
favorable. No we'll informed person. though.
doubts that these insects and do spread IL
What is still more important FOR practical pur-
poses no expert has yet been able 10 find the
parasites in question going through the necessary
development from infancy to maturity anywhere
except in q or in d mosquito. Perhaps the
dead germs exist IN water on the ground where
the mosquitoes in which they lived persisted and
decomposed. Such germs would be powerless
though. Some day live ones may be detected in
new environment, but until they are the only
logical way 10 explain thelr transmission from one
human victim 10 another is the pointed out by
Ross Hence the only safeguard in regions that
are known to be ''rnalarious'' is TO kill exclude
the mosquito.
1t will not do 10 forget the historic experiment
in Italy under the auspices of the Liverpool School
of Tropical Medicine in 1900. Two OF its experts
went 10 the Roman Campagna, which is noted for
the deadly character OF it's alarial fevers in SUN
ne- DR.. Sarnbon and Dr.. Low stayed there four
or five months with other protection than that
furnished by wire netting at their doors and win
dows and the practice OF keeping inside their
houses at evening. Neither they their servants
had the slightest symptom Of malaria during any
part of this venturesome visit
CONCERNED