Omaha daily bee., 1905-10-08

continue their development, their life Is
ended. Therefore. when an insect carries
microbe for which Il Is a host (among
low forms e As almost a biological law
that each parasite has a particular host
and no other) Il must be regarded with
greater fear on account OF its greater pos
sbilities for doing harm. In illustration
Of this. the mosquito serves as an excel
lent example. The mosquito is the host for
the microbes Of both malaria and yellow
fever: when Il bites person suffering
from one Of these. diseases it sucks up
with the blood a few Of the parasites Of
the disease These parasites can I'm no
other way get out OF the afflicted persons
body and would perish II fatal termina-
tion Of the infection resulted; or they
would be destroyed within the persons
body should he recover But the few which
find their way into the mosquitoes body
produce innumerable broods that are from
| time to time innocuated into one person
after another as long the creature is
active. The microbe Of yellow fever Is not
yet to he discovered unless we accept that
one described by working party No. l of
the public health and marine hospital
| service. This party, consisting Of Drs.
| Parker, Boyer and Pothier. while working
at Vera Cruz, Mexico. in 1902, during an
epidemic OF yellow fever, discovered in the
| body OF yellow fever mosquito a microbe
| that bears close resemblance to the
malarial germ. 1t was found only after the
mosquito had bitten a yellow fever patient
| But these doctors were not able to find
the same germ or it's antecedent in the
! blood Of the sick Therefore, until this
| most essential fact in the chain of evil
| dence is supplied. we cannot accept their
| microbe as the cause of yellow fever.
| Nevertheless, despite the fact that the
| yellow fever microbe is not known, we are
fortunately in possession of the impor-
tant facts relating to the spread of the
disease.
known Methods of the Disease.
The conclusion reached by the medical
board Of the United States army. COM
posed of Doctort Reed. Carvall. L.azear and
Agarmonte, submitted in 1900, and those Of
a later report submitted by Major Reed in
1901 contain practically all the facts es-
sential to be known to prevent the spread
of yellow fever Briefly, the conclusions
are as follows:
1. The mosquito, stegomyia fasciata,
serves as the intermediate host for the
parasite of yellow fever.
2. Yellow fever is transmitted to the non
immune individual by the bite of the mos
QUITO LIldL mas previously req on lue DlOOd
of those sick with this disease.
g. An interval of about thirteen days or
more after contamination appears to be
necessary before the mosquito is capable
of conveying the infection.
T. The period OF incubation in thirteen
cases of experimental yellow fever has
varied from forty-one hours to five days
and seventeen hours. (The period of incu-
baton" is the time that elapses between
the mosquito bite and the onset of the
disease).
5. Yellow fever is not conveyed by fom.
ties and hence dsinfection of articles OF
clothing, bedding or merchandise, suppos
eddy contaminated by contact with thos,
/ sick of this disease, is unnecessary.
6. A house may be said to be infected
with yellow fever only when there ar,
present within its walls contaminated mos
quitoes capable of conveying the parasite
of the disease.
Z. The spread of yellow fever can be mos
! effectually controlled by measures directed
/ to the destruction OF mosquitoes and tn,
protection of the sick against the bite
of these insects.
g. While the mode of propagation Of vel
low fever has now been definitely deter
mined the specific cause of this diseas
remains to be discovered.
The Mosquito Theory.
The discovery that a particular genus o
, mosquito conveyed yellow fever led to
study Of this particular insects habits. Al
> impetus had already been given to tn
, study Of mosquitoes as carriers of diseas
through the earlier discovery of Ross tina
\ another genus the anopheles, was tn
p transmitter Of malaria. The study of tn
habits of the stegomyia disclosed marke
. differences between 1t and the anopheles
2 Whereas the anopheles prefers densely pop
Z ulated centers. While on the one han
A the anopheles breeds in naturally still O
, slowly moving bodies of water, the stee
q omyia is domestic in its habits, preferrin
open vessels in and about a household
q Therefore, while the anopheles breeds 1
$ the open In swamps and shallow puddle
r Of water, the stegomyia elects water-bar
9 rels, cisterns, gutter-spouts and even tn
,. shallow vessels placed about table-legs /
l. certain regions to exclude ants.
i 1t was also learned that the stegomyi
i is not so widely distributed as the anc
) pheles, being found chiefly in tropical an
@ sub-tropical countries. Yet If transported
IS as it often has been by rail or boat,
Il may become acclimated in any place whic
!, supplies the conditions necessary for il
ia development And IL perchance It hal
l, bors the parasite of yellow fever, III
n disease is soon spread by it and the youn
IS II breeds For example: Working Part
z No. /, states that while at one time III
10 stegomyia was supposed to be a Goa,
o mosquito, in twenty-eight years It ha
e gradually extended into the interior (Me,
,r ico) to great attitudes along the CONNER
II cial lines OF communication, until now
y is constant inhabitant at places with a
altitude OF from 5000 to 1000 feet. and year,
causes epidemics of yellow fever.
other factors in regard 10 the life-hIstor
of this insect that are OF Importance in tn
connection are: That this mosquito doc
, not bite when the temperature is belo
So degrees F.; that its eggs are not hatche
out below IS degrees; and that an averal
temperature of % degrees F. or higher
required for Il 10 multiply abundantly ]
these facts we find the explanation as
why cool spell decreases the numbt
OF new cases, and frost kills of the d
sease completely.
Confined 10 Certain Localities.
From the foregoing, il is evident VIII
yellow fever occurs principally in tropics
and sub-tropical countries Many contrib
, uting circumstances are essential i'm ordt
that the disease may gain foothold; an
these are supplied by limited number
places. Particularly In the tropics, TO
1aegar In a