New-York tribune., 1905-11-20
Mosquffoes and Fe,0er.
n 4lrah Doy Discusses the Principles Underlying Quarantine

Rules.

sells However investigation has shown that
the patients were taken sick within five six
days after leaving port, and recovered or died
before reaching New-york These vessels have
frequently arrived with suspicious cases on
board. but they have thus far proved not to be
yellow fever. but commonly malarial fever, as
the blood examination has shown The belief
that yellow fever is not infrequently transmitted
by infected mosquitoes on shipboard receives
considerable support from the fact that too
much reliance is placed on the belief that yellow
fever must appear within five or six days after
exposure. 1t is true that five days may be re-
garded as the maximum period Of incubation In
yellow fever; moreover, statistics show that
the disease more often appears three four
days after infection. However. in sub
tects In mild cases the disease may not be
apparent for seven or eight days. Such delayed
cases not infrequently present themselves and
often attributed TO infected mosquitoes on
shpboard.
It may be pertinenty asked, If mosquitoes
alone transmit yellow fever, why is It not rea-
sonable to believe that infected ones may reach
a vessel and transmit the disease either on ship
board or shore There is no doubt that this
may take place and authentic cases have been
reported, but am certain that 1t occurs only iu
instances and that the experience of this
department goes far to prove 1t.
II we consider the mosquito and it's habits
and the character of modern vessels will
have at least partial explanation of what
have already stated. We must understand that
in a community where yellow fever exists. par
ticularly If the outbreak is not extensive,
the number of infected mosquitoes compared
with the non-infected ones is indnitesmal;
Furthermore, that the chance of one of the for
n1er reaching vessel at the dock is remote. for
two reasons-first, because the stegomyia is
notoriously home mosquito, and remains close
TO its breeding place. and second, the residential
portion of a seaport town where yellow fever
exists is not rule, along the waters edge
or in close proximity to vessels. Moreover the
fact that mosquitoes may be found in the YES
sells hold is not in any way evidence that they
are infected ones. During the early part of the
last century commerce with South American,
West Indian and other ports where yellow fever
existed was carried by sailing vessels, which
were frequently in the most unsanitary condi-
ton These vessels remained in port for weeks
in order to secure full cargo which. in part,
commonly consisted of perishable material, and,
with water in the hold of the vessel, many
breeding and feeding places for the mosquito
were furnished board. Therefore when some
one of the contracted the disease, infected
mosquitoes and secondary cases of yellow fever
necessarily followed OF this there is ample proof
in the medical history of the period to which
refer These conditions have long ceased to e0-
ist, and commerce with these sections is now.
carried on by steamships, which remain only for
a few days in port, in comparatively good
sanitary condition, and furnish breeding
places for the mosquito.
For many years vessels have arrived almost
daily at New-York from fruit ports. which are
those on board the vessels those who have
discharged the cargoes of these vessels, or those
who have subsequently dealt with the fruit, yell
low fever has never appeared.
II is logical to assume that If infected mos
Quitoes are to be found in the cargoes of fruit
vessels arriving from ports infected with yellow
fever there should be evidence Of 1t at
New-York; however, none has yet been pre-
sented If yellow fever appeared among those
employed TO unload fruit ships in this port, it
would be reasonable and satisfactory evidence
that it was transmitted by infected mosquitoes
on shipboard. because yellow fever does not
exist here, nor is there any means Of communi-
eating the disease If It reached New-York. On
the other hand, the appearance of yellow fever
among those who unload fruit in one Of the South
ern ports would be far less conclusive as 10 the
origin OF the disease for the reason that the
stegomyia exists in the South, and yellow fever
may be present there in a mild or irregular form
without being recognized. During the present
season many vessels have arrived at this port
from New-Orleans, but there is absolutely no
evidence to show that infected mosquitoes have
reached here in the cargoes Of these vessels.
MOSQUITOES IN BAGGAGE.
Baggage arriving from yellow fever infected
ports has also been regarded as means by
which infected mosquitoes are carried from one
place to another There is more reason to be-
Iieve that this may occur than that infected
mosquitoes found in the vessels cargo be-
cause baggage may have come from house
where yellow fever existed in an infected area.
In some ports it is now required that this ma
terial shall be subjected to disinfection or treat
ment which will destroy the mosquito. ] have
recently made exhaustive experiments TO
determine the length of time that mosquitoes
live in baggage the results of which have
a direct bearing on this part of the subject
The experiments were made in the following
way: Boxes, canvas bags and other recepta-
cles were prepared and packed with clothing,
blankets bedding. etc. Mosquitoes were care