a handbook of the mosquitoes of north america - Systematic Catalog ...

RELATION TO WELFARE 53
the southern States of the United States. Blackwater fever
is a very severe disease. It can be prevented only by the
avoidance of long and continued malaria attacks. It has many
complications and a person who has suffered from an attack
should not continue to live in a highly malarious region. In
order to reduce the incidence of the disease in any area the
only logical procedure is the destruction of malaria-carrying
mosquitoes.
Yellow Fever
Yellow fever is one of the most virulent of human diseases.
Formerly it was rather widespread around the Carribean Sea
and was introduced from time to time to northern cities
where numerous epidemics occurred during the summer. This
disease, so highly fatal to non-immunes remained a mystery
till Reed, Carrol, Lazear and Agramonte definitely estab-
lished, in 1900, that it could be transmitted from the sick to the
well only by a mosquito, the tiger mosquito (Aedes fasciatus,
Aedes nygentezls or Aedcs agypti; unfortunately this mosquito
has many synonyms). Their conclusions have been well es-
tablished and the chain in this disease is again the parasite,
the man with the parasite (the patient), the mosquito, and
finally the transference to a new patient. The parasite of this
disease, though definitely announced from time to time, seems
as yet unknown. Noguchi has isolated an organism, Lep-
tospira icte/oidcs, which may be the definite parasite but final
conclusions do not yet seem to be warranted. The importance
of the mosquito vector in this disease may be stated very
briefly. Aed’es Cpyypti must secure it from a patient suffering
from the disease. This must take place within three to five
days after the first appearance of the disease as the parasite
is known to be present in the blood serum only for a short
time. Within the mosquito, the parasite must undergo a de-
velopment for it requires from 12 to 14 days before the
mosquito is capable of infecting a susceptible person. When a
mosquito is once infected, it remains capable of transmitting