﻿YELLOW 
  FEVER 
  — 
  SAWYER 
  577 
  

  

  and 
  protecting 
  threatened 
  cities 
  and 
  rural 
  populations 
  against 
  

   infection. 
  

  

  The 
  greatest 
  disaster 
  which 
  yellow 
  fever 
  could 
  bring 
  would 
  be 
  the 
  

   renewed 
  involvement 
  of 
  large 
  urban 
  populations 
  in 
  aegypti-spTend 
  

   yellow 
  fever, 
  particularly 
  if 
  the 
  cities 
  affected 
  were 
  seaports 
  from 
  

   which 
  the 
  disease 
  might 
  easily 
  spread 
  to 
  other 
  seaports 
  as 
  well 
  as 
  to 
  

   the 
  surrounding 
  towns. 
  It 
  is 
  therefore 
  a 
  matter 
  of 
  moment 
  that 
  the 
  

   methods 
  of 
  preventing 
  urban 
  yellow 
  fever 
  through 
  suppression 
  of 
  

   Aedes 
  aegypti 
  have 
  been 
  so 
  perfected 
  by 
  the 
  Brazilian 
  Yellow 
  Fever 
  

   Service 
  that 
  any 
  city 
  may 
  easily 
  solve 
  its 
  yellow 
  fever 
  problem 
  without 
  

   excessive 
  cost 
  by 
  making 
  itself 
  noninfectible 
  and 
  may 
  maintain 
  this 
  

   condition. 
  

  

  METHOD 
  IN 
  USE 
  TO 
  PREVENT 
  AEGYPTI-TRANSMITTED 
  

   YELLOW 
  FEVER 
  

  

  The 
  essential 
  improvements 
  of 
  method 
  that 
  have 
  made 
  it 
  possible 
  

   to 
  reduce 
  the 
  breeding 
  of 
  Aedes 
  aegypti 
  almost 
  to 
  the 
  point 
  of 
  local 
  

   extermination 
  have 
  been 
  described 
  by 
  Soper 
  (1937b). 
  The 
  weekly 
  

   inspection 
  of 
  premises 
  for 
  aegypti 
  larvae 
  and 
  the 
  destruction 
  of 
  breed- 
  

   ing 
  places 
  are 
  being 
  supplemented 
  by 
  the 
  search 
  for 
  adult 
  mosquitoes 
  

   by 
  special 
  squads. 
  If 
  any 
  are 
  found, 
  the 
  breeding 
  foci 
  are 
  sought 
  out 
  

   and 
  destroyed. 
  To 
  render 
  the 
  destruction 
  of 
  foci 
  as 
  certain 
  as 
  possible, 
  

   petroleum 
  (3 
  parts 
  fuel 
  oil 
  and 
  1 
  part 
  kerosene) 
  is 
  placed 
  on 
  water 
  

   found 
  to 
  contain 
  larvae. 
  The 
  oil 
  and 
  the 
  necessary 
  subsequent 
  clean- 
  

   ing 
  are 
  much 
  more 
  likely 
  to 
  destroy 
  mosquito 
  eggs 
  than 
  the 
  older 
  

   method 
  of 
  merely 
  emptying 
  out 
  the 
  water. 
  Such 
  methods 
  have 
  so 
  

   reduced 
  breeding 
  that 
  it 
  has 
  been 
  possible 
  in 
  many 
  cities 
  to 
  lengthen 
  

   the 
  period 
  between 
  house 
  inspections 
  and 
  thus 
  to 
  lower 
  the 
  cost 
  of 
  

   the 
  service. 
  

  

  These 
  methods 
  make 
  it 
  entirely 
  practicable 
  for 
  cities 
  to 
  acquire 
  and 
  

   maintain 
  complete 
  immunity 
  to 
  yellow 
  fever 
  regardless 
  of 
  the 
  degree 
  

   of 
  exposure. 
  The 
  nearer 
  to 
  jungle 
  yellow 
  fever 
  the 
  more 
  urgent 
  the 
  

   precautions, 
  but 
  it 
  must 
  be 
  kept 
  in 
  mind 
  that 
  the 
  critical 
  distances 
  

   have 
  been 
  greatly 
  extended 
  by 
  the 
  increased 
  rapidity 
  of 
  travel, 
  

   especially 
  by 
  airplane. 
  Those 
  cities 
  and 
  towns 
  through 
  which 
  yellow 
  

   fever 
  would 
  have 
  to 
  pass 
  in 
  order 
  to 
  spread 
  from 
  the 
  jungle 
  areas 
  

   or 
  to 
  invade 
  an 
  uninfected 
  country 
  have 
  a 
  special 
  responsibility 
  for 
  

   keeping 
  themselves 
  noninfectible. 
  

  

  THE 
  IDENTIFICATION 
  OF 
  YELLOW 
  FEVER 
  

  

  To 
  be 
  completely 
  on 
  their 
  guard 
  against 
  aegypti-tTsmsmittzd 
  yellow 
  

   fever, 
  the 
  health 
  authorities 
  need 
  to 
  be 
  in 
  a 
  position 
  to 
  recognize 
  yel- 
  

   low 
  fever 
  immediately 
  if 
  it 
  should 
  appear, 
  particularly 
  if 
  adequate 
  

   steps 
  have 
  not 
  already 
  been 
  taken 
  to 
  make 
  their 
  cities 
  noninfectible. 
  

   The 
  history 
  of 
  yellow 
  fever 
  contains 
  many 
  instances 
  in 
  which 
  failure 
  

  

  