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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  The 
  first 
  obvious 
  control 
  measure 
  has 
  already 
  been 
  mentioned. 
  

   Cities 
  in 
  South 
  America 
  or 
  elsewhere 
  which 
  are 
  threatened 
  with 
  inva- 
  

   sion 
  by 
  yellow 
  fever 
  from 
  the 
  jungle 
  areas 
  should 
  keep 
  themselves 
  

   noninfectible 
  by 
  the 
  well-known 
  methods 
  of 
  aegypti 
  control. 
  There 
  

   still 
  remains 
  to 
  be 
  considered 
  the 
  more 
  direct 
  control 
  of 
  jungle 
  yellow 
  

   fever 
  itself. 
  

  

  Jungle 
  yellow 
  fever 
  is 
  very 
  widely 
  distributed 
  in 
  sparsely 
  inhabited 
  

   regions 
  and 
  is 
  seldom 
  revealed 
  except 
  when 
  a 
  considerable 
  number 
  of 
  

   susceptible 
  persons 
  are 
  present 
  and 
  become 
  infected. 
  Aedes 
  aegypti 
  

   control 
  is 
  inapplicable 
  because 
  that 
  mosquito 
  is 
  not 
  involved. 
  The 
  

   suppression 
  of 
  other 
  vectors 
  is 
  at 
  present 
  impracticable 
  because 
  it 
  

   is 
  not 
  known 
  what 
  insects 
  play 
  the 
  dominant 
  role 
  in 
  transmission, 
  

   and 
  it 
  seems 
  improbable 
  that 
  thorough 
  and 
  widespread 
  insect 
  control 
  

   will 
  be 
  possible 
  in 
  the 
  jungle 
  areas. 
  Extermination 
  of 
  the 
  infection 
  

   is 
  obviously 
  impossible 
  at 
  present. 
  The 
  prevention 
  of 
  disease 
  in 
  hu- 
  

   man 
  beings 
  through 
  widespread 
  vaccination 
  becomes 
  our 
  only 
  prac- 
  

   tical 
  means 
  of 
  keeping 
  the 
  people 
  of 
  the 
  region 
  noninfectible. 
  

  

  Large-scale 
  yellow 
  fever 
  vaccination 
  has 
  been 
  applied 
  mostly 
  to 
  

   stop 
  an 
  existing 
  epidemic 
  or 
  immunize 
  against 
  an 
  expected 
  one. 
  The 
  

   effective 
  use 
  of 
  vaccination 
  on 
  a 
  large 
  scale 
  in 
  Brazil 
  for 
  such 
  pur- 
  

   poses 
  has 
  been 
  described 
  by 
  Soper 
  and 
  Smith 
  (1938b). 
  In 
  Colombia, 
  

   in 
  the 
  absence 
  of 
  such 
  large 
  sweeping 
  epidemics, 
  much 
  thought 
  is 
  

   being 
  given 
  to 
  the 
  immunization 
  of 
  selected 
  communities 
  for 
  the 
  pur- 
  

   pose 
  of 
  preventing 
  the 
  possible 
  future 
  spread 
  of 
  nearby 
  jungle 
  yellow 
  

   fever 
  through 
  them. 
  At 
  the 
  same 
  time, 
  vaccination 
  is 
  being 
  made 
  

   available 
  to 
  the 
  people, 
  usually 
  relatively 
  few 
  in 
  number, 
  under 
  actual 
  

   exposure 
  in 
  the 
  jungle 
  areas. 
  Even 
  this 
  is 
  an 
  important 
  measure 
  

   to 
  prevent 
  the 
  spread 
  of 
  yellow 
  fever, 
  for 
  it 
  is 
  the 
  nonimmune 
  work- 
  

   ing 
  in 
  the 
  jungle 
  who 
  will 
  become 
  infected 
  and 
  bring 
  yellow 
  fever 
  

   into 
  the 
  towns 
  and 
  cities. 
  The 
  need 
  is 
  for 
  the 
  intelligent 
  mapping 
  

   of 
  the 
  campaign 
  against 
  yellow 
  fever, 
  using 
  both 
  aegypti 
  control 
  in 
  

   the 
  cities 
  and 
  vaccination 
  at 
  strategic 
  points, 
  which 
  are 
  obviously 
  our 
  

   most 
  effective 
  present 
  safeguards 
  against 
  surprise 
  invasion 
  of 
  our 
  

   cities 
  and 
  our 
  commerce 
  by 
  yellow 
  fever. 
  

  

  To 
  use 
  vaccination 
  effectively 
  and 
  on 
  a 
  large 
  scale 
  it 
  is 
  necessary 
  

   to 
  have 
  available 
  a 
  vaccine 
  which 
  is 
  both 
  safe 
  and 
  effective. 
  The 
  

   vaccine 
  in 
  use 
  in 
  the 
  Americas 
  is 
  known 
  as 
  17D. 
  Its 
  safety 
  and 
  

   efficiency 
  have 
  been 
  up 
  to 
  expectations, 
  as 
  is 
  shown 
  by 
  the 
  report 
  of 
  

   Soper 
  and 
  Smith 
  (1938b), 
  but 
  experience 
  has 
  shown 
  that 
  eternal 
  vigi- 
  

   lance 
  will 
  be 
  needed 
  to 
  keep 
  this 
  living 
  vaccine 
  at 
  a 
  low 
  level 
  of 
  viru- 
  

   lence 
  and 
  free 
  from 
  contaminating 
  viruses 
  and 
  at 
  the 
  same 
  time 
  to 
  

   avoid 
  any 
  fall 
  in 
  immunizing 
  power. 
  

  

  Much 
  has 
  been 
  done 
  to 
  improve 
  the 
  vaccine 
  since 
  Sawyer, 
  Kitchen, 
  

   and 
  Lloyd 
  (1932) 
  began 
  vaccinating 
  human 
  beings 
  effectively 
  with 
  

  

  