﻿YELLOW 
  FEVER 
  — 
  SAWYER 
  585 
  

  

  Matto 
  Grosso 
  in 
  the 
  center 
  of 
  Brazil, 
  and 
  which 
  has 
  since 
  then 
  pro- 
  

   gressed 
  eastward, 
  then 
  southward, 
  and 
  again 
  eastward 
  in 
  warm-season 
  

   outbreaks 
  through 
  the 
  states 
  of 
  Goiaz, 
  Minas 
  Geraes, 
  Sao 
  Paulo, 
  and 
  

   Rio 
  de 
  Janeiro. 
  This 
  year 
  the 
  epidemic 
  was 
  manifest 
  in 
  Espirito 
  

   Santo, 
  still 
  farther 
  to 
  the 
  east, 
  and 
  cases 
  were 
  found 
  farther 
  to 
  the 
  

   south 
  in 
  the 
  states 
  of 
  Parana,Santa 
  Catarina, 
  and 
  Rio 
  Grande 
  do 
  Sul. 
  

   It 
  seemed 
  quite 
  probable 
  that 
  in 
  the 
  far 
  south, 
  territory 
  had 
  been 
  in- 
  

   vaded 
  which 
  had 
  previously 
  been 
  entirely 
  free 
  of 
  the 
  disease, 
  for 
  

   yellow 
  fever 
  had 
  not 
  been 
  reported 
  in 
  Rio 
  Grande 
  do 
  Sul 
  during 
  the 
  

   last 
  decade. 
  As 
  the 
  principal 
  epidemic 
  advanced 
  to 
  new 
  territory, 
  the 
  

   area 
  involved 
  during 
  the 
  previous 
  years 
  became 
  almost 
  free 
  of 
  cases, 
  

   probably 
  largely 
  on 
  account 
  of 
  natural 
  immunization 
  of 
  available 
  

   animals 
  and 
  men 
  and 
  partly 
  as 
  the 
  result 
  of 
  preventive 
  vaccination 
  

   of 
  a 
  considerable 
  proportion 
  of 
  the 
  population. 
  

  

  In 
  Colombia, 
  where 
  jungle 
  yellow 
  fever 
  is 
  being 
  studied 
  by 
  Dr. 
  H. 
  

   H. 
  Smith 
  and 
  his 
  associates 
  in 
  the 
  yellow 
  fever 
  service 
  maintained 
  

   cooperatively 
  by 
  the 
  government 
  and 
  the 
  International 
  Health 
  Divi- 
  

   sion, 
  a 
  shift 
  of 
  the 
  involved 
  territory 
  has 
  also 
  been 
  observed. 
  Dr. 
  

   Smith 
  reports 
  that 
  an 
  epidemic 
  of 
  jungle 
  yellow 
  fever 
  has 
  appeared 
  

   recently 
  in 
  areas 
  to 
  the 
  west 
  of 
  the 
  Magdalena 
  River 
  in 
  the 
  states 
  of 
  

   Caldas 
  and 
  Antioquia, 
  where 
  cases 
  had 
  not 
  previously 
  been 
  observed. 
  

   This 
  outbreak 
  is 
  being 
  studied. 
  At 
  the 
  same 
  time, 
  it 
  is 
  becoming 
  

   apparent 
  that 
  jungle 
  yellow 
  fever 
  has 
  largely 
  disappeared 
  from 
  

   the 
  region 
  around 
  Villavicencio, 
  where 
  there 
  were 
  epidemic 
  conditions 
  

   in 
  1934 
  and 
  where 
  a 
  field 
  laboratory 
  has 
  been 
  built 
  to 
  study 
  the 
  

   disease. 
  Cases 
  were 
  diagnosed 
  in 
  the 
  general 
  region 
  of 
  Villavicencio 
  

   each 
  year 
  from 
  1934 
  to 
  1938, 
  but 
  in 
  spite 
  of 
  careful 
  observations 
  no 
  case 
  

   of 
  yellow 
  fever 
  has 
  been 
  found 
  in 
  that 
  area 
  since 
  August 
  1938. 
  Even 
  

   animals 
  with 
  protective 
  sera 
  are 
  being 
  found 
  less 
  frequently 
  in 
  this 
  

   region 
  than 
  formerly, 
  and 
  studies 
  with 
  sentinel 
  animals 
  exposed 
  in 
  

   the 
  jungle, 
  and 
  protection 
  tests 
  on 
  young 
  wild 
  animals 
  have 
  led 
  to 
  

   the 
  belief 
  that 
  active 
  virus 
  is 
  not 
  now 
  present 
  in 
  the 
  area. 
  

  

  THE 
  USB 
  OF 
  VACCINATION 
  IN 
  PREVENTING 
  THE 
  SPREAD 
  

   OF 
  YELLOW 
  FEVER 
  

  

  The 
  present 
  yellow 
  fever 
  situation 
  on 
  which 
  control 
  measures 
  must 
  

   be 
  based 
  may 
  be 
  briefly 
  summarized. 
  There 
  appears 
  to 
  be 
  no 
  yellow 
  

   fever 
  outside 
  South 
  America, 
  unless 
  possibly 
  close 
  to 
  South 
  America 
  

   in 
  Panama. 
  There 
  have 
  been 
  no 
  recognized 
  urban 
  outbreaks 
  of 
  

   aegypti-tr&nsmitted 
  yellow 
  fever 
  in 
  South 
  America 
  for 
  several 
  years. 
  

   Jungle 
  yellow 
  fever 
  occurs 
  continuously 
  in 
  endemic 
  form 
  or 
  as 
  wan- 
  

   dering 
  epidemics 
  in 
  a 
  vast 
  area 
  involving 
  the 
  greater 
  part 
  of 
  the 
  

   Amazon 
  watershed 
  and 
  extending 
  into 
  the 
  interior 
  of 
  Colombia 
  and 
  

   the 
  hinterland 
  of 
  other 
  countries. 
  

  

  