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George (L.). A Report on an outbreak of Yellow Fever of an unusual 

 nature at Brighton-La-Brea, Trinidad.— rnntriar^ and Tobago 

 Council Paper No. 205 of 1914, Port- of- Spain, 1915, pp. 12-18, 

 1 map, 10 charts. 



Ten cases of yellow fever, divisible into four distinct groups, occurred 

 at Brighton La-Brea, Trinidad, at the end of November and throughout 

 December 1913, among white employees in the oil-fields. The relation 

 of the groups of cases and the possibility of infection by mosquitos 

 from one to the other is discussed. La Brea, with a black or coloured 

 population of about 2,000, is stated to be " undescribably filthy, 

 overcrowded and swarming with Stegom.yia,^' but no cases occurred 

 there ; at Brighton, with a population of 50 whites, only 500 yards 

 away, the 10 cases occurred. On the other side, and about the same 

 distance away along the coast, is a coloured settlement of about 600 

 known as " Coon Town," where the conditions were better than at 

 La Brea, though the place was swarming with Stegomyia, and yet 

 there were no cases of yellow fever. 



The possible causes of the outbreak are discussed at length and 

 include : importation ; local infection from cases too mild to be 

 recognised ; and an intermediate host, possibly monkeys. The 

 importation theory had to be abandoned on investigation ; and with 

 regard to infection from the native population as unconscious carriers, 

 it is suggested that (1) the presence of a number of non-immune white 

 men, recently arrived in the tropics, might furnish an intensive medium 

 for the growth of the parasite ; (2) the disturbance and cutting down 

 of large tracts of virgin forest might have caused migration of Stegomyia 

 mosquitos, introducing them for the first time to a feed of human blood 

 and, in the case of the natives, infected blood ; or (3) the effects 

 might be due to a heavy wet season. Against these arguments it 

 may be said, in regard to this particular outbreak, that there had 

 been non-immunes in the locality for many years ; a considerable 

 quantity of forest was being cut down for some years back ; and 

 heavy wet seasons are frequent. The third theory of origin, suggested 

 by Dr. Andrew Balfour of the Wellcome Research Institute, that some 

 vertebrate, other than man, especially monkeys, may also act as the 

 host of the yellow fever parasite, awaits confirmation. There is an 

 old saying amongst the natives of the island that when the monkeys 

 die one may expect an outbreak of yellow fever. 



Body temperature was found to be useless as a warning symptom, 

 as nearly all the inhabitants of Coon Town were found to have a 

 temperature about 100° F., and no cases were discovered there. The 

 supposed screened bungalows of the whites at Brighton were far from 

 mosquito-proof, and the author killed 8 or 10 Stegomyia every night 

 in his bedroom in one of the best of them. The bush was cut down 

 over 150 acres and the exposed ground found to be full of depressions 

 and gullies containing stagnant water. Barrels of distillate oil, fitted 

 with special spigots, were placed in position in some of the gullies so 

 as to give a continuous drip, but the natives having stolen the spigots, 

 spraying with oil was resorted to over a wide area, and in two or three 

 weeks mosquitos became difficult to find in Brighton. The gauzo 

 screens of the bungalows were also repaired and made efficient. The 

 forest appearing to be the focus of infection, all white non-immunes were 



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