1232 



YELLOW FEVER 



It is impossible to close this history without drawing the reader's 

 attention to the great benefit conferred upon mankind by the labours 

 of Reed, Carroll, Agramonte, and Lazear, the last named dying 

 from yellow fever following an experimental bite of an infected 

 mosquito. 



Climatology. — ^As already stated, the endemic area includes a 

 portion of the Atlantic coasts of Mexico and Central and South 

 America, as well as the Antilles. Some of the more important 

 endemic centres at the present time are Guatemala, Spanish Hon- 

 duras, Nicaragua, Costa Rica, Salvador, French Guiana, Dutch 

 Guiana, along the Rivers Magdalena, Orinoco, and Amazon, and in 

 Ecuador. There is evidence that the Cape Verde Islands were in- 

 fected in 1510-15, and that the Gulf of Benin received its yellow 

 fever from this source in 1520, and it is possible that it has been 

 endemic on the West Coast of Africa from that date. Boj/ce was of 

 the opinion that it has been a disease of Africa from time immemor- 

 able, but, though these early historical points cannot satisfactorily 

 be settled, there is more evidence that the true home is Central 

 America, and that Africa is a secondary endemic area, in which very 

 serious outbreaks have been recorded in the past, and where the 

 disease is at times epidemic. 



From the endemic centre the disease can spread by the agency 

 of ships until it reaches 46° 56' N. (Quebec) and 34° 54' S. (Monte 

 Video), which correspond to the isotherm of 60° F. (16° C.) for the 

 mean temperature of the hottest month of the year. At its northern 

 limits the disease is generally very mild, but at its southern limits 

 it may be very severe. 



The areas most usually affected are the Atlantic coasts of North 

 America, as far north as Charleston (32° 46' N.), and of South 

 America as far south as Rio de Janeiro (22° 54' S.). Another region 

 commonly affected is the West Coast of Africa from Senegambia to 

 Saint Paul de Loa do. 



Europe has frequently been attacked — e.g., England (Swansea) in 

 1865, France in 1861, Spain and Portugal in the eighteenth and 

 nineteenth centuries, the last infection being in Madrid in 1878, 

 and Italy (Leghorn) in 1804. 



The disease has apparently more than once reached the Pacific, 

 for it spread in 1740 to Guayaquil, in Ecuador, and in 1854 to Peru. 



The distribution corresponds with that of Stegomyia calopus, and 

 the fact that the disease is endemic in warm climates and more 

 marked in the hot season, while it disappears in the winter of 

 temperate climates, reappearing in the summer, coincides with the 

 habits of the mosquito. Further, the facts that it is carried by 

 infected ships and that it may affect low-lying regions near the coast, 

 particularly ports, in which the dwelling-houses are especially 

 attacked, are explicable by its mosquito transmission. 



It appears to us that the fever associated with black vomit, found among 

 children in ' Grande terre, ' Guadeloupe, must either be a form of yellow fever 

 or closely allied to it, though possibly some cases may be confused with the 



