topographical factors in epidemiology of malaria 
145 
ince of Oriente on the most easterly part of 
the island is considered. Here the malaria 
problem occurs in areas less than 1000 feet 
above sea-level where flat alluvial river 
valleys provide breeding places for A. albi- 
manus. The greater part of Cuba, except 
Oriente, has a solution topography. How¬ 
ever, the general physiography favors 
drainage rather than stagnation of water. 
Similarly, in Jamaica (Boyd and Aris 
1929) small areas of high endemicity occur 
in the lowlands, below 500 feet, as shown in 
Fig. 7, but the central plateau and moun¬ 
tainous areas are relatively free from ma¬ 
laria. In the lowlands A. albimanus is the 
dominant species and is regarded as the 
important malaria carrier. The accom¬ 
panying figures (Figs. 6, 7) show the rela¬ 
tion between the topography of the island 
and the endemic centers of malaria. 
On the island of Haiti A. albimanus 
breeds in coastal swamps and springs near 
towns, at elevations “below 3000 feet” 
(Cook 1930) and, so far as present records 
indicate, malaria is restricted largely to the 
coastal regions. 
In Trinidad (de Verteuil 1933) and 
Grenada (Root and Andrews 1938) malaria 
occurs in the coastal regions, also, but the 
principal vector on these islands is A. tarsi- 
maculatus. This species breeds in man¬ 
grove swamps and in connection with small 
streams and rivers along the coastal low¬ 
lands. The hilly interiors are not ma¬ 
larious. 
The numerous other small islands located 
in the Lesser Antilles have not been sur¬ 
veyed for the distribution of malaria to any 
great extent, but from the observations 
which have been made in other parts of the 
island chain it is probable that coastal ma¬ 
laria predominates. 
Climatological Factors Which Influ¬ 
ence the Distribution of Malaria 
Aside from the more specific effects of 
regional topography on the distribution of 
malaria, it is important to remember also 
that the disease occurs only within certain 
climatological limits. In general, the north¬ 
ern and southern limits follow, although not 
precisely, the mean summer isothermal 
lines of 60 F (60 N to 40 S latitude). Dif¬ 
ferent zones of malaria have been defined 
PARASITE INDICES 
®-20l-30Z<J-l01-20Z@-0l-l0Z 
Figs. 8, 9. Topographical map of the islands of Grenada and Carriacou. Parasite indices in Grenada 
and Carriacou (from Eoot and Andrews 1938). 
