MALARIA AND ALTITUDE 235 
“ Asia.—India, Ceylon, portions of China and Arabia, and the Islands of the 
Malay Archipelago are infected with the malarial fevers. This is also true of 
Asia Minor and the valleys of almost all the great rivers, such as the Indus and 
Ganges. In Japan the benign infections are common, and even upon the lofty 
table lands near the Himalayas malarial infections are often met with. The 
Philippine Islands, until very recently considered as comparatively free from 
malarial diseases, have been proved to be badly infected, a large percentage of 
our soldiers returning from there showing infection with the tertian and estivo- 
autumnal parasites. 
“ Africa.—In Africa are some of the most dangerous lurking places of 
malarial infections, the worst areas being those along the west coast and the 
Senegal, Congo, and Niger Rivers, as well as the regions around the great lakes 
and the jungles, and lake shores of Abyssinia. Madagascar, Reunion, and 
Mauritius Islands present the pernicious varieties of the disease. Around 
Delagoa Bay and along the east coast of Africa, estivo-autumnal fever is prev- 
alent. Lower Egypt, the Soudan, the Nile delta, Tripoli, Tunis and Algeria, 
all harbor these infections.” 
Regarding the vertical distribution of malaria it may be said in a general way 
that malaria decreases with the increased altitude above sea level. The govern- 
ing factors are, on the one hand, the unfavorable effect of low temperatures on 
the development of the malarial organisms, on the other hand, the absence in 
many mountainous regions of conditions upon which the abundance of Anoph- 
eles depends. Nevertheless malaria does occur at considerable altitudes in 
various parts of the world, apparently going highest in the Andes of South 
America. According to Treutlein, at La Paz, Bolivia, it reaches an altitude of 
2564 meters. This author states that while endemic malaria, on account of the 
conditions, unfavorable to mosquitoes, does not occur at La Paz it exists on the 
plain of Potopoto, 100 meters lower, where Anopheles breed in some numbers. 
Ziemann gives the following summary of the occurrence of malaria at high 
altitudes : 
“ While, for example, in Ceylon malaria no longer occurs at 500 meters above 
sea level, the writer still found malaria in Cameroon and also in the Manenguba 
mountains at about 900 meters altitude; however no longer from 1200 meters 
on in the grass land, and the distribution of malaria and of anophelines seemed 
to agree pretty closely. Steuber still found malaria in German Hast-Africa at 
Lake Nyassa at an elevation of 1560 meters. In the mountainous regions of 
Usambara the conditions appeared to be similar to those of Cameroon in that 
malaria there still occurred at 800 meters altitude. In the Himalaya mountains 
it is said that malaria is still found at a height of 2000 meters, in the Andes of 
Peru even to 2500 meters, in the high lands of Persia, on the other hand, only to 
1500 meters. In the German mountains malaria rises to 400-500 meters, in 
Italy to 600-1000 meters. Recently Grassi even found there an endemic malarial 
focus, in the vicinity of Colico, at an altitude 2500 meters. In malarial regions 
comparatively slight elevations above the malaria-infected plain are often 
sheltered, which one can easily explain, with our present knowledge, by the 
relatively small height of the flight of anophelines. Therefore the inhabitants 
of malarial regions always withdrew by preference to the surrounding hills. It 
is known that the shepherds of the Campagna about Rome passed the nights on 
scaffoldings which were several meters above the ground.” 
Edmond Sergent states that in Algeria, while Anopheles abound at all times 
in altitudes of from 1600 to 1800 meters, malaria occurs in those altitudes only 
