92 
PROPHYLAXIS OP MALARIA. 
Table VI.— Sergent's observations in Algeria, Africa . 52 
Age. 
Number 
examined. 
Number 
infected. 
Percentage. 
1 to 5 years. 
1,316 
1,360 
933 
267 
20.2 
6 to 1 O' years. 
326 
23.9 
11 to 15 years. 
272 
29.1 
Adults... 
2,471 
722 
33.3 
Total. 
6,080 
1,587 
26,1 
In Pabna Hope found that while 922 adults showed latent infec¬ 
tion only 862 children showed the plasmodia, thus demonstrating 
that in this locality the adult latent malaria ratio was higher than 
the ratio in children. 
If we consolidate the data relating to latent malarial infection 
obtained from different localities it will be found that the percentage 
of infection varies but little in adults or children in badly infected 
localities, as is shown by the following table compiled from the 
observations of the authors quoted and from my own: 
Table VII .—Consolidated table showing the prevalence of latent malarial 
infections at various ages. 
1 to 5 years.. 
5 to 10 years. 
10 to 15 years 
Adults. 
Total.. 
Age. 
Number 
examined. 
Number 
infected. 
Percentage. 
1,684 
502 
29.8 
L645 
463 
28.1 
390 
437 
31. 4 
4^931 
1,139 
23.0 
9,650 
2,541 
26.3 
From these observations, which comprise only a few of the many 
relating to latent infections, one may gather an idea of the immense 
importance of this subject in the prophylaxis of the malarial fevers, 
where anopheline mosquitoes can not be reduced beyond a noninfec- 
tious minimum, and as this is true of the majority of places in the 
Tropics the recognition and treatment of the latent infections among 
the surrounding native population is absolutely necessary in order 
to control the disease. This was demonstrated at Camp Stotsenburg, 
where a very large part of the infection present among the troops 
was contracted from the latent infections present in the native popu¬ 
lation surrounding the post. Although the greatest precautions were 
taken regarding the abolition of the breeding places of mosquitoes 
and the use of mosquito nets in the barracks, the troops suffered 
greatly from malaria, and it was not until the examination of the 
blood of the natives in the surrounding barrios showed that prac¬ 
tically 50 per cent of them were “carriers” of the infection that the 
prevalence of malaria among the troops was fully explained. It is 
undoubtedly true that a quarantine against the little barrios in close 
