MALARIA SURVEY—METHODS AND PROCEDURES 
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tion in which the different species of plas- 
modium are present (P. vivax, P. falci¬ 
parum, P. malariae). In regions where 
prevalent, a high relative incidence of P. 
falciparum suggests recent transmission at 
fairly high levels of intensity. A relatively 
high incidence of P. malariae, especially if 
P. falciparum is low, suggests a low level 
of transmission during recent years. Re¬ 
cent transmission is revealed by a high 
level of infection in non-immunes, such as 
infants and immigrants. 
If the entomological survey has incrimi¬ 
nated the vector species the problem of spe¬ 
cies sanitation may be taken up. Searches 
for larvae and adult captures may have 
indicated the production areas of the 
vector. The correlation of the distribution 
of clinical cases with the known produc¬ 
tion areas will indicate whether all likely 
production areas have been discovered. 
Knowledge of the bionomics of the vector 
may suggest possibilities for methods of 
biological or naturalistic control. 
