Abstract
Thirty Liberians aged 1-35 years were exposed to infection with sporozoites. Only one showed a patient infection. The strain thus isolated failed to infect another Liberian. The 1st appearance of P. vivax in the blood of the Liberian showed the characters of P. wilsoni. The relative insusceptibility of Liberians is believed to be the main cause of the lack of autochthonous P. vivax in Liberia.
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