The first Plasmodium vivax relapses of life are usually genetically homologous

Abstract

In a prospective infant cohort, 21 infants developed Plasmodium vivax malaria during their first year. Twelve of their mothers also had vivax malaria in the corresponding pregnancies or postpartum period. The genotypes of the maternal and infant infections were all different. Eight of the 12 mothers and 9 of the 21 infants had recurrent infections. Relapse parasite genotypes were different to the initial infection in 13 of 20 (65%) mothers compared with 5 of 24 (21%) infants (P = .02). The first P. vivax relapses of life are usually genetically homologous, whereas relapse in adults may result from activation of heterologous latent hypnozoites acquired from previous inoculations.

Figure 1.

Temporal pattern and genotyping of recurrences of Plasmodium vivax malaria in 8 mothers (A) and 9 infants (B). Each number on the y-axis represents a patient. Filled circles denote the initial infection. An open circle represents a genetically homologous recurrence, and a black diamond represents a genetically heterologous recurrence. Recurrences where genotyping was indeterminate (2 in infants, 3 in mothers) are not shown. One mother’s sole relapse was indeterminate.