title: Acquired transmission-blocking immunity to Plasmodium vivax in a population of southern coastal Mexico.
abstract: Naturally acquired transmission-blocking immunity to Plasmodium vivax was studied in three groups of patients from the southern coast of Mexico: primary cases (Group A, 61% of the study population), secondary cases with the prior infection seven or more months earlier (Group B, 23%), and secondary cases with the previous malaria experience within six months of the present study (Group C, 16%). Anopheles albimanus mosquitoes were fed with patients' infected blood cells in the presence of autologous or control serum, with or without heat-inactivation. Patients from all three groups had transmission-blocking immunity, although the quality and quantity of this blocking activity was significantly higher in the two secondary patient groups (B and C). Only primary malaria cases produced transmission-enhancing activity (23% of the cases), which was dependent on heat-labile serum components. The levels of patient group transmission-blocking immunity and mosquito infectivity were used to calculate the probabilities of a mosquito becoming infective after taking a blood meal from a P. vivax-infected patient from any one of the three groups. This probability was 0.025, with Group A patients providing the major source of these infections (92% risk from Group A and 4% risk for Groups B and C).
authors.affiliation: Centro de Investigación de Paludismo, Tapachula, Chiapas, Mexico.
authors.forename: J M
authors.initials: JM
authors.lastname: Ramsey
authors.forename: E
authors.initials: E
authors.lastname: Salinas
authors.forename: M H
authors.initials: MH
authors.lastname: Rodríguez
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D016780:Malaria, Vivax / Q000453:epidemiology / Q000276:immunology* / Q000635:transmission; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D010966:Plasmodium vivax / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan