Gametocyte infectivity by direct mosquito feeds in an area of seasonal malaria transmission: implications for Bancoumana, Mali as a transmission-blocking vaccine site.
Infectivity of gametocytemic volunteers living in Bancoumana, a village 60 km from Bamako, Mali, was determined by direct feeds of laboratory-reared Anopheles gambiae s. l. Gametocytemic adolescents (10-18 years old) were as infectious to mosquitoes as younger volunteers and appear to be a more suitable population for testing transmission-blocking efficacy as compared with adults (> 18 years old). To begin to validate the membrane-feeding assay, sera collected from these same volunteers were subjected to a standard membrane-feeding assay. The data suggest that areas with intense but seasonal transmission might be feasible sites for testing transmission-blocking vaccines because of the high gametocytemic rates, high mosquito infectivity rates, and lack of pre-existing humoral-mediated transmission-blocking activity. The differences observed between field-based direct mosquito feeds and laboratory-based membrane feeding assays suggests that caution be used in interpreting Phase I study results in which laboratory-based membrane-feeding assays are used as a surrogate for vaccine efficacy.
Toure
Y T
YT
Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Odonto-Stomatology, Bamako, Mali.
Doumbo
O
O
Toure
A
A
Bagayoko
M
M
Diallo
M
M
Dolo
A
A
Vernick
K D
KD
Keister
D B
DB
Muratova
O
O
Kaslow
D C
DC
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000818:Animals; D000852:Anopheles / Q000469:parasitology; D000913:Antibodies, Protozoan / Q000097:blood; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D017780:Malaria Vaccines / Q000276:immunology; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D008302:Mali / Q000453:epidemiology; D018512:Parasitemia / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D010963:Plasmodium falciparum / Q000276:immunology / Q000472:pathogenicity*; D015995:Prevalence; D012621:Seasons
D000913:Antibodies, Protozoan; D017780:Malaria Vaccines