Multiplicity of Plasmodium falciparum infection following intermittent preventive treatment in infants

TY - JOUR

T1 - Multiplicity of Plasmodium falciparum infection following intermittent preventive treatment in infants

AU - Buchholz, Ulrike

AU - Kobbe, Robin

AU - Danquah, Ina

AU - Zanger, Philipp

AU - Reither, Klaus

AU - Abruquah, Harry H

AU - Grobusch, Martin P

AU - Ziniel, Peter

AU - May, Jürgen

AU - Mockenhaupt, Frank P

PY - 2010/1/1

Y1 - 2010/1/1

N2 - BACKGROUND: Intermittent preventive treatment in infants with sulphadoxine-pyrimethamine (IPTi-SP) reduces malaria morbidity by 20% to 33%. Potentially, however, this intervention may compromise the acquisition of immunity, including the tolerance towards multiple infections with Plasmodium falciparum.METHODS: Plasmodium falciparum isolates were obtained from children participating in two Ghanaian IPTi-SP trials (Tamale, Afigya Sekyere) at 15 months of age, i.e., six months after they had received the second dose of IPTi-SP or placebo. By typing the polymorphic merozoite surface protein 1 (msp1) and msp2 genes, multiplicity of infection (MOI) was assessed in 389 isolates. A total of additional 133 samples were collected in Tamale at 3, 6, 9, and 12 months of age. Comparisons of MOI between groups were done by non-parametric statistical tests.RESULTS: The number of distinguishable P. falciparum clones (MOI) ranged between one and six. Mean MOI in Tamale was stable at 2.13 - 2.17 during the first year of life, and increased to 2.57 at age 15 months (P = 0.01). At no age did MOI differ between the IPTi-SP and placebo groups (each, P ≥ 0.5). At 15 months of age, i.e., six months after the second dose, MOI was very similar for children who had received IPTi or placebo (means, 2.25 vs. 2.33; P = 0.55) as was the proportion of polyclonal infections (69.6% vs. 69.7%; P = 0.99). Adjusting for study site, current and prior malaria, parasite density, and season did not change this finding.CONCLUSIONS: IPTi-SP appears to have no impact on the multiplicity of infection during infancy and thereafter. This suggests that tolerance of multiple infections, a component of protective immunity in highly endemic areas, is not affected by this intervention.

AB - BACKGROUND: Intermittent preventive treatment in infants with sulphadoxine-pyrimethamine (IPTi-SP) reduces malaria morbidity by 20% to 33%. Potentially, however, this intervention may compromise the acquisition of immunity, including the tolerance towards multiple infections with Plasmodium falciparum.METHODS: Plasmodium falciparum isolates were obtained from children participating in two Ghanaian IPTi-SP trials (Tamale, Afigya Sekyere) at 15 months of age, i.e., six months after they had received the second dose of IPTi-SP or placebo. By typing the polymorphic merozoite surface protein 1 (msp1) and msp2 genes, multiplicity of infection (MOI) was assessed in 389 isolates. A total of additional 133 samples were collected in Tamale at 3, 6, 9, and 12 months of age. Comparisons of MOI between groups were done by non-parametric statistical tests.RESULTS: The number of distinguishable P. falciparum clones (MOI) ranged between one and six. Mean MOI in Tamale was stable at 2.13 - 2.17 during the first year of life, and increased to 2.57 at age 15 months (P = 0.01). At no age did MOI differ between the IPTi-SP and placebo groups (each, P ≥ 0.5). At 15 months of age, i.e., six months after the second dose, MOI was very similar for children who had received IPTi or placebo (means, 2.25 vs. 2.33; P = 0.55) as was the proportion of polyclonal infections (69.6% vs. 69.7%; P = 0.99). Adjusting for study site, current and prior malaria, parasite density, and season did not change this finding.CONCLUSIONS: IPTi-SP appears to have no impact on the multiplicity of infection during infancy and thereafter. This suggests that tolerance of multiple infections, a component of protective immunity in highly endemic areas, is not affected by this intervention.

KW - Antigens, Protozoan

KW - Antimalarials

KW - Chemoprevention

KW - Drug Combinations

KW - Female

KW - Ghana

KW - Humans

KW - Infant

KW - Malaria

KW - Male

KW - Merozoite Surface Protein 1

KW - Placebos

KW - Plasmodium falciparum

KW - Protozoan Proteins

KW - Pyrimethamine

KW - Sulfadoxine

KW - Treatment Outcome

U2 - 10.1186/1475-2875-9-244

DO - 10.1186/1475-2875-9-244

M3 - SCORING: Journal article

C2 - 20796302

VL - 9

SP - 244

JO - MALARIA J

JF - MALARIA J

SN - 1475-2875

ER -