Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2006-4-24
pubmed:abstractText
Immunity to the sexual stages of Plasmodium falciparum is induced during natural infections and can significantly reduce the transmission of parasites to mosquitoes (transmission reducing activity; TRA) but little is known about how these responses develop with increasing age/exposure to malaria. Routinely TRA is measured in the standard membrane feeding assay (SMFA). Sera were collected from a total of 199 gametocyte carriers (median age 4 years, quartiles 2 and 9 years) near Ifakara, Tanzania; 128 samples were tested in the SMFA and generated TRA data classified as a reduction of > 50% and > 90% of transmission. TRA of > 50% was highest in young children (aged 1-2) with a significant decline with age (chi(2) trend = 5.79, P = 0.016) and in logistic regression was associated with prevalence of antibodies to both Pfs230 and Pfs48/45 (OR 4.03, P = 0.011 and OR 2.43 P = 0.059, respectively). A TRA of > 90% reduction in transmission was not age related but was associated with antibodies to Pfs48/45 (OR 2.36, P = 0.055). Our data confirm that antibodies are an important component of naturally induced TRA. However, whilst a similar but small proportion of individuals at all ages have TRA > 90%, the gradual deterioration of TRA > 50% with age suggests decreased antibody concentration or affinity. This may be due to decreased exposure to gametocytes, probably as a result of increased asexual and/or gametocyte specific immunity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0141-9838
pubmed:author
pubmed:issnType
Print
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
185-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Transmission-reducing immunity is inversely related to age in Plasmodium falciparum gametocyte carriers.
pubmed:affiliation
Ifakara Health Research and Development Centre, Ifakara, Tanzania. chris.drakeley@lshtm.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't