Correlating Protection Against Malaria With Serum Profiles Against Plasmodium Falciparum Antigen Repertoires

Radboud University Medical Center500 enrolled

Overview

A longitudinal study on immune responses in relation to protection against clinical malaria episodes will be conducted in Apac District, Uganda. Three cohorts will be recruited: children 1 to 5 years of age (n=250), children 6 to 10 years of age (n=125) and adults 25 and above (n=125). After finger prick sampling (\~300µL) and examination at enrolment, participants will be followed up for one year. Follow-up will include fortnightly active case detection and three-monthly cross-sectional surveys. Clinical malaria attacks and the associated clinical and parasitological parameters will be related to immunological profiles determined utilizing a protein microarray as a capture substratum to profile the humoral immune response against a vast number of parasite antigens. For individuals who experience a clinical malaria attack or who are diagnosed with high density parasitaemia (≥15,000 parasites/µL) during cross-sectional surveys, a 5mL blood sample is obtained to determine the diversity of parasite antigens in the population in relation to antigen recognition in the cohort.

Study Type

OBSERVATIONAL

Enrollment

500

Conditions

Malaria Schistosomiasis Hiv Infection

Eligibility

Sex: ALLMin age: 1 YearHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * age 1-5 years, 6-10 years or 25 yearsand above * written informed consent must be given * the individual must have been resident of the area since birth or for a minimum period of two years * the individual must be willing to submit required information and to participate in repeated sampling (total blood volume \~2.5 mL over a period of 12 months) * Absence of danger signs (as defined by WHO) or clinical features of AIDS. An HIV-test will be offered to all participants at enrolment and completion of the study. Exclusion Criteria: * unwillingness to sign consent form * unwillingness to reside in the study area during the follow-up period

Outcomes

Primary Outcomes

Immune correlates of protection against clinical malaria episodes with plasmodium falciparum

IMMUNE RESPONSES: protein array. CLINICAL MALARIA EPISODES: (reported) fever with i) P. falciparum parasites; ii) ... at a density \>=5,000 parasites/ul; iii) ... at a density \>=10,000 parasites/ul IMMUNOLOGICALLY PROTECTED INDIVIDUALS: parasitaemic during follow-up without reporting to the health facility with indicators of a clinical malaria episode

Secondary Outcomes

Geographical patterns in malaria morbidity

Households are geo-located by GPS and hotspots of malaria transmission will be determined and related to serological profiles.

Asymptomatic parasite carriage and immune responses in different age-groups exposed to intense malaria transmission

ASYMPTOMATIC PARASITE CARRIAGE will be confirmed by microscopy and PCR.