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

Study Overview
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Brief Summary
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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.

Conditions
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Malaria, Schistosomiasis, Hiv Infection

Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 1 Year

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Children 1-5 years old<br> | |
| Children 6-10 years old<br> | |
| Adults 25 years and above<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. |  |