Clinical trial NCT06064591: Host Immune and Metabolic Determinants of Sexual Conversion in Plasmodium Parasites IMMETASEX
Official title: Host Immune and Metabolic Determinants of Sexual Conversion in Plasmodium Parasites IMMETASEX
Study type: OBSERVATIONAL
Overall status: RECRUITING
Conditions: Severe Malaria
Uncomplicated Malaria
Asyptomatic Plasmodium Infection
Lead sponsor: Institute of Tropical Medicine, Belgium
Sponsor class: OTHER
Collaborators: name: Instituto Nacional de Saúde, Mozambique
name: Clinical Research Unit of Nanoro (CRUN), Burkina Faso
name: Barcelona Institute for Global Health
name: Leiden University Medical Center
name: KU Leuven
First posted: 2023-10-03
Enrollment: 430
Sex: ALL
Minimum age (years): 1
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Pilot:

This study will be performed at the policlinic of ITM, in Antwerp, Belgium.

WP1 Recruitment screenings will be organized in Nanoro village, within the catchment area of the existing health demographic surveillance system (HDSS) of Nanoro Health district (NHD), Burkina Faso.

WP2 The study will include pediatric patients with uncomplicated and severe malaria (aged ≥ 1 and ≤ 12 years, male and female) visiting Chókwè Rural Hospital, Mozambique, and the peripheral health centers in Chókwè district.

Brief summary: Understanding the sexual conversion of the malaria parasite is essential to interrupt malaria transmission. A new tool is developed that, based on expression analysis of sexual stage biomarkers, will estimate sexual conversion rates in natural infections.

Detailed description: Understanding the sexual conversion of the malaria parasite is essential to interrupt malaria transmission. At each replicating cycle within erythrocytes, a proportion of asexual parasites converts into non-replicative sexual stages, which are the only forms able to infect mosquitos. The rate at which sexual stages are produced, is known as basal sexual conversion rate. Changes in the host immune and metabolic environment associated with the development of malaria disease, such as depletion of lysophosphatidylcholine in plasma, have been associated with increased sexual conversion rates in vitro. It is hypothesised that immune and metabolite factors that are altered during malaria infection induce sexual conversion in Plasmodium falciparum parasites. In this project, a new tool is developed that, based on expression analysis of sexual stage biomarkers, will estimate sexual conversion rates in natural infections. The aim is to identify immune factors and metabolites that induce sexual conversion using in-house developed sexual conversion assays, and experimental mosquito infections. Finally, transcriptional mechanisms are explored driving parasite sexual conversion in the host environment during disease using single-cell RNA-sequencing approaches. This research will provide essential knowledge on the factors that affect sexual conversion in the host and potentially inform novel strategies to interrupt transmission.

Eligibility criteria: Inclusion Criteria:

* Age: ≥ 1 year
* Willing and able to provide written informed consent (or assent for minors with written informed consent by parent(s) and/or guardian(s).

Pilot:

-symptomatic for P. falciparum

-/Travel to P. falciparum endemic area within the last month

WP1:

* Resident in Nanoro district
* non-symptomatic individuals

WP2:

* Positive for P. falciparum infection via Rapid Diagnostic Tests (RDT)
* Age: ≥ 1 and ≤ 12 years
* Patients are included when suspected of the following conditions:

I. Severe malaria by infection with P. falciparum is defined in the presence of P. falciparum asexual parasitemia, and as one or more of the following:

1. Impaired consciousness: A Blantyre coma score \< 3 (when patients are ≤ 6 years) or Glasgow coma score \< 10 (when patients are ≥ 6 years).
2. Prostration: Generalized weakness so that the person is unable to sit, stand or walk without assistance.
3. Multiple convulsions: More than two episodes within 24 hours.
4. Clinical manifestation of respiratory distress (e.g., rapid, deep and labored breathing).
5. Diagnosis through exclusion: absence of an identified alternative cause.

II. Uncomplicated malaria by infection with P. falciparum is defined as a patient who presents with lethargic profile (e.g. fever) and a positive parasitological test for P. falciparum, but with no features of severe malaria.

Exclusion Criteria:

* Delayed developmental status or history of chronic illness
* Participation in another study
* Previous malaria treatment or prophylaxis in the last week
* Inability or unwillingness of the parents or guardians to provide informed consent

WP1:

* Symptoms of malaria, as defined by presence of fever (body temperature \>37.5 °C or history of fever during the past 48 hours) with a positive RDT (RDT are performed always when there is presence of fever)
* Any plans to leave the study are in the coming 10 days

WP2:

* Severe anemia (will be determined via clinical examination), since blood samples can hardly be withdrawn, co-morbidities.
* A questionnaire will be used during the clinical assessment that addresses following exclusion criteria:

x Antimalarial drug treatment or other medication during the past week x If the patient had a meal within 4 hours before admission x Patients with acute meningitis (as clinically evaluated according to the local guidelines) x Patients with developmental delay or history of chronic illness x Vaccination during the past week

Primary outcomes:
measure: To validate a Sexual Conversion Estimator tool
timeFrame: 2023-2025
Secondary outcomes:
measure: To investigate in malaria patients associations between host immune and metabolic factors and P. falciparum sexual conversion and infection potential
timeFrame: 2023-2025
measure: To validate associations between sexual conversion and host immune and metabolic factors in vitro
timeFrame: 2024-2026
measure: To explore transcriptional mechanisms driving parasite sexual conversion in the host environment during uncomplicated and severe malaria disease
timeFrame: 2024-2026
Other outcomes:
Locations:
city: Antwerp
country: Belgium
facility: Institute of Tropical Medicine Antwerp
city: Nanoro
country: Burkina Faso
facility: Institut de Recherche en Sciences de la Santé - Clinical Research Unit of Nanoro
city: Maputo
country: Mozambique
facility: Instituto Nacional de Saúde (INS)
Study officials:
affiliation: ITM
name: Anna Rosanas-Urgell, Prof
role: PRINCIPAL_INVESTIGATOR
References: