Assessing the Effect of Neglected Tropical Diseases on Plasmodium Falciparum Transmission in an Area of Co-endemicity

Study Overview
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Brief Summary
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Assessing the effect of neglected tropical diseases on Plasmodium falciparum transmission in an area of co endemicity.

Detailed Description
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The project is divided in three different work packages that cover the life cycle of P. falciparum : In Work Package 1 (WP1) the investigators will assess whether S. haematobium infection increases the human reservoir of P. falciparum by increasing the carriage rate and incidence of P. falciparum gametocytaemia as well as by increasing the proportion and incidence of subject with sub-microscopic P. falciparum infection. The investigators will also determine whether this increase in gametocyte carriage is a consequence of an impairment of the immune response of helminth infected subjects to P. falciparum. In Work Package 2 (WP2) the investigators will determine whether the transmission of the sexual forms of P. falciparum from the human host to mosquito is increased in S. haematobium infected subjects compared to uninfected controls. Moreover the investigators will study whether the immunological changes induced in S. haematobium infected subjects lead to a decrease of the transmission reducing activity of IgG specific to Pfs48/45 and Pfs230 (both capable of blocking/impairing further development of P. falciparum in the mosquito gut). Finally in Work Package 3 (WP3) the investigators will assess whether S. haematobium infection affects the transmission of P. falciparum from the mosquito to the human host. This effect will be determined indirectly by assessing whether S. haematobium infected subjects are more attractive to mosquitoes.

Official Title
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Assessing the Effect of Neglected Tropical Diseases on Plasmodium Falciparum Transmission in an Area of Co-endemicity

Conditions
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Malaria Transmission

Intervention / Treatment
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* Other: Pre-treatment follow up
* Other: S. haematobium treatment
* Other: Post treatment follow up
* Other: Olfactometer experiment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects aged from 6 to 30 years Without severe or moderate disease Agreement to be enrolled in the study (written informed consent or consent by the legal representative and assent) Living in the study area for at least 1 year Exclusion Criteria: Anaemia with haemoglobin less than 8g/dl Know sickle cell disease Macroscopic haematuria Any other know severe disease

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 30 Years

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 |
| --- | --- |
| S. haematobium positives in Gabon<br>Asymptomatic volunteers infected with S. haematobium and living in Gabon | Other: Pre-treatment follow up<br>* No active intervention; medical support provided if needed<br>Other: S. haematobium treatment<br>* Praziquantel-treatment for S. haematobium positive volunteers<br>* Other names: Praziquantel-treatment;Other: Post treatment follow up<br>* No active intervention; medical support provided if needed.<br>Other: Olfactometer experiment<br>* No active intervention; medical support provided if needed.<br>|
| S. haematobium negatives in Gabon<br>Volunteers not infected with S. haematobium and living in Gabon | Other: Pre-treatment follow up<br>* No active intervention; medical support provided if needed<br>Other: Post treatment follow up<br>* No active intervention; medical support provided if needed.<br>Other: Olfactometer experiment<br>* No active intervention; medical support provided if needed.<br>|
| S. haematobium positives in Ghana<br>Asymptomatic volunteers infected with S. haematobium and living in Ghana | Other: Pre-treatment follow up<br>* No active intervention; medical support provided if needed<br>Other: S. haematobium treatment<br>* Praziquantel-treatment for S. haematobium positive volunteers<br>* Other names: Praziquantel-treatment;Other: Post treatment follow up<br>* No active intervention; medical support provided if needed.<br>Other: Olfactometer experiment<br>* No active intervention; medical support provided if needed.<br>|
| S. haematobium negatives in Ghana<br>Volunteers not infected with S. haematobium and living in Ghana | Other: Pre-treatment follow up<br>* No active intervention; medical support provided if needed<br>Other: Post treatment follow up<br>* No active intervention; medical support provided if needed.<br>Other: Olfactometer experiment<br>* No active intervention; medical support provided if needed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with Plasmodium falciparum gametocytes and/or asexual blood stages | Presence of Plasmodium falciparum gametocytes and/or asexual blood stages will be assessed by a quantitative real-time PCR assay in the blood obtained from participants. Unit of measurements for both parameters is numbers/µl. | 15 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with positive serum antibodies specific to the asexual and gametocyte stages of Plasmodium falciparum. | Number of participants with serum antibodies against P. falciparum gametocyte and/or asexual blood stage antigens will be assessed. | 15 months | 
| Percentage of mosquitoes attracted to Schistosoma-infected participants to non-infected individuals in a wind-tunnel assay. | 100 mosquitoes will be released to Schistosoma infected and non-infected participants simultaneously lying in different tents in a two-way olfactometer. | 15 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Schistosoma haematobium plasmodium falciparum transmission