Malaria Transmission
Conditions
Keywords
Schistosoma haematobium plasmodium falciparum transmission
Brief summary
Assessing the effect of neglected tropical diseases on Plasmodium falciparum transmission in an area of co endemicity.
Detailed description
The project is divided in three different work packages that cover the life cycle of P. falciparum : 1. 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. 2. 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). 3. 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.
Interventions
OTHERPre-treatment follow up
No active intervention; medical support provided if needed
OTHERS. haematobium treatment
Praziquantel-treatment for S. haematobium positive volunteers
OTHERPost treatment follow up
No active intervention; medical support provided if needed.
OTHEROlfactometer experiment
No active intervention; medical support provided if needed.
Sponsors
University Hospital Tuebingen
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
6 Years to 30 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of participants with Plasmodium falciparum gametocytes and/or asexual blood stages | 15 months | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of participants with positive serum antibodies specific to the asexual and gametocyte stages of Plasmodium falciparum. | 15 months | Number of participants with serum antibodies against P. falciparum gametocyte and/or asexual blood stage antigens will be assessed. |
| Percentage of mosquitoes attracted to Schistosoma-infected participants to non-infected individuals in a wind-tunnel assay. | 15 months | 100 mosquitoes will be released to Schistosoma infected and non-infected participants simultaneously lying in different tents in a two-way olfactometer. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Proportion of Plasmodium infected Anopheles mosquitoes per individual per night | 3 months | Mosquitoes will be collected by Human Landing catches and species of mosquitoes and presence of Plasmodium falciparum will be determined by morphology and PCR. |
Countries
Gabon, Ghana
Outcome results
None listed