Assessing the effect of neglected tropical diseases on Plasmodium falciparum transmission in an area of co endemicity.
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.
Study Type
OBSERVATIONAL
Enrollment
380
No active intervention; medical support provided if needed
Praziquantel-treatment for S. haematobium positive volunteers
No active intervention; medical support provided if needed.
Ayôla Akim ADEGNIKA
Lambaréné, Albert Schweitzer Hospital, Gabon
KCCR
Kumasi, Ghana
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.
Time frame: 15 months
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.
Time frame: 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.
Time frame: 15 months
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No active intervention; medical support provided if needed.