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

Completed

• Conditions: Malaria Transmission
• Interventions: Other: Pre-treatment follow up; Other: Post treatment follow up; Other: S. haematobium treatment; Other: Olfactometer experiment

• Registration Number: NCT02769013
• Lead Sponsor: University Hospital Tuebingen

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.

Study Timeline

• Study Start: 2016-04
• Study First Submitted: 2016-04-21
• Study First Submitted QC: 2016-05-09
• Study First Posted: 2016-05-11
• Status Verified: 2017-10
• Primary Completion: 2019-10
• Study Completion: 2020-10
• Last Update Submitted: 2020-11-03
• Last Update Posted: 2020-11-04

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 380

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

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
S. haematobium negatives in Gabon	Pre-treatment follow up	Volunteers not infected with S. haematobium and living in Gabon
S. haematobium negatives in Gabon	Post treatment follow up	Volunteers not infected with S. haematobium and living in Gabon
S. haematobium positives in Ghana	Pre-treatment follow up	Asymptomatic volunteers infected with S. haematobium and living in Ghana
S. haematobium positives in Ghana	Post treatment follow up	Asymptomatic volunteers infected with S. haematobium and living in Ghana
S. haematobium negatives in Ghana	Pre-treatment follow up	Volunteers not infected with S. haematobium and living in Ghana
S. haematobium negatives in Ghana	Post treatment follow up	Volunteers not infected with S. haematobium and living in Ghana
S. haematobium negatives in Ghana	Olfactometer experiment	Volunteers not infected with S. haematobium and living in Ghana
S. haematobium positives in Gabon	Pre-treatment follow up	Asymptomatic volunteers infected with S. haematobium and living in Gabon
S. haematobium positives in Gabon	S. haematobium treatment	Asymptomatic volunteers infected with S. haematobium and living in Gabon
S. haematobium positives in Gabon	Post treatment follow up	Asymptomatic volunteers infected with S. haematobium and living in Gabon
S. haematobium positives in Ghana	S. haematobium treatment	Asymptomatic volunteers infected with S. haematobium and living in Ghana
S. haematobium positives in Ghana	Olfactometer experiment	Asymptomatic volunteers infected with S. haematobium and living in Ghana
S. haematobium positives in Gabon	Olfactometer experiment	Asymptomatic volunteers infected with S. haematobium and living in Gabon
S. haematobium negatives in Gabon	Olfactometer experiment	Volunteers not infected with S. haematobium and living in Gabon

Primary Outcome Measures

Name	Time	Method
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 Outcome Measures

Name	Time	Method
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.

Trial Locations

Locations (2)

KCCR; 🇬🇭 Kumasi, Ghana

Ayôla Akim ADEGNIKA; 🇬🇦 Lambarene, Albert Schweitzer Hospital, Gabon