Community Dynamics of Malaria Transmission in Humans and Mosquitoes in Fleh-la and Marshansue, Salala District, Bong County, Liberia

Sponsor

National Institute of Allergy and Infectious Diseases (NIAID) (NIH)

Overall Status

Recruiting

CT.gov ID

NCT04704674

Collaborator

(none)

600

Enrollment

Location

Anticipated Duration (Months)

20.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Background:

Malaria is a disease that affects many people in Liberia. It is caused by germs (parasites) that are spread by mosquito bites. Researchers want to gather data that may help them understand the best way to use a malaria vaccine in Liberia, which will be important in getting rid of the disease.

Objective:

To find out how often people of all ages who live in Fleh-la and Marshansue, Liberia, get malaria.

Eligibility:

Healthy people ages 6 months and older who live in Fleh-la and Marshansue in a household with adults and children.

Design:

Participants will be screened with a physical exam and questions about their health.

Participants will have monthly study visits. They will be asked about any symptoms of malaria and their use of bednets. Their vital signs, such as blood pressure and temperature, will be checked. Blood will be taken from the participant s arm or finger with a needle. If they have a fever, they will get a malaria test. If positive, they will get drugs to treat malaria.

Once a month, participants houses will be examined for mosquitoes. The team will remove all mosquitoes they collect. As part of this collection, participants houses will be sprayed with a chemical to kill mosquitoes and other insects. Participants will not be allowed in their house while the team is inside. The spray will not harm the participants.

Once a year, at the monthly visit, an additional blood sample will be taken.

Some of the participants blood samples will be used for genetic testing.

Participation will last for up to 3 years....

Condition or Disease	Intervention/Treatment	Phase
Malaria

Detailed Description

A vaccine that interrupts malaria transmission is critical to eradicate the disease, but improved assays are needed to measure the efficacy of vaccines. Transmission-blocking vaccines (TBVs) work by inducing antibodies that inhibit parasite development in the mosquito interrupting transmission. Efficacy of vaccines may be estimated by in vitro membrane feeding assays using immune sera and laboratory mosquitoes, but qualified assays that measure transmission in the field are needed to assess transmission-blocking interventions in natura. Clinical trials of TBVs have started elsewhere on the continent in Mali, and we expect to expand TBV studies here in Liberia in the near future. This protocol will use a longitudinal cohort to gather information of malaria transmission based on the rates of blood smear positive individuals by month, season and year in Fleh-la and Marshansue, in Salala, Bong County, Liberia. Individuals in the villages will be approached first for participation, including permission to contact their household and neighbors of their compound for participation. Households will be identified using census data and individuals will be consented for participation. Malaria smears will be obtained at monthly visits, in conjunction with mosquito collections in/around village residences. Parasite infection rates in locally caught mosquitoes will be assessed longitudinally for differences by season and year. A total of 400 volunteers from Fleh-la and Marshansue will be enrolled. Participants will be followed for up to 3 years, to collect data that will guide the design of future community-based trials of TBV.

Study Design

Study Type:

Observational

Anticipated Enrollment :

600 participants

Observational Model:

Cohort

Time Perspective:

Prospective

Official Title:

Community Dynamics of Malaria Transmission in Humans and Mosquitoes in Fleh-la and Marshansue, Salala District, Bong County, Liberia

Actual Study Start Date :

Sep 30, 2021

Anticipated Primary Completion Date :

Feb 29, 2024

Anticipated Study Completion Date :

Feb 29, 2024

Arms and Interventions

Arm	Intervention/Treatment
0.5 - 5 years Age bracket for infants/children up to age five years
10 - 18 years Age bracket for children 10 - 18 years
19 + years Age bracket for adults over 19 years
5 - 10 years Age bracket for children ages 5 - 10 years

Outcome Measures

Primary Outcome Measures

Measurement of Monthly rates of blood smear positive individuals by age [one year]
Rate of blood smear positive individuals

Eligibility Criteria

Criteria

Ages Eligible for Study:

6 Months and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

INCLUSION CRITERIA:

Subject Inclusion Criteria:

6 months of age and above
Known resident of Fleh-la and Marshansue or the surrounding villages and planning to remain for duration of study
Willingness to allow stored laboratory specimens to be used for future research
Acceptance and signature of the written informed consent and the assent for children aged 12-17 years who are not otherwise emancipated

Household Inclusion Criteria:

To be eligible for participation, households must meet the following criteria:

Household with at least 3 residents eligible for participation.
Household with at least one compound member who is below 18 years of age whose parents or caretakers are willing to provide informed consent for the child to participate.
Household members willing to accommodate mosquito sampling in their compound, both indoors and outdoors.

Exclusion Criteria:

Subject Exclusion Criteria:

Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator affects the ability of the subject to understand and cooperate with the study protocol.
Other condition that, in the opinion of the investigator, would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.