An observational study in Malaria, sponsored by National Institute of Allergy and Infectious Diseases (NIAID). Completed at 2 sites in Mali. Open to participants aged 6 Months and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-10-31.
Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) · Observational
Background:
Malaria is caused by parasites carried by some mosquitos. When the mosquitos bite people, the parasites can infect them. One of these parasites is Plasmodium vivax (P. vivax). Some children have P. vivax in their blood. They did not have malaria symptoms, but some also had a blood problem called anemia. This can make people feel tired or weak. This could have been caused by P. vivax. Researchers want to know how P. vivax infects these children, and if it affects their health.
Objective:
To collect blood, stool, and urine monthly from children to look for infections with P. vivax, worms, and other parasites.
Eligibility:
Children between 6 months and 10 years old
Design:
For screening, the study will be explained to the participant s parents or guardians, who will provide consent.
Participants will have a visit once a month for about 3 months, from November to January, and then for about 6 months from June to November 2018. Visits include:
Questions about their health
Medical history
Physical exam
Blood draw by pricking the finger tip
Urine and stool collection. They may collect these at home and bring them back.
If participants have P. vivax in their blood, them may need to come back to the clinic within 3 days. They will have blood taken from their arm using a needle.
If participants feel ill during the study, they can go to the clinic for an exam and blood tests.
If participants develop malaria while on the study, they will be treated.
Participants samples will be stored for future research studies.
...
Plasmodium vivax was thought not to be a problem in Duffy blood group negative Africans. However, recent research has found that P. vivax infection occurs not only in areas where Duffy-positive and -negative people live side-by-side, but also in areas where populations are predominantly Duffy-negative, such as Bandiagara, Mali. In this region, our research group recently observed 25 P. vivax infections in children, all of whom were Duffy-negative. Furthermore, some preliminary data suggest that, despite having extremely low parasitemia and no malarial symptoms (no fever, muscle aches, or chills), the children of Bandiagara with P. vivax may have a drop in hemoglobin.
The present study involves two substudies to detect P. vivax infections in children and adults of two predominantly Duffy-negative Malian populations where P. vivax infections have previously been identified. The cohort study will be conducted in the Bandiagara region. We will conduct physical exams and collect blood, urine, and stool samples at baseline and monthly (urine samples will be collected only at baseline) for about 10 months. Our goal is to detect and characterize P. vivax infections, focusing on molecularly characterizing how P. vivax invades erythrocytes in Duffy-negative individuals. Specifically, we want to identify the parasite ligands involved in this invasion. We will use RNA sequencing (RNAseq) of P. vivax in blood samples of infected subjects to define the level of expression of parasite invasion ligands. From the parasite DNA found in blood samples, we will determine whether there is gene expansion of the parasite ligand Duffy binding protein (PvDBP) (the number of copies of PvDBP in each genome), and identify the sequence of PvDBP to determine whether it can bind an erythrocyte receptor other than the Duffy blood group antigen (i.e., Duffy-negative erythrocytes). An additional focus will be whether P. vivax leads to anemia in the Duffy-negative children.
In addition, we will conduct a cross-sectional study to investigate the prevalence of P. vivax in the general population in Yirimadio, a periurban setting of Bamako, which is the sole place in Mali besides Bandiagara where P. vivax infections have been reported in Duffy-negative individuals. This will be achieved by undertaking a cross-sectional survey. Subjects will provide blood for blood smear and filter paper analyses to identify the presence of P. vivax infection at 3 different time points.
1,184 studies on the registry are indexed under Malaria; 79 are open to participants now.
This study's enrollment of 667 is above the median of 582 across 204 observational studies indexed under Malaria.
Browse Malaria studies →National Institute of Allergy and Infectious Diseases (NIAID) is the lead sponsor of 2,446 studies on the registry; 179 are open to participants now.
Of its 405 completed or terminated interventional studies of FDA-regulated products, 302 (75%) have results posted.
Counted across the registry records on this site, refreshed daily.
Subjects will be selected to enroll based on community permission and sensitization strategies for both the Bandiagara and Yirimadio sites.
For inclusion in the cohort substudy, a child must meet the following criteria:
For inclusion in the cross-sectional substudy, an individual must meet the following criteria:
EXCLUISION CRITERIA:
The following criterion is exclusionary in either substudy:
Children of both sexes between 6 months and 10 years of age.
Children and adults of both sexes 6 months and older.
Identify the P. vivax ligands for infection of Duffy blood group negative Africans by RNA sequencing (RNAseq) of blood from P. vivax cases.
Identify the P. vivax ligands for infection of Duffy blood group negative Africans by RNA sequencing (RNAseq) of blood from P. vivax cases.
Time frame: Monthly surveillance visits throughout length of the study
Determine the prevalence of P. vivax in Yirimadio in Duffy negative population
Time frame: Beginning, peak, and end of transmission season
Identify the vector populations in and around the study area that may transmit malaria, including during the dry season, as well as the infection rates in these populations.
Time frame: Monthly surveillance visits throughout length of the study
Study the association between P. vivax parasitemia and anemia in Duffy-negative Africans.
Time frame: Monthly surveillance visits throughout length of the study
Determine by stool examinations the presence of hypnozoites in the liver that fail to cause blood infections.
Time frame: Monthly surveillance visits throughout length of the study
Determine the number of clones of P. vivax circulating in the community by DNA sequencing of polymorphic parasite proteins.
Time frame: Monthly surveillance visits throughout length of the study
Ran from Jun 2021 to primary completion in Mar 2023, 20 months.
Of 85 non-industry observational studies under Malaria, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 36. This study's 20 months is below that.
Counting every sponsor, half of 93 studies reached it within 24 months; a quarter within 16 and three quarters within 44.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Feb 2023. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
National Institute of Allergy and Infectious Diseases (NIAID) →