Malaria Surveillance and Research Studies in Liberia and Guinea-Conakry

National Institute Of Allergy And Infectious Diseases

Investigators

Linked publications & trials

Abstract

MALARIA BURDEN STUDIES IN LIBERIA AND GUINEA-CONAKRY In FY 2018, LMIV began developing two similar protocols for a cross-sectional survey of malaria and helminth prevalence in pregnant women and children at two health care facilities in Liberia (Protocol # 19-I-N007) and one health care facility in Guinea-Conakry (Protocol # 19-I-N141). The primary objective of the studies is to estimate the burden of P. falciparum in these at-risk populations. The secondary objectives are to estimate the frequency of infections due to non-falciparum malaria and to helminths (such as Strongyloides stercoralis, filarial infections, or Schistosoma) in these cohorts. The projects gained approvals from the NIH IRB (both protocols), the Liberian National Research Ethics Board (Protocol # 19-I-N007) and the Guinea National Ethics Committee for Research in Health / Comit National dEthique pour la Recherche en Sant (Protocol # 19-I-N141). In FY 2021 enrollments continued in Liberia until the study team felt that sufficient participants had been enrolled to satisfy the primary and secondary objectives of the study. Enrollments were completed in January 2021 at both sites and the protocol was closed to new enrollments and remains open for data analysis only. A total of 1262 participants were enrolled in total across both sites: 1121 pregnant women and 141 infants, with 575 pregnant women and 99 infants enrolled at C. H. Rennie and 546 pregnant women and 46 infants enrolled at Duport Road. In addition, all dried blood spot cards have been shipped to NIAID in Bethesda where they will soon begin processing for malaria PCR and helminth serology assays. The study team is also cleaning the database for lock before preparation for manuscript writing. In FY 2021 enrollments in Guinea have continued. As of 30 July 2021, the study in Guinea-Conakry has enrolled 1063 participants to date, 718 pregnant women and 345 infants. MALARIA TRANSMISSION STUDIES IN GUINEA-CONAKRY, LIBERIA, AND BURKINA FASO Community Dynamics of Malaria Transmission in Humans and Mosquitoes, Guinea-Conakry, Liberia, Burkina Faso Primary Objective: Study community dynamics of malaria transmission by estimating the rate of blood smear positive individuals by month, season and year stratified by age in Guinea-Conakry (Protocol #000160), Liberia (Protocol #000158) and Burkina Faso (Protocol #000135) Exploratory Objectives: --To assess the intraclass correlation of blood smear positive individuals among households --To assess infection rate in live wild-caught mosquitoes --To identify host and parasite factors associated with transmission --Compare mosquito infection rates between direct skin feeding experiments and membrane feeding experiments (Burkina Faso only) --To identify individuals who have not been previously vaccinated with TBV but have naturally occurring transmission-blocking activity (Burkina Faso only) In FY21, plans were made to initiate community transmission epidemiology studies in Guinea-Conakry, Liberia and Burkina Faso as part of the EDCTP TBV Consortium headed by Dr. Issaka Sagara of MRTC, Mali. To date, protocols for each country have been written and approved by both the NIH IRB and the local ethics boards. To date, studies in Liberia (Protocol #000158 ) and Guinea-Conakry (Protocol #000160) are preparing for study start. The study in Guinea-Conakry will be conducted at the Mafrinyah site and will enroll up to 400 individuals aged 6 months and older. The site has completed renovations on the insectary and the site is preparing for the site initiation visit by the study monitors from MRTC, Mali. The study in Liberia will be conducted at two sites Marshansue and Fleh-la in Salala district and will enroll up to 400 individuals aged 6 months or older. The site is in the process of upgrading insectary facilities to allow for storage and dissection of potentially malaria infected mosquitoes on site. Liberia is also preparing for the site initiation visit by the study monitors from MRTC, Mali. The study in Burkina Faso was initiated in June 2021 and to date 603 individuals in the Sabou district, aged 6 months and older, have been enrolled. Enrollment was completed in early July 2021 and individuals have begun monthly visits. At each monthly visit, a physical exam is performed before a blood sample is taken for hemoglobin level measurement and malaria blood smear; residual blood is stored as a dried blood spot for future exploratory analyses such as parasite genetic diversity. Monthly mosquito collections of houses in the homes of those enrolled in the study will be initiated in Q4 2021. These collections will involve a live mosquito catch with blood fed mosquitoes transferred to the Sabou insectary where they will be maintained for 7 days, then dissected and examined for the presence of malaria parasites. Following live collections, spray knockdown with insecticide will be performed and mosquito carcasses maintained for future exploratory analyses such as sporozoite detection and species identification. Direct skin feeding assays and direct membrane feeding assays are planned to start in Q4 2021.