Comparison of molecular surveillance methods to assess changes in the population genetics of in high transmission.

A major motivation for developing molecular methods for malaria surveillance is to measure the impact of control interventions on the population genetics of as a potential marker of progress towards elimination. Here we assess three established methods (i) single nucleotide polymorphism (SNP) barcoding (panel of 24-biallelic loci), (ii) microsatellite genotyping (panel of 12-multiallelic loci), and (iii) coding (fingerprinting gene diversity, akin to microhaplotyping) to identify changes in parasite population genetics in response to a short-term indoor residual spraying (IRS) intervention. Typical of high seasonal transmission in Africa, multiclonal infections were found in 82.

Measuring changes in census population size in response to sequential malaria control interventions.

Here we introduce a new endpoint ″census population size″ to evaluate the epidemiology and control of infections, where the parasite, rather than the infected human host, is the unit of measurement. To calculate census population size, we rely on a definition of parasite variation known as multiplicity of infection (MOI ), based on the hyper-diversity of the multigene family. We present a Bayesian approach to estimate MOI from sequencing and counting the number of unique DBLα tags (or DBLα types) of genes, and derive from it census population size by summation of MOI in the human population.

Molecular epidemiology of continued disease transmission after an outbreak in Ecuador.

To better understand the factors underlying the continued incidence of clinical episodes of falciparum malaria in E-2025 countries targeting elimination, we characterized the molecular epidemiology of disease transmission after a clonal outbreak in Ecuador. Here we study disease transmission by documenting the diversity and population structure of the major variant surface antigen of the blood stages of encoded by the multigene family. We used a high-resolution genotyping method, "coding", involving targeted amplicon sequencing to fingerprint the DBLα encoding region of genes to describe both antigenic diversity and repertoire similarity or relatedness in parasite isolates from clinical cases.

Indoor residual spraying with a non-pyrethroid insecticide reduces the reservoir of in a high-transmission area in northern Ghana.

High-malaria burden countries in sub-Saharan Africa are shifting from malaria control towards elimination. Hence, there is need to gain a contemporary understanding of how indoor residual spraying (IRS) with non-pyrethroid insecticides when combined with long-lasting insecticidal nets (LLINs) impregnated with pyrethroid insecticides, contribute to the efforts of National Malaria Control Programmes to interrupt transmission and reduce the reservoir of infections across all ages. Using an interrupted time-series study design, four age-stratified malariometric surveys, each of ~2,000 participants, were undertaken pre- and post-IRS in Bongo District, Ghana.

The impact of indoor residual spraying on Plasmodium falciparum microsatellite variation in an area of high seasonal malaria transmission in Ghana, West Africa.

Here, we report the first population genetic study to examine the impact of indoor residual spraying (IRS) on Plasmodium falciparum in humans. This study was conducted in an area of high seasonal malaria transmission in Bongo District, Ghana. IRS was implemented during the dry season (November-May) in three consecutive years between 2013 and 2015 to reduce transmission and attempt to bottleneck the parasite population in humans towards lower diversity with greater linkage disequilibrium.