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Jonathan Juliano, MD, MSPH, Jessica Lin, MD, MSCR, and Jonathan Parr, MD, MPH.

Jonathan Juliano, MD, MPSH, Professor of Infectious Diseases and Associate Director of the Institute for Global Health and Infectious Diseases, with fellow IDEEL investigators Jessica Lin, MD, MSCR, and Jonathan Parr, MD, MPH, and co-PIs from the University of Florida (UF) and Centre Pasteur Cameroon, has received a $3.4 million R01 grant award to study the changing epidemiology and transmission of relapsing malaria in sub-Saharan Africa.

“We are excited to launch this multidisciplinary study to better understand the epidemiology and transmission of malaria species that cause relapse in Africa,” said Dr. Juliano, principal investigator leading the team of epidemiologists, vector biologists, field researchers, molecular biologists and genomicists.

“We are leveraging novel techniques to answer questions about these malaria species that we have never been able to assess before. This includes CRISPR-ENHANCE based point-of-care diagnostics, developed by collaborators at UF, to find infections and single cell sequencing to understand parasite biology. As these species of malaria become more resistant to the current control measures, novel approaches will be increasingly important for controlling them.”

Sub-Saharan Africa carries a disproportionately high share of the global malaria burden mostly due to P. falciparummalaria, the most life-threatening of the five Plasmodium species (single-celled malaria parasites) that can infect humans. However, as levels of P. falciparum decline, evidence shows other species of malaria, such as P. vivax and P. ovale, are becoming more common and may cause more illness. These species differ from falciparum malaria in their ability to cause latent infection in the liver not cleared by standard antimalarial therapies, leaving those infected with vivax or ovale malaria vulnerable to one or more relapses weeks or months later.

The study will build on Dr. Lin’s research investigating relapse patterns in P. vivax infections that suggest the liver acts as a reservoir containing high levels of genetically diverse parasites. Over time, this reservoir is depleted as latent parasites reactivate, causing successive relapses of distinct parasite strains that makes it difficult to distinguish relapse from re-infection by mosquitoes.

The researchers will focus on the epidemiology of P. vivax and P. ovale malaria in both symptomatic and asymptomatic infections, find which mosquito species may be sustaining transmission, and investigate alternate invasion mechanisms by which P. vivax is overcoming the genetic barrier to infection.

“I first became interested in this very thorny issue of pinpointing which recurrent infections are due to relapse while working in Southeast Asia, where vivax malaria causes the bulk of disease,” said Dr. Lin, who works in the Infectious Disease and Epidemiology Lab (IDEEL).

“It is gratifying to be able to take what I’ve learned there and apply it to sub-Saharan Africa where the burden, due to these relapsing species, is likely even greater, but only starting to be appreciated. There are myriad unknowns.”

Co-PIs include Rhoel Dinglasan, PhD, MPH (University of Florida), and Eveline Sandrine Nsango, PhD (Centre Pasteur Cameroon). Collaborating institutions include the University of Dschang (Innocent Ali, PhD) and Brown University (Jeffrey Bailey, MD, PhD). Pete Zimmerman, PhD, is a consultant.