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Maternal transmission of Trypanosoma brucei gambiense Human African Trypanosomiais (gHAT) - a silent reservoir of infection.

This project will examine the role of silent carriers of gHAT infection and maternal transmission in the maintenance of gHAT.

Our surveys in HAT foci have shown 5-14% “healthy individuals” to be carrying gHAT parasite DNA in their blood, indicative of a large silent carrier population. The large numbers of individuals carrying trypanosome DNA; the generational periodicity of gHAT epidemics; the long incubation periods; evidence of maternal and sexual transmission all point to humans being long-term carriers of infection. The contribution of these carriers to the burden of gHAT is unknown. Congenital transmission is acknowledged but the frequency remains unknown as unless a mother is known to be infected, deaths in infants are will not be ascribed to gHAT. 

To meet WHO target of elimination of HAT as a public health problem by 2030, the role of silent carriers and the frequency of occurrence of maternal transmission of gHAT must be determined. 

This project will refine and apply our novel sensitive and specific DNA based diagnostic to a) determine the prevalence of silent carriers within gHAT foci and b) examine congenital transmission of gHAT, screening mothers that were infected between 1990-2000 and their offspring, born both before and after treatment. Control samples are available from outwith the gHAT focus (Sudan).  This study will also examine for epigenetic influences contributing to the generational cycling of gHAT epidemics (Prof. Jin Zhang, Zhejiang University).

Project outcomes will include a validated diagnostic tool for case management of carriers and their offspring across gHAT foci (identification of silent carriers enables early stage treatment and integration of gHAT maternal and child health screening within general health system screening); will generate data to enable revised gHAT burden calculations and that can be used to predict whether we will face a new cycle of gHAT emergence.

Primary supervisor

Prof Sue Welburn

Prof Sue Welburn lab

 +44 (131) 242 6457

sue.welburn@ed.ac.uk

Co-supervisor

Dr Kim Picozzi

Co-supervisor

Prof Jin Zhang (Zhejiang University)

Further information

Beyond Tsetse--Implications for Research and Control of Human African Trypanosomiasis Epidemics. Welburn SC, Molyneux DH, Maudlin I. Trends Parasitol. 2016 Mar;32(3):230-41. doi: 10.1016/j.pt.2015.11.008.