When parasites slow down viruses: VdF Doctoral Award for Dr Jana Hey
New clues from Madagascar on the interaction between schistosomiasis and dengue
Dr Jana Hey from the Bernhard Nocht Institute for Tropical Medicine (BNITM) has received the doctoral award of the Vereinigung der Freunde des Tropeninstituts Hamburg e.V. (VdF). In her doctoral research, she investigated why Madagascar reports only few dengue cases despite favourable conditions, and what role the parasitic worm disease schistosomiasis might play. The award is endowed with €2,500.
Madagascar would seem to offer ideal conditions for dengue: the climate is suitable, and both the virus and its vector, Aedes mosquitoes, are present. Yet dengue appears far less frequently in official reports than expected. At the same time, schistosomiasis is among the most common neglected tropical diseases in Madagascar, affecting more than half of the population. This striking combination led Dr Hey, who works in the Implementation Research group, to her PhD research question: do Schistosoma infections influence the occurrence of dengue virus infections? To answer this question, she combined epidemiological analyses with laboratory investigations.
Her results show that, in the regions studied in Madagascar, only a small proportion of people had evidence of previous contact with the dengue virus (up to 3.3 percent). In laboratory experiments, Dr Hey observed that blood serum from people with schistosomiasis, particularly those with a severe chronic form of the disease, can measurably reduce dengue virus infection in cell culture. This finding could indicate that schistosomiasis offers some protection against dengue fever.
The available data do not yet fully explain how this effect occurs. Dr Hey therefore explored which changes in the immune system might play a role. Among other things, she analysed inflammatory signalling molecules (cytokines) and IgE (immunoglobulin E), a class of antibodies that the body produces especially during allergic reactions and when responding to parasitic infections.
She also examined immune cells from blood samples of people with schistosomiasis in more detail, using modern methods such as single-cell RNA sequencing. This technique makes it possible, in effect, to read out cell by cell which genes are active in an individual immune cell at a given time. Dr Hey was particularly interested in genes involved in antiviral immune responses.
Her work highlights why co-infections deserve more attention: in regions where several pathogens circulate at the same time, they may influence one another. This can affect risk, disease burden and prevention.
The VdF doctoral prizes are awarded annually to recognise outstanding achievements and to support early-career researchers at the BNITM.
Original publication:
Hey J. et al. An exploratory study to assess the influence of schistosomiasis on the occurrence of dengue virus in Madagascar. Infectious Diseases of Poverty 2025. DOI: doi.org/10.1186/s40249-025-01370-0
Contact person
Dr Jana Hey
Research Group Implementation Research
Email : jana.hey@bnitm.de
Dr Anna Hein
Public Relations
Phone : +49 40 285380-269
Email : presse@bnitm.de
Further information
