After successfully defending her thesis "Shedding light on malaria hypnozoites: Dissecting dormancy and activation", Dr Annemarie obtained her doctorate yesterday.
Dormant malaria parasites
In vivax-type malaria, "dormant" stages of the malaria parasite, known as hypnozoites, can settle in the liver. Over time, these stages can reactivate, causing disease again and transmission through the mosquito. This makes it difficult to eliminate malaria and therefore new drugs are urgently needed against this latent parasite stage. However, virtually nothing is known about the biology of hypnozoites.
In vitro culture system
The vivax-type parasites that cause malaria in humans are difficult to study, due to a lack of a in vitro blood stage culture system needed for transmission. The closely related monkey malaria parasite Plasmodium cynomolgi offers a more accessible hypnozoite research model. The research described in this thesis has been performed with this parasite. The aim of this thesis was to map the genetic properties of hypnozoites and to use this knowledge to optimize drug assays against hypnozoites.
In order to study these rare forms, we inserted DNA into the parasite, with which we could visualise and purify the parasite. Over time we saw the parasites changing into more dormant stages. Only certain core processes remain active. We showed that these parasites can nevertheless "awaken" in culture and continue their growth. Moreover, using DNA technology, we were able to detect hypnozoites in culture in a fast and sensitive manner. This makes it possible to test drugs on a larger scale that can eliminate hypnozoites.