Evaluating the impact of policy change for the prevention of malaria after splenectomy and characterizing the hidden splenic parasite burden in patients undergoing splenectomy in Papua, Indonesia

This fellowship aims to: 1) evaluate the effectiveness of new policy by following hospital patients in Papua that have had their spleen removed and monitoring their health for at least 1 year; 2) collect the spleen, which would otherwise be discarded after hospital surgery, to examine the proportion of malaria parasites that are hiding in the organ, including searching for dormant forms; and 3) identify novel early red cell populations (the cells that are specifically targeted by the vivax parasite) that accumulate in the spleen.

Just 250 kilometers north of Australia, Papua has the highest number of malaria cases in Indonesia. Reduction of malaria morbidity and mortality is a key aim of HOTNORTH’s research network based in Timika, Papua. While it has been long-known that certain parasite forms (vivax) can remain dormant for long periods in the liver and cause repeated illness, we now have preliminary evidence that a significant proportion of malaria parasites may also be hiding in the spleen.

The spleen is traditionally understood to help control and remove malaria infections, but our recent research predicts that the spleen may also be harboring actively reproducing parasites that can evade detection with normal blood tests and still cause both illness and transmission. In Papua, we found that individuals requiring spleen removal are 5 times more likely than normal to get malaria, and surprisingly, this is mostly the vivax form of malaria and mostly in the first 3 months after spleen removal. As a result of our research, from 2019 onwards the District Health authority and hospitals in Papua have implemented a new policy to treat all patients having their spleen removed, regardless of blood test, with antimalarials that include eradication of vivax parasites (radical cure).

Impact:
a) If the new radical cure policy prevents early malaria this policy may be extended beyond Timika district and to other areas where vivax malaria occurs; b) provide a better understanding of how the malaria parasite causes disease and transmission.