Written by Kerre A. Willsher, PhD.
Scientists have recently discovered that Malaria treatment and containment is even trickier that first thought because plasmodium can also be concealed in the spleen as well as the liver. The spleen has a vital role in immunity to disease, destruction of parasites and the filtration of blood.
The discovery which was made in Papua Province, Indonesia, was reported in a recent editions of the New England Journal of Medicine (Kho, Qotrunnada, Leonardo, Andries, Wardani, Fricot, Henry, et al., 2021) and PLOS Medicine (Kho, Qotrunnada, Leonardo, Andries, Wardani, Fricot, & et al, 2021). The 22 spleens had been removed as the result of trauma and the tissue examined revealing the presence of Malaria plasmodium in 21 of them. Mainly plasmodium vivax but also plasmodium falciparum were found in the specimens.
The implications are that people who have Malaria parasites in their spleen could be carriers as they are asymptomatic, have negative test results but at times, spread malaria when the spleen releases the parasites into the blood stream (Kho, Qotrunnada, Leonardo, Andries, Wardani, Fricot, & et al, 2021; Kho, Qotrunnada, Leonardo, Andries, Wardani, Fricot, Henry, et al., 2021). The hidden biomass in the spleen also significantly contributes to anaemia and challenges mathematical models for measuring malarial anaemia. Plasmodium, particularly vivax has probably evolved to maximize survival in the spleen. Research is ongoing to find out if the results from regional Papua also occur in South-east Asia and Africa (Weule, 2021).
References
Kho, S., Qotrunnada, L., Leonardo, L., Andries, B., Wardani, P. A. I., Fricot, A., & et al. (2021). Evaluation of splenic accumulation and colocalization of immature reticulocytes and Plasmodium vivax in asymptomatic malaria: A prospective human splenectomy study PLoS Med 18(5). https://doi.org/10.1371/journal.pmed.1003632
Kho, S., Qotrunnada, L., Leonardo, L., Andries, B., Wardani, P. A. I., Fricot, A., Henry, B., Hardy, D., Margyaningsih, N. I., Apriyanti, D., Puspitasari, A. M., Prayoga, P., Trianty, L., Kenangalem, E., Chretien, F., Safeukui, I., del Portillo, H. A., Fernandez-Becerra, C., Meibalan, E., Marti, M., Price, R. N., Woodberry, T., Ndour, P. A., Russell, B. M., ., Yeo, T. W., Minigo, G., Noviyanti, R., Poespoprodjo, J., Siregar, N. C., Buffet, P. A., & Anstey, N. M. (2021). Hidden Biomass of Intact Malaria Parasites in the Human Spleen. New England Journal of Medicine, 384(21), 2067-2069. https://doi.org/10.1056/NEJMc2023884
Weule, G. (2021). Malaria is not only a blood disease, it also hides in the spleen, scientists have discovered. Australian Broadcasting Corporation https://www.abc.net.au/news/science/2021-05-27/malaria-is-not-only-a-blood-disease-it-also-hides-in-the-spleen/100165812?utm_campaign=news-article-share-control&utm_content=link&utm_medium=content_shared&utm_source=abc_news_web