Biology of the malaria parasite--on the special issue for the 10th BioMalPar conference.

Abstract

Considering the rapid advancement of the biomedical sciences, the molecular and cellular biology of most host–parasite interactions remains still largely enigmatic. Some of the best understood parasites are those that cause malaria, one of the leading causes of death from infectious diseases throughout human history and still today. This special issue on malaria testifies how much progress has been made, but also shows how much more remains to be discovered. Not only do we lack a proven rationale for a cheap vaccine, but there are still many open questions about the most basic processes of malaria parasite biology and how the parasite interacts with its hosts. This leaves plenty of scope for new and fundamental discoveries that would gain immensely from attracting scientists from other fields and funding agencies alike. Excerpt from the comic ‘Malaria – the battle against a microscopic killer’. Comic written and created by Jamie Hall and Edward Ross, cover designed by Luke Pearson and colouring by Tom Humberstone. This comic is funded by the European Commission FP7 Network of Excellence EVIMalaR © 2012. This special issue is thus also a tribute to the many researchers that have not only worked hard and openly exchanged their ideas and findings on sometimes very competitive issues but also to those that provided for the future by inspiring and training the next generation of researchers. Within these pages you will find a showcase of international work with contributions from colleagues in North America, Europe, Asia and Australia but an ominous absence of contributions from Africa, where malaria causes most deaths. This single fact highlights the ongoing and urgent need for stronger research capacity building right where it is most needed. There are myriad interactions between the malaria parasite and its different host cells and tissues and no special issue would be able to even attempt to portrait them all. Nevertheless, the selection of review and primary research presented here give a good overview of the divergence of research topics in malaria research and hence the scope of the problem. This research has always benefited from the use of model organisms from the discovery of parasite transmission by Ronald Ross using birds and the discovery of the liver stages using monkeys as well as the use of mice for early vaccine studies in the late 1960s. Therefore, a timely review examines the success and promise of humanized rodent models for the study of malaria infection (Kaushansky et al.). Similar to animal models the cultivation of a parasite in cell culture is necessary to advance our understanding of its molecular biology. This is highlighted by another review focusing on how Plasmodium knowlesi, a parasite mainly infecting monkeys but also deadly for humans, can be cultivated (Grüring et al.). To understand the pathology of parasite host interaction the first contact is often of great importance. This is mediated by proteins on the parasite surface that can interact with proteins on the host cell. How these specific proteins help to attach parasites to their host cells is thus the topic of a third review (Malpede and Tolia). Malaria parasites are ancient organisms and thus feature organelles that seem alien to students of metazoan biology. To this end a fourth review (Harding and Meissner) describes one such essential organelle that defines malaria parasites and related organisms. The primary research reported in this special issue touches almost all parts of the malaria parasite life cycle. Starting from the bite of the mosquito, which delivers Plasmodium sporozoites into the skin (Carey et al.), the development in the liver (Austin et al.) to the invasion of merozoites into red blood cells (Knüpfer et al.; Yap et al.), the trafficking within and adherence of the infected red blood cells to the vasculature (Brugat et al., Esser et al. and Siau et al.), the escape of the parasites from the red blood cell (Wirth et al.), the penetration of the mosquito gut wall by ookinetes (Kan et al.) and the conversion of these into cysts where new sporozoites are formed (Andreadaki et al.).