Guest Editor: Ananias A. Escalante
Malarial parasites are part of a diverse genus with more than 200 recognized species. Such diversity translates into multiple biocenoses involving parasites, vertebrate hosts, and dipteran vectors species across almost all known ecosystems worldwide. In particular, Plasmodium infecting nonhuman primates have been of great interest in better understanding the origin and biology of those parasites infecting humans. For example, Plasmodium knowlesi was the species in which antigenic variation was first reported, a convergent trait in Plasmodium falciparum. It was also a concern whether those parasites could infect humans. The importance of this question was made evident in the findings that zoonotic infections by P. knowlesi in Southeast Asia and other nonhuman primate parasites are more prevalent than previously thought.
This Thematic Series in Malaria Journal honors the 50th anniversary of the publication of "The Primate Malarias," the collective effort of Drs G. Robert Coatney, William E. Collins, McWilson Warren, and Peter G. Contacos. This seminal work, paraphrasing Professor Garnham's words, summarized the authors' experiences on Plasmodium infecting primates and, to some extent, their views about malaria. It is not by any means a revision on clinical aspects. Its organization aimed to compare the characteristics of the "malarias" based on parasite life-history traits that the authors deemed relevant.
Following the books' logic, this thematic series emphasizes its comparative nature. One article provides an overview of the Plasmodium species diversity known in humans and nonhuman primates. Considering that the book extensively reported experimental infections, one work is devoted to understanding the infection dynamics in nonhuman primates using a system biology approach. As the book was concerned with the possibility of zoonotic and anthropozoonotic malarias, three articles revised the issue, two in Southeast Asia, one in vectors and the other on the parasite side, and one in the Americas with the origin of Plasmodium simium. Then, an article revised our knowledge of Plasmodium ovale curtisi, P. ovale wallikeri, and Plasmodium malariae and its related parasites, including Plasmodium brasilianum. Finally, a paper focuses on the hypnozoite since understanding this dormant stage is perhaps one of the biggest challenges in Plasmodium biology. A topic not covered in these articles is the parasites-vector relationship. Perhaps, this is a task that others may wish to pursue.
'The Primate Malarias' is freely available at https://stacks.cdc.gov/view/cdc/6538 and is still incredibly relevant to those interested in getting a broad perspective of these parasites. In a world where we usually dig ourselves into a subject, going over this book, its detailed plates, tables, and graphs, remind us of a time when those interested in malaria control and elimination were also curious scholars who understood the importance of basic biology and natural history.