In nature, organisms are commonly infected by an assemblage of different parasite species or by genetically distinct parasite strains that interact in complex ways. Linked to co-infections, pathocoenosis, a term proposed by M. Grmek in 1969, refers to a pathological state arising from the interactions of diseases within a population and to the temporal and spatial dynamics of all of the diseases. In the long run, malaria was certainly one of the most important component of past pathocoenoses. Today this disease, which affects hundreds of millions of individuals and results in approximately one million deaths each year, is always highly endemic in over 20% of the world and is thus co-endemic with many other diseases. Therefore, the incidences of co-infections and possible direct and indirect interactions with Plasmodium parasites are very high. Both positive and negative interactions between malaria and other diseases caused by parasites belonging to numerous taxa have been described and in some cases, malaria may modify the process of another disease without being affected itself. Interactions include those observed during voluntary malarial infections intended to cure neuro-syphilis or during the enhanced activations of bacterial gastro-intestinal diseases and HIV infections. Complex relationships with multiple effects should also be considered, such as those observed during helminth infections. Moreover, reports dating back over 2000 years suggested that co- and multiple infections have generally deleterious consequences and analyses of historical texts indicated that malaria might exacerbate both plague and cholera, among other diseases. Possible biases affecting the research of etiological agents caused by the protean manifestations of malaria are discussed. A better understanding of the manner by which pathogens, particularly Plasmodium, modulate immune responses is particularly important for the diagnosis, cure and control of diseases in human populations.

In all the taxa and genomic systems, numerous trn genes (specifying tRNA) exhibit at specific conserved positions nucleotide triplets corresponding to stop codons (TAG/TAA). Similarly, relatively high frequencies of start codons (ATG/ATA) occur in fungi/metazoan mitochondrial-trn genes. The last nucleotide of these triplets is the first involved in the 5′-D- or 5′-T-stem, respectively. Their frequencies are tRNA species dependent. The products of these genes which bear one or two types of these codons are called ss-tRNAs (for stop/start). Metazoan mt-genomes are generally very compact, and many same strand overlapping sequences may simultaneously code for tRNAs and mRNAs. However, this study suggests that overlaps are not a direct mechanism to substantially reduce genome size. For protein-encoding genes, occulting possible overlaps, there are only alternative start codons and/or truncated stop codons, but the first putative in-frame standard initiation codon or complete stop codon is in the upstream or downstream overlapping ss-trn sequences, respectively. Even if, to date, experimental data are missing, stress signals might regulate producing extended or not proteins. Finally, possible implications of tRNA/mRNA hybrid molecules in the “RNA world” to “RNA/protein world” transition will be discussed.

The two main puzzles of this study are the onset and then sudden stopping of severe epidemics in western Provence (a highly malaria-endemic region of Mediterranean France) without any deliberate counter-measures and in the absence of significant population flux.

Scientific evidence strongly suggests that parasites are directly or indirectly associated with carcinogenesis in humans. However, studies have also indicated that parasites or their products might confer resistance to tumour growth. Plasmodium protozoa, the causative agents of malaria, exemplify the ambivalent link between parasites and cancer. Positive relationships between malaria and virus-associated cancers are relatively well-documented; for example, malaria can reactivate the Epstein-Barr Virus, which is the known cause of endemic Burkitt lymphoma. Nevertheless, possible anti-tumour properties of malaria have also been reported and, interestingly, this disease has long been thought to be beneficial to patients suffering from cancers. Current knowledge of the potential pro- and anti-cancer roles of malaria suggests that, contrary to other eukaryotic parasites affecting humans, Plasmodium-related cancers are principally lymphoproliferative disorders and attributable to virus reactivation, whereas, similar to other eukaryotic parasites, the anti-tumour effects of malaria are primarily associated with carcinomas and certain sarcomas. Moreover, malarial infection significantly suppresses murine cancer growth by inducing both innate and specific adaptive anti-tumour responses. This review aims to present an update regarding the ambivalent association between malaria and cancer, and further studies may open future pathways to develop novel strategies for anti-cancer therapies.

Letter to the Editor.International audienceI read with great interest Charlier et al.’s [1] report of the microscopic detection of Schistosoma in embalmed viscera of Saint-Louis..

This article focuses on the episodes of bubonic plague recorded around 543 AD in Frankish Europe which on re-reading appear doubtful. Beginning in 541 and for two centuries, the Justinianic plague ravaged the Mediterranean area over several successive waves. The first mentions concern Egypt; the plague then spreads northward to Constantinople and almost concomitantly or shortly afterward moves westward until it reaches Western Europe. For this last region, the main source is Bishop Gregory of Tours, who in both his historical and his hagiographic writings, provides numerous data on the first outbreaks that raged in Frankish Europe, episodes to which he was a contemporary (even if for the first, he was still in early childhood). According to Gregory, around 543, bubonic plague ravaged several areas under Frankish rule. However, among others, intertextual, contextualized and chronological analyses strongly suggest that these events were in fact fictional. Gregory seems to have wanted to balance during epidemics of plague, the behavior of two bishops of Clermont that were totally opposed. In the episode of 571, when plague struck the episcopal city, the unworthy Bishop Cautinus, to escape disease, had fled the city in cowardice. In the other episode, through the intercession of Gregory's paternal uncle, the virtuous Gallus, the immediate predecessor of Cautinus and that of a saint specific of the paternal branch, the city, including the diocese, was spared from the plague. Other references to similar events in which, through saints, the plague is driven out, or territories are protected from it are also dated arbitrarily from this period. Furthermore, unlike the episode of 571, the plague of 543 is never considered a punishment for sin; moreover, no miraculous healing of plague patients is recorded. Contemporary texts from other authors of Frankish Europe, although they are rare, do not mention any epidemic around 543 - especially the Vita of Caesarius of Arles, written shortly after the death of this bishop (from 542 to 547-9) by several hagiographers - while two of Gregory’s texts, which are repeated almost verbatim, indicate that the province of Arles was the region most affected. This fact underscores the decisive contribution that hagiographic texts can make in the analysis of facts considered to be historical. Finally, the dramatic deteriorations in the health situation described in Gregory’s reports could have a background of truth and be the consequence of the climatic cooling observed from 536, likely due to volcanic eruptions, but did not involve the bubonic plague.