Characterisation of a rare, reassortant human G10P[14] rotavirus strain detected in Honduras

BACKGROUND Although first detected in animals, the rare rotavirus strain G10P[14] has been sporadically detected in humans in Slovenia, Thailand, United Kingdom and Australia among other countries. Earlier studies suggest that the strains found in humans resulted from interspecies transmission and reassortment between human and bovine rotavirus strains. OBJECTIVES In this study, a G10P[14] rotavirus genotype detected in a human stool sample in Honduras during the 2010-2011 rotavirus season, from an unvaccinated 30-month old boy who reported at the hospital with severe diarrhea and vomiting, was characterised to determine the possible evolutionary origin of the rare strain. METHODS For the sample detected as G10P[14], 10% suspension was prepared and used for RNA extraction and sequence independent amplification. The amplicons were sequenced by next-generation sequencing using the Illumina MiSeq 150 paired end method. The sequence reads were analysed using CLC Genomics Workbench 6.0 and phylogenetic trees were constructed using PhyML version 3.0. FINDINGS The next generation sequencing and phylogenetic analyses of the 11-segmented genome of the G10P[14] strain allowed classification as G10-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. Six of the genes (VP1, VP2, VP3, VP6, NSP2 and NSP4) were DS-1-like. NSP1 and NSP5 were AU-1-like and NSP3 was T6, which suggests that multiple reassortment events occurred in the evolution of the strain. The phylogenetic analyses and genetic distance calculations showed that the VP7, VP4, VP6, VP1, VP3, NSP1, NSP3 and NSP4 genes clustered predominantly with bovine strains. NSP2 and VP2 genes were most closely related to simian and human strains, respectively, and NSP5 was most closely related to a rhesus strain. MAIN CONCLUSIONS The genetic characterisation of the G10P[14] strain from Honduras suggests that its genome resulted from multiple reassortment events which were possibly mediated through interspecies transmissions.

Study of P. falciparum-infected erythrocytes and induced anisotropies under optical and fluid forces.

BACKGROUND & OBJECTIVES: The effect of P. falciparum on erythrocytes has been studied for a long time at the population level but actual studies at the single cell level remain largely unexplored. The aim of this study was to address the host-parasite relationship at the single cell level under two different kinds of forces, an optical force and a fluid force. The questions addressed were about the basic host-parasite interactions, but our findings have larger implications in diverse fields of parasite biology. METHODS: Erythrocytes were monitored under optical forces (using optical tweezers) and fluid forces (using microfluidic chambers) and dynamical images were captured in real-time video clips. These videos were then split into their respective frames so as to yield temporal information and various parameters pertaining to membrane structure, ionic imbalance and interaction with different forces were studied. RESULTS: The results of this study mainly bring to fore the inherent differences between infected and normal cell populations at the single cell level under various external forces. We probed three different criteria folding times, rotation speeds and rolling frequency to show inherent difference in various cell populations and also the dependence of the above to the cycle of the parasite. INTERPRETATION & CONCLUSION: This study portrays the importance of single cell observations pertaining to the host-parasite relationship. It shows the effect the malarial parasite has on erythrocytes and how the intrinsic property of the infected and its neighbouring uninfected cells change as compared to normal erythrocytes. There are thus implications in the fields of cytoadherence, parasite invasions and host immune evasion.