Score: 12.2, Published: 2024-01-31
DOI: 10.1101/2024.01.29.577888
Understanding transmission routes of arboviruses is key to control their epidemiology and global health burden. Using West Nile virus and Culex mosquitoes, we tested whether arboviruses are transmitted through mosquito excreta. First, we determined the presence of infectious virions in excreta and quantified a high concentration of infectious units per excreta. Second, we showed that virion excretion starts early after oral infection and remains constant for a long period, regardless of mosquito infection level. These results highlight the infectiousness of excreta from infected mosquitoes. Third, we found that both larvae and pupae were susceptible to infection, although pupae were highly permissive. Forth, we established the proof-of-concept that immature mosqui-toes can be infected by infectious excreta, demonstrating a new excreta-mediated mode of transmission. Finally, by mathematically modelling excreta-mediated transmission in the field, we demonstrated its potential impact on arbovirus epidemiology. Our study uncovers a new route of transmission for arboviruses, unveiling mechanisms of viral maintenance in mosquito reservoirs and of vector species shift that contribute to zoonotic emergence.
Score: 5.8, Published: 2024-02-17
DOI: 10.1101/2024.02.09.579586
BackgroundThe Myxozoa is a group of at least 2,400 endoparasites within the phylum Cnidaria. All myxozoans have greatly reduced in size and morphology compared to free-living members of the phylum. They are best known for causing disease in economically important fish across the world; for example, Myxobolus cerebralis causes whirling disease, which can kill 90% of infected juvenile salmonid fish. In 2017, a new myxozoan species was identified in Alberta. Myxobolus rasmusseni n. sp. causes distinct lesions in fathead minnows, which are ultimately fatal. Here, we sequenced, assembled and analyzed the genome of M. rasmusseni to understand how the parasite interacts with its fish host and identify potential strategies to counter this emerging threat. ResultsAt 185 Mb, the M. rasmusseni genome is the largest myxozoan genome sequenced so far. This large genome size is, in part, due to the high repetitive content; 68% of the genome was interspersed repeats, with the MULE-MuDR transposon covering 18% of the M. rasmusseni genome. Similar to myxozoan genomes, the M. rasmusseni genome has lost many genes well conserved in other eukaryotes. However, we also identified multiple expansions in gene families--serine proteases, hexokinases, and FLYWCH-domain containing proteins--which suggests their functional importance in the parasite. The mitochondrial genome of M. rasmusseni encodes only five of the thirteen protein-coding genes typically found in animals. We found that the mitochondrial gene atp6 was transferred to the nucleus and acquired a mitochondria-targeting signal in M. rasmusseni. ConclusionsOur study provides valuable insights into myxozoan biology and identify promising avenues for future research. We also propose that M. rasmusseni is promising myxozoan model to explore host-parasite interactions in these parasites.
Score: 1.0, Published: 2024-02-10
DOI: 10.1101/2024.02.07.579295
Echinoderms and vertebrates both possess mesodermal endoskeletons. In vertebrates, the response to mechanical loads and the capacity to remodel the ultrastructure of the skeletal system are fundamental attributes of their endoskeleton. To determine whether these characteristics are also inherent in Echinoderms, we conducted a comprehensive biomechanical and morphological study on the endoskeleton of Asterias rubens, a representative model organism for Echinoderm skeletons. Our analysis involved high-resolution X-ray CT scans of entire individual ossicles, covering the full stereom distribution along with the attached muscles. Leveraging this data, we conducted finite element analysis to explore the correlation between mechanical loads acting on an ossicle and its corresponding stereom structure. To understand the effects of localized stress concentration, we examined stereom regions subjected to high mechanical stress and compared them to areas with lower mechanical stress. Additionally, by comparing the stereom structures of ossicles in various developmental stages, we assessed the general remodeling capacity of these ossicles. Our findings suggest that the ability to adapt to mechanical loads is a common feature of mesoderm endoskeletons within the Deuterostomia taxonomic group. However, the material remodelling may be a specific trait unique to vertebrate endoskeletons.
Score: 0.8, Published: 2024-02-14
DOI: 10.1101/2024.02.12.579969
Chagas disease is a parasitic infection caused by Trypanosoma cruzi. Diagnosis of chroni Chagas disease in dogs relies on limited serological test options. This study used a new Tc-24 recombinant antigen ELISA on an archival set of 70 dog serum samples from multi-dog kennel environments in Texas subjected to three existing Chagas serological tests. Tc-24 ELISA produced a quantitative result and could detect anti-T. cruzi antibodies in dogs with high sensitivity and specificity. Comparing individual tests to Tc-24 ELISA resulted in strong associations and correlations, which suggest that Tc-24 ELISA is a reliable and accurate diagnostic tool for dogs with a single test.